I think it's definitely worth the cost of a proper release chem. Tom, the wax I used was meguires mirrorglaze 16 and it didn't like me at all so I guess that must be significantly different to the "8"?
I plan, due to a succession of rusty ones on my tin top, to reproduce at least one panel (sunroof) in carbon, or a carbon/fibreglass mix. It's
distinctly possible I'll paint over them to match (if I can ever find a colour match, which is proving tough as it is).
What do folk recommend for ensuring the fibreglass mould I make of the panel doesn't stick to the panel itself (just in case I need it again!).
The last time I tried this I polished two bonnet vents thoroughly with a paste wax, coated them in 3 layers of fibreglass and never managed to pull
them back out. Took me hours of hacking and eventually the OEM paint came off the vents before the polyester resin came off the paint!
[Edited on 10/8/13 by coyoteboy]
You have to use mould release wax (not polish) I use the one from meguiars, called mirror glaze #8 or you can use a pva release agent but the wax gives a better finish
A chemical release agent such as Easy-Lease, forget old school Wax and PVA. Or if you want to do it Locost style cover the original panel in cling film, Polyester or Epoxy Resin won't stick to that. You will have to do more "fettling" to the mould surface with that method.
Cheers Carbonman - the idea of cling film scares me - I can't even wrap my bloody sandwiches in that without getting wrapped up and creases
everywhere I think it's definitely worth the cost of a proper release chem.
Tom, the wax I used was meguires mirrorglaze 16 and it didn't like me at all so I guess that must be significantly different to the
"8"?
quote:
Originally posted by coyoteboy
Cheers Carbonman - the idea of cling film scares me - I can't even wrap my bloody sandwiches in that without getting wrapped up and creases everywhere
Tom, the wax I used was meguires mirrorglaze 16 and it didn't like me at all so I guess that must be significantly different to the "8"?
It's probably going to need a few small paint marks fillering and wet n drying, then sealing first I suspect.
quote:
Originally posted by coyoteboy
It's probably going to need a few small paint marks fillering and wet n drying, then sealing first I suspect.
Make the mould with a vinylester gelcoat, not a polyester gelcoat if you're intending to use it to manufacture a carbon part. Carbon/epoxy
systems and polyester systems will release from a vinylester mould quite easily (given a suitable release agent/wax), but a carbon/epoxy system will
be troublesome in a polyester gelcoated mould. Chemical release agents are great, you can wax over the top of them too. Release of anything can be
eased with water, compressed air and luck.
My advice, if you're making a quick copy of a something, stick to a full GRP system. Polyester is very easy and very cheap to work with.
I've had a rather high failure rate on attempting vacuum bagging heavy curved panels (my Jedi engine cover), but a flatish panel (i.e a Clan
Crusader roof) went quite well. I'm not a trained composites worker, merely a chemist having a go. Materials for carbon bagging are NOT locost.
quote:
Originally posted by Carbonman
quote:
Originally posted by coyoteboy
It's probably going to need a few small paint marks fillering and wet n drying, then sealing first I suspect.
If they are just small stone chips and the like I wouldn't bother. If they are "low spots" on the original then they will become "high spots" on the mould, easily flatted and polished out.
As M-M says if you are planning on wet-lay then sick with the same resin system. Poly doesn't like sticking to poly but Epoxy will stick to Poly like the proverbial to a blanket. With wet-lay using CF you will always have problems on corners etc the cloth just wont conform to them without vac. If you are planning on painting the part or using a gelcoat then it isn't a problem as the voids will fill with resin. However if you want a carbon finish then expect to be disappointed, wet-lay will leave air pockets and voids all over the surface of the part.
I've had good results with wet layup before without voids, but it looks like I'll have to sneek the vacuum pump and some vac bag materials
out work when they're not looking Going to make making the mould more complex than I'd hoped.
[Edited on 10/8/13 by coyoteboy]
quote:
Originally posted by coyoteboy
I've had good results with wet layup before without voids, but it looks like I'll have to sneek the vacuum pump and some vac bag materials out work when they're not looking
[Edited on 10/8/13 by coyoteboy]
With wet-lay the very action of brushing on the resin introduces air into the resin, which will
appear in the finished part. Also CF cloth doesn't follow contours when wetted out like CSM does, so it wants to lift from the mould surface on
corners/recesses etc. If you are "borrowing"
the vac pump from work then make sure you get some perforated release film and breather cloth
as well. this is wet lay up .
Wax WILL release from anything. Bare mdf to concrete blocks to glass.
The experts here should know that the trick isto put the wax on, a layer at a time, allowing the wax to dry off, then polish it, then allow at least
an hour for the polished surface to properly harden up(this is where most go wrong), then repeat at least six times if it is the first release.
Meguirs release wax in the ideal, if not, Simoniz in the gold tin is near enough to the same thing.
Been doing it for the last 50+ years the same way, and only ever fails when I rush it and don't let each coat harden up.
Cheers,
Nev.
quote:
Been doing it for the last 50+ years the same way, and only ever fails when I rush it and don't let each coat harden up.