Discussion in 'The Grumble' started by Mike Labbe, Apr 3, 2009.
According to this month's grumble poll, at least 2 of us use glue only
Good catch Mike.
I would really like to hear which glue they use and how long they have been framing.
When properly applied, standard wood glue is incredibly strong... tensile strength well over 2000 psi (most epoxies are about 1900, yellow glue is about 3800). The key here is when properly applied. This means that the miter is perfect, the wood is smooth and clean, there is 100% contact between the two pieces being joined, and adequate clamping pressure is applied until the glue cures. Any gaps in the joint will leave areas of weakness.
My guess is that Old Man Framer could cut a perfect miter every time and had just the right jigs to clamp the thing up nice and snug. Oh, and he LEFT things clamped at least overnight (although the glue may set in half an hour to an hour, it takes at least eight hours to develop maximum strength).
For those of us who use glue, most joining techniques serve two purposes: (1) to pull the pieces together while the glue sets (in lieu of clamping) and (2) to serve as extra reinforcement for the joint.
Would you feel any differently if I told you the frame pieces had no visible impact damage? No obvious way to tell which corner it had been dropped on?
I was fortunate enough to spend some time with my uncle at his furniture workshop. He used some biscuits but mostly just glued. There was considerable geometry to his maple chairs. Simple rectangles, if working on the "first do no harm" principle, would seem to me to need that little piece of steel to give casual damage a fighting chance against becoming catastrophic damage. Kudos to nail less Colorado for using plexi.
I'm feeling openminded on the subject in light of Jerry's post. I don't mean to suggest that a mastery of the technique is anything less.
Maybe one of our pollsters will start a thread called, "No, really, be awesome like me and you don't have to nail your frames." But be prepared to elaborate.
And I've neglected the upkeep on my woodworking terms, Baer. In layman's terms I would say gluing is not so much a "join" as a "courtship."
we still have a problem here....Houston!
Baer is correct....gluing the joints is joining the frame. I have in 30+ years joined a frame with only glue -- not many times, but it is joining the frame, technically.... Actually on the one occasion that I recall, the frame was a very small octagon, less than 7 inches in height My point is that it is the glue that holds a frame together. Any other device used accelerates the joining process and prevents the contents from spilling out, if ever a joined corner should fail. (To your point of concern!)
Jim is correct, but the one thing he didn't mention is that end to end grain on a wood frame as in a standard mitre creates one of the weakest wood to wood bonds of all, hence the use of a fastener, like a brad (pin - UK), V-nail, wedge, etc.
Indeed! "Extra" being the operative word here.
John, mitre joints are not end grain to end grain; they're probably 30 to 45% long grain to long grain and that makes a joint plenty strong enough for a picture frame. If I had the time, I'd use glue only and leave out the mechanical fasteners. When we make high quality furniture pieces in our cabinet shop, we use no mechanical fasteners. (see the craftsman style refractory table at our web site under the Frame Outlet's Back Room Gallery)
There is a very good reason for not using mechanical fasteners in top quality wood joinery including picture frames (especially metal fasteners): it's easier to repair a failed joint and contrary to what I read here, a properly (we're supposed to know what we're doing, aren't we?) joined mitre isn't going to fail suddenly- none of mine have ever failed that I know of. The expansion and contraction at the joint over time (at least 30+ years) can, but not necessarily will, weaken the joint to the point that it'll need repair. Mechanical fasteners will actually make weakening more likely. In modern houses this expansion and contraction is much less that we probably think due to fairly uniform temperatures and humidity found in houses today.
I can't recall the number of times we've been called upon to repair frames that have been cross nailed in the mistaken belief that the joint will be stronger. All the cross nailing accomplished was to make the repair harder and more noticeable. We're repaired countless chairs and tables that have been nearly ruined because an owner has made a repair with a mechanical fastener.
Now we use top of the line light industrial v nailers in our frame business not because the v nails make the joint stronger but because they make making a frame faster and, thus, more economical. If you have the time to make a glued mitre joint, there is absolutely no good reason to insert a v nail or nail, for that matter, into it. The only reason you'd be able to break that joint with only the strength of your hands is the huge mechanical advantage the two legs at 90 degrees to each other offer.
The only caveat I'd offer is that you have to know what you're doing which is true of any woodworking joint. The only exception I can think of in using mechanical joints is a dovetailed drawer and recent tests have shown that finger joints which don't introduce a mechanical joint are at least as strong.
Most mechanical joints were developed in an era without the excellent glues we have today. Museums are full of fine furniture with splitting panels caused by mechanical joints (metal screws and nails)employed to make the cases stronger because of fears that glue joints would fail. Strangely the glue joints didn't fail but the mechanical ones did.
