I'll carry on watching it tonight while the other half watches her soaps...
I wonder if I could get some thoughts on a method of panel build that I'm planning on. It's a process that has been inspired by this;
http://www.carbonmods.co.uk/Products/Carbon-Fibre-Skinning-Starter-Kit__CMCFSK300.aspx
This skinning kit doesn't use a mould, it's a decorative coating on any surface.
So, the plan is for the following;
What type of resin are you planning to use? You need Epoxy for Carbon Fibre, but it won't dissolve the emulsion used to bind the glass fibres in chopped strand mat.
I have two different types of resin to match the materials, I can't remember off hand what I bought but I was aware the materials needed
different properties.
It's also partly why I think I need to stop at the fibreglass stage, let that cure and THEN do the carbon fibre layer. I have no idea what the
two types of resin would do with each other if they're not allowed to cure, but the laminating kit does talk about it working fine on GRP so I
assume once it's cured it's 'safe'.
YOu will never get an A1 surface, as your rubbing down will inevitably rub into some of the carbon plys, but it can be a useful method to build a one
off....
A coat of lacquer can make it look more 'finished' than if you just try to sand it to a gloss finish.
I get the impression that the additional coats of resin on top of the carbon fibre will give me more scope for rubbing down before getting back to the
fibre? I'm only doing one layer of fibre, but three layers of resin.
When you mention lacquer, are you talking about a two pack spray lacquer?
Slimy, we're not too far from you, ternhill, and have been vacuum bagging cf panels for the gta, u2u me your tel no and I'll give you a call, it may be worth you coming over to have a look
Ooh, now that's a very welcome offer! It's the GTA that has 'inspired' me to look into this sort of thing, I'd love to see what you're doing with it.
If using polyester first then epoxy, the poyester does need to be fully cured as you say, at least 14 days at a decent temperature. You would get the
best final finish if you did the fairing BEFORE the carbon laminates rather than after.
The twill weave will show every undulation in the sub-surface. Let the polyester fully cure then apply an epoxy filler or fairing compound, flat that
off then laminate with the CF.
quote:
Originally posted by plentywahalla Let the polyester fully cure then apply an epoxy filler or fairing compound, flat that off then laminate with the CF.
Watch this i filmed it at stoneleigh last year.
http://www.openfilm.com/videos/ckc-workshop-stoneleigh-2011-carbon-laminating
Excellent, thanks. It starts off with a comment about resins that I didn't realise, and which will save me money. It's saying that polyester
resins will work with carbon fibre, but at the expense of ultimate strength. As I'm using it as decoration rather than as a structural layer, I
might try the polyester rather than the epoxy.
I'll carry on watching it tonight while the other half watches her soaps...
Its not just the strength of Epoxy that's an issue, its also clarity. Epoxy laminating resins are completely transparent and allow the weave to
show at its best.
If you use a standard polyester laminating resin it will not be clear but tinted green or blue. When catalysed it will turn brown. How brown depends
on the amount of catalyst and the temperature it is allowed to reach as it cures.
I don't know how large a moulding you are planning to make but it would be a great PITA if for want of a few quid of decent resin it ended up
looking cr%p.
Although polyester is arguably easier to work with at home.... It is far more tolerant of mix ratio. But agreed - epoxy is the superior choice with carbon.
Yeah, good point. I must stop being a complete and utter skinflint!!
A couple of points need clearing up...
Yes, you can use poly resin with carbon, just don't rely on the strength. I've done so for many years for cosmetic items. Use a lot of
vinylester as well. And you CAN use epoxy with chopped strand glass mat. See previous. It's done in the boatbuilders around here all the time.
Poly resin isn't clear. Since when? Some cure water clear, some any colour from straw/lager colour to browns. Water clear is also available. Same
for epoxies.
Putting csm on then carbon then resin to flat back and polish is a non starter. That layer of csm will have more ripples and bumps than the fat lady
at the circus's backside. Any filler you put under the carbon layer will show through the carbon weave. Best to put a layer of tissue over the
base, wet out with black pigmented resin, then quickly get the carbon over that, then the resin.
I'd take the time to do a proper pattern and mould, it's worth the effort.
Cheers,
Nev.
