Is it necessary to use a fibreglass mold?

[arunmenon]

Hi. We are a first year team and we are running a bit short on budget. So we will be using fiberglass to make the bodywork. So, I was thinking why i should make a mold first and then make the part inside it with the releasing being troublesome. Instead, can i use the mold as the part itself after applying a gel coat layer to smoothen the outer surface?

Please post your suggestions...

[,4lex S.]

Using your mould as final bodywork will do one of two things.
1) Give it a really poor surface finish, or
2) Result in a very heavy final structure

Now, it is up to you what is acceptable weight wise, but you can take a quick look at the effect of weight with Optimum G's lap simulator (Optimum Lap). It is probably less significant than getting the car done.

If I was in your situation, I would look at aircraft fabric for the side panels, and focus on building a good male plug, female mould, and final part for the nose cone.

Aircraft fabric is this stuff I think. We have a bunch of old stuff laying around, so I am not sure. You basically epoxy it to your frame rails and heat shrink it to a tight fit. It can look good.

[Dunk Mckay]

If you do use fibreglass make sure it's woven, not just matte.

[AxelRipper]

If you want to be even less costly (and simpler) go with aluminum. Its surprisingly light in thin sheet form relative to even carbon, and can be done without molds.

[jlangholzj]

Originally posted by ,4lex S.:
Using your mould as final bodywork will do one of two things.
1) Give it a really poor surface finish, or
2) Result in a very heavy final structure

Now, it is up to you what is acceptable weight wise, but you can take a quick look at the effect of weight with Optimum G's lap simulator (Optimum Lap). It is probably less significant than getting the car done.

If I was in your situation, I would look at aircraft fabric for the side panels, and focus on building a good male plug, female mould, and final part for the nose cone.

Aircraft fabric is this stuff I think. We have a bunch of old stuff laying around, so I am not sure. You basically epoxy it to your frame rails and heat shrink it to a tight fit. It can look good.

Go with this stuff instead:

Fabric

We've put that on a few cubs and a stearman, It doesn't get any better. Also if you look at the poly-fiber page on spruce they've got a practice kit and additional instructions/materials.

this was our '12 car with the fabric on and painted before final assy

[Charles Kaneb]

Covering the nose with a nylon or polyester "jacket" with a zipper anchored in a few places to the steel always fails at our design reviews for being "too janky for a team with Texas A&M's resources" - but it's light and easy to do. You'll have to attach some rollcage foam in a couple places to meet minimum-radius requirements.

[arunmenon]

Originally posted by ,4lex S.:
Using your mould as final bodywork will do one of two things.
1) Give it a really poor surface finish, or
2) Result in a very heavy final structure

Now, it is up to you what is acceptable weight wise, but you can take a quick look at the effect of weight with Optimum G's lap simulator (Optimum Lap). It is probably less significant than getting the car done.

If I was in your situation, I would look at aircraft fabric for the side panels, and focus on building a good male plug, female mould, and final part for the nose cone.

Aircraft fabric is this stuff I think. We have a bunch of old stuff laying around, so I am not sure. You basically epoxy it to your frame rails and heat shrink it to a tight fit. It can look good.

I was thinking i can make a male mould and use that as the final part. Then the exterior would be smooth right?

And the final structure can be made such that there is enough strength to keep it intact throughout the run and with more support at the points where fasteners will be present. So i hope it wont be too heavy.

What is your opinion?

[arunmenon]

Originally posted by AxelRipper:
If you want to be even less costly (and simpler) go with aluminum. Its surprisingly light in thin sheet form relative to even carbon, and can be done without molds.

The design we came up with after a series of analysis is a fairly complicated one. The curves will be difficult to make with aluminium. And it wont look as good as fibreglass right?

[arunmenon]

Originally posted by jlangholzj:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by ,4lex S.:
Using your mould as final bodywork will do one of two things.
1) Give it a really poor surface finish, or
2) Result in a very heavy final structure

Now, it is up to you what is acceptable weight wise, but you can take a quick look at the effect of weight with Optimum G's lap simulator (Optimum Lap). It is probably less significant than getting the car done.

If I was in your situation, I would look at aircraft fabric for the side panels, and focus on building a good male plug, female mould, and final part for the nose cone.

Aircraft fabric is this stuff I think. We have a bunch of old stuff laying around, so I am not sure. You basically epoxy it to your frame rails and heat shrink it to a tight fit. It can look good.

Go with this stuff instead:

Fabric

We've put that on a few cubs and a stearman, It doesn't get any better. Also if you look at the poly-fiber page on spruce they've got a practice kit and additional instructions/materials.

this was our '12 car with the fabric on and painted before final assy

</div></BLOCKQUOTE>

I dont think i will be able to make our design with aircraft fibre. Its a bit complex

[jlangholzj]

So bodywork as in a nose, sidepod or what? You're going to be able to make just about any shape with aircraft fabric.