The International Cessna 170 Association

Yes. Enjoying them. Keep em coming!

And this is why it is so important to clean, scotchbrite, acid etch, and alodine around the rivet heads and seams! It's the first areas to let go of the paint over time.

Before and after stripping. I'm using "Jabsco" professional. It's as good as anything else I've found but not cheap. First coat takes off top color and softens primer. Scrape with hard plastic or phenolic scraper. Even a wooden block with a sharp wedge cut into it works well. Second application "mostly removes residual top coat and primer. I use a wire brush to lightly clean around the rivet heads and seams. VERY IMPORTANT..... if you use a wire brush.... it has to be light gauge and stainless steel! I will finish sand with 400 grit on a DA mouse sander. VERY IMPORTANT.... do NOT sand the rivet heads!! You can scotch Brite around them in a twisting motion and it'll be fine. More on that during the painting stage.

please do not use stainless wire brushes on aluminum as stainless steel isn’t stainless steel as we all think. It will intro duce ferrous material into areas that loves to corrode. I know it’s a pain in the you know what but scotch brite is the only way .

As simple as the process is, little mistakes can cause major headaches. An example would be to allow a water based paint remover to dry between the sheets. Once dry and not removed, the stripper awaits for its next job, the new paint. 170 fuselage’s top lap joint running the length of the fuselage will gobble up stripper if it’s slapped on.
So, only my opinion, but I would not recommend your techniques.

I agree completely. And thus the reason I preach ONLY stainless steel. Because it will impregnate the aluminum with trash that will cause issues. So..... let me clarify. Do not use Home Depot wire wheels on a drill or high speed die grinder! They are junk and not real stainless brushes. Use only high quality (expensive) stainless brushes from Falcons crest or other aviation supply store. They are true stainless made with chromium. AND.....only use them by hand. I've done this for 30+ years and never had an issue. I was taight this by one of the premier aircraft refinishers in the country. Of course.... you MUST clean the metal afterwards and definately acid etch and alodine!! Or your asking for trouble. No disrespect for the difference of opinion.....and will add..... if there's any doubt in "whose correct"... please default to only using scotch bright! Can't go wrong there. AND..... I left out..... I ALWAYS use an pressure washer to blast and trace of stripper out of the seams and joints!!

For mechanical removal of paint around rivets “ paint donuts” I use these products.http://www.jusntyme.com/JNT411B60_p_24.html.
I’m no paint expert, but scotchbrite is fairly safe

I also use this stuff, note the price is for a 55 gallon drum, which I estimate can strip about 10 completely painted 170’S
https://www.skygeek.com/akzonobel-spc90 ... paint.html
Thanks for adding further details on the methods.
Everyone has their own favorite way of doing things, so there’s many right ways, just no really quick ways of paint stripping an aircraft.The pros probably have lots of ways to knock time off the process. I can do it in a summer, so I guess I’m no pro and won’t be taking away any business from anyone. Another aspect to the job now has been the change in materials. The old chemical strippers (now banned for environmental reasons) would strip all the paint off in 30 mins in one coat. And you really knew right away when a drop touched you skin. Whereas the SeaSky stuff, you can shove your hand into it and really nothing (probably still not good for you). Sounds like great stuff but on the downside I had to often use 3 applications of the stripper to get everything off.

Jazasaguma,
Thanks for taking the time to detail your restoration project. I added Cessna's SNL93-3 Cabin Skin Panel Corrosion Inspection and Repair to the Mx Library. In addition to ScotchBrite they include aluminum oxide sandpaper in the material list. Dennis Wolter at Air Mod has written a series of articles on aircraft restoration and corrosion control. He says not to use sandpaper because "sand is a low form of glass that can impregnate the aluminum with small glass-like fragments, reducng the adhesion ability of zinc chromate and other finishes." Contrary to the opinions here he uses stainless steel brushes. He gets his from Solo Horton Brushes. Kent White also sells stainless steel brushes which are used to prep aluminum prior to gas welding.

Well said Gary. I have to remember to be careful to not have my content be presented as a "how to" series of articles. They are only a reflection on "what I did" only!! Lol. But yes, another clarification I need to make about sandpaper...."aluminum oxide ONLY" please.

Went ahead and split the case. Ugh!!! Everything was like new!!! With only 97 hrs SMOH, i figured it would be. But in a weird way.....I was kinda hoping I'd find something horrible to justify the tear down!! Lol. But.... after sitting for 18+ years, I would have never had the peace of mind if I hadn't. I'll go ahead clean and check everything dimentionally and magnafux and polish the crank and go back with all new bearings, gaskets and seals. New rings, hone the cylinders with a good cross hatch on the walls. Lap the valves. Cut the starter pinion for the light weight Sky tek starter and add an oil filter kit as well. Sent off the mags and Carb as well.

n2582d wrote:Jazasaguma,
Thanks for taking the time to detail your restoration project. I added Cessna's SNL93-3 Cabin Skin Panel Corrosion Inspection and Repair to the Mx Library. In addition to ScotchBrite they include aluminum oxide sandpaper in the material list. Dennis Wolter at Air Mod has written a series of articles on aircraft restoration and corrosion control. He says not to use sandpaper because "sand is a low form of glass that can impregnate the aluminum with small glass-like fragments, reducng the adhesion ability of zinc chromate and other finishes." Contrary to the opinions here he uses stainless steel brushes. He gets his from Solo Horton Brushes. Kent White also sells stainless steel brushes which are used to prep aluminum prior to gas welding.

I hope to know 1/100th what you do one day, Gary. Your resources and library are amazing!

Ryan,
Thanks! What's amazing about this website is that there is such a wealth of information here from some very talented folks. I especially appreciate when guys like Jazasaguma take the time to share their restoration or rebuild project with us. In addition to the information, these threads are real encouragement for me to get my butt in gear on my project. Here’s some links to other projects we’ve read about over the years:
“Metal Master” Jim’s TCM IO-360 installation
Dillon Barron’s ‘54
Miles’ 98C

Don't mean to side-track this rebuild thread. I'd forgotten we talked about using a stainless steel brush when Dillon Barron was documenting his restoration here. (On page one of that link I like the way Dillon removed the side sheets to make cleaning the tail cone area easier.)

This is from AC43.13-1B Chapter 6-136.d

(1) Non-Powered Corrosion Removal.
(a)
The removal of corrosion products by hand can be accomplished by use of aluminum grit and silicon carbide abrasive, such as non-woven, non-metallic, abrasive mat (Spec. MIL-A-9962), abrasive cloth, and paper. Aluminum wool, fiber bristle brushes, and pumice powder are also acceptable methods.
(b)
Stainless steel brush (Spec. H-B-178, type III, class 2) may be used as long as the bristles do not exceed 0.010 inch in diameter. After use of this brush the surface should be polished with 60 grit aluminum oxide abrasive paper, then with 400 grit aluminum oxide paper. Care should be exercised in any cleaning process to avoid breaking the protective film.
(c)
Steel wool, emery cloth, steel wire brushes (except stainless steel brush) copper alloy brushes, rotary wire brushes, or severe abrasive materials should not be used on any aluminum surface.

Several years ago there was an A&P on our field using soda blasting to remove corrosion on a C-172 fuselage. My concern with using soda was the challenge of getting it removed from every nook and cranny afterwards. Anyone else have experience with soda blasting?