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PostPosted: Wed Aug 27, 2008 9:08 pm 
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Joined: Mon Aug 11, 2008 10:22 am
Posts: 157
Location: Morayfield
Hi guys im just wondering what you need and how to make moulds, like dashes, Flares and spoilers

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PostPosted: Wed Aug 27, 2008 10:57 pm 
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Joined: Tue Mar 04, 2003 9:19 pm
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Location: Perth WA
an original piece to make the negative mould, like taking a bowl and laying FRP around one side then peeling it off, this is your negative, from here you lay more glass onto the negative to make a "copy" of the original (bowl).

also:
glass (matting)
resin
catalyst
release agent
brush
mixing tube (icecream containers are best)
etc
etc
etc


go into a fibregalss shop and say:
HELP me i knows noss-ing, help.

thats what i did in high school, they were very helpful.

oh and practice first.

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PostPosted: Wed Aug 27, 2008 11:39 pm 
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Joined: Mon Sep 26, 2005 4:34 pm
Posts: 195
Location: Melbourne Sth East
Hey, I'll give you a quick run down on what you need to do.

Basically you get the peice you want to mould (this peice is called the 'plug'), you then get some mould release wax (same as what you would use in the mould) and you wax the plug really well, like a good 5-15 coats of wax.
You then spray the plug in PVA, again give it plenty of coats.
Now you are ready to start your mould.
Mix up some gelcoat and brush or spray this onto the surface of the plug. You wait til this gelcoat has cured enough that it will still move if you touch it with your finger but wont leave a mark on your finger (can be a few hours to a day).
Next mix up your resin and brush some all over the gelcoat surface.
Lay some Chopped Strand Mat(CSM) that you have cut to size over this surface and use your brush to push the resin thru the mat (like your soaking the mat - called wetting out), use more resin where necessary. Roll out all the air bubbles and repeat with a few more layers depending on the thickness you want.

When its fully cured remove the mould from the plug (can be a PITA, some water can help), peel of the PVA and your done.

Give the mould a light sand before you use it and make sure you give it plenty of coats of wax to break it in.


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PostPosted: Thu Aug 28, 2008 12:31 am 
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Good run down Sean, might use it :) . I've been doing some research into carbon fibre stuff as well, and I found some good info on here -> http://www.fiberglassforums.com/


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PostPosted: Thu Aug 28, 2008 12:36 pm 
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Location: Morayfield
Where do you get the matting and the resin

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PostPosted: Thu Aug 28, 2008 12:58 pm 
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Location: Melbourne Sth East
godzilladat wrote:
Good run down Sean, might use it :) . I've been doing some research into carbon fibre stuff as well, and I found some good info on here -> http://www.fiberglassforums.com/


Feel free to use it, if you need any other info like resin to mat/cloth ratios or whatever just ask.

Working with carbon fibre is way better than working with fibreglass IMO. It is actually easyer to work with (despite being a bit fiddly). Just make sure you mask where you want to cut it to stop the strands pulling.

With carbon fibre you basically follow the same process, except rather than using gelcoat, you just put down a coat of resin first, then put your first layer of carbon on, wet it out, roll and so on. Subsequent layers of carbon should be at 45 or 90deg.
With carbon, always use epoxy resin rather than the cheaper polyester resin!
You can use a clear gelcoat with carbon, but IMO the raw epoxy finish is better, the clear gelcoat ends up looking cloudy and is normally just used to mask the use of poly resins, which also have a cloudy finish.
Epoxy resins also have better UV resistance, but you can clearcoat your peices (automotive clearcoat) for a great looking finish that is fully UV resistant.
Also, if you just want the CF look, you can do your first layer in carbon fibre, wait 12hours or so, then do subsequent layers in fibreglass (mixing a bit of black oxide into the resin) and as long as you only see one side of it (eg dash, door trim, gauge panel), no one will ever know! This is how 90% of automotive CF are made anyway! Its much cheaper this way.


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PostPosted: Tue Jun 13, 2017 6:23 pm 
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Joined: Mon May 08, 2017 8:54 am
Posts: 93
Making plugs and moulds is precise work and your mould work should be done in tooling gel coat any way. Lots of folk use foam as a base for plug making.I use some too but tend to use mdf or wood as I come from a cabinet making back ground.I find one layer of glass is a great base to use body filler on with plugs.When making moulds you may need to use reinforcing ribs and gussets.If your mould is too thin and not reinforced enough your finished item can set distorted.Moulds need to handle a little bit of thermal shock so to speak as curing resin generates heat according to thickness of laminating done at times.You can use a finished item as a plug and copy lots of things.A good guard ,boot or bonnet can be copied fairly easily but there is quite a bit more involved in it too.Making plugs and moulds from scratch is very time consuming.You need to be a perfectionist to be honest.
DatsEZ


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PostPosted: Tue Jun 13, 2017 9:29 pm 
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Location: Bendigo
All depends on what you are making some parts are easier than others. If the part has Natural draft it's relatively easier to make a mould. Other parts will require loose pieces and or complex jointlines to extract the part if it doesn't have Natural draft. You can also use silicone to make the mould flexible. Look up pattern making to give you an idea.

Most people use polyester fibreglass as it is cheaper than epoxy fibreglass. Most of the light Grey glass parts you see for sale are polyester. I prefer epoxy as it's alot tougher but is more expensive.

In my opinion if it small quantities you want to produce make a mould any way you can and get a boat builder or fibreglass Shop to lay it up for you as they can do small jobs out of the left overs of there big jobs alot cheaper than you can. Materials are expensive.

As long as the mould you make is reasonable you should get 10-20 parts from it before it starts degrade.
Without going into alot of detail I do the following

Mould release part
(I use mould release and apply 3-4 coats with a brush finishing with a light Polish)

2 gel coats
(I use the white epoxy gel and allow to tac off between coats. Could get away with one coat but most good shops use two)

2-3 layers of glass
(Precut cloth before you lay up the job so you don't end up wasting material and time. Use resin and a brush to apply cloth. Firstly paint gelcoat with resin then add cloth and brush in. Don't Press to hard or use a stiff brush or you can go through gel. Let it tack off and repeat resin, cloth etc.

To be honest it doesn't really matter it the gel or resin goes off before you put next layer on as it sticks but it's just not ideal. It does matter if it's too wet though as it can stick to the mould.

Get your mix ratios spot on with the products and as long as it has taper on the part and adequate mould release it should fall out.


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PostPosted: Fri Jun 16, 2017 10:55 pm 
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Joined: Sat Jul 09, 2005 6:54 pm
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Location: Blue Mountains, NSW
What sort of things have you made moulds of? Have you got any photo's of your work?

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