Am getting a new fuselage and wondered what the current thoughts are on these two subjects since I am sure some fuselages have now been out in the field for awhile with powder coated frames and/or no oil in the lower tubes.
I put epoxy paint on the outside and hot linseed oil on the inside in 1969, and so far no problems. I believe most tube problems were due to the factory external coat, which wasn't much. Leaving an airplane sit in one spot for ling periods of time can destroy tubes and other stuff.
Thank you gentlemen for your replies, have heard that powder coating can hide problems with rust. Any truth to that? Also, are the problems that the linseed oil was designed to prevent not as prevalent today?
I had a powdercoated tube crack and not show through until I happened to notice it moving. Never again. Air Tractor had a number of nightmares with powdercoating as well. I understand it's a better process now, but I think it's maybe a little too tough. I wont sign off any powdercoated structures. I also use Polyfiber's "Tubeseal" on all tube structures. It sure doesn't hurt anything or at least I've never heard about it hurting anything. Just my personal opinions.
John
Thank you gentlemen for your replies, have heard that powder coating can hide problems with rust. Any truth to that? Also, are the problems that the linseed oil was designed to prevent not as prevalent today?
If you get to Lake Hood I can show you my Cessna's gear legs. Advanced coated them 17-18 years ago and they've been parked outside ever since. Full exposure to the elements and they've had a few gravel dings to the coating through the years. They still look great. Look around and compare them to painted gear legs with a few years on them and decide for yourself which coating is more rust prone.
New 4130 tubes are pretty well oiled inside as is so nobody I know is drilling holes in a new airframe to add more oil.
Here's a cut and pasted item right off the Airframes Alaska website. They use powder coating, too.
Finishing Note: Fuselages are shipped with the options of bare metal, prime powder coated, 1-color powder coated, or 2-color powder coated. We use an extensive FAA approved and FAA audited powder-coating process to ensure a strong and durable finish.
FWIW, I just picked up my airframe and the majority of steel parts that belong with it. As usual the quality is exceptional. A perfectly uniform coating that reaches into every channel and cluster. No runs or puddles. To look at the detail of the welds through the coating makes me smile. The work on this airframe is a thing of beauty. And at 19'8" it just barely fit into the 20' oven. Happy day.
A hint from Walter, particularly handy for me since I forgot to add a rudder light attachment before I dropped the parts off.... oops! Advanced recommends POR-15 brand "chassis paint" for doing touch-ups. They say it's the next best thing to powder coating and the satin black in a rattle can should match my powder coating perfectly. I'm told Carquest stocks POR paints. I'll be fetching some today. :???: