Making a fiberglass seat pan. HELP!

[new_idea]

I am about to grind off that god awful bar towards the back of the frame that sits a mile high. A lovely new flat bar will be welded on in its place. I am going to attempt to make my seat pan out of fiberglass.

1. I have no idea how to attach it to the frame! My creativity has left me high and dry. Any ideas? I want to easily take it off without any tools. I would like to get a round about idea of how to do that before I start just in case something needs to be there when I glass.

2. How do you attach upholstery to fiberglass? What is this magic?!

 

[BBS360]

What model bike?

I've been looking into maybe eventually doing a fiberglass seat pan. Lots of work that I don't have much experience with though.

1. The stock mounts on the 80-82 specials are pretty straightforward. Should be able to reuse the front mounts. Simplify the rear attachment to a rod through that cross bar with a cotter pin.

2. Figured I'd either upholster the seat leather and padding onto a small wood backing and screw that to the fiberglass OR use split pins from the underside of the upholstery into holes in the fiberglass.

It'd be a bit more work but it might work out well to make a plug and mold to layup the fiberglass in, rather than simply building the seat out of fiberglass, though I've seen guys get great results

 

[Wolfe_11B]

For the upholstery attaching to the fiberglass-
Normally you make the seat, and then make a separate seat pan that the upholstery gets applied to. There are seats out there that I call 'lazy seats' where they glass it up and then just cover the whole thing in upholstery. Looks cheap if you ask me but to each there own. What did you have in mind?
The go to attachment method is SS upholstery staples straight into the fiberglass pan. Just need to do the math on what length will penetrate the fabric and pan without going into the foam(and your butt).

Something to keep in mind- if you are removing that high bar on the frame, and putting a flat brace in its place, the tire will hit the bar. Don't do this unless you plan on raising the ass end up with longer shocks to compensate. Then you need to figure out how the raise the front end to match the raised rear, or else you'll have a crap tastic handling 400.

 

[new_idea]

Thanks for chiming in!
I suppose telling you guys which bike I have would help! It is an 81 Special II. I was actually thinking out keeping that front mount for the seat so that is probably what will happen there.
Wolfe_11B, thanks for the tip. I recently changed out my shocks to some monsters. I didn't realize how huge they were until I got them on the bike. It looks so stupid. I plan to replace them again in time...but I will ride the dumb ass ones I have for now. I want a seat that follows the frame. She has wide hips and I want to go with those lines. I hate it when you see a straight seat on them and there are gaps as it passes by the wider parts of the frame...no offense...it just isn't for me. I haven't cut the back end off so it will be a bit tricky to get the look I want. I want a flat seat but I don't want it to be brat style thin. Pan, foam, and upholstery all together will be about 3- 3.5 inches thick. I love a cafe but I just do not have the time to put into making that kind of seat look good. I am a perfectionist and getting that thing the way I would want it would be far too much work.

Something like this is what I am going for. Easy upholstery job
http://www.motorcycleseatsdirect.co...fe-racer-motorcycle-seat-with-metal-pan-4180/

 

[Wolfe_11B]

Well the easiest way to attach a seat like that is to hard fit studs when you lay the glass pan. Position them to go through the horizontal braces you weld in, then just drill a few holes, add wing nuts, and call it a day. These are the studs I am referring to, they work great for glass work, Just add them after a few layers of glass then add a few more over them- http://www.mcmaster.com/#standard-threaded-rods/=18xaba9abiinauqfyf

I think I have a few 1/4-20 of those left over from my build If you'd like to save some money instead of buying a bunch more than you need. They are long studs, you just cut off the excess that sticks out.