12-09-2012, 08:55 AM
Joined: Sep 2010
Location: Tacoma, WA
Time has been a slim comodity lately, but I have managed to get some work done in the shop.
I mounted the final test version of the exhaust shroud. So far it is holding up very well.
Then it was time to finish up the BMW X 650 chain guard mold.
I applied the gelcoat to the back side of the mold after I had removed the flanges from the previous side.
Then I layed it up with mostly fiberglass and finished with some carbon fiber scraps that I had laying around to add a bit of strength.
After the second side set up over night, I drilled the bolt holes, and trimmed the top flange.
Next, I pulled the whole mold off the mount. Here you can see the original chain guard in both parts of the mold.
I pulled off all the plastic flanges and seperated the mold halves.
Next came the job of trimming the ragged edges of the mold. The mold is pretty thick (averag 1/8th" thick), so the cutting was slow with the Dremel and the dust was going everywhere. I can't imagine not wearing a respirator and protective eye wear.
Here is the still dirty mold, but trimmed.
Scrubbed the mold in the sink to remove the PVA and clay. The epoxy "gelcoat" is very hard and the abrasive scrubby did not harm it in the least.
Here is the clean mold bolted together, ready to be waxed, PVAd and layed up to make a part.
The shape of this mold is fairly complex, and to be honest, I'm probably a little over my head with this one. Or, I suppose that it could be said that this part probably isn't even composite friendly, but you know me. Why not give it a shot and learn a thing or two. That's why I do all this stuff anyway.
I spent a good part of a couple of days trying to figure out how best to lay the fabric in the mold for the finished part. I finally decided that it would be best to lay it up with multiple pieces in order for the fabric to lay in the contours of the mold. I used pieces of aluminum foil to create templates.
Here the four individual pieces of foil are placed in the mold to ensure full fabric coverage.
Here are the four pieces layed flat.
Next I traced the foil templates onto poster board in order to create rigid templates.
Then I used these templates to cut out the carbon and glass fiber with a rotary cutter. BTW, a rotary cutter and cutting mat work much faster and is much easier than using scissors. I'll never go back.
If you have a 90 degree angle, the rotarty cutter only partially cuts that junction, so you have to finish the cut with a razor knife.
This part is made up of 6 layers. Actually the part is much thicker in most places due to overlap, but this is good because the part needs to be strong. Erik crashes a lot.
The first layer which is the facing layer is 2x2 high density 3k carbon fabric from Solar Composites. This carbon is very nice, and very high quality. When you look at it compared to the discount stuff that I have been using from US Composites, it's very easily to tell the difference. The second layer is the US Composites 2x2 twill CF. Third and fourth layers are 2x2 twill 8.5oz fiberglass, and the last two layers are more of the discount 2x2 5.7oz carbon.
Here we can see the fabric and vacumm bagging materials ready for action. You can also see the vacumm bag that I made for this project.
Finally the mold was waxed, PVAd, and layed up. After all the layers had been placed into the mold, I sealed it up in the vacumm bag and placed it under the heat lamps for a little cure help (cold temps).
I'll post more when I pull the part and trim it up.
therivermonster screwed with this post 12-09-2012 at 09:35 AM