Thanks for the comprehensive reply Neville. The carbon (or more specifically the silver weave that I bought a sample of) will be purely cosmetic, it
will be good old CSM to provide the structure. If the panel is too weak, I'll be adding CSM to the back rather than carbon to the front!
You mention the resin showing through the cloth, and it's something that the video also picked up on. That is one thing I hadn't considered.
When I first tried fibreglass many moons ago, the resin that came with the pack cured to a bright orange, if that shows through the fabric it is going
to be hideous! What the video suggested was a cheaper fabric to provide a colour base, then the 'show' fabric on top.
It's also interesting you mention tissue. EVERY fibreglass tutorial, webpage, youtube video etc all say never bother with tissue. But I could
never figure out why that was. To my untrained eye it is a finer fibreglass used for surface finishing, and as such it's structural benefits are
significantly less than CSM. What you're saying about it being used as a filler coat along with a coat of resin makes sense.
I think I'm going to try a few options. I have about a square metre's worth of everything (although I'll need to buy a small amount of
tissue), so I'm going to make a few A4 sized panels using various sequences. So first my original plan, then one with a resin filler, then a
resin plus tissue filler. That will show the effect of working with the rough side of CSM. I'll then try several layers of resin on the top of
the fabric to see what needs to be done to get it to a smooth finish (if it's at all possible).
With regards to the mould, I still have it as plan F or G, but I want to try this method first. Apart from anything this will give me practise with
fibreglass for when I do the full monty!
We are using 3mm foam core with 2 layers of 375gsm ttwill weave either side and it's incredibly strong. I do have some fibreglass cloth knocking about that would add more substance than tissue your welcome to a bit for testing if you want
quote:
And you CAN use epoxy with chopped strand glass mat. See previous. It's done in the boatbuilders around here all the time.
quote:
Originally posted by plentywahalla
quote:
And you CAN use epoxy with chopped strand glass mat. See previous. It's done in the boatbuilders around here all the time.
I didn't say you cannot use epoxy with csm. I said that it does not dissolve the emulsion. Dissolving the emulsion allows the fibres to move and the sheet follow complex shapes on contours. This does not happen with epoxy. This combination is only suitable for flat or gently curving profiles.
P.s. I am a boatbuilder!
Well Nev ... This is getting a bit personal.... To answer your question we use West 105 and SP Ampreg epoxies and Ahlstrom cloths.
Read what West say about Epoxy and CSM. http://www.westsystem.com/ss/chopped-strand-mat-epoxy/
There are two different types of CSM. The most commonly used is emulsion bound. There is also powder bound which it sounds like you are talking about.
That would wet out with epoxy but we never use that stuff because it is very difficult to handle and get a decent uniform lay-up with compared to
emulsion bound. It would not be suitable for the OT's purpose as he was looking for a smooth finish for skinning with CF.
I used to build flybridge motoryachts
Here's one I made earlier!
[img]
Sealord 44
[/img]
Cheers
Richard (MRINA)
That west link talks about release fabric, which I've managed to follow a trail to something called 'peel ply';
http://www.ecfibreglasssupplies.co.uk/p-374-peel-ply-1-mt-wide.aspx
Would that help with getting a smooth surface?
Epoxies should be overcoated within 48 hours as the amine comes to the surface and act as a very efficient release agent. This can be overcome by
using peel ply which can be left on the surface if overcoating is longer. It also allows surplus resin to be removed as carbon cloths should not be
over resinated.
It would help with your project. You usually have to purchase a whole roll. If you cannot get hold of any I can post you some.
Looks like East Coast sell it by the metre so I'll tag a bit on to my next order, thanks for the offer though.
quote:
Originally posted by plentywahalla
Well Nev ... This is getting a bit personal.... To answer your question we use West 105 and SP Ampreg epoxies and Ahlstrom cloths.
Read what West say about Epoxy and CSM. http://www.westsystem.com/ss/chopped-strand-mat-epoxy/
There are two different types of CSM. The most commonly used is emulsion bound. There is also powder bound which it sounds like you are talking about. That would wet out with epoxy but we never use that stuff because it is very difficult to handle and get a decent uniform lay-up with compared to emulsion bound. It would not be suitable for the OT's purpose as he was looking for a smooth finish for skinning with CF.