I'd like to add that Brandon and I have been surprised at the strength of end grain to long grain joints; they're way stronger than we imagined. There was a time when we didn't apply glue to these joints thinking it would be a waste of time. I guess the old craftsman who consistently applied glue to the shoulders of mortise and tenon joints knew what they were doing. Also,a picture frame mitre joint doesn't have to be as strong as a long grain to long grain joint because frames are handled, or at least they should be, more gently than, say, a chest of drawers which is under a lot of stress (if for no other reason that its weight) when it's being handled. If you want a mitre joint that's really, really strong, stick a spline in it (see the closed corner teak frame at our web site under The Frame Outlet examples); we use splines on some frames but I think for decorative purposes rather than for strength.
Other - Pre-glue then VNail
I find that I can get the best join by pre-glueing in a vise, once the glue sets up, I vnail the corners.
Warren, old frames are rather desirable around here. At auctions I've seen women battle for large ornate frames. Refitting an antique frame is a rather common event at my shop (two yesterday). I don't believe I have ever seen a single one that had all 4 joints solid. More typical is a frame with all 4 joints failed and held together with mechanical fasteners.
I've also never seen furnature held together a butt joint like is suggested for framing with no nails. Actually butt joints are to cabinet makers what paper mats are to many framers. Even wooden dowels and bisquit joints are "mechanical". The only joints we see in wood working with no fasteners at all would be specialized joints like a lock joint or mortise and tenon or the splines you mention.
Using the types of mitered butt joints we use with the relatively small surface area of a typical frame, I feel strongly we should be supporting the joint with some mechanical means.
Having said that, I do join wood for my guitars with no fasteners. However the wood is 2" thick and 18" long. Thats much more bonded surface area than a typical frame.
I agree. Using glue ONLY to join moulding corners together would be very strong. The advantage of using glue AND nails is you save a great amount of time. If a customer orders 10 - 24 x 30 frames (frames only) and want them as soon as possbile, i can chop and assemble the corners together within ONE hour vs. 24 hours :sleep: minimum if only glued (24 hours IF you have 40 corner clamps).
I guess there are pitfalls to every method. I don't knock glue-only, its just not what I use. I can't argue that its a stronger or a weaker joint. But I know I'd have to have a lot more patience and time than what I have to do it. In this case, it wasn't the join itself that just failed it was dropped. On the other hand, a framer that uses duct tape needs a speech or two.
I join use v-nails and glue.
While I can easily say that I've repaired frames with glue-only joints (twice in 3 years) that have fallen off the wall, I've also repaired three times that many of other joins.
In a nutshell, I don't know why people who have frames fall off the wall expect them to not break. Although falling off the wall is certainly a hazard of framing, making frames indestructible isn't my main concern.
People should be prepared to pay for repairs to any possessions that get damaged. Why should framing be any different?
Hi janet. I use glue and v-nails also. Most of the time, when customers bring in frames damaged after falling off a wall is because of framing they had done elsewhere which, for example, they put the eyes screws too close to the rabbit or the eye screws they used were too small and/or too short for the weight! mad: I never liked eye screws...I quit using eye screws a few years ago.) Very rarely are any damaged frames brought in that are only glued and not nailed AND glued...
Screw eyes seem to be the culprits in a lot of fallen frames around here as well. Ususally done years ago and the wire is too tight and the screw eyes have pulled out of the frmae legs.
I knew a framer that wouldn't glue the ready mades he put together. Just v-nailed them.
Plenty of diverse opinions on this thread, eh?
Yes, glue is what holds a corner tightly together, but I would not want to rely on glue alone. Ever.
The modern polyvinyl acetate and polyaliphatic resin glues commonly used for framing are very strong, and do not deteriorate much over time. The same can not be said for the wood. Normal expansion & contraction stresses miter joints, as does gravitational stress according to the weight of the assembly. And of course, incidental impact from handling can break corners loose.
The glue may stick perfectly to the wood fibers, but those wood fibers can readily shred and, one by one, separate from the other wood fibers. Have you seen a broken miter joint that looks like the glue still has wood fibers attached? It happens often.
Mechanical fasteners hold a corner tight until the glue sets up. That is important because any movement during drying would weaken the glue joint. Later, mechanical fasteners prevent catastrophic failure of the corners if glue joints fail - usually by impact during handling, but also from constant gravitational stress.
In terms of construction methods, picture frames do not compare to furniture. Most furniture joints are not simply butted together. But even if they were, a piece of furniture is a more complex, three-dimensional structure, heavy, and stationary. Most furniture joints are not under the sort of stresses that picture frame corners endure continuously. And furniture doesn't get handled as roughly, dropped, or fall off the wall as routinely as picture frames.
I've got a question for you wood glue joinery experts. Occasionally I will glue the miter together and leave it in a vice for a while to let the glue set up, then fire the v-nails into it (rather than when the glue is still wet). Does the act of firing a v-nail into the frame at that point break the bond that the glue has already created?
