Saito2 6686 Posted July 19, 2019 This has probably already been covered and I missed it. I was tearing down on of my re-release SRBs for a good cleaning. The gearbox was particularly dirty so I gave a shot of some Simple Green cleaner. It took the silver finish off like it was paint, exposing what looked like the finish of the old originals (which I'm assuming was just raw, unfinished die cast "pot metal" alloy). Oh well, lesson learned. Now, what to do with it? Polish it? Repaint it? Share this post Link to post Share on other sites
Juggular 4964 Posted July 20, 2019 I did not know that. I don't have SRB. But I'll keep your lesson in mind, just in case other parts are painted also. It would have been interesting to see "before-and-after" photos. Spray painting with metallic color of your choice, maybe? Share this post Link to post Share on other sites
KEV THE REV 2319 Posted July 20, 2019 I wasn't aware that the parts were painted either , are you sure it isn't the cleaner chemicals have taken off the lustre of the original finish and made it dull rather than removing paint ? . I sprayed some old SRB gearboxes with Ford Moondust spray , looks ace Share this post Link to post Share on other sites
max69vk 708 Posted July 20, 2019 It’s a chemical reaction with the simple green that heavily dull the finish, though at this stage you might as well paint the gearbox whatever colour you want, just make sure you use etch primer if you decide to change the colour or it will easily come off. Share this post Link to post Share on other sites
Saito2 6686 Posted July 20, 2019 Here's a pic: 20190720_171737 by Scott Weiland, on Flickr I don't know what the finish is. It ran off like paint but it might be a kind of anodizing like the TXT-1 chassis. I etch primed and painted it as suggested. I may not be handing out suggestions anymore for fear of spreading misinformation through my own ignorance, but at least others can learn from my stupid mistakes. Live and learn as they say. 1 Share this post Link to post Share on other sites
Raman36 1656 Posted July 27, 2019 Simple Green does not react well with certain metals. I used it long time ago on anodised part and it ruined the finish. What you’re seeing is a chemical reaction Share this post Link to post Share on other sites
waterbok 1282 Posted July 28, 2019 Try using Google and search for simple green and aluminium. Guess this also applies to Tamiya SRB as they are low flying objects 😉 > Below are excerpts of some of the information available on the web: > Aircraft Cleaners > Simple Green and other cleaners that are not listed in the Technical Manuals are taboo for a very good reason - they hurt the metal used to build the machine. > It has been brought to the attention of the U.S. Army Aviation Missile Command (AMCOM) Depot Maintenance Engineering Team that numerous units are using the commercial product SIMPLE GREEN as an aircraft wash. > STOP! This product has been through Department of Defense (DOD) testing and was determined to be highly corrosive on aircraft aluminum and also a catalyst for Hydrogen Embrittlement in high strength aircraft alloys. While a highly effective cleaning agent for floors and non-aluminum / non-high strength alloy vehicles this product is not approved for aviation usage. If your unit has been using SIMPLE GREEN on a regular basis, it is recommended that a thorough fresh water wash with the approved cleaners per the appropriate airframe maintenance manuals be accomplished as soon as practicable. This should be followed up with a corrosion inspection / treatment and application of approved Corrosion Prevention Compounds (CPCs).CPC 2 Share this post Link to post Share on other sites
Grumpy pants 4485 Posted July 28, 2019 My rere SRB gearbox became tarnished after running it in the surf and in the sand. I figured it was a standard pot metal reaction with a corrosive substance. Share this post Link to post Share on other sites
Shodog 1835 Posted July 28, 2019 4 hours ago, Grumpy pants said: My rere SRB gearbox became tarnished after running it in the surf and in the sand. I figured it was a standard pot metal reaction with a corrosive subsense. The salts and other minerals from the ocean are enough to dull the pot metal and rust most every steel screw. My runner shows proof of that. Makes me wonder if the rere parts were tumbled in a media at the factory. They seem shinier than vintage. Basically a polished to shiny finish. Would explain why the luster came off so easily. Share this post Link to post Share on other sites
SuperChamp82 743 Posted July 28, 2019 Are there a number of questions here ? Simple Green and aluminium is a chemical disaster - its meant for steel - but Tamiya pot alloy also isn’t pure Al. Lots of vintage SRB gearboxes have been sprayed over the years - largely because @Shodog @Grumpy pants are right re the effects of running them on a beach (or any corrosive environment) ... and the cost / pita of media tumbling to bring back to factory is often prohibitive. As far as the re re goes I suspect Tamiya reduced the cost of a factory finish and sprayed bare pot metal because they knew it would likely happen anyway - and @Saito2 just stripped it away. 1 Share this post Link to post Share on other sites
Saito2 6686 Posted July 28, 2019 Wow, now paranoia is setting in and I'm wondering if I should trash the gear cases altogether and get new ones. Hydrogen Embrittlement is now on my mind . 1 Share this post Link to post Share on other sites
waterbok 1282 Posted July 28, 2019 1 hour ago, Saito2 said: Wow, now paranoia is setting in and I'm wondering if I should trash the gear cases altogether and get new ones. Hydrogen Embrittlement is now on my mind . Don't worry, Just run them till they start to disintegrate. And don't forget to post pictures when they do. :p 2 2 Share this post Link to post Share on other sites