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Discussion Starter · #1 ·
I'm trying to make a fiberglass cafe seat for my Kawasaki.

I welded (some people wouldn't call it that, but hey) up a mock-up positive and plan on making a plaster mold from it as soon as I have it smoothed out and looking the way I want it. Then, I want to lay up the fiberglass inside the mold - what do I need to do/not do as far as prep, tools, procedure, etc.?

So far I've been making it up as I go - cut and welded an old Suzuki dirtbike tank to form the "boattail" then fabbed up a pan out of sheetmetal...

Thanks,
Jay
 

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I would not use plaster I have found blue foam sheeting that is used in construction.I glue peices togther and use a hot wire knife which we home built to carve the part out and then lay fiberglass mat with a 2 part epoxy mixed in it to form it.Then cover with putty coat and block sand.I have been meaning to do a tech post on this for sometime but time has not been on my side.I have one pic here of a mini chopper tank that i built.It did not hold liquid it was more for the look.Not the best pic I could possibly post some others tonight if wanted.
Shoe
 

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TRIUMPH TERROR said:
I would not use plaster I have found blue foam sheeting that is used in construction.I glue peices togther and use a hot wire knife which we home built to carve the part out and then lay fiberglass mat with a 2 part epoxy mixed in it to form it.Then cover with putty coat and block sand.I have been meaning to do a tech post on this for sometime but time has not been on my side.I have one pic here of a mini chopper tank that i built.It did not hold liquid it was more for the look.Not the best pic I could possibly post some others tonight if wanted.
Shoe
I'm thinking about making a WL primary cover from fiberglass (covering a dry primary - just to keep my toes out of harm's way). First, I need to find someone willing to lend me a perfect original or good repop. I plan to just lay epoxy and cloth over the original (with some type of mold release) to make the mold. My only fiberglass experience was pretty sad - I made a racing seat from a mold years ago. My parents' house smelled wretched for a good week or so and the seat had plenty of pock marks and holes.

I could also use some solid advice on the topic. I think the fiberglass should withstand heat where it attaches to the engine case if I use some type of spacer or insulating gasket. Anyone got any insight? Carbon Fiber would be really cool but beyond my very limited skills. Anyone wanna temporarily lend a 45 primary cover in exchange for a fiberglass copy?
 

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TRIUMPH TERROR said:
I would not use plaster I have found blue foam sheeting that is used in construction.I glue peices togther and use a hot wire knife which we home built to carve the part out and then lay fiberglass mat with a 2 part epoxy mixed in it to form it.Then cover with putty coat and block sand.I have been meaning to do a tech post on this for sometime but time has not been on my side.I have one pic here of a mini chopper tank that i built.It did not hold liquid it was more for the look.Not the best pic I could possibly post some others tonight if wanted.
Shoe
What he said. Just make sure it's an epoxy resin, not the standard stuff. Regular fiberglass resin will disolve the foam.
 

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the plaster mold would be fine, done this many times myself. just spray some decent paint down on it to seal the porosity of the plaster. use plenty of mold release (looks lke crisco). as far as temperature resistance, that boils down to the resin more so than the fibers you use. carbon is no more difficult than glass to form the parts, to form them well with the weave looking all tricked out is though. west marine is a good source of knowledge on composites and supplies but they are expensive.

brandon
 

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Discussion Starter · #6 ·
stolenmojo said:
the plaster mold would be fine, done this many times myself. just spray some decent paint down on it to seal the porosity of the plaster. use plenty of mold release (looks lke crisco). as far as temperature resistance, that boils down to the resin more so than the fibers you use. carbon is no more difficult than glass to form the parts, to form them well with the weave looking all tricked out is though. west marine is a good source of knowledge on composites and supplies but they are expensive.

brandon
That's pretty much what I was thinking. I had thought of going the foam route, but for some reason I was able to visualize the shape better in hacked up pieces of metal. As I said before, I already have the metal seat/tail all fabbed up and am smoothing it out - I really like the shape I've got going, so I'd hate to start over in foam. I'd run the metal pan except that I think it's going to weigh too much by the time I'm done slathering Bondo all over it to cover up my poor metal working skills.

