pilot-as14 Posted August 25, 2022 Report Posted August 25, 2022 I'm new here and say hello to everyone. I have been restoring a M20C (in Germany) for several years. The fuel tanks are leaking. I want to clean them from the old sealer and reseal. Can someone give me a tip how and with which tool to open the hand cover? Thank you in advance for any information. Alex info@vintagewings.de Quote
Fly Boomer Posted August 25, 2022 Report Posted August 25, 2022 1 hour ago, pilot-as14 said: Can someone give me a tip how and with which tool to open the hand cover? If I understand your question, the only advice I have read on MooneySpace is to use something broad and flat. A screwdriver will likely bend the cover. Quote
Browncbr1 Posted August 25, 2022 Report Posted August 25, 2022 harbor freight sells plastic ones that are also good for scraping sealant... https://www.harborfreight.com/4-piece-nonmarring-scraper-set-95832.html Quote
Jim Peace Posted August 26, 2022 Report Posted August 26, 2022 7 hours ago, pilot-as14 said: I have been restoring a M20C (in Germany) Where in Germany? I get to Koln often.... 1 Quote
carusoam Posted August 26, 2022 Report Posted August 26, 2022 Welcome aboard as14! There is an interesting thread around here that details many of the steps you are about to take… See if you can find Alex / @Raptor05121 He bought an M20C and was restoring it project by project… fuel tank reseal was one of his first big projects…. There is a lot of detail to be found for strippers, sealants, and procedures…. He wrote and took pics for a long time… Hopefully the pics are still there… Best regards, -a- Quote
pilot-as14 Posted August 26, 2022 Author Report Posted August 26, 2022 6 hours ago, Jim Peace said: Where in Germany? I get to Koln often.... I'm in Hannover and in EDVH Hodenhagen Quote
pilot-as14 Posted August 26, 2022 Author Report Posted August 26, 2022 12 hours ago, Browncbr1 said: harbor freight sells plastic ones that are also good for scraping sealant... https://www.harborfreight.com/4-piece-nonmarring-scraper-set-95832.html Thank you! Is there a trick to opening the fuel tank caps? They're glued on bombproof... Quote
pilot-as14 Posted August 26, 2022 Author Report Posted August 26, 2022 2 hours ago, carusoam said: Welcome aboard as14! There is an interesting thread around here that details many of the steps you are about to take… See if you can find Alex / @Raptor05121 He bought an M20C and was restoring it project by project… fuel tank reseal was one of his first big projects…. There is a lot of detail to be found for strippers, sealants, and procedures…. He wrote and took pics for a long time… Hopefully the pics are still there… Best regards, -a- Many thanks! I found his profile, but how can I write to him personally? Didn't find out... Quote
carusoam Posted August 26, 2022 Report Posted August 26, 2022 7 minutes ago, pilot-as14 said: Many thanks! I found his profile, but how can I write to him personally? Didn't find out... When you click on his @Raptor05121 it should give options for a private message… PM. He was around here earlier in the day… Best regards, -a- Quote
Jsno Posted August 26, 2022 Report Posted August 26, 2022 to open the fuel tanks, remove the screws and then carefully work a thin flexible putty knife between the flange of the panel and the wing skin and work with a sawing motion all round the edges. It takes patience and some muscle. The panel on the right wing top, next to the door ,under the wing walk, has a bracket extending inboard and outboard. This has some flush screws in it so be sure to remove them before attempting to remove the panel. Aircraft spruce sells Polygone 310 that you can apply to the sealant in the tank to loosen it. Then use plastic scrapers to remove the sealant. You can resharpen them with sand paper as they will dulll quickly. Dontas use steel to scrap. Be sure to Aldine the metal before resealing to prevent corrosion. Quote
pilot-as14 Posted August 26, 2022 Author Report Posted August 26, 2022 2 hours ago, carusoam said: When you click on his @Raptor05121 it should give options for a private message… PM. He was around here earlier in the day… Best regards, -a- aaaa... ok, thanks Quote
pilot-as14 Posted August 26, 2022 Author Report Posted August 26, 2022 2 hours ago, Jsno said: to open the fuel tanks, remove the screws and then carefully work a thin flexible putty knife between the flange of the panel and the wing skin and work with a sawing motion all round the edges. It takes patience and some muscle. The panel on the right wing top, next to the door ,under the wing walk, has a bracket extending inboard and outboard. This has some flush screws in it so be sure to remove them before attempting to remove the panel. Aircraft spruce sells Polygone 310 that you can apply to the sealant in the tank to loosen it. Then use plastic scrapers to remove the sealant. You can resharpen them with sand paper as they will dulll quickly. Dontas use steel to scrap. Be sure to Aldine the metal before resealing to prevent corrosion. Thanks for helpful tips! I suppose, I should completely remove the old sealer, first mechanically and then with Polygone 310, right? My fuel tank is only leaking in one spot. What do experienced Mooney mechanics say, should you completely remove the old sealer or just reseal the leak? Applying a new coat to the old sealer? Quote
N201MKTurbo Posted August 26, 2022 Report Posted August 26, 2022 The repair procedure is in the service manual. It describes the process quite well. I would look up the Don Maxwell method of locating the leak. The best scrapers are Celcon. 1 Quote
