Custom Racer with Aluminium Frame and Sportster Engine

Sav0r said:
I forget the name of the material, but for various items (wings, diffusers, end plates, etc) we used a machinable material that was baked after machining to form the mold. No coolant was needed, no dust was created, and the molds are perfect and permanent. No foam required. Clean up was more friendly than an Aluminum job.

I'd be very interested in knowing what material that is....
 
I am a big fan of carving foam to shape and then skinning the result with a composite. Standard fiberglass and epoxy as you have done here is my nearly universal choice. I've done a fair bit, and learned a couple of things. Dissolving the foam with a solvent is a dreadful mess, so I cut the part in two and mechanically remove the foam by scraping/grinding/sanding if the part has to be hollow like a tank. Wrapping the form is plastic and waxing sounds like a good idea that I haven't tried. The components are very easy to glass back together. The other thing I am careful to do is make a REALLY good form. Time spent there really pays off in less time at the finish. I am also super fussy with the laminates, do a lot of planning and take a lot of care to make the finish layups as close to perfect as I can. Often I will block sand the part out between layers to keep the shape as accurate as possible. On bike parts, which are always quite small. I use very light weight cloth - sometimes called finishing cloth for all the laminates. It is very easy to make conform to compound curves and tight radii. One trick I use for difficult parts is to paint a light, thin coat of epoxy on to the part and let it cure up until very tacky and squeegee down the cloth. The sticky epoxy glues the cloth down quite dry and does not soak in. Once it is perfectly in place and bonded down tight I saturate the cloth with epoxy and squeegee out the excess. This makes for a pretty easy and relaxed laminating process which results in better parts for me. I realize this isn't particularly helpful now as you are clearly past this point, but maybe it will help others inspired by your build. I think a lot of people consider making their own tanks and body work from fiberglass. Project is looking good! Would like to see a pic from a bit farther away!
 
SONIC. said:
I'd be very interested in knowing what material that is....

He may be referring to Last-A-Foam.

http://shop.fiberglasssupply.com/Core_Materials-Urethane_Foam.html
 
I wish I could remember the product, it's been three or four years. We milled it in my buddies Haas. It did require some sanding and fine tuning after milling, but I think that's understood. We had some issues with one batch warping when we baked it, which was annoying because the material is expensive, but we eventually got it figured out.
 
Are you taking about renshape? https://www.freemansupply.com/products/machinable-media/renshape-modeling-and-styling-boards
 
jpmobius said:
One trick I use for difficult parts is to paint a light, thin coat of epoxy on to the part and let it cure up until very tacky and squeegee down the cloth. The sticky epoxy glues the cloth down quite dry and does not soak in. Once it is perfectly in place and bonded down tight I saturate the cloth with epoxy and squeegee out the excess. This makes for a pretty easy and relaxed laminating process which results in better parts for me.

Nice! One of the dissuasions of glassing complex shapes for me is the inevitable difficulties around the bottom curves where gravity pulls the cloth off form. I usually make a proper mess of things. Your idea will help greatly, thanks!
 
Not to hijack this thread but I’ve been searching on how to repair existing fiberglass parts with cracks or worn mounting holes for body work.

Again sorry to get off topic or hijack


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You do not want to take a close look at the tank I just TIG welded. Talk about ugly. Thank goodness it's under a pretty carbon fiber cover to hide its shame.
 
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