coyoteboy
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| posted on 10/8/13 at 08:25 PM |
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Carbon panel-copying
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]
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tomgregory2000
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| posted on 10/8/13 at 08:31 PM |
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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
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Carbonman
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| posted on 10/8/13 at 08:35 PM |
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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.
Carbon Copies Ltd
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coyoteboy
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| posted on 10/8/13 at 08:43 PM |
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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"?
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Carbonman
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| posted on 10/8/13 at 08:53 PM |
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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 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"?
This what I use (other products available) and never had a bad release since. The surface of the mould will be exactly the same as the part being
moulded (good or bad)
 
Description
Carbon Copies Ltd
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coyoteboy
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| posted on 10/8/13 at 09:04 PM |
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It's probably going to need a few small paint marks fillering and wet n drying, then sealing first I suspect.
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Carbonman
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| posted on 10/8/13 at 09:08 PM |
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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.
Carbon Copies Ltd
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motorcycle_mayhem
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| posted on 10/8/13 at 09:19 PM |
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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.
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coyoteboy
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| posted on 10/8/13 at 09:27 PM |
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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.
Hmm that's a good point, they are little stone chips. Just trying to minimise work but I guess it's easier to sand out little blips than
filler and sand and seal the panel first.
Thanks M_M, I'll dig through the materials and see what's compatible over at easy composites. We have some composites suppliers near here
but they're very much large marine work based, not carbon carrying I don't think.
I wasn't going to vac it, to be honest, I'm not looking for a structural superlight part - a wet layup is easy enough and a 1m bit of
carbon should do me 3 ply on the roof part, which is very flat. Edges concern me a little.
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Carbonman
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| posted on 10/8/13 at 09:41 PM |
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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.
Carbon Copies Ltd
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coyoteboy
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| posted on 10/8/13 at 09:43 PM |
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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]
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Carbonman
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| posted on 11/8/13 at 05:20 AM |
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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 Going to make making the mould more complex than I'd hoped.
[Edited on 10/8/13 by coyoteboy]
Depends what you mean by "good results" 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.
If you envelope bag it then you shouldn't need to make the mould any differently. Just make sure there are no sharp edges on the mould to
puncture the bag.
Carbon Copies Ltd
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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Volvorsport
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| posted on 11/8/13 at 11:37 AM |
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this is wet lay up .
www.dbsmotorsport.co.uk
getting dirty under a bus
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Neville Jones
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| posted on 13/8/13 at 04:04 PM |
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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.
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coyoteboy
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| posted on 14/8/13 at 12:27 PM |
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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.
Distinctly possible it wasnt left long enough. It got 3 coats. It did not realease, it didn't release after being soaked in hot water for an
hour, or with a knife trying to chisel it off the surface.
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