Fibreglass and Vacuum forming

[DylanF]

Hi all

I've been making shapes with hand lay up polyester resin from a positive mould. I've read through a few threads on here and DrCrash's site (cheers) and have thought about doing this with a vacuum forming machine seeing as I use one already to degass silicone.

A couple of questions:

What sort of plastic should I use for the vacuuming that will bind best to resin and fibreglass?

I finish the parts with a sand and resin coating, would this still be possible with the plastic?

Thanks for responses in advance

[05fmtc]

Im not sure, but I think you're referring to a process known as vacuum bagging.

If you have a vacuum pump for degassing, you're 1/2 way there... That the big cost in vacuum bagging.

Next, you'd need the materials:
- Vacuum bag material and tape
- Your piece, resin, and fabric
- Peel Ply Fabric
- Breather Fabric

To run through the whole process is a bit lengthy, so google what you can and if you have any questions let me know!

[svenakela]

When vacuum bagging epoxi is the thing, Polyester will boil pretty early in the evacutaion process (and it will make a useless layup and in worst case a broken pump).

[05fmtc]

also if you could make a female mold, finished correctly that'll save you tons of time not having to sand!

[05fmtc]

and several places you could buy bagging material are

fiberglast.com
compositeenvisions.com
avtcomposites.com
uscomposites.com
airtechonline.com

also check out your local boat store... Many carry bagging kits made by West System.

[High Seas]

DylanF welcome aboard! And you too 05fmtc!
Check out joewoodworker website for some basic ideas to incorporate your degassing pump (system) into other projects. Yes, he is focused on doing veneer work - but the principles are the same and a good free pdf build "log" too. Not sure which way you were pointing fiberglasing -- or vacuum forming - so try these ideas:

For FIBERGLASS VACUUM BAG setups:
Most "slick plastics will not stick to your resin.
For your vacuum bag - if the project is dual; sided - use the HEAVY DUTY - OVERSIZE zipLock bags. If on a flat surface, you can pick up a clear shower curtain! Cheap as chips and effective. TO hold down - brown packing tape - but make sure you check is compatible before buying a case!
Yes - poly will "cook" early - BUT you can work with it that way in a vacuum system - just need to have it promoted correctly. Helped build a 54 ft catamaran 's hulls - using the process -- with polyester!
But svenakela is right - you should build and use a resin trap to save your gear!
For peel ply - you can substitute NYLON ( like parachute cloth) - way cheaper and just as effective.
In the Uk can't say who is best buy - but here in the US - you can't beat uscomposites -- (and I had to pay FL sales tax too).

FOR THERMOFORMING:
I'll post some pics of my recently completed vacuum setup - and I'm building a thermoforming deck for it - then a separate heating platform too. One thing at a time.
Check tk560 web site for a few good thermoforming heating element build logs too.
Any more questions - just ask!
Jim

[High Seas]

A couple of questions:

What sort of plastic should I use for the vacuuming that will bind best to resin and fibreglass?

I finish the parts with a sand and resin coating, would this still be possible with the plastic?

Let me try again maybe a better (more helpful answer to what I understand mightbe your questions)
1 Plastic does not stick very well to resin and fiberglass. That is why it gets used as a release agent.
2. If the finish is gritty-enough - you might have better luck getting it to stick - by melting into the rough finish. but still may seperate.

Is the purpose of the vacuumed plastic to give a deep luster? Or protection -- or? Or is the mold resin and fiberglass and you are concerned the vacuumed plastic will stick to it?
Hope thats not too many questions to get a better bead on yours?
Jim

[svenakela]

DylanF welcome aboard! And you too 05fmtc!
Check out joewoodworker website for some basic ideas to incorporate your degassing pump (system) into other projects. Yes, he is focused on doing veneer work - but the principles are the same and a good free pdf build "log" too. Not sure which way you were pointing fiberglasing -- or vacuum forming - so try these ideas:

For FIBERGLASS VACUUM BAG setups:
Most "slick plastics will not stick to your resin.
For your vacuum bag - if the project is dual; sided - use the HEAVY DUTY - OVERSIZE zipLock bags. If on a flat surface, you can pick up a clear shower curtain! Cheap as chips and effective. TO hold down - brown packing tape - but make sure you check is compatible before buying a case!
Yes - poly will "cook" early - BUT you can work with it that way in a vacuum system - just need to have it promoted correctly. Helped build a 54 ft catamaran 's hulls - using the process -- with polyester!
But svenakela is right - you should build and use a resin trap to save your gear!
For peel ply - you can substitute NYLON ( like parachute cloth) - way cheaper and just as effective.
In the Uk can't say who is best buy - but here in the US - you can't beat uscomposites -- (and I had to pay FL sales tax too).

FOR THERMOFORMING:
I'll post some pics of my recently completed vacuum setup - and I'm building a thermoforming deck for it - then a separate heating platform too. One thing at a time.
Check tk560 web site for a few good thermoforming heating element build logs too.
Any more questions - just ask!
Jim

Isn't fantastic what high price can make one to try? I use nylon fabric too instead of breather fabric that's way more expensive.
Here we have uge rolls with plastic film (double folded 120 cm, that's 47" width) for really good prices at the wood market. It's used as a damp barrier in outer walls in houses, and it's thick and vacuum proof. A little bit too thick to be perfect as it doesn't wrap as easy as one can hope, but still really good.
For small pieces I use butchers plastic film, not as wide as the damp barrier but if you can get away with 70 cm width (27.5") it's like the real vacuum film. At 1/10 of the price.