I'd prefer to get all the wiggling done with the glue wet. Anything you do that could weaken the joint can't be fixed after the glue is dry. But if the glue were wet, it can still dry and bond the wood together.
It can yes. I have done it and discovered that I wasted my time waiting on the glue to dry.
So it would be very beneficial to leave a frame sit for hours or overnight after joining with glue and vnails?
The glues vary, BUT in general, most of the modern glues obtain 75% of their "cured" bond in less than 2 hour (most in 1 hour). But all reach 98% in 12-24 hours.
Wood Workers Journal did quit an extensive glue join testing of all the common and some of the uncommon joints. Some of the #/sq in to fracture were very interesting. Understand all of these were "without metal" fasteners, but with clamping and "mechanical" means.
If you go to your kitchen and look at the doors on your cabinets, and if they are not one whole sheet of plywood, or particlewood wrapped in melimeine, they are more than likely what is called "plate and rail" (actually plate/rail/stile) and resemble our four sticks and "art" in the middle. The four sticks are "coped" or rounted to a shape, and the ends of the top and bottom stiles are coped in the male of that profile so they stick in the side rails. These four joints are simply glued. No nails.
If it Kaftmade, then the glued up unit is held in clamps and runs though a micro wave that instantly cures the glue. Time in clamps is under 2 minutes. The shop I used to work at used a huge rotating machine called a "Clamp Daisy" and it took about an hour to make the circut from in the clamp to out. Plenty of time. Then stress on a cabinet door is not huge. But take it off the cabinet, hold it up and drop it 6' and at least one of those joints will pop. But their secret is all that coped shape creates a glue surface that is up to three times more than a flat but-to-side joint. Also it all the side surface as apposed to face.
BTW: in the test..... a standard mitre joint was abismal in performance. And they weren't dropping... it was "load" test instead of impact. I think it was a 2x3 surface and didn't even take 25lbs.
Personally, when it comes to repairing.... I'll take a cross nailed frame over a v-nail any day.
I'm saying this really slowly now: mitre joints are not butt joints which are fairly weak as glued joints go; they are more like 30% to 45% long grain joints. I would think any knowledge of the joint would include this understanding. Again, mitre joints are not butt joints, far from it. Fine Woodworking two issues ago tested all comon joints one of which was a miter joint and it was surpprisingly strong. Way strong enough to to serve as a picture frame joint. Baer, anyone who buys a cabinet door from us will get a cope and stick joint *with a mortise and tenon* in each corner (actually we use a haunched tenon in doors).
And I repeat, there is nothing to be gained by using a mechanical fastner in a properly glued and clamped miter joint. I think there is a picture in one of the back room gallery sections at our web site that shows a properly clamped mitre joint. That joint is not going to fail "catastrophically"; it's not going to fail at all. I guess my experience in 30 years of framing has been limited but I've yet to see an example of a catastrophic failure. I know we've had to take glued frames apart for various reasons and it's difficult. In my experience, picture frames come apart; they don't explode. If they did, believe me doing arround 30 frames a day for years and years we'd know about it. Sure we have occasional joints loosen but they don't just turn lose, fall apart.
Has anyone ever heard of Master Clamp made by Baruch Framing Tools? Baruch has a whole highly successful system aimed at glue only joints. Baruch made very expensive frames for years and never used mechanical fastners and lived to tell about it. The main weakness of the system is that it takes too long for common frames, not that it doesn't work. Anyone making only a few frames a day would do well to consider glue only.
Another misconception I'd like to touch on here is that a glued joint has to be under great pressure until the glue sets up; that's far from the case. A successful joint only needs mating surfaces to stay in contact until the glue sets up. In fact a common problem in glued joints that do fail is that the joints are starved because clamping forces most of the glue out.
Here's the way old frame craftsman jointed corners. First they glued the joints and applied minor pressure and waited until the joints began to set, say half an hout. They then broke the joints apart and reglued them. According to folk wisdon, those were very strong joints sans fasteners.
I really want to say, "look, we make picture frames, cabinets, furniture for a living (a good living I might add) and we're good at it and we know what we're doing. A properly glued mitre joint doesn't need mechanical fasteners to ward off the possibility (and I'd have to say the extremely remote possibility) of some sort of catastrophic failure resulting in glass shards flying accross a living room injuring anyone in their path and the mass of the framing package colliding with a priceless vase in the near vicinity. If you think that's likely to happen, lay on the fasteners after you've joined the frame. We use v nails because they make joining a frame fast and that's the only reason. I might add, on expensive one off frames we don't use v nails, only glue and occasionally dovetail splines and plain splines for decorative purposes (why else would we use contrasting woods?, again, see our web site for examples).
If a glued joint were to come loose then there is only two ways it wouldn't fall completely apart. Either a mechanical fastener was used or it was joined with magic glue that bonds to thin air to hold the frame together. Is there a third option assuming duct tape wasn't used?