I used to build flybridge motoryachts
Here's one I made earlier!
[img]
Sealord 44 [/img]
Cheers
Richard (MRINA)
My issue with the poly resin is that it STINKS, whereas the epoxy doesn't. Enough for me to pay more for it, especially in winter.
And thanks, Ash, for that vid, for those of us who can't attend Dickens' events (but wish they could.) He really knows how to put it in the
normal person's language, as it were.
[Edited on 18/2/12 by RK]
Nev ... Enough said.
Nev ... Enough said.
quote:
Originally posted by RK
My issue with the poly resin is that it STINKS, whereas the epoxy doesn't. Enough for me to pay more for it, especially in winter.
And thanks, Ash, for that vid, for those of us who can't attend Dickens' events (but wish they could.) He really knows how to put it in the normal person's language, as it were.
[Edited on 18/2/12 by RK]
Great. Thanks for the information. Back to the drawing board.
quote:
Originally posted by RK
Great. Thanks for the information. Back to the drawing board.
If people are honest and open about things, most are totally baffled by half of what goes on around them. This car thing just puts a fine point on it, I think.
Hi Slimy38,
Would you not want to consider laying the carbon on a flat piece of class and vacuum bagging it? I plan to make my side panels in this way.
I intend to lay up the carbon and possibly two layers of bi-ax glass, (all one hit) my preferred resin material will be Vinylester as you get improved
mechanical properties compared to PE but reduced cost over Epoxy. Plus, there is scope to use the resin infusion (RI) method…. Though East coast
composites are selling a PE RI resin at the moment… any one used this?
RI will help get that ‘naked’ look you’re after. Pin holes will be the biggest problem if you don’t vac it.
Nev is right though, I always thought the smell of Styrene was bad, but actually it is less harmful than what you can’t smell or see in Epoxy. I got
Ampreg 22 hardener on my face once and had to go home from work as I came out in red sores! Was painful.
I have to agree, rubbing things down never gets a perfect finish, I made a Carbon bonnet for my friend’s Evo 4 a few years ago and it went wrong, we
‘flow’ coated it with resin and flatted it back, which sort of fixed it, but you could tell where you sanded through the layers of resin, I learnt
that that wasn’t the best way, possible, but not the easiest and possibly won’t give that superior look your after.
I will post photos in the future of my panels, working on a plug at the moment for a component for the locost…….
Rob
Unfortunately the plan I had wouldn't have worked with flat panels, there would have been a few curves in it so I couldn't use glass. Having
said that, I don't think the buck would have been that difficult to get flat.
Having looked further into it, I don't think my problem is going to be the 'upside down' method of working. Having seen a GTA body in
person (thanks Mac!) it did bring home the enormity of the task. I think making body panels just in fibreglass is going to be the first challenge,
given the physical size of a GTA or Fury type bonnet. Progressing from there to getting a carbon fibre skin to work on such a large area is going to
be virtually impossible regardless of the method I use.
I am a novice in the car field but what the OP is trying to do sounds quite like building an old style custom surf board - and I've bult a few of them ( not boats I admit ). SP systems made ( and I think still make ) an epoxy resin system for this purpose including an epoxy flow coat that with the right skills ( sadly I don't have them ) could produce a truly perfect surface finish. Needs a lot of wet and dry to achieve but I have seen the professional results. Resin is crystal clear too.
OK, I've made the base panel for this 'experiment', but I just wanted to ask the opinion of the more experienced fibreglassers. The
base panel was two layers of 300g csm, layered up with about 2.2 times it's weight in resin. It seemed to soak in very well, I didn't have
too much left over and I could see where it had dissolved the binder.
It's cured now, and the panel separated from the wood beautifully. But it seems awfully transparent? It's about the same as a frosted glass
window, if it's stood up you can't see through it but if you lie it on a newspaper you can pretty much read all the text.
Is it meant to be like that? Is this a sign of me doing the process wrong?
It will be translucent unless you used a gell coat with a pigment as a first layer.
Cheers
Fred W B
As Fred says, that's what gel coat is for.
Here's what I'd expect - colour of yellow can vary depending on resin, level of translucency depends on how thick.
Yep, that's pretty much what I've got, nice one!