Carbon Fiber Overlay - Possible tip

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#1

I say this could be a possible tip, because it might not work for you. One thing I really like to have is a clean, straight line when making seams on CF overlay. If you put the cloth in layers, it can sometimes lead to “bumps” that need to be filled with more resin and sanded. If you have ever seen a prepreg seam, it is perfectly clean with no fraying. I have had good success using the following for cutting clean lines in non-prepreg cloth. One note is that this only seem to work well using electric cutters like EZ cutters. Before cutting the cloth, I spray the underside with a coat of 77 and allow it to tack up. Then using the cutters I can cut a perfect line, no fray. The adhesive holds the fabric together. The cutters quickly, but gently cut the fabric without pulling at it. Then this piece goes directly on the overlay part.

What are other people doing to get good overlay seams?

#2

Masking tape and shears!! Reason I don’t use #77 don’t want it to interfear with the resin curing.

#3

What are these ez cutters your speak of?

I like that idea of getting a good seam out of two pieces. Sounds like a winner to me seeing as I was going to have to figure that out with carbon that doesnt get painted.

#4

This is the cutter -

I just did a quick search and here is some info - http://www.esmfg.com/electric_cordless_cutter.htm

The problem I have with the tape method, and maybe there is an opportunity for me to learn something here, is that when you are making a seam in the middle of a layup, the tape cannot be removed from the fabric without it fraying and if left on, it gets gummy in the resin or hard to cut out. Never had any problems with 77 and resin, but this is probably dependent on the resin you are using. I actually have such good luck with 77 and my resin that I almost never have to vacuum bag an overlay and they always hold their position. I am finishing up a whole bunch of overlays now and can post some pics of the issue I speak.

Here is a pic of the clean cut, no fraying. Maybe you can do this with tape, but mine always frays. This gives me clean results.

#5

Also can get them from fiberglast http://www.fibreglast.com/showproducts-category-Fabric%20Aids-109.html

#6

Thats sweet! Makes me alot happier than thinking I need to just tap an oversize section off and then trim it all up when its dried.

I may have to try that process when I cut out my fabric in an exact shape of my template. I could save inches like this with every part!