Good Material For Splines?

[Joe Wood]

What's a good material that will absorb glue but not swell as much as a 3/16 x 1"cedar spline would? I don't want any problems when assembling this octogon frame, like what happens when a spline swells up to much to fit into the grooves easily.

[Edwin Santos]

To avoid this problem I do not apply glue to the spline, only to the slot. This assumes you are using PVA glue. I do the same with M&T joints, cut them snug, and only apply glue to the mortise, not the tenon.
Another alternative is to use a non-water based glue.

[Joe Wood]

Hhmmm, never thought of that Edwin. I could also use a hardwood but I only have softwood scraps in the shop.

[Kevin Jenness]

I think wood is a reasonable material to use. I can't think of any porous material suitable for pva glue that won't swell somewhat. You may need to get the pressure on faster or use splines a few thousandths thinner. Maybe another stable wood like mahogany would absorb the water more slowly.

For maximum strength the grooves, splines and endgrain should be coated. You might consider clamping blocks across the joint faces, although many a 1/2" stub tenon has been clamped only in one direction.

There are ways of breaking up the assembly into smaller parts, like gluing the splines into one half of the grooves and letting the glue cure before proceeding. You could glue up one or a few of the joints at a time using miter clamps (Collins clamps or similar) or adding clamping ears sawn into the waste sections or added with hotmelt glue. You could halve the gluing by tenoning one side of the joints.

Finally, you could use an adhesive with little or no water like Unibond 800, epoxy or polyurethane.

I like your moon gates.

[Joe Wood]

Yeah this will be a difficult glueup likely to take us some time so I'll go with epoxy!

[Kevin Jenness]

How do you typically glue these up? Titebond 2 or 3 and a band clamp?

[Mel Fulks]

The grain needs to run across the two pieces, like a plank ship to shore ….or ocean ! Argh !