londonsean69
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| posted on 3/4/09 at 06:22 PM |
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Bonding Carbon Fibre to Ali
OK, so a litle idea popped into my head - which is probably a bad thing.
I would quite like a bit of carbon on the car, mainly for looks, rather than any weight saving ability.
I would also like to have it where I can look lustfully at it's brilliant technologically advanced form, so am thinking of the transmission
tunnel.
So as to avoid having to get into all this mould making nonsense, complete with vacuum bagging etc. I am thinking of bonding a layer or 2 of CF onto a
(slightly thinner than normal) aluminium panel.
It wouldn't be vacuum bagged, and I'm not too bothered about a little extra epoxy, because that (should) mean extra glossy finish.
Anybody done anything similar?
I have read on t'interweb that there is a possibility of galvanic corrosion between the 2, but this can be prevented with a thin (40gm) layer of
GRP, or a few decent coats of etch primer.
Any advice gladly appreciated
Sean
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Keith Weiland
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| posted on 3/4/09 at 06:30 PM |
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Why not just buy some CF sheet and get rid of the ally completely?
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Hammerhead
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| posted on 3/4/09 at 06:35 PM |
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two words - galvanic corrosion
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Colnago_Man
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| posted on 3/4/09 at 08:24 PM |
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quote:
Originally posted by Hammerhead
two words - galvanic corrosion
Bang on! Discovered the effects of it this afternoon while trying to remove a very expensive carbon fibre seat post from an alumium bike frame!
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londonsean69
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| posted on 3/4/09 at 08:33 PM |
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quote:
Originally posted by Keith Weiland
Why not just buy some CF sheet and get rid of the ally completely?
I thought abou this, but mostly because people like carbon mods etc. want silly money for sheets.
£107 for 1 Sq. M, there will be wastage etc.
it's about £28 for 1 Sq. M of carbon fabric, obviously there is the cost of the resin and ally on top of that, but a lot less wastage.
I know they are super cool pre-preg (although the above price was for wet lay-up) and stuff, but it's a lot of dosh.
I may also do a carbon/ally dash, and if it all works well various other parts, which might not be totally flat.
quote:
Originally posted by Hammerhead
two words - galvanic corrosion
Very helpful, I will refer you to the 30 or so words I wrote regarding this in the original post
quote:
Originally posted by londonsean69
I have read on t'interweb that there is a possibility of galvanic corrosion between the 2, but this can be prevented with a thin (40gm) layer of
GRP, or a few decent coats of etch primer.
Sean
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twybrow
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| posted on 3/4/09 at 09:00 PM |
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Abraid the aluminium, making sure you take off any oxidsed material. Abraid the CF. Degrease both, then bond with your favoured glue. PU works well as
long as the Al is very well keyed. Epoxy would be good (Araldite etc).
I have a CF dash, tunnel, boot, airbox etc (I play with CF for a living), with no major problems bonding bits together as long as you prep well. As
you have already said, a thin layer of glass (or the adhesive you are using) will help to protect from galvanic corrosion. I hope this helps.
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catman
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| posted on 3/4/09 at 09:08 PM |
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its not on there web site but carbon mods now do self adhesive real cabon sheets, they are flexible to, so one single seamless sheet will do the
job
Ed
caged supersix
Carbon/GRP
210 bhp silvertop
190 lbft
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omega0684
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| posted on 3/4/09 at 10:04 PM |
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how does Galvanic corrosion occur between aliminium and CF? i thought that galvanic corrosion occurred between two metals in contact when sub merged
in electrolyte
"Galvanic corrosion is an electrochemical process in which one metal corrodes preferentially when in electrical contact with a different type of
metal and both metals are immersed in an electrolyte"
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londonsean69
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| posted on 4/4/09 at 10:53 AM |
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Ahh, sensible answers.
@twybrow
I'm actually planning on doing a wet layup direct onto the aluminium, rather than gluing a sheet of ready cured CF down.
@catman
The thing with a stick on sheet, is it won't provide any structural strength.
I know I want it mainly for looks, but if I can go down a thickness in ally then it's all good.
Certainly an option I would condiser though.
@Omega
Well, because CF is conductive maybe that has somethin to do with it.
I am still stuggling to see why or how it would happen, and even if it did, eventually all the ally would be eaten away, then I could put another
layer of CF on the inside and have a full CF panel.
Although that would probably take 10 years or something
Cheers
Sean
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twybrow
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| posted on 4/4/09 at 07:52 PM |
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If you are wet laying onto Alu, then just start with a layer of glass. The other problem I see, is the surface finish you get. It will take a lot of
sanding and laquering to get an A1 finish. Maybe you could cheat, by pressing a mould released sheet of glass (a mirror or similar) onto the wet CF,
to act as a basic mould face....
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