mixing up some epoxy resin with methylated spirit and spraying it onto the mould

What proportion of epoxy resin to methylated spirit use to the mixture?

Thanks Matt for your help, now I can go shopping

Follow this link to Paul's Resin Infusion Resin Usage Calculation.

Matt Statham
Easy Composites / Carbon Mods - Technical Sales

Thank you very much for your reply. It is very helpful.

One more question:

At one topic on the forum I saw the equation to how many I  needed epoxy Infusion Resin to comply with an object, but unfortunately I can not find it now. Can I ask to enter it in this thread.

Thank you very much.

Hi Sawral,

On the movie you use GC50 Compatible Epoxy Polyester Gelcoat. What to use to activate it to stuck CF to the surface.

This is a complicated one and something that's haunted us a bit since we made that video. We shot the video over last Christmas with a 'prototype' version of the GC50. That version of GC50 did become tacky when a small amount of acetone was sprayed onto it and so we used this method to tack down the carbon to the gelcoat. Since then, we had to make some changes to the GC50 in order for it to stay receptive to resin for longer and when we made these changes, this bonus effect that the gelcoat became activated by acetone doesn't really exist anymore. The GC50 that we finalised and put on sale does not behave in this way.

Instead, to tack to the mould surface, whether there is gelcoat there or not, you will need to use an epoxy compatibel spray tack like the Zyvax product (which infortunately is not currently available) or by mixing up some epoxy resin with methylated spirit and spraying it onto the mould or gelcoat (as we've described many times before on this forum).

Then on the bottom of the bonnet to use another spray stuck CF perfectly to the surface. What is spreyyou useing?

This would be the Zyvax Stay-Z product, see above.

I hope this helps and sorry for any confusion we cuased with this. I'll add some captions to the video to make this clearer.

--Matt


Matt Statham
Easy Composites / Carbon Mods - Technical Sales

Acetone is used to activate the gelcoat and make it sticky. I don't think you need much.

Between layers spray adhesive is used. Now they offer an epoxy based spray adhesive that fuses with the dominant resin system. In the video however, i think it is regular spray adhesive which can also be okay when used very sparingly.

cheers

HI,

On the movie you use GC50 Compatible Epoxy Polyester Gelcoat. What to use to  activate it to stuck CF to the surface.

Then on the bottom of the bonnet to use another spray  stuck CF perfectly to the surface. What is spreyyou useing?


Thank you very much and best regards

thanks to all of you for these great questions and answers. I have no degrees in these fields. I am considered an old hick around here and when I want or need something i just go build it. from new tools to new toys and have another project in mind. all of your talks here have helped me to grasp concepts and processes and will save me a whole lot of time and money on mistakes. thanks again to you all, Nate

Matt-

Thanks so much for your reply and for sharing your expertise. 

This is indeed an ambitious project to say the least, but we'll see if I'm able to put some traction to it once the project gets to that stage (which is probably a couple years away if I'm lucky!). 

Conceptually it seems like I'm trying to "have my cake and eat it too" by trying to mould a large, complex part that has the CF exposed for cosmetic reasons.  Exposed CF plus relatively simple part (car hood, trunk lid, etc) = doable if shape and size/contours permit.  Large, complex, painted part = doable because the underlying fiber structure with all the cosmetically "ugly" relief cuts and join lines would be painted or gelcoated over. 

If I understand you correctly, the multi-part mould is not really a "show stopper" for cosmetically perfect exposed CF parts... the mould parts are sealed as you describe below (the UV-resistant clear gelcoat sounds like a good choice since the tackiness would aid in positioning the first layer of fabric), then after de-moulding the gelcoat flash lines are flatted/polished, then the final part is painted with lacquer / clear-coat.  Voila, no evidence of the parting line.

Sounds like the biggest obstacle to pulling off what I'm envisioning is the complexity of the part.  Even with ProFinish, laying up the outermost layer of CF in a large mould like a single piece nose or rear clip while keeping the relief cuts cosmetically acceptable sounds like it may be a bridge too far.  Also, since it appears only the 2x2 twill is available in ProFinish, that limits my options cosmetically.  I presume that the ProFinish process is proprietary and/or not able to be applied to dry CF by an end-user?  There are some pretty neat "patterned" CF fabrics out there now that would make a great "rally stripe" on an exposed CF panel!

Thanks again for the assistance,

-Jon

Hi Jon,

It's good to have you on board. Few projects this size get past the planning stage but when they have, like Andy's rear clip for his Noble, they can go really well and be very rewarding projects. Answers to your questions as follows:

a)  How do you make the parting lines vacuum tight?  Sealant tape on the flange?  Mould a channel for sealant tape? 

If you're vacuum bagging against the mould's flange (i.e. not envelope bagging the whole thing) then one technique for sealing the flanges is to use a small bead of silicone sealant near the edge of the flange where the moulds will come together. Silicone sealant will make an airtight seal but won't prevent you from separating the two moulds when it's time to de-mould the part. It will peel off the moulds easily ready to use the next time.

The other alternative is to spray a gelcoat surface onto the inside of your moulds, once they're fixed together. The gelcoat itself will for an airtight seal over the seam. If you do this, use a special gelcoat like our GC50 Epoxy Compatible Polyester Gelcoat. 

b)  How do you maintain the cosmetic integrity of the part?  Fill the parting line gap on the mould side with gelcoat and polish it flawless (a solution for production of only a very few number of parts... i.e. ONE or maybe two, since it would obviously crack away as soon as you separated the mould and would have to be redone every time)?  Fill it with filleting wax or sealant tape or ???? and doing the corrective work on the part itself to sand down the extra resin?

Almost always, if you are making a part as large as a multi-mould car panel then generally you would be painting it afterwards either with coloured paint or with a clear 2k lacquer/clear coat, meaning that the flash lines where the moulds have come together are not a problem. You would flat them before painting and then just paint over them whereby they would disappear. Alternatively, if you've gelcoated your part then you should just be able to flat the flash line away and polish the seam to be left with no visible seam.

a) Can two sheets of CF be joined together with a simple sewing operation in a presentable way without the need for industrial equipment? For example, laying two 1.5m sheets on top of each other and running the edge through a sewing machine to get an ~3m wide cloth. How viable is this from a cosmetic perspective? If making a CF-Soric-CF sandwich, one would obviously want to back any seams with reinforcement or perhaps do a full second layer behind the cosmetically presentable one.

No, you can't stitch carbon fibre together. Where possible you avoid having a join-line. If you need to have a join-line (i.e. widths over 1.5m or when the contours of the mould require relief cuts) then we would suggest using ProFinish Carbon Fibre so that you have have really neat cut-lines. ProFinish carbon fibre has a binder on the back to hold it together well meaning it's much less likely to distort and it won't fray at all on cut lines. Using this material it's possible to arrange a 'V' shape stright down the middle of a panel (like you would see on a Pagani Zonda for example).

b)  If sewing CF to meet size requirements is possible, could this concept be extended to sewing a full pre-formed 3D pattern?  I.e., draping paper over the plug, making cut lines and folds in order to then transfer that to a piece of CF fabric to be cut out and pre-sewn into a 3D shape loosely conforming to the mould shape?  What is your experience with the challenges and resulting finished product quality associated with this approach?

As above; you can't (successfully) stitch carbon fibre together.

I hope this helps and look forward to working with you.

--Matt

Matt Statham
Easy Composites / Carbon Mods - Technical Sales