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Old 09-03-2018, 12:05 PM
BTromblay BTromblay is offline
ADMINISTRATOR MetalShaper of the Month August 2018
 
Join Date: Oct 2015
Location: Mukwonago, Wi
Posts: 567
Default Getting all the dents out?

Hi,

I have a question. In the last three weeks, I had to fix two separate airplane crash parts, no one was hurt in either accident. In both accidents, the airplanes thin aluminum (3003 x .040"), looked like you drove over it with a truck. I forgot to take pictures of the second part, due to the timeline to get the job done.

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With skill sets that I learned from Peter Tommasini, Dan Pate and Kent White, I was able to knock out the dents in short order with hand tools, and my pneumatic planishing hammer. I had a buck, to confirm my finished shape. I will be welding up the extra holes from the earlier repair patches. The surface looks and feels much flatter, than the photos are showing, the discoloration of the stripped paint is creating an optical elution.

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My Question,

What I need more help with understanding is, metal finishing the finished surface. I have a window behind my P-hammer and the natural light helps a bunch, as it washes over the panel during the repair. I will also make the panel wet, and/or use gloves and I can feel the highs and lows. If it looks good with light and you can't feel any thing, do you need to go any further? When I watch a autobody guy, prepare a surface for paint, they seem to find stuff, that I cant see or feel and I don't know "how they do it".

Both of my repair parts, will be painted again and it is up to the painter guy, to fix if need be. But if I had to repair a part on a polished aluminum airplane, is my process, good enough for a polished surface, (I don't think so)? Jim Hery, took some time with me down at Will's, this past spring. We used a body file and fixed highs and lows. Do you always need to file or sand a surface, for it to be flat?

How do you metal finish?

Thanks Bill
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Bill Tromblay

"A sign of a good machinist, is one who can fix his F$@& Ups" My mentor and friend, Gil Zietz Micro Metric Machine.

Last edited by BTromblay; 09-03-2018 at 12:08 PM.
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