Board logo

Making molds
pbs - 22/10/05 at 10:31 AM

Just about finished making my bonnet and nose cone buck(pictures in my archive) and after painting will start making the molds. Having not done any fiberglassing before has anyone got any tips or advise on how to go about this?


Triton - 22/10/05 at 11:12 AM

messy...very messy


derf - 22/10/05 at 12:23 PM

read here:

fiberglast.com

look for their forum andsign up, they have lots of valuable info


Volvorsport - 22/10/05 at 12:52 PM

CFS have a write up i believe


Simon - 22/10/05 at 08:01 PM

Also, check Steve Gusterson's site

locostbuilder.co.uk.

ATB

Simon


JoelP - 22/10/05 at 08:11 PM

all good sites. However, if you stuff it up it could make a real mess of your mould. Id either practice a lot on less important parts, or get an expert to whip a mould off it for you not necessarily as expensive as it sounds.


TheGecko - 23/10/05 at 04:00 AM

I agree wholeheartedly with JoelP - have a practice on something else before possibly destroying your bucks! I did evening classes on fibreglassing and mold making at a community college - highly reccomended if you can find something similar near you. The most important point I took away from the mold making class was this - you can not put enough effort into getting the finish of the buck right. It absolutely has to be as clean and smooth as you can make it. And when you wax it before laying up the mold, don't just give it two "near enough is good enough" coats of wax. Thouroughly apply and buff out as many as four or five coats to enure complete coverage. And then put a good coat of mold release PVA on. The absolute most disheartening thing about mold making is having the mold stuck on the buck and destroying one or both getting them apart So, smooth-smooth-smooth, wax-wax-wax, PVA-PVA-PVA. Then, pay careful attention to where you put your parting lines and flanges so you don't trap any undercuts in the design that will lock the mold to the buck. Not trying to scare you off, just making it clear that it's not as easy as it looks in the books. That said, with care and attention to details, you can turn out very good parts in your own garage.

Having said all of that, some comments on the design. I like the shape of the bulge/scoop a lot and the flange at the side of the bonnet does a good job of disguising the extra width for the V8. Well done and look forward to seeing some photos here of the finished items.

Dominic


pbs - 23/10/05 at 01:53 PM

Thanks a lot for the reply guys. I have some smaller parts to make for housing my rear lights which are off a Fiat Coupe so I think I will practice on those first.

I did think about getting someone to make the molds and parts for me, can anyone recommend someone in the Glasgow area that could carry out the work?


quattromike - 25/10/05 at 09:24 PM

So once you've made the buck or plug what do you make the actual mold out of?
Is it just fiberglass?

Mike


JoelP - 25/10/05 at 10:29 PM

fibreglass but thicker, and often with wood embedded to give it more strength


Volvorsport - 26/10/05 at 12:17 PM

and usually gel coat first ! , the mold is normally 3 times thicker than the component you want to make , other people work to different guidelines - some use high heat polyester resin to make it more stable during curing .

unless i knew i was having a problem during release (oo er) - i would not use PVA - it never leaves a good surface finish.

if youve taken all that time getting back to a 2000 grade finish , and put the flange lines in the correct place , PVA isnt necesary .