Poly Fiber SuperFil for Casting and Modeling Putty

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1st Lieutenant
May 30, 2011
Cape Canaveral
Yesterday I needed to smooth out some small dents in the horizontal tail leading edge of my Ercoupe. I want to protect the leading edge and plan to use both paint and some leading edge tape, but figured the tape would not do well covering those very small but not shallow dents.

So, after laboriously cleaning and applying an alodine conversion coating the leading edge I applied some Poly Fiber SuperFil. It is a two part material, a putty, which might be called Aircraft Bondo. But it is much better than Bondo, having actual adhesion to the surface and is much lighter as well as tougher than Bondo. It sands and shapes very easily with ordinary hand tools.

In the process of mixing up the SuperFil I used a little plastic tub that had once held margarine. When I scraped the hardened SuperFil out of the tub I noted that it had rendered the contours and even the impressed writing on the tub quite accurately.

I think that SuperFil would work very well as a putty for modifying models as well as a casting agent for making parts. At $35.50 for 1 qt it ain't cheap, but then again the clear casting resin at Michaels goes for about $30 a quart. Biggest problem is that it is not liquid; both components are a putty, so mixing it in the proper proportions ain't that easy. But I managed to do it. Also, it is best kept in the refrigerator if you want it to last; mine had been in the fridge for years and still worked fine.
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