Is clamping entirely necessary?

[Jay Michaels]

I'm working on some frames for some small step-stools. These are simply made from 1x2" poplar with 6x30 dominos at the joints. The steps that I'll be adding later will be small 1" thick (a true 1") pieces of elm from a tree I had milled a couple years ago.

I realize I could buy some CA glue (or devise another option) to temporarily glue on some small angled pieces to the sides so that I could properly affix clamps to this assembly while the glue sets, but rather than going that far, I'm curious what thoughts people on this forum have about simply forgoing clamping all together.

For what it is worth, the dominos are very tight on both sides of each joint, I'm using titebond III, and when I push the parts together, they fit together nice and snug.

Would clamping this up during the glue up really make this a substantially stronger joint, or not?

420416

420417

420418

[roger wiegand]

My favorite answer, hot hide glue. Push it together, hold it for about 30 seconds, and done.

[Brian Holcombe]

Traditional mortise and tenon with draw bores.

[Jim Becker]

You don't necessarily need to clamp with huge force, but you'll get more consistent results if you can get a clamp on to insure things are pulled together tightly. Painter's tape can be used for some smaller work to do that when shapes are more difficult. A "modern" variant to what Brian suggests is to pull them together tightly, perhaps with a combination of your hand and tape and then shoot one or more 23 gage pins through the tenons. (and I do count Dominos as that) I would not do this for big heavy things but it may be effective for a face frame. (Honestly for face frames, i use pocket screws on the backside...)

[Lee Schierer]

Clamping will always give you a better joint. You can use double sided tape to hold your blocks in place.

[J.R. Rutter]

For stuff like this, a ratchet strap or some blocks strategically tacked to a flat piece of scrap and some wedges will snug it up nicely.

[Andrew Hughes]

Yes plan on clamping.
When you add glue the joints will probably need more then your hand pressure to close.
I use dominos a lot I had the same thoughts as you.
So don’t mess this up your almost there.

[Jim Morgan]

Traditional mortise and tenon with draw bores.

I have used dominos with drawbores as well. No need for clamps in that case as the drawbore pulls the joint together tight and keeps it tight even if the glue should later fail. 30mm is probably too short for this, however.

[Edward Dyas]

Clamping is always a good idea but sometimes it's problematic. The important thing is the joint be held together as snug as possible even if tape is all you can get to work.

[Doug Garson]

I often use elastic bands for small glue ups with shapes that are hard to clamp, for bigger glue ups sometimes bungee cords can be useful, maybe a staple or finishing nail to prevent it from sliding out of place.

[Bill Carey]

I often use elastic bands for small glue ups with shapes that are hard to clamp, for bigger glue ups sometimes bungee cords can be useful, maybe a staple or finishing nail to prevent it from sliding out of place.

I use surgical tubing. Works great. Wrap it and tuck it under one of the tight runs and walk away.

[Alan Schwabacher]

I agree about the surgical tubing as a great method. To apply more force, just use more wraps. The one thing to watch out for is squeeze out that contacts the tubing: it can stick.

[Keith Westfall]

Black electrical tape! Pull and stretch it tight and it clamps pretty tight. Works well where sometimes you just can't get a clamp on it.

[Bradley Gray]

Looks like you could flip one side end-for-end and clamp them both with a couple bar clamps.

[Mark e Kessler]

If you want a tight stable joint, yes or like Brian H said, draw bore..

[Jim Becker]

Looks like you could flip one side end-for-end and clamp them both with a couple bar clamps.

Ding...ding....ding....! Excellent idea! It will need support on the open ends, however to keep the clamping from pulling them askew. But that would be simple to cut from scraps since he'll know the angles.

[Steve Rozmiarek]

I always thought the point of clamping was to encourage a thinner glue line, which is stronger for titebond glues. Maybe I'm wrong, but it hasn't failed me, so maybe it's right.

[glenn bradley]

Draw bore, surgical tubing, wedges, pocket holes, etc. All of these are a form of clamping the joint. Applying a PVA glue and simply setting the assembly on a flat surface will not provide the strength of a clamped joint. Different glues change shape and volume as they set depending on formulation. Placing them under pressure assures the mating parts are stable as the adhesive changes. Visit some wood glue manufacturer's sites and see if any of them advise NOT using clamps. There are all sorts of things that people do or have done over the years. I'm an ex-geek and so tend to follow the manufacturer's advice since they make the product :D.

From Franklin, for example:

Clamping

A variety of clamps and clamping systems are available for assembly joints. Enough clamping pressure is recommended to provide a thin glue line along the entire surface of the joint. Direct contact of the gluing surfaces is required to obtain maximum strength.

[Robert Hazelwood]

When we are talking about glueing mortise and tenon joints, the clamps are usually just to ensure that the shoulder is well seated. The actual glue joint is between the tenon cheeks and mortise walls, and the clamps aren't affecting that. If the fit is snug enough then I think you could seat it with mallet taps or something, and then just avoid disturbing it until the glue sets, and I don't think the joint would be any weaker. But I would still find a way to clamp it if I could, just to make extra sure the shoulder is perfectly seated.

[Richard Coers]

When we are talking about glueing mortise and tenon joints, the clamps are usually just to ensure that the shoulder is well seated. The actual glue joint is between the tenon cheeks and mortise walls, and the clamps aren't affecting that. If the fit is snug enough then I think you could seat it with mallet taps or something, and then just avoid disturbing it until the glue sets, and I don't think the joint would be any weaker. But I would still find a way to clamp it if I could, just to make extra sure the shoulder is perfectly seated.

Well seated and to prevent any hydraulicing that could let the tenon slide back out a bit if air is trapped inside the joint.

[Ross Manning]

You don't need clamps for the joints in question if the concern is strength of joint. The members are butted end grain to long grain, and no amount of clamping will make this a strong glue joint. As stated above, the strength of your joint comes from the long grain to long grain of the mortice and tenon, and this is unaffected by any clamps. All clamps would do for you is help ensure the gaps are closed (still important) but if you can achieve that to your satisfaction via other methods, you can avoid using clamps.

[Jay Michaels]

Excellent input -- all of it -- thank you.

420748

I took up Bradley on his recommendation for flipping one end-for-end and butting it against the other to make the clamp-up easy with some scraps to line everything up. That has the added bonus of making it much easier to square them up too; not just hold them tight. I then used a couple of off-cuts to aid clamping on the short ends (those off-cuts are not glued/taped/cemented in place; they don't need to be since they are trapped by the straightedges clamped to the sides).

Thanks again.