Soda Blasting

This is the third and final day in my bachelor building binge. The girls have been out of town and my goal was to press on to get the fuselage primed and ready for covering. Unfortunately this hasn’t worked out for a few reasons. The first is that I’m out of reducer for the expoxy primer. This stinks, because I need to paint the fuselage right after it’s blasted. My original plan was to go rent a compressor and sand blaster today, but earlier this week I was talking with a friend who asked if I had looked into soda blasting. Soda blasting uses baking soda as a blasting media with equipment that seems very similar to sand blasting. The soda is not as harsh as sand, which means less likelihood of blowing holes in the thin steel tubing. I figured I should at least get a quote, which came to $100. That was less than I was going to have to spend to rent the other equipment, and that’s not to mention that I wouldn’t have to do the miserable job of the blasting.

I met the friendly blaster early in the morning and moved the fuselage out into the sun.

Ready for Soda Blasting

Ready for Soda Blasting


Soda Blasting in Action

Soda Blasting in Action


While he did that, I made some minor adjustments to one of the stringers. This one is the upper left sringer, which rubbed on one of the diagonal fuselage tubes. I cut a little relief out of the stringer with the Dremel:
Take a bite out of stringers

Take a bite out of stringers


Then I added a little dam of aluminum to help seal the area

Then I added a little dam of aluminum to help seal the area


The idea is that I’ll fill this hole with some epoxy to seal the bottom, then top it off with some Superfil.
Epoxy first

Epoxy first


Meanwhile, the kind blasting gentleman was through, and I was able to learn the second main reason why I wasn’t going to be able to prime today- the soda blasting wasn’t harsh enough. I don’t think it’s the fault of the operator, but rather the process. Soda blasting just isn’t suitable for prepping welded steel tube structures.
Soda Blasting Results

Soda Blasting Results


Note the little bits of oxidization in the low spots.

Note the little bits of oxidization in the low spots.


These were too hard for the soda to remove, but sandblasting would have yielded fresh, bare metal. I think the process is very well suited for paint removal- the blasted areas looked just like they did before I painted them with a temporary primer. This was a disappointing setback, but these have still been very productive days. I took the rest of the afternoon off and came back later in the evening to prepare for the landing gear alignment project. I would have preferred to get the alignment done before the blasting, but time constraints wouldn’t allow that this week. With my new delayed schedule, I can return to the preferred order and get the alignment done next. The first step in aligning the gear is getting the fuselage positioned at the right height and level in all dimensions. Then I need to secure the fuselage in that position so that I can make reliable measurements, and presumably be able to bend the landing gear without having the fuselage moving around. To start, I installed augers in the floor to use as tiedowns. These are in the right spot to serve as wing tiedowns later on.
Installing anchors in the floor

installing anchors in the floor


I also spent some time locating and adhering the position light mounting pad to the left wingtip.
Wingtip Position Light Mount

Wingtip Position Light Mount


I left the hangar in the wee hours of the morning, somewhat defeated, but only reminded that deadlines and goals need to be flexible with this kind of project.

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Hours Logged This Session: 4.1
Total Hours: 1883.75