Saturday, July 28, 2012

The long hard grind continues...

I have been working this project for quite a while now and believe I have finally zeroed in on a suitable method for removing the excessive number of disparate paint coatings that have been layered on over the years. When I started, I began with Aircraft Stripper - primarily since it is the most caustic that I could find, but would not affect the structure; but that took multiple passes and still met with only limited success. It also does not work well in the heat because it needs to stay moist in order to chemically soften the paint. When that did not make much headway I then began trying an industrial wire wheel with knotted stainless steel bristles. That worked better but still had trouble where the coatings were really built up. The wheel would "smear" the paint before it eventually came off, and it took quite a bit of time and effort. All of this was a means of working from the least intrusive method in order to find a system that would not result in more refinishing work after the coatings were removed.

Well last trip while working around a rust-out on one of the boosters I was doing basic bodywork using a 9" grinder and a 24 grit disc - then using a "ding" hammer to test the soundness of the rust spots. I was having a tough week so I kept going with the grinder and after a couple hours had removed all the coatings. What I found interesting was that when I went back this week I could still see the remains of the manufacturers production paint markings - so obviously I wasn't introducing more damage. This picture does not do it justice but you can just about make out the NK - 5 - 63

Having had such good fortune with this, I decided to try the same method on Castor. Before I started the section looked like this:

After a day of manning the grinder (and working with 16, 24 and 32 grit discs) I ended up with this:

I must say it was pretty satisfying.The really, really cool part was when I was working the booster nozzle. It must have a high magnesium content because it was throwing long Blue-White sparks from the disc maybe 2 - 3 inches! I will still need to sandblast the connecting structures since the disk cannot fit in there but it did an outstanding job on both the corrosion on the alloy tanks and the rust on the steel tank (as much as anything could).

You can also get an idea of how much material was removed by looking at the layer on the floor. I swept up several pounds of ground paint.

Next trip I will get help to roll these babies over and finish the removal

'til next time....

Blazing Skies!!!

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