Author Topic: Polyester Resin  (Read 486 times)

dunworkin

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Re: Polyester Resin
« Reply #15 on: 31 Dec 21, 08:40 pm »
Almost finished this process on my Maserati body, 4 coats of wax, 2 of pva followed by 3 layers of 225gsm chopped strand mat. I broke out the buck from the inside with no problems at all. Ive made the body in one piece and will cut openings for axles, engine access etc. Ive just ordered a big tin of filler to fair in the body before paint. Not the text book way, every one says make moulds first but just more time and money, and where to store the moulds etc. Sorry no pics, I find posting them a complete PITA, there are some on the FB pages if you look back a bit.

Seven racer

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Re: Polyester Resin
« Reply #16 on: 31 Dec 21, 11:53 pm »
Couldn't agree more, having gone down the mould making route, it's a lot more work, but I just wanted to learn how to do it. The only two advantages I can see are that there is repeatability should you need it, and the finished job is exactly the same size as the buck.

As you note, the downside is that there's a load more work, and a load of moulds to find a home for.

For the scuttle and tail I might well follow your example, the tail in particular is so much bigger.

Can I ask where you get your grp supplies?

Peter

Chris Brown

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Re: Polyester Resin
« Reply #17 on: 01 Jan 22, 01:36 pm »
I tend to buy off ebay these days, not using as much as I used to, one possibility: https://www.ebay.co.uk/itm/334050017712?hash=item4dc6eec1b0:g:QJsAAOSw22Vg0jiv.

For the boat hulls I use one layer of 300gsm overall, and a second layer where there's no form stiffness. Weight matters in that application, for your use two layers of 300gsm should be plenty. You can always incorporate D section stiffeners if you want, can be made from rolled up paper, or PVC foam packing, no strength needed, they are just forms for the glassfibre. I've got some PVC foam tube you can split to use as formers if you want some.

RhysN

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Re: Polyester Resin
« Reply #18 on: 01 Jan 22, 03:57 pm »
Personally I never use anything lighter than 225CSM, yes the old textbooks say to use surfacing tissue, I just find there are no positives at all, except maybe on models.
I get all my fibreglass supplies from East Coast Fibreglass. For the mould I would use no more than a 225 against the gelcoat and nothing more than 2 more layers of 225 or 300. If you really feel the need, an extra strip about 100 mm wide round the edge will stiffen the wotsit out of it.
For your cut outs the surface doesn't need to be great as you are cutting them anyway, I have used layers of masking tape to cover some in the past as al I was doing was stopping the laminate from dropping into the holes.
I have  never had any fisheye with proper release wax, nor PVA. I did once when I got caught out and used car polish.
I reckon the time fairing a buck/plug is no more than what you would do to fair a piece pulled off the buck and then fair the glass, and you can make the actual moulding as light as you want having seen how stiff your mould is. To me a mould is usually worth the effort. Some say "tomatoes, I say tomatos  " :)
« Last Edit: 01 Jan 22, 04:07 pm by RhysN »
We must avoid torturing our brains with false problems, it occupies but it can annoy. In jest!

Seven racer

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Re: Polyester Resin
« Reply #19 on: 01 Jan 22, 06:26 pm »
Thanks Chris and Rhys,

I will get some materials on order, actually making the mould, is the extra work in all this, and I do think that having to keep them somewhere is an additional problem that might not be an issue for many, but is going to be for me. The nose isn't an issue, but the tail sections may be, however let's learn to walk first shall we and get this sorted.

Thanks to those who have pointed me in the right direction, full build thread and videos will be along soon, but I want to get some substantial progress before properly breaking cover.

Here's what I've been up to today.

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Thanks again

Peter