Curved seat base

Hi all

I'm getting close to the end of my current project and am starting to turn my mind to my next major job - a dining table and matching chairs.

For the chairs, I'm keen to go for a more casual setting, not the high back style that's so common these days. I'm also looking for something with relatively simple joinery.

I quite like this kind of thing, with curved plywood for the back and seat. But I don't want to paint it, I'd rather have natural timber finish.

I haven't done it, but I think it would be relatively easy to bend plywood in a vacuum bag to get the right shape (once I have an appropriate form). But I am thinking of using a walnut/blackwood veneer over the plywood. How do I avoid having the plywood showing at the edges? Most plywood is pine or birch so it is pale in colour and will not look good (IMHO) next to the walnut/Blackwood veneer.

One option I thought of would be to form the back with ply. Then veneer the edges and flush trim it to the plywood. Then veneer the main faces.

Any better ideas?

Trav

Hi Trav,
There are SO many answers to so few questions!
If you have access to the vacuum bag and can make the former then you could make the whole base or back out of walnut or blackwood veneers? 4 veneers 3mm thick would do it nicely. You could also use the light coloured edge as a design feature on the back, base and possibly a lighter lamination in the middle of the back legs?
Another possibility, have you seen the House of Dunstone Alpha chair kit? It seems pricey at first ($295) but, as I am currently making my own set of chairs, my timber purchases PLUS steam box PLUS formers PLUS bandaids is mounting!

While doing the research for my chairs, I also came across this clever little trick....

https://www.youtube.com/watch?v=5SveP71RLs4&app=desktop

good luck with your quest!
fletty

I have seen two options for forming the curved seat and back.

The first is to to do as suggested above and cut your own veneers from the required timber and laminate the blanks in a vac bag or by clamping around the required form. If you play attention to relay the veneers in the order that they were cut, you get a near perfect grain match around the edges once you trim the blank. Primary issue is the amount and cost of primary timber required by the time you cut and machine the veneers, often need twice as much raw stock by the time you saw and dress individual veneers.

The other option is similar but using secondary timbers to form a core, then continuous edge it with the primary timber and flush trim to the core surface, then laminate on face and back veneers in the primary timber, which hide the glue line between the core and edge, and blend in with the edge, giving the appearance of a solid piece of timber. Needs more labour to prepare the edging and apply it, but saves on expensive primary timber and allows you to complete each component with 2 pieces of thin commercial primary timber veneer

Plywood is generally stable and would resist the bend (except for bendy ply) and try to return to flat once released from the form.

Quote:

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Originally Posted by Trav

I haven't done it, but I think it would be relatively easy to bend plywood in a vacuum bag to get the right shape (once I have an appropriate form).

Most plywood is pine or birch so it is pale in colour and will not look good (IMHO) next to the walnut/Blackwood veneer.

One option I thought of would be to form the back with ply. Then veneer the edges and flush trim it to the plywood. Then veneer the main faces.

Any better ideas?

Trav

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In my experiences, bending plywood depends very much on the quality of the plywood. You are possibly better off getting a 2 core ply or making one from 3 ply by removing one of the faces, bending will be much easier. You can bend in a 2 part form using clamps if you like.

Pine or Birch? Luxury! Reasonably priced ply is usually Luan or some sort of hardwood in bracing ply.

Just paint the edges. A lot simpler... but better?

Thanks Fletty and Malb.

I like the idea of making it out of solid timber veneers, but the cost gets prohibitive. Especially if I want to use walnut. I also like the idea of contrasting the timbers, but plywood has that very distinctive appearance from the side that will be very obvious.

I think I will use an edge veneer, the face veneer over the top.

Regardless of the timber I use, how do I get veneers big enough for a seat base? Say I needed three pieces of veneer to cover the full base. Should I joint a thick board, resaw the veneers, line them up then tape them, then apply glue and fix it with the vacuum press?

Trav

Quote:

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Originally Posted by burraboy

Pine or Birch? Luxury! Reasonably priced ply is usually Luan or some sort of hardwood in bracing ply.

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Yes, Luan is right. Birch ply is nice, but you need to sell your firstborn to afford it.

Will need to do a bit of research about the best kind of plywood to bend. Not sure what 3mm MDF is like for bending? Any thoughts?

Trav

MDF will bend, but it'll usually try to spring back once removed from the mould. The seat is flat enough that it'll probably behave, but the back might give you some grief.

I can highly recommend 3mm 2-core ply for bending, that's what we use at work for pretty much every moulding job. It's just 2 layers of timber (Lauan i think) pressed at right angles. Highly flexible and zero post-mould spring with PVA. 3-4 layers is strong enough for almost anything, 5-6 layers you can jump on without it breaking. Cost is about $15 for a 2440x1220 sheet
We get it from Timberwood Panels in Melb, not sure where to get it elsewhere but they'll probably deliver.

Quote:

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Originally Posted by Trav

Thanks Fletty and Malb.

I like the idea of making it out of solid timber veneers, but the cost gets prohibitive. Especially if I want to use walnut. I also like the idea of contrasting the timbers, but plywood has that very distinctive appearance from the side that will be very obvious.

I think I will use an edge veneer, the face veneer over the top.

Regardless of the timber I use, how do I get veneers big enough for a seat base? Say I needed three pieces of veneer to cover the full base. Should I joint a thick board, resaw the veneers, line them up then tape them, then apply glue and fix it with the vacuum press?

Trav

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If you wanted a contrast band showing on the band, you could use a secondary timber for the core and edge with whatever timber you want for the contrast then face front and back with your choice of primary timber veneer. This doesn't need to be thick unless you want it to be, where I have seen this method used (FW curved front cabinets videos etc), the outer skins have been standard 1/32nd or thereabouts commercial veneer sheets matched and joined before laminating onto the core, but if you want thicker skins you could resaw your own veneers and match them. Again it comes down to what you want, and the timber volumes required.

I think using anything other than natural timber or bendy ply for the core will give you more grief than joy.