Cub Lift Strut inspection

I have a set of PA-12 lift struts that I intend to use on the Wag 2+2/PA14 that I am building. These struts appear to be in very nice condition. I have looked inside with a borescope and they loop pretty good. It's pretty hard to determine what inside is globs of old linseed and scale or corrosion. Scraping the inside with a welding rod and a rifle cleaning rod brings out the same kind of stuff inside new 4130 but I want to be sure before I use these. The best method of inspection would be an ultrasonic inspection. Does any one know who does that type of inspection in California? I'm on the Central coast south of San Luis Obispo. Any ideas? Any other ideas other than the regular punch test; or is that test ok? If these are good I'll use them otherwise it's $2K+ to replace.
Thanks,
Marty

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Originally Posted by Martyfeehan

The best method of inspection would be an ultrasonic inspection. Does any one know who does that type of inspection in California? I'm on the Central coast south of San Luis Obispo. Any ideas? Any other ideas other than the regular punch test; or is that test ok?

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Don't know of anyone on the West Coast but shouldn't be too hard to find. An ultrasonic inspection should run you ~$200 for all four struts. Well worth it and I would also include some kind of NDI on the strut forks as well. If you have to pack them up and ship somewhere, that cost would be additional.

Marty,

I went through the same process last year with some used Univair J-4 struts that I found. A borescope up the barrels revealed not a spec of rust, which was good enough for me. The punch test has been made pretty much obsolete by the borescope, in my humble layman's opinion. If it was rusted enough inside to fail the punch test, you'd see it with the borescope. That said, if you do find a good place to do the ultrasonic inspection, please let us know the results.

Jeff,
I have a low res borescope from Harbor Freight. The inside has what looks like globs of linseed oil and slag from the welding around the barrels. I can see some black around the welds and was able to scrape some of it out with a welding rod. Color was black and gritty, maybe magnetic but not sure. When I scrape pretty aggressively inside what comes out is shimmy, nothing red or rust colored. How clear was the borescope you used? It may be worth finding a better borescope to get a good look inside.
Marty

My chapter bought a high quality Snap-on borescope a couple of years ago and that's what I used. A better scope might indeed help. The images were clear enough that I was satisfied with what I saw. Unfortunately I did not take pictures with it to show you.