Jointing or Biscuits

Thats a job they invented biscuits for, prevents up/down movement, but allows lateral movement. Very strong as well.

I've done this both ways and had satisfactory results. That's using a biscuit jointer with biscuits about every 150-200mm; a router bit with a wavy glue profile and a spindle moulder block with similar profile cutters.

There is an argument in favour of the glue joint approach in that there is more surface area for gluing on the edge. OTOH, the biscuits make up for some of that.

Really important is to have a flat surface for gluing up and plenty of good clamps to make sure that the pieces remain in the same plane. If you don't have any already, Bessey K clamps are really good for this because they are solid and heavy and you can arrange everything to lay flat. There are Chinese equivalents which aren't too bad. Some pieces of softwood between the clamp jaws and the material are a good idea because clamping tightly is important.

Using a pair of sticks as winding sticks to check for warping etc before the glue goes off is a Good Idea.

I will give the glueing set up a dry run and I'll make use of all the clamps I have. I have a lot of quick grip clamps and three 9" steel g clamps.

Will waterproof pva be good enough?

Arthur

For these types of woods, I have tended to wipe the surfaces to be glued with acetone and then apply a very thin layer of polyurethane glue to one face and a wipe with a damp cloth to the other. PU glue cures with moisture.

Then clamp at least overnight. That seems to work reliably.

I tried without the acetone cleaning once and the joint broke apart easily at the glue line. AIUI, the issue is that the oils in certain tropical hardwoods reduce the ability of the glue to penetrate the pores of the wood.

Why should there be any lateral movement? It's a parallel long-grain joint.

Why should there be any lateral movement? It's a parallel long-grain joint.

By lateral movement I meant that if you are joining two boards along their long edges, you have movement along those long edges IYSWIM. So you could get the ends to line up for example.

Isn't that lateral?

Longitudinal.

Re: Jointing or Biscuits

it's called the munchies when after jointing you crave biscuits

Longitudinal.

I do that with a pencil mark (crudely), then trim the ends to length _after_ I've jointed, joined and thicknessed them. I like long ends left on boards before jointing, if there's any snipe caused by the jointer, chances are that it's on a bit I'm going to trim off anyway.

Thanks for all advice, gents.

Arthur