skippydiesel Posted October 7, 2019 Share Posted October 7, 2019 My aircraft uses a composite fuel tank. I burn 95/98 RON very very rarely AvGas At the top of the tank there is a circular metal plate that houses/contains the fuel gauge sender mechanism, and the three fuel pipes (Main, Aux & Return). The plate is secured by many screws. I assume (never dismantled it) that it is a "sandwich" type securing sealing system, utilizing a gasket and/or sealing compound. Recently I have noticed that this structure has developed a small fuell weep, with a brown sticky stuff oozing from the area that is weeping. I would like to effect a good repair. All suggestions welcome, with particular advise regarding suitable fuel resistant sealing compounds. Link to comment Share on other sites More sharing options...
M61A1 Posted October 7, 2019 Share Posted October 7, 2019 PR1776 is a good fuel tank sealant, but it sounds like you should make a new gasket. Viton sheet is available in 1.6mm. Link to comment Share on other sites More sharing options...
skippydiesel Posted October 7, 2019 Author Share Posted October 7, 2019 Thanks M61A1 - checked out your suggestions. I have no doubt that they would do the job very well BUT the cost $$$$$. I would need to measure the plate but my estimate is its about a 100mm diam circle - I would hope for a much less costly solution. Link to comment Share on other sites More sharing options...
Downunder Posted October 7, 2019 Share Posted October 7, 2019 I helped repair a leak in a top inspection hole on a wing. It had a cork gasket. We cleaned it well with acetone an applied a sealant from an automotive store. It was called "something" putty. I was worried it was going to be thick like muffler putty but was more like thick silicone. Worked well. I'll try and find full name. "Downunder, from rainy Tassie!" Link to comment Share on other sites More sharing options...
nomadpete Posted October 7, 2019 Share Posted October 7, 2019 Do you mean to say that you are down under downunder.........? 1 Link to comment Share on other sites More sharing options...
Downunder Posted October 7, 2019 Share Posted October 7, 2019 Yes....first time! Rosebery....arrived Devonport today on Qantas. All free for work... Last Monday I was at Mt Augustus....middle of WA.(on my own dollar) Bit of a difference... Link to comment Share on other sites More sharing options...
Marty_d Posted October 7, 2019 Share Posted October 7, 2019 I bought some rubberized cork gasket material (1.5mm) to use as a cushion / anti-rub separator between the oil tank and the bracket it sits on. Cost me about $20 for a roll of it, certainly enough to get a few 100mm circles out of. As far as I know it's fuel/oil resistant. Got it from a local engineering place. Ring around - someone will have a solution. Link to comment Share on other sites More sharing options...
onetrack Posted October 7, 2019 Share Posted October 7, 2019 This stuff is the answer to any oil or fuel leak, in anything mechanical. Been around for yonks, still can't beat it. https://www.permatex.com/products/gasketing/gasket-sealants/permatex-form-a-gasket-no-2-sealant/ 1 Link to comment Share on other sites More sharing options...
skippydiesel Posted October 7, 2019 Author Share Posted October 7, 2019 This stuff is the answer to any oil or fuel leak, in anything mechanical. Been around for yonks, still can't beat it. https://www.permatex.com/products/gasketing/gasket-sealants/permatex-form-a-gasket-no-2-sealant/ That's my man! - about $12 - even I can afford that and I probably already have some cork gasket sheeting lying around that might make a new gasket. 1 Link to comment Share on other sites More sharing options...
facthunter Posted October 8, 2019 Share Posted October 8, 2019 I've gone onto better for engine crankcases which are accurately machined surfaces. I'd rely on a neoprene gasket preferably without any sealant on that situation. Nev 1 Link to comment Share on other sites More sharing options...
kgwilson Posted October 8, 2019 Share Posted October 8, 2019 Permatex is indeed a great fuel resistant sealant. I used it on all of the threads etc in fuel line nipples from fuel pumps and I have never had a problem. Without it even though the brass fittings have tapered threads they leaked. 1 Link to comment Share on other sites More sharing options...
onetrack Posted October 8, 2019 Share Posted October 8, 2019 Skippy, some composite gasket material (nitrile bonded, rubberised cork) could be a better choice than just plain cork gasket. Plain cork is good for vibration and noise reduction, but the composite of cork and nitrile rubber is particularly good at stopping weeps. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now