Thanks everyone for the tips...I'll let you know what happens. More tips and info are always welcome.

Later,
Jay
 

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Discussion Starter · #8 ·
TRIUMPH TERROR said:
Heres a few more pics of the process of the mini chopper tank.I ahve also made some nose for the front of Super Comp dragsters and such.

Shoe
That's good lookin' stuff!

I bought some fiberglass and some resin from one of the big auto parts stores a while back - should I use that or look for something different?

There's a boat place down the road a bit - never been there, but they may sell fiberglass supplies - would that be a better bet?

Thanks,
Jay
 

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Instead of plaster, why not use body filler? You can form it more easily while it's still partially cured, whereas plaster needs to fully dry before you can play with it. You can use a cheese grater tool to shape your form, sand it smooth, shoot some primer and even some paint on it so you can get a smooth surface from which to pull your mold. The rest has already been covered pretty well.

I started my automotive careeer building Corvettes from pieces of Corvettes. I hate fiberglass..............

Also, don't plan on building a fuel tank out of fiberglass. They never last ( I know "my friend down the street had one in the 70's" but where is it now? In the garbage, I'd be willing to bet. There are metal fuel tanks still out there from 100 years ago......). The gas out there today is even worse than it used to be. It's much stronger as far as it's solvent capabilities go (because of all the additives in it now). It eats tank liners like Kreem like it never did before. I hate that. I like Kreem. Now I can no longer use it. It's especially tough on fiberglass. I dropped a chunk of cured fiberglass in a coffee can of gas to see what would happen to it. Remember those experiments in science class with the hard boiled egg in a jar of vinegar? About like that, only toxic.....
 

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Dont use fiberglass with foam the heat from the resin will melt the foam when it is curing.I will post up the name barnd of stuff and some other products when I can get time to look them up.By far the foam is the best and easiest for shape stuff quickly.I have tried all the others and I am all about easy:D rough cut out your shape and use a electric carving knife to get it closer and then use a da with 80 grit and a long board 80 grit on a block for final shaping before applying the cloth with epoxy. Then you come back and use filler and finish sand for buildable priemer. Maybe in the next week or two I will try to whip up something and document it as I have been wanting to make a custom head lamp hsg.

Shoe
 

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For the projects I have done I have always just made a wood skeleton of the part and either filled in the voids with expandable foam or covered it in fiberglass and used body filler to get the shape smooth then shoot the piece with a parting agent (Part-All, etc.), then brush paint on gelcoat and lay fiberglass onto it. After it is done curing and you pull that female mold off the original buck the inside is just as nice as you got the buck. Spray parting agent in to the female mold, gelcoat it, then lay fiberglass in (making sure it is smooth and touching all the gelcoat). When you pull the final peice out if all went well no body work should be needed and it will already have gelcoat on it. Used this method to do the bodywork for an enclosed electric motorcycle project and it came out great.

The wood skeleton is nice because you can do do the design in a program like autocad or whatever, make cross sections and have them printed out full size to glue on the plywood and then you can make the piece way more accurate than just carving on some plaster.

the dude
 

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Discussion Starter · #12 ·
the dude said:
For the projects I have done I have always just made a wood skeleton of the part and either filled in the voids with expandable foam or covered it in fiberglass and used body filler to get the shape smooth then shoot the piece with a parting agent (Part-All, etc.), then brush paint on gelcoat and lay fiberglass onto it. After it is done curing and you pull that female mold off the original buck the inside is just as nice as you got the buck. Spray parting agent in to the female mold, gelcoat it, then lay fiberglass in (making sure it is smooth and touching all the gelcoat). When you pull the final peice out if all went well no body work should be needed and it will already have gelcoat on it. Used this method to do the bodywork for an enclosed electric motorcycle project and it came out great.

The wood skeleton is nice because you can do do the design in a program like autocad or whatever, make cross sections and have them printed out full size to glue on the plywood and then you can make the piece way more accurate than just carving on some plaster.

the dude
That's kind of the idea I had.

Here are a couple of pics of the metal positive I have worked up so far...

 

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