i've been gathering info about how to manufacture GRP and i get the global picture, but i cant find out a clear process on how to do it.
i've searched here too, but found little info..
can anyone tell me what it is I need, and what each part is for?
i understand GRP is made out of Polyester resin mixed with chopped strand mats of fibre glass, and, then a gel coat to make it nice and shiny and a
release agent (PVA) to prevent it from sticking to the mould...
from the "book" and Lionel Baxter's book i gather the procedure is to make a mould out of polystyrene, cardboard, other, then make the
initial GRP buck and then the final piece, but it is the procedure in between these i lack knowledge of...
anyone care to fill in the blanks for me?
Cheers!
[Edited on 5/12/06 by robertst]
The one you make first is the buck. This is the foam, wood etc bit.
You need to make sure this is sealed proplerly. Gel coat and resin will melt polystyrene.
Some folk use plaster or filler and then varnish or paint. You have to use 2K paint or sililar varnish.
I have found that things that use a hardener to activate are usually resistant to GRP.
Experiment first to make sure.
Once you have your shiney buck you can start to polish. I use a carnuba wax polish. Rub on, leave to dry then buff off. I generally do about six coats
on a brand new part.
Once that is done you can add the pva release. You only need a thin coat. So add with a brush or a sponge . You can also spray it on or use an
atomiser.
Once this is dry add you can start to make your mould.
Brush on the gel coat. Best to brush in one direction only. aim for a 16th on an inch thick, hard to get good straight off.
Leave this to set.
When the gel is ready you will be able to press fairly hard on in and only leave a finger print. If there is any on your finger it isnt ready.
Easist way to do the next bit is first brush some resin on the gel this will help stick the matt down and get you started. Then stipple resin into the
mat and get it saturated. Try and minimise the bubbles you see in it. You can use a paddle roller to help in this bit. Add as many layers as you think
it needs.
Leave to set.
When you are removing the part you can pour hot water in to melt the pva. There are lots of different ways to pull things apart so the best way would
depend on the mould you are making.
You now have a mould.
To make the final part do the same thing as above, now using the mould.
[Edited on 5/12/06 by emsfactory]
I've been thinking of doing my own glassfibre too but will probably end up buying it, I think it will work out cheaper for a better result but I
like doing things the hard way so I dont know yet.
I got a book on it called Automotive Glassfibre by Dennis Foy, very down to earth & easy to understand but first published in 1987 so mabye a bit
out of date now & I've yet to put any of it into practice.
The bloke at our local body supplies place recommended a local canoeing place for good quality materials.
On the website of www.DDRmotorsport.com was a nice build diary of their car. From scratch to a full body, also a bit chassis building, but
mainly the body. Since the new website they've taken it off-line. But I still have the pictures. The pictures name explains the steps. Just run
them in order and you'll see what's needed.
I've sent you a u2u with the location of the zip file containing the pictures. (7MB!)Anyone else interested, just u2u me and I'll leave you
the link.
So with the explanation of emsfactory and the prictures you should be able to make your own moulds.
I also have a 250MB movie of the creation of a carbon fibre model airplane wing. But it's a bit difficult to get it to you.
Thanks a lot for the zip file! pretty impressive, a complete mclaren F1 in GRP!! i was hoping on just a measly lotus 7 nosecone! anyway, it was
useful, but i still dont really know what i'm supposed to be looking for to start experimenting with GRP, is there a book on this? it might be
from the 80s, but if it explains how to make GRP....
IIRC, didnt mark allanson make his own GRP panels? or was it someone else?
Fortunately i have found that there is no need for the tedious translation into spanish as the materials are called the same here (i.e: Gel coat is
called gel coat here and CSM is also referred to as CSM here..)
However, GRP is named here as PRFV.... sounds like the acronym of a ministry or public office!
You mention polyester resin, but there is cheaper and more widely used styrene resin.
You just have to remember that styrene can only be used on polyester foam and vise versa.
Using them is the same.
my 2p worth; the materials are not cheapest, unless you have a supplier nearby, you would pay for postage too.
Work out how much the part would cost you to make then see how that compares to ready made one.
I had this idea of making my own cycle wings, made the mould, bought the stuff then managed to pick up 2 pairs off ebay for about same price
oh
well, saved me breathing in the nasty fumes.;O
ofcourse if you are making a unique part, then there is no choice 
well.. considering the alternative which is to order the ready-made pieces and have them shipped, which will cost a fortune, plus it will take months
to get here... i suppose it might end up being cheaper to make them... if i get the materials here that is...
plus i might end up using the technique i learn to make other GRP pieces for other purposes... such as... err... a GRP christmas tree?
Do a search in this section under my UserID - been round this loop....
Quite a lot on my site if you have the time to look.....
quote:
Originally posted by stevebubs
Do a search in this section under my UserID - been round this loop....