Butt joints,wood glue strong enough?

[JapanDave]

Hey, just a quick question, I am in the proccess of build a set of line arrays with internal bracing , made out of MDF and will be veneered. The question remains if when using butt joints, will wood glue be strong enough? Or will I need to use screws as well? The front baffle is 1" and all other sides and braces are 4/5" thick.

TIA

[planet10]

Originally Posted by JapanDave

The question remains if when using butt joints, will wood glue be strong enough?

Yes. It will be even stronger & stiffer if you use good multiply.

dave

[pinkmouse]

Originally Posted by JapanDave

...will wood glue be strong enough?

Yes.

[JapanDave]

Thanks guys.

@Planet10, forgive my ignorance, but what is multiply?

[kevinahcc20]

Let me add a caveat...glued butt joints can be adequately strong provided the underlying construction is accurate. If the parts are flat (not warped, twisted or bowed) and the cutlines are true, straight and square so that all of the mating surfaces meet closely without gaps then a good quality wood glue will provide a quite strong joint. It won't be as strong as a screwed and glued joint or nearly as strong as a biscuited glued joint, but it will be adequate. This is because wood glues provide the highest strength in very thin layers but are not good at gap-filling. It is interesting that at diyAudio we regularly obsess over capacitor brands, cable and connector features and esoterica such as thin coatings applied in intricate patterns to speaker cones; conversely when it comes to the fundamental structure that is the foundation of a speaker we ask what is "good enough"!

[nightanole]

Throw a old cabinet off your house, or hit it with a sledge hammer. The butt joints will be the last to give. So good enough means the joint is stronger then the panel. Another question would be does a butt joint sound better then a biscuit joint...

On the other hand whats the hardest to align, a butt joint.

[JapanDave]

Can you apply too much pressure with clamps, effectively squeezing out too much glue from the joints? And is standard wood glue ok? The ingredients of the glue I am going to use here in Japan is "Vinyl acetate resin emulsion form"

TIA

[Conrad Hoffman]

I think that's PVA, which is good, but the best glue I've found is Titebond III. The III is important. If you can find it, not much will beat it other than epoxies.

[JapanDave]

Originally Posted by Conrad Hoffman

I think that's PVA, which is good, but the best glue I've found is Titebond III. The III is important. If you can find it, not much will beat it other than epoxies.

Yes, you would be correct, it is PVA glue.
And I think I may be able to source some here. Is this the stuff you are talking about?

[454Casull]

Originally Posted by JapanDave

Thanks guys.

@Planet10, forgive my ignorance, but what is multiply?

He means multi-ply, as in plywood.

Re: aligning butt joints - I like to dry clamp everything together and drill pilot holes. That way, I can simply glue along the joints and tighten/align at the same time with drywall screws. After the screws are tightened, I still put the bar clamps on, though.

Whether one removes the screws afterwards is up to personal preference and finishing method.