[project] Nothing To Do With 205's, But Behold!

[Mandic 0]

Have asked Uncle Google about it and found this:

 

Shrinkage is a function of exotherm temperature, filler content, filler type, percentage catalyst, and volume cast. If you are using a true casting resin, it should contain a lower percentage of styrene monomer than laminating resins. Keep your catalyst to 1% max. and if you can, try to conduct the heat away after gelation and during the exotherm.

 

Polyester resins are much cheaper, but you can fudge the catalyst and also fill to the max with limited shrinkage, although this resin will shrink no matter what. Without filler, up to 7%, with filler, maybe 2 or 3%.

 

From: http://www.sculpture.net/community/showthread.php?t=1887

 

Hope it helps...

 

 

Cheers

 

Ziga

[M3Evo 0]

Phew, you had me worried there dude!

 

The people on that site attribute high rates of shrinkage to the build up of heat in their castings and the heat having nowhere to escape to.

 

I believe that the large, thin and fairly uniform thicknesses of laminate components are able to disipate heat quickly so the temperature doesn't get all that high during the cure.

 

Having said that, the boot lid mould I'm about to make is about 1.4m long and has clearly defined edges which I can measure to so we'll see how much it's shrunk by when I release it.

 

I'm thinking that I can probably use an electric blanket to bring about an elevated temp post-cure of the epoxy components in epoxy which might help prevent them going funny in later life.

 

I'm absolutely fascinated by all this laminating lark so even the bits which go wrong aren't a total loss as long as I learn something from them

[Mandic 0]

Yeah, when I first started fiddling about with epoxi and polyester stuff, I realised that it costed about twice as much as if I would take it to the professional at first place, part to the fact I didn't know what components and tools to use (which release agents, etc.). But it went better next time and so on. So yes, it might get a bit pricy but in the end You have learned something and done things by Yourself, and that's what counts.

 

Like I said, I have never used polyester for large® sheets, only for small stuff, so don't know how it performs, but just for info about how much heat there is, I left some polyester in those plastic pic-nic cups, about 1cm high, and there was so much heat, that the whole bottom end of the cup melted, so maybe try using less catalyst to keep shrinkage down.

 

 

Cheers

 

Ziga

[M3Evo 0]

Guess the materials themselves are quite cheap, but the costs do start to mount up quickly! Certainly wouldn't be a way to make money let's put it that way, but as it's just a hobby it makes it all a bit more bearable

 

I guess the composition of the stuff we're both using must be quite different Ziga, I tried exactly what you mention there yesterday and the cup didn't melt or anything, didn't even feel all that hot.

 

Anyway, done the first three layers of the boot mould so just another few to do and we'll be able to see how much it's shrunk by

 

 

Awesome! Got another two things crossed off the list yesterday!

 

The inlet manifold is done:

 

 

 

And so is the exhaust manifold with the bypass plumbing being properly welded together now!

 

Made sure everything was properly bolted together before starting the welding so everything still lines up when you take it apart now....phew!

 

[Bonzai 2]

started my CF/composite course today, any questions you would like me to pose to my instructor whilst i have the chance?

[M3Evo 0]

Ooh yeah, could you ask them about shrinkage in wet-layup bits which haven't been post cured.

 

Thinking about it, a black panel on a hot day is going to get bloomin' hot so they'll all need doing I'd guess but it'd be interesting to know.

[Bonzai 2]

i will ask for you, lucky the course lecturer is a bit fo a car nut, he was on about scimitars today and how shrinkage caused crazing on the wings.....

 

its a bit difficult for me though because most of the stuff im doing is honeycomb centre with 3 layers of CF either side and we do more repair work rather than manufacturing. Having said that from what ive seen of your work and what i think ive picked up on the course you would definately benefit from vacuum bagging it should totally prevent any bubbles which will delaminate in time. Have you done a tap test on your first pieces?

[M3Evo 0]

Is a tap test going over the surface with a coin and tapping to find any dead sounding bits?