I think this is an area where we can just disagree on. I have as much empirical evidence for my reasoning as you do and that's very little. You very seldom seen frames with busted joints and I rarely see one over 20 years where they haven't all busted loose.
I will ask one question though. If there is nothing to be gained by using fasteners (like 99.999999% of framers do) then is the opposite true? Is there a penalty to using a v-nail? If so how much would you say it compromises the joint?
I don't know Jay. On another thread there is two guys telling me that thumb-nailed frames are falling apart all over the place.
I guess the demise of the Big Box framers will be soon be happening.
Double down ditto. Never saw a cross nailed joint that didn't make me want to slap whoever.
I really appreciate your comments, Warren, because it's important to hear what a professional wood joiner considers good technique. I would suggest the frame I referenced in this thread was not joined with appropriate technique since it came apart rather easily.
My shop, like many other framers, is not a professional carpentry shop. I've been cutting and joining frames for just under a decade, but haven't transferred these skills to greater furniture building.
The community I live in is very fond of huge paintings of buffalo with big wide frames. I've made dozens of them and I do a pretty good job. One thing I always do with a molding bigger than 4" is strap clamp the whole thing together, let it set up overnight and then try it on the painting before nailing. I don't do the corners one at a time since that's caused some frustration for me in the past when I get to the 4th. I have my dead brain days like anybody and a couple of times I've made the wrong size and had to break the frame apart to harvest the long legs and make a new one. This is why I don't nail big frames as they set.
When I break this frame apart, especially if it's large, like a 4' x 5', I have to stand the frame on a corner so it's like holding a big diamond. I can grab the pieces and dangle my whole considerable weight with no effect. So I know that it is super super strong. But I still have to break it, so I stand on the table, raise the frame about three inches off the floor and exert very sharp downward pressure. Basically, pick it up and slam it into the floor. Exploding is exactly what it does. I don't allow any person in the room where I am doing this. It doesn't fly across the room, sure, that's crazy. But it's forceful and all 4 corners break and the legs bounce off the carpet. I don't think slamming it three inches is very different from the force gravity exerts if the frame falls four feet and lands on a corner. Could be my skills not being up to par, I suppose, but if the miter meets perfectly, I don't know how I could do better. Maybe I should hire Baer after all
I don't nail it until I know it fits because it's a pain in my huge tookus to get the nails out and the nails cause more damage to the molding when you snap. I use the same technique to break it, but the whole thing stays together.
So while I have absolute faith that a real craftsman can build a joint without fasteners as you have explained, your average bread and butter picture framer should use some kind of nails. They're cheap and they work. If someone drops a frame, they are usually standing under it, not worth the risk, unless one is an exceptionally competent craftsman.
By the by, when I do frames this size I use nails, not v-nails. I know you can stack them, but I've seen stacks of v-nails come out in huge chunks, still cradling v's of wood. I take two or three big ol 4" nails, pre-drill the hole, and fill it. The idea being to hold the pieces together with steel in the event of the unthinkable.
Just because the customer was from Denver, doesn't mean the framing was done in Denver.
Former Denver area framer.
Yup, you've lead a sheltered life. Some of my "best", (well, most expensive at least) frames did just that.... 'explode'. But then, that's what a strip of C2 and det-cord are all about.... ("B" grade movies on "D" grade budgets.... staight to VCR)
Now back to the 'real' world... no they don't explode.... but when they fall or are shaken off the wall, and three of the four corners are cracked open big enough to swipe your credit card still in your wallet through them... I personally call that a "catastrophic" failing. And if there aren't any "mechanical devises in the joints, the glass and package are coming out.... unless you glued them in there with Silicone.
Sorry if I flustered your feathers Warren, but in my wood back ground you can have it only one of two ways Haunched tenon, or coped. The fact that you don't trust the coped joint is your own personal thing, personally I'd never waste that time. You must be using a bunch of them fancy pants machines. Some day I even hope to posses one of them fancy new fangled things called a "matched pair of coped planes"..... but I'm not holding my breath.
BTW, I'm shocked that you were surprised at how strong finger joints are. They are the ultimate box joint after all. And they don't catestropically explode either.... thats why they made dynamite boxes using them. :tongue:
I know that a good glue joint is very strong, and if I was to deliver and hang every frame I make, they would probably stay joined for a very long time. (except where the wood unexpectedly decides to warp badly one day in the future.)
I know how to hold and carry a frame so that no external twisting forces are placed on the joints, but my customers don't necessarily know that.
They will try to stuff the frame in the car holding, lifting and pushing one corner, which twists the frame. Twisting a glued frame, especially a sizeable one, where it's cross section is not very deep, will often pop the front of the joints open.
I use vee nails in all my joints for two reasons:
1. Vee nails add reinforcement that resist the twisting motion and are less likely to pop open.
2. It takes less space in the workshop and fewer clamps if I vee nail frames with wet glue. The vee nails act as my clamps.
