clear film over the carbon fiber

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#1

Hi all,

I have a quick question:
I have seen on you tube a company that applies a clear film over the CF laminated part.

So basically they are doing a wet lay up. They sand the part, apply the CF and than instead of going with CF over it they apply a thin film over the part and than on top of that they apply the resin (epoxy or vinyl ester…no sure). Do you guys know why?

here is the link:
[ame=“http://www.youtube.com/watch?v=Rg7f9EaXpoA&list=LLKzCOkonb94JMcJbzpYmWGg”]CARBON FIBER BY: ROBSON DESIGN - YouTube[/ame]

Mercer

#2

I believe they don´t leave the clear film on top of the part, it is rather to help stick the dry carbon fiber to the tacky surface. Especially for the edge of the part. After curing, they unwrapped the foil and continue with applying resin and the usual following steps.

#3

Its no different than the youtube videos where plastic wrap is covered over a cf wrapped item . The fabric is prevented from lifting while it’s adhesive layer of resin dries while maintaining a smoother surface over just the weave by itself .

#4

Well it seems that when they apply the resin, the film is still there, unless the resin has dried and looks like a plastic wrap.

Do you have the link to that Youtube video?

#5

Yep, I thought so too, but if you watch the next “process” they show this guy applying resin on a part that looks like it has a plastic transparent cover on it…

#6

I think it’s just the resin that has dried. There is no point leaving the plastic under the resin because the resin wouldn’t stick.

#7

I do this quite often on repairs for the top cosmetic layer. The film (I use transparency film for overhead projectors) comes off after cure and leaves a smooth glossy surface ready to be sanded and clear-coated without having to topcoat it first. It only works for concave surfaces. Flat or convex will cause bridging.

#8

Hold on, so you basically lay the film over the wet resin while is curing and take it of after is cured?? I don’t quite get what you do.

#9

Yes, that’s exactly what I do. I first do a wet layup and over saturate the fibers, taking care to get as much air out as possible with the brush. Then I lay a piece of plastic sheet over it and compact with shrink tape. Using “too much” resin gives a better finish. Remember, this is only for the cosmetic top layer.

#10

Looks like the film they use is some kind of soluble tape? After they apply the resin over, it must dissovle or cross link somehow. Probably a quicker way to build up depth and also keep a nice level surface to minimise final fairing. Would like to know more about that tape either way, and how they eliminate any air voids beneath it.

#11

Stretch tape over the laminate to consolidate it. From the video, it looks like they are just applying the tape over dry laminate for purposes of the video. It doesn’t look like they followed the normal path from mold to finished part (dry sand and then laminate?). Normally, the tape would be applied over wet laminate and then peeled off after cure. The product is then hot coated with resin to fill weave and ridges. The part is then sanded to fair and topcoated with a clear paint.

I’ve been involved with enough video production to know that the guys who put the video together don’t always understand the process they are filming. They just use clips as they see fit to create what they think is an appealing presentation.

#12

Any particular brand of stretch tape that you all would recommend?

In that video, it looks like they overlap the edges of the tape when they wrap it…will the “stepped edges” from overlapping the tape show up in the surface of the carbon fiber?

#13

Hey Roger,

Just wondering what you mean by “hot coated”? Is that like a flow coat after the tape has been removed?

#14

Yes, hot coat, flow coat, same thing. I guess it’s left over from building surfboards way back when. I have know idea why we called it a hot coat. It was just the common term for it around here (at least with the knuckleheads I hung out with).

#15

Ahh… cheers, gotcha. I would have clicked the “thanks” button except I seem to be unthankful at the moment (must have run out!)

Did they used to apply heat to help it flow out easier? Anyway, good to know the different terminology.

#16

Although heat will reduce the viscosity, it also reduces gel time. With polyester resin that was typically used at the time, heat was our enemy. When I was a kid without much money, it was a choice between buying lunch or material. I didn’t want to miss too many meals so losing a batch of resin wasn’t something I wanted to happen very often. We’d just squeegee on a coat, let it gel, squeegee on a second coat (with wax this time) and let it cure. Then sand, sand, sand.