Sunday, November 18, 2007

Laying the carbon roof for the e30



Today started out with mixing a test batch of "Poly-Epoxy" resin to determine how much working time I have before it gels. Well, turns out I have a lot of time. At least 90 minutes...it's very slow, probably due to the cooler weather. After my test was complete, I slopped on a liberal amount of PVA mold release and let dry. Now that the carbon is laid up, I'm less than confident that the PVA will help part the roof. Oh well, I guess we'll see in a day or so.
The first layer went on easily, I just poured the resin directly onto the fabric and worked it in with a small-nap roller. When I tried to lay the second layer, it got stuck to the first layer and caused some wrinkles when I tried to fix it. I probably should've had a helper for that part, but I thought I fine. The 2nd layer ended up looking pretty good, but there were some visible imperfections where the fibers had been distorted.

I waited about 4 hours to do the 3rd and final layer, mostly because I was deciding to even do a 3rd layer. After seeing that it wasn't enough fabric to do the trunk lid in one shot, I decided I might as well do it. It hopefully won't add too much weight :) The 3rd layer went on the best, and it helped hide the imperfections in the first 2 layers and the resin finish looks the best. I applied the resin with a squeegee this time, and that is definitely the way to do it. Much better resin control and easier to remove excess.

I have two heaters from Costco that are keeping the assembly warm while it cures. I was shooting for 120 degrees, but the heaters are only able to get the surface up to about 100. If this was summer, I could just park the thing outside and get 120 degrees easily. Oh well, the part isn't load-bearing, so it should be fine.

Now I get to wait and see if the carbon ever separates from the car so that I can cut the sheet metal away.
Also- I took the trunk lid off to prep it as another mold and I was really suprised at how heavy it is. Must be about 25lbs.

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