Pinecone Posted August 26, 2022 Report Posted August 26, 2022 One leak, the normal advice is to patch. More leaks, you start leaning to remove and reseal completely. Quote
carusoam Posted August 27, 2022 Report Posted August 27, 2022 Once you see inside the tanks… You might find the quality of the older sealants wasn’t very good…. After 50years… The sealant itself starts flaking off in many places…. This is reseal time. Often, a small defect causes a hard to find leak source… this is the DMax method of finding the leak… Other small leaks… screws and rivets…. Easy to repair… If the tank has been resealed in the 90s sometime… it may only need a patch… If the sealant is original… it may be time to clean it all out and start fresh… Fuel sealants and their procedures have come a long way in 50 years… Best regards, -a- Quote
pilot-as14 Posted August 27, 2022 Author Report Posted August 27, 2022 Hi, I have studied several topics about Maxwell Method here. If I've removed old sealer mechanically, there will probably be some leftovers. Is it possible to remove these remains with Polygone 310? What is then used to remove polygons and clean the bare metal? Thank you for reply Alex Quote
carusoam Posted August 31, 2022 Report Posted August 31, 2022 Alex, Read up on the Polygone procedures… I believe their website has all of the basic details… Essentially, this product is a viscous solvent that is good at softening the sealant from everywhere…. Some tough spots need additional passes… Leaving old sealant behind will affect the quality of the new seal…. Take pics as you go… post and ask questions… PP thoughts only, not a mechanic… Best regards, -a- Quote
DCarlton Posted August 31, 2022 Report Posted August 31, 2022 9 minutes ago, carusoam said: Alex, Read up on the Polygone procedures… I believe their website has all of the basic details… Essentially, this product is a viscous solvent that is good at softening the sealant from everywhere…. Some tough spots need additional passes… Leaving old sealant behind will affect the quality of the new seal…. Take pics as you go… post and ask questions… PP thoughts only, not a mechanic… Best regards, -a- Is Polygone the same solvent used by the 2-3 professional tank strip and seal shops? Any idea where to find the specs for the sealant ? Thank. Quote
pilot-as14 Posted August 31, 2022 Author Report Posted August 31, 2022 Thank you! I checked in with the camera yesterday, the tanks look really bad. I'm trying to find the leaks with the water method Quote
carusoam Posted September 1, 2022 Report Posted September 1, 2022 23 hours ago, pilot-as14 said: Thank you! I checked in with the camera yesterday, the tanks look really bad. I'm trying to find the leaks with the water method If you want to…. You can always post your pics here… If you are seeing sealant flaking off of bumps like rivets and screws…. There are going to be a lot of them…. If layers are coming off… the appear as worms in the fuel…. Strip and reseal is the only way… There are a lot of eyes around here that have seen what you are seeing… sharing pics is helpful. Best regards, -a- Quote
FlyingDude Posted September 1, 2022 Report Posted September 1, 2022 On 8/26/2022 at 2:56 AM, pilot-as14 said: Thank you! Is there a trick to opening the fuel tank caps? They're glued on bombproof... Best scraper ever: https://www.amazon.com/gp/product/B076BBW1WM/ref=ppx_yo_dt_b_asin_title_o05_s00?ie=UTF8&th=1 You need to soften the sealant with acetone or butanone (MEK) before mechanically removing them. Even if it's old and crappy sealant, it won't come off easily. 2 Quote
pilot-as14 Posted September 5, 2022 Author Report Posted September 5, 2022 On 8/27/2022 at 8:55 AM, carusoam said: Once you see inside the tanks… You might find the quality of the older sealants wasn’t very good…. After 50years… The sealant itself starts flaking off in many places…. This is reseal time. Often, a small defect causes a hard to find leak source… this is the DMax method of finding the leak… Other small leaks… screws and rivets…. Easy to repair… If the tank has been resealed in the 90s sometime… it may only need a patch… If the sealant is original… it may be time to clean it all out and start fresh… Fuel sealants and their procedures have come a long way in 50 years… Best regards, -a- Quote
Fly Boomer Posted September 5, 2022 Report Posted September 5, 2022 On 9/1/2022 at 6:55 AM, FlyingDude said: You need to soften the sealant with acetone or butanone (MEK) before mechanically removing them. Even if it's old and crappy sealant, it won't come off easily. Paint damage is almost a certainty. At a MooneyMax conference a few years ago, I looked over the Houston Tank contract and it said something to the effect "I WILL damage your paint in the process of sealing your tanks." Emphasis is probably mine. Quote
pilot-as14 Posted September 5, 2022 Author Report Posted September 5, 2022 Hello, I found a company in France, www.aviatec.aero, that has Polygone 310 and Chemetal MC780. I would like to ask the question here, can someone tell me how much polygon and sealer is needed for both tanks of M20C? The tanks are completely smeared with the old sealer The plane is disassembled, I can turn the wing. How did you clean the top corners in the tank through the top hand covers and seal them with sealer? Or do you have to open the lower hand covers as well? Thank you! Quote
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.