After having some issues over the years with brittle resin blanks losing chunks while barrel trimming - especially circuitboards, polyester resins and inlace acrylester - I came up with a way to protect my investment, on the cheap:
Harbor Freight black electrical tape 3/4" x 60' @ 10 for $4.99
Tightly wrap each end of the blank you want to trim, I use about 6 or 7 layers, then trim as usual. I cut off the tape with a utility knife (you could just leave it on and turn it off on the lathe) and I'm ready to turn.
I've never had a blowout with my trimmer using this method.
Interesting that the electric tape did work, why...! because the tape is extremely elastic, even after a few layers of it...!
I have been suggesting the use of a strong masking tape or a tape that doesn't stretch, because of that elasticity situation which in my view, is less effective to hold the Polyester resin from chipping, my recommendation has been more focussed on the drilling of some of my fragile Polyester blanks, well in fact, all the cast blanks I did so far (9 years), as been with the Polyester that, I'm now trying to replace with a better quality resin, other than the Alumilite that we don't have here in Australia.
I have had a few failures using the common grey tape used in the Air-con. Industry, strong stuff but still very elastic and in my view, to prevent the resin to chip/crack in the firs place, anything than a quite "solid" support, if may fail, to the fact that, I have also suggested some folks that keep blowing some of my blanks when drilling that, if they "box" the blank with so thin but strong strips of hardwood CA' ed to each joint (shown there before here), the blanks won't suffer any extension/expansion cracks when drilling so, the principle seem to work that way so for trimming Polyester blanks, a small wooden (or other materials) jig could be made to support tight the 4 surfaces of the blanks on each end, something that could easily be used again and again so, thinking minds, let make that jig, huh...!:wink:
With this said, if the electrical tape is working for you guys, that is an wonderful thing...!:wink::biggrin:
Cheers
George
