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Brian Jackson
09-30-2004, 10:36 AM
Hello all.

Gotta question about paint thickness on a square tube airframe... think "automotive multicoat". Normally this would be irrelevant. However, in the case of the GyroBee it could be a potential problem for hole tolerances. Here's why:

The keel and tail boom overlap by several inches, and are held together by the cluster plates. When the holes for these are drilled and reamed, the material is bare aluminum, probably clamped together to ensure a perfect fit. Later when the material is painted, the paint finish build-up increases the distance between the keel and tail boom by twice the finish thickness, thus the cluster plate holes will now be misaligned by that distance. See what I'm getting at?

I would like to compensate for this finish build-up during the drilling process, but I do not know how many thousandths of an inch to allow for paint. Does anyone here know or have access to this paint thickness data? Granted it's a function of the type of finish being used, but if someone could point me in the right direction I'd be grateful.

Thank you.

Brian Jackson

StanFoster
09-30-2004, 05:17 PM
Brian: Paint and painting techniques will effect the thickness. I would just make a test sample using exactly your paint...and your sprayer...and then measure it with a caliper. I honestly think this thickness will be less than .005 and would be such a miniscule amount to even consider.

Stan

Caribean_gyro
10-01-2004, 03:03 PM
It could go up to 4 mills. now when putting it back togheter just ream the holes again. It happen to me many times.Is not a big deal
chuck

donshoebridge
10-02-2004, 09:25 PM
Brian,

Since the holding forces between the cluster plates (and other plates) and the tubes is actually from the friction between these components, why worry? Drill the holes .005-.010 inches oversize and move on.