View Full Version : Styrofoam Rear Seat Repair

07-02-2006, 12:11 AM
"New to me" 1988 Prostar 190. Styrofoam base of rear seat has a broken, missing, melted(?) area about 4 inches wide and two feet long. The "void" is where the bottom abuts the back and on the passenger side. I'm guessing styrofoam damage is fairly common from stepping on back seat.
Anybody ever repair / patch styrofoam? First thought was spray foam insulation (like Great Stuff). Now, I'm thinking epoxy a piece of Corning rigid styrofoam insulation. Any hints would be appreciated.

07-02-2006, 10:27 AM
88inNH - If you are planning to glue/bond a new piece of Styrofoam (or SM) to the existing Styrofoam I would break off a small piece of both - old and new - and test it with your bonding resin first. The reason I suggest this is you want to make sure the resin is compatible with both pieces of foam and does not melt it. :eek: You may know this already, but just thought I would mention it so you don't accidentally make the hole bigger.

If the existing Styrofoam is the white closed cell stuff that you can scrub off into small little pieces, it would likely have very different flex/strength characteristics from the SM (blue Corning) panel you are considering using. Is it possible to replace the whole existing piece with a SM (blue Corning) piece? Another option would be to resin your patch in place and then wrap the repaired Styrofoam in a layer(s) of fiberglass mat and epoxy resin (make sure to test resin first see comment above).


Good luck with the repair.

07-02-2006, 03:36 PM
Good tip on the melting. A previous owner must have tried some sort of "incompatible" patch because there's a "melted", very uneven edge. I plan to cut that back to get a "clean" edge to butt to the patch. I saw some pink insulation at Home Depot that looked about the right thickness. Fiberglass skin over the patched area sounds like a good idea. I was hoping someone out there might have done this before and rattled off "I used 2 1/2 inch xzy styrofoam from HD and filled the void with blah...".
Bottom line, I just want to get something strong enough to step on but light enough to easily remove the seat myself. Stuffed the space with rags last night to eliminate the sag so the family could enjoy the annual 4th of July fireworks from the lake.

07-02-2006, 04:08 PM
If you know someone at a local body shop, they get all kinds of big parts in boxes that are packaged around all kinds of formed and set in place styrofoam blocks and chunks. With a good sharp knife and hand saws and make a replacement part or parts you need out of these chunks.

mark g
07-02-2006, 05:00 PM
I had the same problem i used the expanding foam in a can, if you wet the area to be bonded to first and fill void with expanding foam when it has cured you can cut the excess of and sand down to the same level, did mine two years ago and its still fine.
word of caution though tape up any vinyl close to the area that stuff is a real pain to remove and dont over fill.

07-04-2006, 08:37 AM
mark g - when you say foam in a can, to you mean something like Great Stuff available at Home Depot for insulating voids? Or, do you mean some sort of 2 part marine foam? Do you happen to recall any specifics on the product you used and where you got it?

mark g
07-04-2006, 05:56 PM
Over here in the uk we use it for filling voids, comes in a can with a short tube on the end when it is sprayed in it will expand to fill the void, a company called evo stick make it over here along with other brands it is just called expanding foam.
i guess if your home depot is the same as our diy outlets then it should be the same.
we use it a lot in the construction industry over here.