Contour Trimming 3mm Edgebanding

Advice on rounding over and trimming plastic edgebanding without melting the material. August 31, 2010

Question
I’m looking for suggestions for an efficient method for trimming and rounding over 3mm on curved surfaces (ex.: curved display top). We are using "Ultraflex" to go around the relatively small corners. I think it's a PVC/Rubber blend. It goes on nice, but doesn't cut worth a darn.

Tried trim router with follower bearing and it melts and gums up the bearing quickly. I tried a lipping planer, but even it dug in occasionally on that soft material. I tried a stationary trimmer with top and bottom heads set for a 3mm round over, but it tries to cut too much and it chatters, plus the table is too small for a top. For the one or two occasional top, I can't justify a custom dedicated secondary top set up. The best results have been to trim it near flush with a bottom cutting bit in the trim router with a custom offset base. Then I come back with hand tools (sharp chisel, file to round over) but I’m not happy with the results or the efficiency. Thanks for your suggestions.

Forum Responses
(Cabinetmaking Forum)
From contributor J:
Have you tried one of the laminate trim bits with the square bearing? Fastcap?

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From contributor G:
Trim flush to face with an old plane iron ground dead flat with a very slight bevel on the underside which is held slightly askew but flat to the surface in order to effectively shear. Then use a laminate trimmer - it works great for me. If you're getting melt-back, then switch to a sharper cutter and increase the feed rate/move a little faster.

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From contributor P:
Look for a Betterly PVC Trim Router with a 3MM round over bit. I got mine from a company in Georgia but I can't recall the name. It works great and is made specifically for contours.

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From the original questioner:
I haven't tried the square bearing bit yet. I thought we'd be better off with the router base that carries the bearing on an outrigger assembly below the bit. Especially since the banding seems to have a slight crown in the middle.

Contributor G - I have a flat chisel I've done that with, but not with 3mm PVC. I'm afraid I'd peel the banding off before cutting through something that thick. I'll give it a try though.

Contributor P - I have the Betterly catalog and I'll check it out. Again, the problem seems to be this softer material (Ultraflex vs. solid PVC).