There is also the leverage factor. If you take two small pieces of wood and glue them together with just a spot of glue, you will have a hard time trying to pull them apart. But if you use the same amount of glue on the ends of two long rails you can easily break the join because the length of the rails acts like a lever and magnifies the force applied to the join. It's a matter of basic mechanics.
There is also the torsion effect caused by the hangings. On a narrow frame, the weight of the whole package is usually taken by fixings on the side rails. Because the hangings are not in the center of the molding but on the back, the force is offset which causes a twisting effect. This is transfered to the joints. So as long as the picture is hanging the joint is under a constant strain. It may never give way, but one day the joint could recieve an unexpected shock (someone banging a door??) and the shock will break the join. If it has a v-nail in the joint, this will help to absorb the shock and protect the joint. Even if the glue fails in this circumstance, the failiure will not be catastophic. Worst case, the join will start to gape open slightly.
A glued-only joint in a 30" square frame made in 1/2" molding will as strong as the same joint in a 3" sq frame. But the bigger one will be more vunerable to breakage. It's largely a matter of intuition. If it feels flimsy is is flimsy.:icon11:
I do a lot of frames with narrow beveled liners. Some are quite big (40x30ish). No problem once they are fixed inside a substantial outer frame, but I have to be very careful handling them. One slight knock will break the corners.:icon11:
Baer, I wasn't surprised that finger joints were as strong as dovetail joints. Also, we make *doors* entry doors, doors for large cabinets and small. We make cope and stick doors and we make doors with applied moldings. All of them, though, have mortis and tenon joints, and yes, we do have dedicated mortisers, sliding table shaper and a raft of "fancy" machines that we can afford because we're good at what we do. Take a long look at our web site; all the cabinets there are shop made, most would be considered furniture grade. When we make door panels, they're book matched and we have a fancy machine called a re-saw band saw with a 3"blade for just that purpose. We have a 16" jointer, which no one would describe as "fancy" at over 1600 lbs. We have it for a reason: for the type of work we do, we need it. An, Baer you made my point for me; that frame you describe with corners loose is going to be a heck of a lot easier to repair if it doesn't have mechanical fastners in it. If it was one of our frames, though, it probably would. My experience with mechanical fastners comes from repairing furniture more than frames, but in either case mechanical fastners cause problems. In many cases they make repair impossible or imperfect. I would think that anybody who's repaired a frame would know the job would be a lot easier with a better outcome if the fasteners weren't there. If you repaired one of our common frames, the fasteners would be there but that doesn't alter the fact that things would be better if they weren't. I'm not even suggesting that framers abandon v nails, but that v nails' purpose is to make frame making faster and easier, but not stronger, because they don't, and that if a frame has been properly joined with good glue there is no reason to shove v nails into its joints.
Jay, I'm not rtying to be snarky but surely in your experience you've seen failed picture frames and you must have observed that not all of the joints fail uniformly, that there is paper glued to the back of the legs; some corners may be gone but other's are holding, and, yes, it's not only possible but, in my experience common, for joints to loosen up gradually-that is some part of the joint is still holding while other parts aren't. There is a cost to using v nails, they make joints fail faster and they make joints harder to repair. I know from years of working with wood that metal fasteners do more harm that good. They're used universally to make joining faster and easier, not stronger, in cabinet making, picture framing, furniture making, and, heck, even in house framing (a timber framed house with no metal fasteners is way stronger than a stick framed house that's been nailed together).
I'm not a little surprised that in a forum composed of people working with wood that they don't know all this. I honestly don't know one fine woodworker who disagrees with me. V nails are necessary for quickly assembling frames and for me and my picture frame business, a godsend, but they don't make a better joint and they certainly don't make a stronger one. I can't remember what Cassesse's first name is but I've had this discussion with him at least twice and his advice, always given if asked, is use the minimum amount of v nails to hold the joint together until the glue sets. "Why", I've asked him, "do you offer machines that can insert multiple v nails if that's the case." His answer is that occasionally they're necessary to hold a joint together and strengthen a weak joint (one whose surfaces don't completely mate and so would have a weak glue joint) and that his customers have demanded that feature because they are making joints with no glue.
I glue and v-nail every frame we join.
Over the 28 years I've been in business, I've repaired or reframed many pictures customers brought in from other framers that were only glued, had plastic splines in them, or were cross nailed.
I've only had a couple v-nailed frames come back because the joints came apart.
Personally, I would never let a glued only frame out of this shop, because I've seen what can happen when the wood dries up and the joints fail years down the road.
Just my opinion.
