Butt joints,wood glue strong enough?

[Cal Weldon]

Andrew, I sympathize. Biscuit joiner and screws were my method of choice before I bit the bullet and got the nailer. I will never, repeat never regret the decision. Screws seem like torture now, especially when you get into the trickier stuff.

[Mickatroids]

I am making some smaller 2 ways at the moment with marine ply, I want the ply to be the final exterior finish so no screws. I am going to use just a few biscuits and rely on but joints and some cleats. Nothing fancy, just softwood braces that will help me to align everything on glue day. Will use PVA glue, stuff is impermeable once set in my experience.

Have always used screws in the past, millions of them. They add up so fast!

[Cal Weldon]

Hi Mick,

I think you'll find biscuits and cleats do similar things so you can probably drop one or the other. I can't think of why you might need both.

[Mickatroids]

I suspect you are right Cal, thanks. In that case the cleats are preferable because they will be also add rigidity. On the other hand I have not spun up my biscuit joining thingy for a while so I might whip a few in for good measure

I used screwed cleats (again to help align things) and butt joint screws and glue in my last sub project. It is ultra tuff!

[phase_accurate]

There is wood glue available that expands and foams upn curing. This one will also fill small gaps and make the cabinet airtight - all at once.

Be aware that you will not be able to remove it from clothes, fingers, furniture ......

I can post a picture of a raw cabinet that used this type of glue if anyone likes.

Regards

Charles

[simon7000]

Originally Posted by phase_accurate

There is wood glue available that expands and foams upn curing. This one will also fill small gaps and make the cabinet airtight - all at once.

Be aware that you will not be able to remove it from clothes, fingers, furniture ......

I can post a picture of a raw cabinet that used this type of glue if anyone likes.

Regards

Charles

But it is not as strong as PVA! Been there done that.

Cal, are your boxes watertight? I haven't bought a nailer in a while, but I thought they cost less than a biscuit joiner and I am pretty sure nails cost less than biscuits.

PVA even cured will fail with weather exposure. It will take getting wet once or twice.

Glue blocks started with hide glue, you really need them and properly used you rub them to join the panels and no clamping is needed.

Modern glues set differently and clamping is good. The idea when using screws is that they act as clamps until the glue dries and then they really aren't needed. With a modern nail gun run at the proper air pressure the same clamping action happens!

One precaution about modern PVA glues is some have a filler added to allow it to be thicker and extend working time, really don't like that stuff.

The second is never let it freeze.

A semi-serious consideration with wood block reinforced butt joints is the wood used for blocks. When you rip the wood into strips it may warp on you. When buying the wood for the reinforcements look for long straight parallel grain. "Figured" wood is not a good idea. Yes, pines work well. I would avoid red oak, where maple is probably best. Heartwood is particularly good.

[Cal Weldon]

I have posted some testing done on wood glues.

The lowdown on wood glues

[Cal Weldon]

Originally Posted by simon7000

Cal, are your boxes watertight?

You bet, I use them for river rafting during the summer months.

I haven't bought a nailer in a while, but I thought they cost less than a biscuit joiner and I am pretty sure nails cost less than biscuits.

Mine is air so there aren't cheaper but 5000 nails are pretty cheap. Mind you nailers are fun to use so I probably put about 5 times the nails I need.

PVA even cured will fail with weather exposure. It will take getting wet once or twice.

Yup.

Glue blocks started with hide glue, you really need them and properly used you rub them to join the panels and no clamping is needed.

Unless you attach them to one panel ahead of time. I do that so there are no alignment problems with butt joints. Everything just falls into place. Adding them after defeats that.

Modern glues set differently and clamping is good. The idea when using screws is that they act as clamps until the glue dries and then they really aren't needed.

Right but I can't remember actually going back and removing them can you?

With a modern nail gun run at the proper air pressure the same clamping action happens!

Well now let's not forget that even plywood warps a little and the clamps are there to bring the pieces up snug during nailing. 1 1/4" nails aren't so good at that.

One precaution about modern PVA glues is some have a filler added to allow it to be thicker and extend working time, really don't like that stuff.

I use the thicker stuff a.k.a. yellow glue but because it sets up faster not slower.

The second is never let it freeze.

I've made that mistake.

A semi-serious consideration with wood block reinforced butt joints is the wood used for blocks. When you rip the wood into strips it may warp on you.

Oh ya, looks like curly fries sometimes.

"Figured" wood is not a good idea. Yes, pines work well.

Is figured wood what we call dimensional lumber ie 2X4? If so I agree. Doesn't stop me from using Spruce though. The Pine in these parts is far too knotty.

[jimbro]

Or - you could use 2 different materials to make the panels, like particle board and ply. Make the inner panel smaller so they form rabbets. It'd take some planning and care laminating but assembly would be fast and you'd get acoustic benefits. Or so I've read. I've made bookcases like this but never speakers. Don't think I'd attempt it on those octagons.

[simon7000]

Cal,

Attached is what I mean by "Figured" wood. And if you raise your own pine it would probably be better behaved.

The family Pinaceae covers both commercial spruce and pine forgive me for being so imprecise.