How can I straighten (self)-laminated wood?

[wavanberkel]

Hi,

I have have built ship models in the past (Baltimore clipper, Valley Belle, both abandoned for lack of experience), but I am now building a model of a Handley Page V/1500 bomber of the first World War.

The problem I engage is the following: I am working on the cockpit floor, which was originally made of cross-wise applicated slats on a plywood base.

I tried to replicate this in 1/32, also with wood. These planks were meant for deck planking, and are 0.8 mm thick. The wood - I think- is linden. The bottom is is a single sheet of 0.9 mm birch.

I used simple PVA wood glue, but the bottom is warped because in same places I used the glue a little too liberally.

Does anyone know a way to resolve this without the slats coming of? It was tedious work and I really don't want to make a new one...

Regards,
Willem

 

[DARIVS ARCHITECTVS]

The part does need to be wetted, but not soaked to the point of popping the glue joints. The part needs to be pressed not only flat, but bent beyond flat and slightly curved in the opposite direction, and held there until it dries 100%, with no moist spots left. If this is done carefully using a shallow wooden mold that you cut just for this, the part will spring back to near flat.

To make the press mold parts, cut a piece of scrap 2x4 with a shallow curve using a bandsaw. Place the wet part between the form parts and use a vice or large clamps to slowly force the part into the inverse curve. How much curvature the form parts need to have is a matter of judgement. The curvature of the upper mold must press into the part with contact on the entire upper surface when fully clamped. If you press on the center only, it may snap. If you feel you are pushing the part too far, and threatening to break the lattice on top, you may have to start over and make the part over again. If you wait overnight, it should be dry. You could place the entire rig in the kitchen oven at 150 deg F for an hour or two and speed the process. Linden wood is very forgiving as far as soaking and bending goes. Birch, not so much as it is coarser in grain, and is especially at risk since you are bending in along the grain.

 

[wavanberkel]

The part does need to be wetted, but not soaked to the point of popping the glue joints. The part needs to be pressed not only flat, but bent beyond flat and slightly curved in the opposite direction, and held there until it dries 100%, with no moist spots left. If this is done carefully using a shallow wooden mold that you cut just for this, the part will spring back to near flat.

To make the press mold parts, cut a piece of scrap 2x4 with a shallow curve using a bandsaw. Place the wet part between the form parts and use a vice or large clamps to slowly force the part into the inverse curve. How much curvature the form parts need to have is a matter of judgement. The curvature of the upper mold must press into the part with contact on the entire upper surface when fully clamped. If you press on the center only, it may snap. If you feel you are pushing the part too far, and threatening to break the lattice on top, you may have to start over and make the part over again. If you wait overnight, it should be dry. You could place the entire rig in the kitchen oven at 150 deg F for an hour or two and speed the process. Linden wood is very forgiving as far as soaking and bending goes. Birch, not so much as it is coarser in grain, and is especially at risk since you are bending in along the grain.

Hi Kurt,

Thank you for your quick and elaborate answer. Reading this, I think this could work.

Although I do not have a band saw, I think I can find a former that will do the job.

Kind regards,
Willem

 

[DARIVS ARCHITECTVS]

Hi Kurt,

Thank you for your quick and elaborate answer. Reading this, I think this could work.

Although I do not have a band saw, I think I can find a former that will do the job.

Kind regards,
Willem

There's always the coping saw, and that works faster than you would imagine. After cutting, you could power sand the waved out of the cut and go with it.