How about a little evidence. I'm not as familiar with our web site as I should be so after directing readers to in in my previous posts, I thought Id take a closer look and found an excellent example to buttress my point. Take a look at the Frame Works section and go to Pricing Examples (examples but no pricing) and scroll down to the shovel shadowbox/display case and follow its construction. The Hoffman (and yes, Baer, we have a "fancy" pnuematic cabinet model Hoffman router ((you can see it, i think in the Frame Outlet backroom gallery)) dovetails Brandon is using are at most 3/4" long and you can see how wide they are compared to the corners they're holding together. Their sole purpose is to hols the sides of the frame together untill we can get clamps on it and to keep the legs from sliding when the clamps first apply pressure. The have no structurual
100% of the frames I've seen with busted joints were held together with nails. I've never seen a joint just glued that has failed pointed out in the opening of this thread. By what metric do you use to suggest that vnails cause a joint to fail faster? Using your logic, if the glue joint was good, then shouldn't the vnail be a non issue?
I'm not sure what all the defensive statements about "so called" wood workers, repeating “slowly” and such is about. This is the only “snarky” comments I see. Disagreeing with me isn't.
When a framer miters a frame and glues the two ends together this is called a mitered butt joint. I'll agree with you that it is probably a stronger joint than a regular butt joint (end grain/long grain). Still it's a very weak joint. If you want to glue together larger frames with lots of surface area, then I really don't have any beef with that. The joint will probably be much stronger than it will need to be. Yet most of our frames do not have enough surface area to hold the size and weight of the packaging that it does. Not to mention moulding distorting and stressing joints from wire hangers and handling.
Almost all mitered butt joints rely on stronger joints like a keyed joint, dowels, or biscuits. All these additions to the miter are typically wood and often of a different type. I suspect this is to increase the surface area of the wood on wood contact and to limit stress on joints. You mention this and suggest that you use different woods for aesthetics. I think you have this backwards. The aesthetics are a bi-product of combining different wood types. Luthiers have paired up different woods for years because it makes necks more sturdy just as it does frame miters. Does metal do the same thing? You say "no" and I agree mostly!
A metal fastener does nothing to increase the quality or surface area of the joint but it does limit stress on the joint and holding a broken joint is a nice bi-product. That is why I stop just short of agreeing completely with you. The wood we use is much thinner with smaller joints than in cabinetry. Picture frame moulding bows and flexes with normal handling and as the frame settles on the wire. A metal fastener does help to reinforce the glued joint. Perhaps this is the only point of contention?
I do agree that too many fasteners can weaken the joint. A v-nail does displace the wood around it and actually reduce, to a small degree, the glued surface area of the miter. Excessive amounts of nails do weaken the glued joint greatly. This is my biggest problem with thumbnail wedges also. It routes out a large section of wood where a v-nail displaces very little wood.
Absolute statements are a tricky slope.
I have seen frames that have failed that were joined with vnails, with nails, cross nailed, those funky metal splines, glue only and none glued.
I have also had metal frames that failed. They fell off the walls, and the metal has been bent. I don't think the metal frames were joined with vnails, cross nailed or glued.
But what ever caused the frames to fail does not matter to me. What matters is that I have a reputation for being able to make frames to order, and to be able to repair frames that had been broken. I have customers that come to me to get frames fixed, to get glass replaced and to be treated with respect for them and their wallets. In these times where everyone is trying to save money at the framer's shop I think the important thing is that they came in to you to get it fixed.
Oh and one thing I learned about "fixing" antique frames is to be #### sure that before you step down on that chopper pedal that you know where the antique nails are! I have ruined too many chopper blades cutting down old frames!
It's currently accurate. Notice the "I've seen" part. Oh wait...the "nails". I should have said "fastened". What I mean is that i have never seen one that was only glued fail. Maybe thats because they are so gosh darn good? Or maybe it's becuase its been ruled out and rarely done? Who knows?
jay, not to be snotty, but if you work with a lot of antique frames, and if glue only is no longer done, then the glue only frames would be antiques.
So if you, being an expert on antique frames, have seen many failed, nailed antique frames and have never seen any glue only frames then maybe glue only is the way to go since no antique glue only have failed.
We may have to rethink the whole glue, vnail, cross nail debate!
I've read that 3 times and I don't have any idea what you're saying. But I agree except that I"m an "expert on antique frames". I've never made such a claim.
Maybe the glue only joints don't fail because there is no metal in there. I bet metal expands and contracts at different rates than wood.
If it does, one would think that it would cause stress fractures to happen.
And that is just a wild @$$ guess.
I had a job for reframing a few weeks back. The original frame was practically non-existent. I'd say about <6mm across the back of the molding and no more than 8mm deep. And that's the whole depth, not just the rabbet. It was glued and had two nails in each corner. What's more, the joints were still sound. There again, I've seen enormously wide frames with huge great iron nails in the corners that had opened-up corners. Most of this is caused by modern heating systems though. If the wood decides it is going to warp, it will defeat the stongest glue and/or fastenings. The bigger the molding the more force is exerted.
