Can I put a tight bend in plywood

Wunja

Wunja

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I'm considering making a hatch garage by laminating plywood. My first idea was a frame with laminated plywood top, with just a shallow bend from side to side.
However, I'm wondering if I could incorporate the sides into the lamination. This would necessitate a 25 mm radius.
I'm thinking of using 4 laminations of 4mm exterior plywood.
Is this a possibility?
 
Wunja said:
I'm considering making a hatch garage by laminating plywood. My first idea was a frame with laminated plywood top, with just a shallow bend from side to side.
However, I'm wondering if I could incorporate the sides into the lamination. This would necessitate a 25 mm radius.
I'm thinking of using 4 laminations of 4mm exterior plywood.
Is this a possibility?
Click to expand...

i very much doubt it as a diy job with limited equipment
 
Wunja said:
I'm considering making a hatch garage by laminating plywood. My first idea was a frame with laminated plywood top, with just a shallow bend from side to side.
However, I'm wondering if I could incorporate the sides into the lamination. This would necessitate a 25 mm radius.
I'm thinking of using 4 laminations of 4mm exterior plywood.
Is this a possibility?
Click to expand...


Would be easier if you used more sheets of thinner ply and perhaps a steam wall paper stripper. I have a tiny piece of plywood left at the 1mm range, but I was told it is hard to come by now (the chap told me it was high quality, aeronautical ply that I had managed to pick up)
 
Far easier to have a shallow bend in the top part and have the sides vertical from another piece(s) of timber. Then have a generous fillet on the inside, and f/glass tape on the outside bend.
Before glassing the outside curve, you can always shape it with the angle grinder and grit discs. Glassing will make the outside of the join waterproof.
 
No way not without lots of temp and pressure. At work we produce shallow curved laminates by getting two MDFB ends drawing on a curve then drilling for broom handles which slide across between the ends. The ply (4mm) to be laminated is laid across the broom handles and rachet clamps are used to pull it down. The ply has to be cut exactly to rest on the apex of last broom handles or it will not go down. I am not very keen on the system but my boss loves it so easy to bend to the breeze. Personally I think having a radised inside curve would look unusual on a boat, The curved top will suit the hatch and stop water sitting, the vertical sides mean the garage can accomadate the hatch as efficiently as possible. Form and function type stuff. You could always make an MDFB mould and make a GRP garage.

Have fun.
 
It is possible to buy special bendy ply that will curve around quite sharp curves, comes in various thichnesses. The disadvantage is that is more expensive and has fewer plys for the same thickness.
 
Make Assembly Using Easy Bends and Then Cover With A Single Sheet of Veneer

I have seen ply bent to tight radiuses by grooving the wood on the inside of the curve to achieve the desired turn.

Alternatively, you could make the sides out of solid wood shaped such that it had a curve that suited your garage requirements and was integral with the frame that you suggest. The curved solid sides and frame could be stepped to take your thicker ply over the top but at the larger radius. The whole lot would then be glued to form the shape.

To finish you could cover the final shape with a single veneer that would curve around the solid sides and the top ply giving an allusion of one piece of ply.
 
I've used aeroply of 1.0 and 1.5 mm thickness to laminate small stuff in the past. Tighter bends are possible if you get the grain the right way but doubt that as little as 25mm radius is possible. It's wbp grade and top quality stuff so it's dear but probably laminations are birch which isn't reckoned durable - altho epoxy coating should sort that.
If twere me I'd do solid sides and 2 laminations of 6mm marine play for the curved top.
 
BlowingOldBoots said:
I have seen ply bent to tight radiuses by grooving the wood on the inside of the curve to achieve the desired turn.

Alternatively, you could make the sides out of solid wood shaped such that it had a curve that suited your garage requirements and was integral with the frame that you suggest. The curved solid sides and frame could be stepped to take your thicker ply over the top but at the larger radius. The whole lot would then be glued to form the shape.

To finish you could cover the final shape with a single veneer that would curve around the solid sides and the top ply giving an allusion of one piece of ply.
Click to expand...

+1.
 
I have made several instrument pods, no mould needed, no special tools and no fuss.

Get yourself some closed cell foam, cut a little oversize and using a hand saw cut slots in the underside about 8mm apart to make the curve form easy, compound curves can be made by more cuts in the desired direction.

Butter the underside with some Micro-Balloons and bent to the required curve and leave to set.

Sand off any stray bits of Micro balloons and sand the vurve to perfect shape, now you only have to glass over it, sand it, add more micro balloons as required and coat it with flow coat.

Job done.

Good luck and fair winds.
 
Vince, when I tried this on Indecision I tackled it the other way round.

I epoxied marine play under the existing hatch and fitted a lip on the leading edge. This had the advantage of restricting the hatch opening as far and if any water did get under it there was no where for it to go as it couldn't get over the lip.

Due to not having a sprayhood I took some big waves over the bow and hatch but never found any water came through.

Not sure if that makes sense. If you need more detail PM me and I'll do a simple diagram better explaining it.
 
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