 

If it is then I'll give it a go tomorrow!

 

The one CF bit I've made was just a single skin and is useless as a component.

 

Be interested to know whether just two layers of CF would be stiff enough to make a car body panel as long as it had strategically placed stiffening ribs on the back of course.

[Bonzai 2]

yep use a 2pence coin and tap the piece in a uniform manner and if you hear a dull sound then its not bonded/delaminated

[M3Evo 0]

Ooh, think I'm doing alright with the penny testing! Got a couple of little dead spots right at the edges of the flanges, but they can be trimmed off

 

Here's a question for ya though; I found a washer-roller at my parent's house and have just given it a go on the boot lid mould I'm making. It seems to do an absolutely incredible job of getting air out of the laminate, much better than a paddle-roller. The question is though, could you use a washer-roller on CF twill without buggering it all up?

 

 

Have decided to scrap the charge cooler I was making and start afresh with a pair of Setrab oil coolers, 310mm long which form the cooler cores.

 

The plan is to use the lost foam process to make a pair of carbon fibre shells and seal them to the cores. Hopefully this will be lighter than the previous attempt and (most importantly!) not leak water into the engine!

 

So here's the final resting place of the cores, unfortunately didn't have any polystyrene so starting on the CF shells will have to wait, but did manage to get the brackets and splice plates done.

 

 

 

 

 

Also got some springs through in the post so the actuators are done now:

 

 

 

Gonna rig up a solenoid to the ECU in miamistu's car and nick some vacuum from his engine to see how well one of them works. It's great fun testing things!

[Bonzai 2]

Ooh, think I'm doing alright with the penny testing! Got a couple of little dead spots right at the edges of the flanges, but they can be trimmed off

 

Here's a question for ya though; I found a washer-roller at my parent's house and have just given it a go on the boot lid mould I'm making. It seems to do an absolutely incredible job of getting air out of the laminate, much better than a paddle-roller. The question is though, could you use a washer-roller on CF twill without buggering it all up?

 

 

honestly im not sure. its not something we'd ever do because we vacuum bag everything. The only way to find out is to try. My tutor gave me the name of a company that supplies all of the goodstuff http://www.glasplies.co.uk/

 

im now qualified to do pre-preg and wet layup CF composite repairs up to 250^F but that doesn't mean i know what im doing

[M3Evo 0]

Will have to give glasplies a call, although the place I've been getting stuff from is priced about the same.

 

Dear God Ampreg20 is expensive! It's bout £110 for 3.75kg of the stuff!

 

Think I'm gonna try SP106 as it's less than half that price! It also mentions CF reinforcements specifically in the data sheet which I can't seem to find in any of the West literature!

[Gavin Waddell 18]

hey ive been reading your posts on composites and well there is a few things i could add.

 

when it comes to exotherm:

 

Polyester will exotherm if you laminate something that is 5mm thick, what happens is that in the centre of the laminate will start to cure and heat up as it does this will in turn heat up the surrounding area whick will then start to cure as well but heat up because of the extra heat, it can be a snowball affect. What you can do is but less harder in when i laminate bumpers i put about 1% its not like expoxy which has to be a precise mix. Polyester aslo cures quicker when hot or so if its 25 degrees out sideit will go off sharpish.

 

For laminateng a sunroof it should be fine because you need 2 layers of cf and then maybe 2x150 and 3x400 which will give you some thing which is 1.9mm thick as a 100g is 1/10th of a mill and so on. You can lay the cf wait while it cures and the 150 wait do the 400, and ahnd consolidate evert layer to get rid of bubbles in the cf weave. when you lay up put clear mold gel coat in the mold then aresin and lay the cf on the resin as it will soak through an push bubbles out.

 

As for epoxy we use ampreg22 all day long and with slow hardnder it will have a pot life of 1 h 1h half, always mix small batches if it is a tricky part as it can exotherm in the pot, if it is a slop it on job then you can mix bigger batches.