What? You mean they didn't want to use the original frame? The fitting on that would be fun.
I got into a discussion with another woodworker about miter joint strength when glued only - he felt I would have knowledge because I'm a picture framer. I didn't have any solid advise but said I would test. I started cutting and joining left over moulding until I had a stack of about 30 pieces made up of 2 sides 16 inches long joined with my usual glue and clamped overnight. All mouldings were about 3 inches wide. Then I broke them. I put one end on the floor and pushed down with my hands on the other end - no special test equipment. A few just fell apart with little push, a few didn't break and held all my weight, and the rest were in between and suitably strong. The ones that fell apart were a bit of a surprise, just no strength at all. Same glue in the same amount, clamped the same, and left in the clamp for the same time. What it seemed to come down to was the wood - some woods glue well and some don't.
I just got back into town after a harrowing experience with my hound. We've spent the last couple of days at the Veterinarian Specialists Hospital in Raleigh (actually Cary -is there a difference?) I'm about 3 thousand lighter and the hound is laid up and still there but there is hope.
As soon as I got back I went into the library for the Jan/Feb 09 issue of Fine Wood Working, pretty much the magazine of record for wood workers. Here are the results of their experiments testing wood working joints. Glued miter joints were able to withstand a peak load of 1,374 lbs. "Surprisingly strong". Baer, the cope and stick, by comparison, came in at 313 lbs. Interestingly, a butt joint withstood a peak load of 473 lbs., somewhat stronger than a cope and stick. So much for increased surface area. That 1,374 lbs.of the miter joint is pretty impressive. The mechanical biscuit butt joint was a mere 545 lbs. To quote Fine Wood Working, "However, as the wood expands and contracts over time (30 years?), the 45 [degree] geometry will change causing joint failure at the outside corner (note, this is not a sudden, complete failure). They don't recommend the joint for furniture making but it's surely fine for a picture frame. The peak load withstood by the mitre joint compares favorable with the 1444 lb. peak load of the mortise and tenon. A joint that is d*mn near as strong as a mortise and tenon joint is certainly strong enough for picture frames. I think the concern for expansion and contraction is misplaced because, as I mentioned, the temperature changes in modern houses are not extreme nor are the changes in humidity. The proof of this assertion are the many picture frames that have been glued and v nailed and have not failed for over 30 years. The v nails would not affect the glue joint. In fact I think there is evidence that the v nails accelerate joint failure by inhibiting wood movement, especially when two are present (not stacked). I now that's the case where metal fasteners are used in furniture. Fine Wood Working is available to anyone; go check it out. This is not anecdotal evidence which has been very much in evidence in this discussion.
The glued mitre joint is a very strong joint that's not improved by inserting mechanical fasteners. We need to understand the purpose and function of v nails in mitre joints. The purpose is to make frame making faster and easier and the function is to hold miters together until the glue sets up, and, might I dare to suggest, to make imperfect joints, joints whose faces don't completely meet, stronger. Anyone who is inserting v nails into a properly glued and set up joint is not only wasting his time but probably making the joint weaker and certainly harder to repair. Of course, the key here is properly glued joints. A v nail will be added insurance for imperfect joints, joints that are no tglued up properly and that's a reasonable function. I really don't have a dog in this fight because I use v nails in my business and intend to continue to do so, but I'm not blinded by my use. I know why we use them: faster and easier. If you are using a v nailer and it's not making joining a frame faster...
I have noticed that the miters of very old frames are often open at the outside of the miter but tight at the inside. I recently rebuilt a frame 175 years old which had arrived from Holland. The moulding was about 6 inches wide by 2 1/2 inches deep. The miter joints had failed completely. There was lots of glue in the joints which was probably hide glue. There was no wood failure, only glue failure. Someone had hammered in 4 finishing nails about 3 inches long in each corner to hold it together. I removed the nails and put the 4 sides together to decide how I would rejoin the frame. With the inside of the miters together the outside was open by more than 1/4 inch. I asked an old friend that's forgotten more about wood than I'll ever know and he told me about the problem with miter joints. Wood expands and contracts across the grain as the humidity rises and falls. Where the wood in this frame is 6 inches wide if it expands 2% which isn't uncommon for many woods, it expands 1/8th of an inch. But out at the point of the miter it expands very little if at all. So when the full width of the wood expands at the inside of the miter it is tearing the joint apart at the outside of the miter. He also pointed out that the wood at the point of the miter dries out to a point that it shrinks to it's minimum 0 % mositure size and no longer absorbs moisture and expands so it's common for the outside of a miter to be open after many years.
I recut the old frame, joined it with pocket screws in the thick part with no glue, opened the rabbet so the painting would fit, rebuilt some of the gesso that had been lost, spray painted it gloss black as this was the original finish and then rubbed fireplace ashes over it to age it. The old fellow was very happy, he hadn't seen the painting for 50 years.
