Bookmatching/ glueing

guidothepimmp

Folks... so im about to get my grubby lil hands on some nie ash wood.. it isnt wide enough though so i have to glue the 2 bits together. im happy enough getting the grain as close as possible but will regular wood glue be strong enough to hold the bits together with clamping.

is there something else i should use? dont want it to come undone while routng or something

AlanRatcliffe

Wood glue - there's a clue in there somewhere. ?

Joined and clamped properly, there's nothing wrong with using wood glue. If you're really paranoid, epoxy is an option.

StephenG

what about a biscuit joiner at 2 or 3 spots along the join?

you still glue all surfaces, but the 2 or 3 biscuits could add some seriously decent reinforcing to the join??

would it have any negative impact at all?

guidothepimmp

lol... thanks Alan..

i guess i wanted to.know that woodglue would be all i needed. got some nice straight edges so heres holding thumbs

whos a biscuit?

what on earth is a biscuit join ?

edit..googled it... thanks

flatfourfan

guidothepimmp wrote lol... thanks Alan..

i guess i wanted to.know that woodglue would be all i needed. got some nice straight edges so heres holding thumbs

whos a biscuit?

what on earth is a biscuit join ?

edit..googled it... thanks

Dude, Top tip is to wet the ends that are going to be joined. The water allows the glue to be soaked in better to each peice.

Genkem is my choice on wood glues. That and 3-4 nice decent door frame clamps. My warlock was done with tongue and groove and then 40 bricks were stacked on top to prevent buckling as I only had 2 clamps for the bottom and none for the top.

guidothepimmp

thanks man.. will keep that in mind..

Wizard

Wood glue is supposed to be stronger than the wood itself ... so no issues there.
Make sure the edges are perfectly straight and flat so that there is proper contact between the two pieces.
You should get the edges jointed ... and then glued soon afterwards, before the wood has had any chance to twist.

I support the idea of putting weight on top - clamping tightly on the edges has a habit of pushing it up in the middle.

Gearhead

ok call me dumb, but I honestly don't understand some of the advice in this thread.
Perfectly straight sides are important, agreed. But if they aren't perpendicular to the top you are going to push the center up or down when clamping. Sure, this can be remedied by offcenter clamping or weights, but that will leave residual stress in the body that cannot be good for long term stability.
Then the fancy ideas about biscuit or profiled joints. These are meant for positioning parts relative to one another or for allowing gaps without affecting strength. You don't actually need that much strength in a guitar body but you do need soundwaves to travel freely, so gaps are out of the question. If all great guitar builders prefer a flat joint smack down the center, why not trust that technique?
Then the glue. I personally think that there is not that much difference in glue strength if your layer thickness is 10 micron. If the thickness is 2mm, sure it's very important to have strong glue. Again the strength is less important than the sound propagation so the less glue there is in between your wood, the better. It comes down to your ability to get the glue on all of the surface and then to get almost all of it out - or into the wood. This comes with experience and not with brand names.
I have developed a love/hate relationship with epoxy while building a wooden boat. I love the result you can get but hate everyting else about it. Having become allergic does not help - cover your every bit and clean everything. During clamping, most epoxies become very very slippery. This makes it hard to position parts unless you build in references. In the build I am working on I used dowels that will come out while routing cavities, so you do not affect sound running though the body. The next downside is gelling. Once epoxy starts reacting, it will go from syrup to gelatine in a couple of minutes. Once you notice the change, you are too late to clamp or move or whatever. Stop, scrape and sand later.
Really, cold glue is better.

guidothepimmp

whoa.. thanks Gear...

will keep that in mind. so as thin a layer of glue over the entire surface it is..

AlanRatcliffe

Good post GH. +1 on using dowels to prevent slipping with epoxy - it's also common with fixing neck breaks.

I have seen angled joins specifically to match the endgrain for more unobtrusive joints and to provide more surface area for glueing, but they are far more difficult to get right, so best avoided.