Laminating a new boomkin

[evangeline44]

Hi all experienced woodworkers

I have to replace the boomkin on Evangeline and need some sound advice on using West system epoxy to laminate Clear Douglas Fir.
The old boomkin had 9 thin Flat laminations for a finished thickness of 50mm, length1600, maximum width 180. (the spars are cut to a shapely curve).

1. Where can I get good quality CDF in North Wales?
2. Do I have the pieces planed or just Sawn?
3. Do I first wet-out with unthickened epoxy and then join with a thickened mix?

Thanks

 

[TQA]

Can't help you with 1

2 sawn

3 yes also don't overtighten the clamps squeezing all the epoxy out.

 

[evangeline44]

Thanks for that.

Other folk elsewhere have said to use planed timber so still confused.

Presumably the epoxy is stronger than the timber so the warning against overclamping pressure makes a lot of sense.

I Think???

 

[TQA]

I have been told that the sawn faces absorb glue/epoxy better than planed and the slight roughness gave a degree of mechanical grip.

As for the clamping that is from West Systems guides and they say you squeeze all the epoxy out of the joint. I can not see this myself but that is what they say. The epoxy is stronger than the wood.

 

[vyv_cox]

The recent articles in PBO suggested that the timber should first be primed with unfilled epoxy, then thicken it and apply to the faces before the primer sets. The unthickened resin is absorbed more readily into the timber and gives a stronger joint. It also makes the statement about not clamping too strongly.

 

[TimBennet]

It depends on the sawing! Too course a cut and you have mechanically damaged wood fibres on the outer surface. Although a planer can 'polish' the surface, the ideal is a rough (60 grit) sanded finish to either a sawn board or planed. Much easier to wet out.

When epoxy coating any wood, we always ensure we do it on a 'falling temperature'.

For example, if laminating this boomkin in summer I would lay out the timber in the sun until lunch time, then when the epoxy was mixed, I would bring the wood into the shade to coat it. Warming the wood (or other substrate) is the only acceptable way of 'thinning' epoxy and the 'cooling' wood prevents outgassing from the pores and even helps draw the epoxy into the wood.

I see lots of people who work with the wood in the shade and then put the coated bits outside in the sun to help it 'kick' and are disappointed to find it full of tiny bubbles.

 

[jerrytug]

It depends on the sawing! Too course a cut and you have mechanically damaged wood fibres on the outer surface. Although a planer can 'polish' the surface, the ideal is a rough (60 grit) sanded finish to either a sawn board or planed. Much easier to wet out.

When epoxy coating any wood, we always ensure we do it on a 'falling temperature'.

For example, if laminating this boomkin in summer I would lay out the timber in the sun until lunch time, then when the epoxy was mixed, I would bring the wood into the shade to coat it. Warming the wood (or other substrate) is the only acceptable way of 'thinning' epoxy and the 'cooling' wood prevents outgassing from the pores and even helps draw the epoxy into the wood.

I see lots of people who work with the wood in the shade and then put the coated bits outside in the sun to help it 'kick' and are disappointed to find it full of tiny bubbles.

Good tip!