Just wonder whether these tests apply to:
All varieties of wood?
Straight grain, wavy grain, knotty grain?
All types of glue?
All types of clamping?
All cross sections of wood?
All types of mitreing equipment?
All persons doing the joining?
One single mitre joint or four mitre joints on a complete frame?
Pressure applied to the joint in any direction?
Or are the tests conducted under strict, exacting controlled conditions. If that's the case then perhaps the multitudes of us framers may not be able to join all of our frames under those exact conditions.
First and foremost I want to clear up one thing, my throat......
Thank you, I feel so much better.
FWW, is a self absorbed egocentric slick publication that resembles all the others like it found in every other craft, Martha, AD, Dwell, and a few others that come to mind but I'll leave it at that.
I only say that to clear up another point that Ormond, (another woodworker with some extreme proven prowess; while we're pissing sawdust here behind the school house). Their test is completely skewed to make them right for the year of 2009.... then they can hope everyone moves on and doesn't ask for an update on the long term affects of those joints.
Even at 1% shrink across the grain at the corner of the diagonal that is the interior glue join, micro fracturing occurs. Over time, whether it is 10 year or 40, the joint, without any mechanical bonding agent (tenon, bisquit, nail, screw, spline, dowel, bowtie, sliding dovetail, pegged and counter pegged or "V"nail) is going to fail. And the only thing that it will be held together with, is the backing paper.
As for the old bodgers tale about letting the glue set then breaking the bond and regluing..... we've had this discussion 4 or 5 years ago. It's bunk. It was a practice used with hide glue and the glue was let to soak in, then the joint was broken open, the glue scraped off and fresh very thin coat applied to re-heat the bond driving the already soaked in glue to soak in even farther (so it was believed). So the glued up seat bottoms either don't break or they don't break, which lamination is stronger? Yup, bunk.
Bandsaw, what you are discribing was a (thank goodness) short lived practice of chopping the miters at 44 degrees or 88 degree joint. Then the frame was pulled into closed joints. This was believed that it would counter the lateral shrink that was causing the joint to break apart and open on the inside. It just didn't take into effect the tri-axial reclusing of wood over time.
Not only will the moulding shring across the width, which causes it to draw back at the inner point more, but the lip is thinner and therefore the distal shrink is more rapid which exaserbates the nature of the drawback at the sight in the joint.
Argumentum ad hominem, Baer, I thought better of you. What earthly reason would Fine Wood Working have for skewing the results of a joint test? At any rate the methodology is clearly reported. I never suggested that the glue joint wouldn't fail, only that out wouldn't fail with the frame falling off the wall. We all have experience with the longevity of glued miter joints, they constitute just about every frame we make. How many of our frames are hanging with loose glue joints held together only with nails, v nails, etc and backing paper. And, again, the joints on that hypothetical frame you imagined hanging on to life with only backing paper is going to be easy to repair and can look forward to a whole new 30 years of blissful display.
Well I guess we can close this chapter now. Mab what you have there isn't furniture store junk. Quite the opposite. What you have is a classic joining style adopted by master craftsman and finest frame makers of centuries past. The frame joinery used on your frame is surely the standard at inimitable boutiques across Italy and Spain. Your nescient eye missed how well the artisan leaf finish incorporates with modern adhesive bonding agent to create the perfect blend of form and function. Not only is the frame a perfect accent piece but the “break away” joint is specifically un-supported with inferior mechanical means lending itself to effortless repairs.
Oh. Nevermind. I may be mistaken. It may be furnature store junk? As you can tell there is a fine line between fine framing and junk.
And there's a lot of money in junk.
OK so there was no question, just a suggestion to consider joining the frame before selling it to a customer.
Where did all the ego get into this thread? We have many fine woodworkers in this forum, each with their special talent set and skill set and method of working. Yet we hate each other? We question each other's skill? I doubt that.
Can we get off our soap boxes? I mean really all this pissing and moaning about woodworking techniques is taking away from our valuable yelling at each other about politics! Get your priorities right for god's sake! Why can't we get back to respecting each other's talent and skill and start questioning our sanity and beliefs again? That's where the real animosity belongs, not with each other's abilities.
BTW I'm being serious, only half in jest. We all have got an area in woodworking that we feel strong. You don't step higher on your pedestal just because you took 3 inches off the other guy's perch. Jay I was giving you a raft of #### about your work with antique frames because I thought you would good naturedly take it (which you did) and that the others would see what an ### I was being. Which, I guess they didn't because they kept on being asses.
Baer, Warren, come off it. After reading your back and forth I'm no longer respecting your skills, just questioning your openness to the thinking of others. Baer I can read a really crappy magazine or book and still glean good information from it. While Warren, whose skills with wood are better than mine can probably do better than I at weeding out the bad info from the good. You get out of your reading what you bring to the table.
Right on! Thanks for a good laugh to start the day.
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