 

For vacum bagging you will need vacum bag, bleeder, breather, tacky tape and a pump. every thing we buy is in 100m rolls

 

Every one thicks coposites is easy, ive been doing it for 5 years now working in a boat yard, we built the winnig americas cup boats for Alinghi. these are 25m racing yatchs full CF. ive done wet laminate, pre preg, infusion. Its not that easy there are lots of tricks of the trade that ive picked up from the guys in the work shop.

 

I wouldnt bother going to sp waste of time go to some one who specialises in composites as they would probably sell you vacum bag etc. Or look on the net as there will be sime one who will sell smaller quantaties of resin etc for example www.swiss-compoites.ch

 

i would love to be able to help more but i live in switzerland so so its a bit far to commute.

 

best of luck and polyester stinks and gets you high so wear a carbon filter based mask.

 

Gavin

[Sandy 189]

SP106 is their equivalent of West 105, it's a general purpose resin, much the same thing.

[M3Evo 0]

I've only been laying up a couple of layers at a time so I guess heat buildup isn't gonna be too much if a problem

 

Think I'm gonna give SP106 a go as it does at least say it's suitable for CF specifically. Can't really afford the 20, and I guess that 22 is just as expensive is it?

 

 

OH the mess!

 

Have been cracking on with the new charge cooler and various bits of air plumbing, spurred on by the idea of using the lost foam process to make carbon fibre bits.

 

Bought a massive sheet of polystyrene from Wickes and have been cutting it up (in the house ) all day.

 

Started off having a check of under-bonnet clearance for the cores. There's not much, but there's enough!:

 

 

 

Then got on with making some foam bits to support the shell of the cooler:

 

 

 

 

 

And then got on with making foam bits for the air plumbing which will hopefully improve flow to the little turbo.....hopefully!

 

 

 

 

Will try to make the other side of the cooler assembly tomorrow and order up all the lovely lovely carbon fibre and resin I'll need.

 

Gotta order up enough to make the sunroof and boot lid too as I should be finishing off the boot lid mould tomorrow too

[M3Evo 0]

Oh yeah, forgot to add that the other side of the charge cooler foam bit was finished on Sunday.

 

For some reason this one seems to clear the bonnet alot better than the old one did but still has a larger x-sectional area where it thins down.

 

Guess the core must be in enough of a different position for it to work or something, not complaining either way!

 

 

 

 

Will have to have a last check for clearance with the throttles in place before I start making the CF bit, but looks like it should work....tentatively!

[Dom9 2]

I really love this thread!

 

SO many ideas!

 

Brilliant!

 

Keep up the good work my man!

 

D

[M3Evo 0]

Hey Dom, cheers mate how you doing?!

 

 

Ooh, it's not come out bad that!

 

So we now have both boot lid and sunroof moulds done and ready to fill with CF.

 

Speaking to the guys at East Coast Fibreglass, they said a good way to keep the cost down a little bit for no discernable difference in stiffness is to lay up a CF outer, a diolen middle and a CF inner.

 

Totally makes sense too as the diolen is just on the neutral axis of the sheet so it's only ever loaded in shear which is a nice easy force to deal with if you're a bit of material

 

Gonna order all the kit I need now

 

 

 

So that just leaves FIVE moulds to make

[Dom9 2]

I am good thanks mate... Just busy with work (moving jobs again in a couple of weeks) and going to buy another flat towards the end of the year... Probably something glassy, on the Thames and hopefully with underground parking! Although... I miss having a garage but I am living vicariously through this thread to get my homebrew fix!

 

I said I wasn't going to modify the 911 a few weeks back... But I suddenly have lots of carbon bits (seats, strut braces etc), track wheels & tyres, suspension, brakes and bits of engine & exhaust cluttering up the spare room, much to Louise's amusement... Not!

 

I think that will become my 'project' car and I will look at something else, fruity for the commute

 

Keep up the good work and hopefully I will be able tos ee thsi beasty one day! There seem to be a hell of a lot of turbo BMWs in PPC these days, so you need something special LOL!

