Abrasive blasting an airframe.

H. Paul Shuch is a Light Sport Repairman with Maintenance ratings for airplanes, gliders, weight shift control, and powered parachutes, as well as an independent Rotax Maintenance Technician at the Heavy Maintenance level. He holds a PhD in Air Transportation Engineering from the University of California, and serves as Director of Maintenance for AvSport of Lock Haven.

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Joined: Mon Dec 03, 2007 10:08 pm
Location: Columbus, Ohio

Abrasive blasting an airframe.

Postby n3pup » Wed Dec 05, 2007 10:26 pm

I just got an n3 Pup and am completely taking apart the 21 yr old aircraft. When it comes to sandblasting off the rust on the 4130 tail feathers and fuselage, what blasting media is usually used. The tubing is light gauge and I don't want to over do it. Usually articles just day that the frame was blasted but no other details are given. TP tools has a 90 grit round particle abrasive that I thought might be worth looking into rather than glass beads or walnuts which may be too light for a frame. I will be doing it outdoors in the backyard this spring so recycling the abrasive will not be very efficient. Thanks for any input.

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Postby Cub flyer » Sun Dec 09, 2007 11:44 am

We use sand or glass beads. Don't stay in one spot for too long. Just work along and as soon as the paint is gone move on to another area. It takes a while to get all the paint off. Usually I walk away and come back and find more spots I missed. I'm usually around 90-100lbs air. The blaster does not lift sand real well at lower pressures.

Paint the tubing with Randoph epoxy primer or Stits. I use stits process but like the randoph primer better. The stits should be top coated with Aerothane.

If you use Airtech be sure to double the amount of hardener in the fuselage tubing paint or the glue will wrinkle and lift the paint.

Super seam and Poly Tak will lift PPG Concept and Delta off the frame.

HVLP works good for spraying the tubing after blasting. Be careful not to get any skin oil or contamination on the tubing. Paint the same day you blast if you can. Low humidity.

Powder coat does not work very well on old tubing.

Hope this helps Charlie
"Perfection is finally attained not when there is no longer anything to add but when there is no longer anything to take away." Antoine de Saint Exupery

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