The Upholstery Forum

I'm making a motorcycle seat and the stock OEM seat pan is molded steel with indents and peaks. The original foam was destroyed by the time I saved this bike, so I'm trying to figure out how to create a flat base to build up layers of seat foam, which I'll then cover in fabric.

Here's a few pics so you can see what I'm working with:




I covered it in painter's tape because I've already laid down a layer of Great Stuff, which I had planned to trim/shave down to even out everything. But I've been told that GS will compress and not rebound, so I think I'm going to remove it and find another solution. I tried trimming small bits of roll foam to fill the lows, but I'm still left with a peak (square in the middle) that I can't offset. I can't think of anything else at this point.

How would you folks handle this? Also, is it critical that it's a flat base to start, or will the upholstery accommodate lumpy roll foam? The seat base should be about 3-4" thick when covered.

I would take a dense foam and cut out pieces the same size as your valleys. Not same in height. Glue those down to your base. Then come back and sand them down so they are flat with the base if they are too high. Then take another layer of foam and glue it down on top of that filling the valleys. Then sand down to be level with the next peak. Do this till there is no more peaks to be level with. You can them add just flat pieces of different softer foam on top of that till you get your desired thickness. Hope that makes sense.

Good advice and make sure you use enough glue surface to surface.