need a little help on a seat

[modifiedamerican]

im going to be making a custom bump seat for my kz750. im going to be making a flat seat out of metal and then a removable bump seat so that i can ride my wife around if she wants. which i hope wont be very often. lol. any way, my plans for making the bump is foam like this

comes in various thicknesses ect. and fiberglass over the foam to make the hump. from what ive read the fiberglass will eat the poly foam?. ive also read that epoxy resin wont eat the foam.
my idea is so to make the bump part of the foam, then fiberglass over it for more strength. not sure on what to do.

 

[RoadRash]

Once you have the foam shaped the way you want it, cover it with plastic wrap or foil. It will act as a barrier so the foam is left intact.

 

[modifiedamerican]

the fiber glass will stick to the foil? i thought the foil would act like a releasing agent?

 

[KVoom]

It should stick to it unless you put release agent on the Aluminium.

 

[RoadRash]

Oops! Yeah, don't forget the releasing agent!

 

[modifiedamerican]

That's the thing. I dont want it to relase. I want to to lay the fiberglass over the foam and keep it that way. I don't want the fiberglass to relase from the foam. So if I don't put a releasing agent on the foil the fiberglass will stick? Because from everything that I've read online the foil it's self will act as the releasing agent

 

[teazer]

Why do you want to keep the foam? It offers no strength to the finished part. Its job is done.

 

[BriMed1983]

You only need the foam to get your basic shape. Once the glass hardens, the foam has done its job and can be tossed.

 

[modifiedamerican]

Thats what I was thinking but the idea I have I have nothing to go off of cuz it hasn't been done before from what I can see. The hump that I'm making is going to be wrapped in leather so that why I wanted the foam intact so that it fills the fiberglass and doesn't leave the fiberglass hollow I'f that makes sense.

 

[Rgrpfdr1]

The fiberglass should be strong enough without the foam, and if not the foam won't add any real support anyway.

 

[modifiedamerican]

I only want thE Foam left so that it will mame it easier to wrap in leather. I need all side of the bump wrapped so that there are no open end.

 

[rockcitycafe]

there's going to be an open end where your leather ends anyway, drill holes along the perimeter of the base of the seat, wrap and stretch the leather and rivet it to the bottom holes from the backside

 

[BriMed1983]

I admire your your drive to try something new. If you really want to completely glass a foam bump then I suggest using a fiberglass compatible foam. My shop uses it all the time (I have no idea what this stuff is called. I can find out for you on Monday) it has the same density as florist foam, but wont break down when resin is applied directly on it. Here's a pic of a chunk that I'm using to make my seat plug out of

 

[johngofast]

Have you considered glassing the plug all the way around and encasing the foam? I personally would be reluctant to leave the foam and only fiberglass one side of it. Vibrations and flex of the fiberglass (when you're on the seat) will cause the foam to break up and start crapping all over. Trust me you don't want to try and get ground up foam off of your chain or anything else sticky.

 

[modifiedamerican]

Ya man see if u can find out the name of the foam. I'd appreciate it. The hump is only going to be for keeping my butt from sliding. It's not going to be sat on at all.

 

[CafeRacerSeats]

I use a two part pour foam for my production seat pans. I'll cut the base out of wood with a jigsaw to shape the base. I'll then box in the hump area so I can pour in the foam. I find that the pour foam, while a bit more expensive, cuts and sands better, and does not give you those pesky glue seams. It is far easier to shape and smooth, and it is made to glass over.

Once I'm happy with the shape and surface, I'll lay down a single layer of cloth to hold it together for making a mold. I will apply filler and sand to a finished grade, then primer and paint. Because I'm making molds, I'll apply mold release and PVA.

You are only making one part, so you could cover the foam with foil before applying a few layers of glass to make it thick and sturdy. The foam will pop out leaving you a nice pan.

A prospective customer just asked me to make a pan just like this one. One that allows the hump to be removed when the wife wants to ride.

 

[Rusnak_322]

I used the pink foam. Covered it in foil. Covered the foil in clear packing tape and waxed the packing tape with release wax. it was still a PITA to get the foam out.

There is also a resin that is made for building surf boards that doesn't dissolve foam. I got a gal of it but didn't try it.