Is there any danger in sanding lexan?I know you must wear a mask with fiberglass,but I can't find anything on lexan.I want to round off my fin edges.

Hi CJP- I used to work for GE Plastics, the TM owner of Lexan. Sanding polycarbonates is not a major health hazard, but be warned that the plastic will melt and either clog the sand paper, or flow as slag as a result of the sanding energy. Fiberglass is different- it won't melt, but...the reason for the mask is to prevent the little glass fibers from nesting in your lungs and causing silicosis or worse. Sanding Polycarb smells like what you'd think it would- very "plasticky". Keep it from combusting and you'll be fine.
If you want to put a clean edge on the Lexan, use a rasp or high-grit paper that will clean itself easily. Go slow, and be prepared to put a polish back on the edge if you want it to restore to crystal clear- after sanding it'll be milky white. Once you're satisfied with the curve, hit it with 200-400-1000 grit paper (wet sand at the finer grits) and the edge will virtually disappear!
I'd like to see a pic of what you're working on!

Thanks for the reply.Here some pictures.Nose cone,centering rings and body tube from BMS.I had to go with their reg BT70 tube as the nose cone will not fit heavy duty.I'm going to slot the tube after I attach the fins to the fin can.Finished the paint yesterday when the temps hit near 70.The hardest part was masking the top of the nose cone after I painted the whole nose cone white.

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All of the NCR by Estes photo models used lexan for fins - it was much easier to get a great finish that way, especially since the models were never intended to fly.

We just used a sharp knife or razor blade to scrape the square edges to eliminate the sharpness and left it at that.

Impact strength of lexan for fins didn't seem to be as good as plywood - we had a lot of fins snap on landing when we tried it for flying models.

Just be sure to use a big chute in your model to ensure a soft landing and you should be fine. The model looks like it is coming along nice.

Matt

Doug

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