[M3Evo 0]

He he, it's almost impossible to resist the modifying bug isn't it! Not sure I'd wanna mod an expensive Porka though

 

Hooray! Have made a start on wrapping one of the foam cores with CF.

 

I can't believe how conformable the fabric is! I wrapped the alloy stub and first bit of the foam using some 100mm wide plain weave carbon tape and as long as you work progressively over it's surface you can easily get it to adopt a compound curvature.

 

Then used a larger piece of twill weave cloth to wrap the larger part. Had imagined that I'd have to do the very tight return under the foam in more than one piece, but once you've got part of the CF sitting in the resin, all you have to do it kind of tap it into position with your fingers and the weave all adjusts itself to suit!

 

Anyway, here's the first two layers. Think I'll go for four layers in total and add some vertial struts to help stop it puffing up under boost.

 

 

 

[tom_m 0]

wow, it looks so much nicer in CF than it did as polystyrene! I thought it was going to look like some hideous freak creation, but it looks goooooooooooooood

 

are there any issues over the end where its all creased over itself, is that unavoidable and is it going to weaken the stracture any?

[M3Evo 0]

Cheers dude, I'm pretty please with it myself! Going to add another layer or two of carbon in epoxy and then finish it off with a single skin of carbon in this super clear surfboard resin I've got so that the weave is the same all over.

 

The bit where it's creased over itself is gonna get trimmed off on the finished article, I just folded it over like that to keep the fabric above in contact with the polystyrene. Bit of a waste of material but the layers in those pics were all made from fabric which had been glued onto the roll at the suppliers by mistake so it was a bit buggered up as it was.

 

Now's it's pretty well cured, I can't believe just how strong two layers of carbon in epoxy is! It's just so rigid!

 

Have started waxing up the moulds I've made for the boot and sunroof today in the hope of some nice weather next week. Really looking forward to making the boot lid for some reason, can't wait to see how the fabric drapes over the compound curve the boot has I think!

[M3Evo 0]

Well how about that!

 

It's not too bad as a first attempt at a full scale carbon panel.

 

Definate thumbs up for the 106 epoxy resin from SP Systems, I tried West System epoxy for the charge cooler part there and not only does it not mix as cleanly, but it went milky white and cloudy whereas the SP has stayed really clear. Did both on rainy days which does have a large effect on epoxy resins so SP wins as a more usable system for the DIYer!

 

My housemates reckon the plain weave border I put on looks weird, but I actually quite like it myself. Whadda people think? should I do the same for the bonnet?

 

Just gotta laminate up some reinforcements on the back including the hinge and lock mounting points and it's done....once it's been trimmed.

 

It's just SO light too, and pretty rigid despite the very large unsupported areas it has. Will try and get it properly finished this weekend and make a start on the sunroof

 

Here's the overall thing. The torn looking bits are just release agent which I've not cleaned off yet, whereas the almost dented looking bits are just my poor laminating technique causing distortions in the weave:

 

 

 

The slightly bubbly badge rebate:

 

 

 

And the 50mm wide border the whole panel has. Interested in people's opinions in this as I quite like it, think it adds a little detail to the panel.

 

 

 

[hman205 1]

Thoughts on the edges not keen on them myself was there any particular reason you did them like this Strength? etc...

 

your topic has been very useful im considering making some 306 maxi style arches for my track 306 in the future and this has been a very useful insight into how I should go about it,

[M3Evo 0]

I had thought I might be able to do a neat border in the 50mm tape, then cut the main cloth so that the edges overlapped the tape but wouldn't be seen.

 

At some point between laying up the tape and doing the main plies I decided against that but actually it might still serve a purpose in giving a clear defined line to cut up to.

 

Think for making one off components, using the polystyrene method is cheap and easy, but it turns out that making moulds isn't all that difficult to do.

 

Gonna use the lost foam method to make a gauge pod for the dashboard. Hopefully it'll be fairly easy to get the pod to hug the contours (such as they are in the 80's beemer )