builders expanding foam

twhitehousescat

sort vbof a wierd question , is it compressable?

I need to build part of a motorcycle seat up , and the easiest way would be to "tank" all 4 edges (say 1in - 1.5 inches) and fill the area (9in x 9in) with "something" , lightweight

this is a fibreglass base ,when done this will be covered by hi density foam and then the seat cover


the aea is not flat enough to start glueing sheets of ??? down

pic for ref and I have drawn in the area I refer to

Head_The_Ball

I suspect that expanded foam would disintegrate and collapse the first time you sat on the seat. It really isn't suitable for upholstery or saddles.

You could buy some firm upholstery foam and cut it to shape.

twhitehousescat

Head_The_Ball wrote: »

I suspect that expanded foam would disintegrate and collapse the first time you sat on the seat. It really isn't suitable for upholstery or saddles.

You could buy some firm upholstery foam and cut it to shape.

I have hi density foam , but at that thickness it is to soft , I have a foam base from another bike that fits , just need level lifting

Norman_Castle

Would polystyrene work?

Kiran

Neither option is really suitable. If you want to test it roll your knuckle across a piece of kingspan insulation and see the imprints that it makes. Then imagine all your weight rolling across the seat. Same effect. Thin ply and foam may work

Lorian

Long time since I've ridden a bike, but shouldn't the front of the seat be a bit lower/deeper anyway?

The seat on my last bike was made on a metal frame that attached, the seat itself being mostly high density old brown foam.

FreeBear

When making a bucket seat for a race car, it is quite common to pour some PU foam in to a plastic bag and then sit the driver in it. As the foam expands and hardens, it forms a very tight fitting seat for the driver. Normally, these things are only used for one season at most...

If you talk to an upholsterer, you can get a variety of foams of differing densities ranging from rock hard to very soft - If you are limited in selection, you could use PU foam with a layer of upholstery foam over the top. It may only last a year or so, but that would give you time to find alternatives.