CHOP CULT HOME
Email Password
Search
Page 1 of 2 12 Last
  1. #1
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Oct 2016
    Posts
    2,436

    Default To seal or not to seal, that IS the question

    I am just finishing up the molding on my bike and before I start shooting primer I need to decide if I should seal the tank ( and what I should use ).

    The tank is a brand new repop 2.5 gallon sporty tank ( bought from a U.S. vendor but my guess is made in China ), seems to be good quality and it stood up to a 2 hour 15 lbs pressure test.

    Technology has changed a lot since my last build, as has gasoline composition.

    So the question to those of you with a lot of experience Would You seal it or not? And if you did what would you use.

    Thanks,
    -DB

  2. #2
    tzienlee
    Guest

    Default

    DONT SEAL !!!
    do not believe the bullshit, sealants are effected by modern alcohol fuels and cause more shit than they are worth.

    if you need to weld repair the tank anytime in the future you wont be able to because of the sealer as well,....

  3. #3
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Oct 2012
    Posts
    1,834

    Default

    Last I heard there were 187 chemicals plus alcohol approved as gasoline additives. There was some quickie mart gasoline up north a few years ago that would dissolve powder coat and JB Weld. It doesn't matter what the liner manufactures do the the additives are out there that will melt them. The worst horror stories seem to come from people riding state to state and mixing lots of different formulations in the tank. If it leaks weld it and air check over night.
    Dusty

  4. #4
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Apr 2013
    Posts
    9,769

    Default

    Only way I'd seal is if the tank were exceptionally valuable. then I'd use aircraft integral fuel tank coating, but that costs a lot more than a generic repop tank.

  5. #5
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Sep 2012
    Posts
    12,407

    Default

    I'd seal it if it was mine..... I don't trust China welds.... Or metal for that matter.... You have to much time in molding...

  6. #6
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Oct 2012
    Posts
    1,834

    Default

    Quote Originally Posted by farmall View Post
    Only way I'd seal is if the tank were exceptionally valuable. then I'd use aircraft integral fuel tank coating, but that costs a lot more than a generic repop tank.
    If they are antique and worth saving I open them sand blast then tin the whole inside. I haven't found any modern fuel that will dissolve solder. Unfortunately there are lots more additives in road fuel than avgas. I agree the FAA approved redcoat is better but even it dissolves in some road blends.
    Dusty

  7. #7
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Sep 2012
    Posts
    347

    Default

    Tanks that start to leak do so for several reasons. One is rust in the bottom over years. You don't have that problem, no should you if you keep the tank topped off with treated gas when you're not gonna ride it for a couple months or more. Another is being mounted under stress. This is especially true with fatbobs. Another is a tank rubbing against something, like a rocker box. One more is poor quality welds. You've pressure checked it, so yours are at least OK to start with. If you don't seal it, and a weld lets go, it will leak. If you do seal it and a weld lets go, it may leak anyway, (but maybe not) and you'll have to strip the sealer before you can fix it. Plus, if you do seal it, there's always the chance of the sealer letting go or dissolving in the crap gasoline and gumming up petcocks, filters and carbs. I've always felt that my odds are better of staying problem free by not sealing. This opinion is worth the cost of the paper it's printed on, but only if you print it out.

  8. #8
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Dec 2012
    Posts
    768

    Default

    I also have been struggling with this decision, MOTher you make some really good points.

  9. #9
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Apr 2013
    Posts
    9,769

    Default

    I agree the FAA approved redcoat is better but even it dissolves in some road blends.
    I don't mean any of the stuff sold for hot rodding, but the modern aircraft sealants serious suppliers like PRC or PPG etc sell to the aviation industry. Those are two-part, not solvent cure. You can contact their tech support for the latest choices and application info. Red Coat is consumer shit thinned with MEK therefore soluble in solvent even after cure.. I learned about the good stuff in the Air Force (back when expired sealants could be given away instead of having to be tracked as part of the total "waste stream"), but I wasn't Fuels so I didn't get into depth. Search "sprayable fuel tank sealant" etc but the goo costs as much as a repop fuel tank so I wouldn't bother on any common tank. Sealants come in many viscosities.

    Tank rusts and it ain't special? Save it for mockups or experimentation. Too bad there are no suppliers selling stainless fuel tanks. That would really solve the problem. Plain steel is intended to be disposable, but its cheap.

  10. #10
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Apr 2010
    Posts
    2,448

    Default

    Don't

  11. #11
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Oct 2016
    Posts
    2,436

    Default

    OK I am leaning toward not sealing it. I am less worried about having to repaint if it should begin to leak as I am trashing a carb.

    Next question, I tested it with 15 PSI, felt that was safe, would you go higher and if so what is a safe pressure to test at.

    -DB

  12. #12
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Dec 2017
    Posts
    2,758

    Default

    I wouldn't go higher than 15 PSI; 10 PSI is probably enough. Any higher than that and you risk deforming the tank or splitting apart the seams - it was not built to be a pressurized vessel.

  13. #13
    tzienlee
    Guest

    Default

    This is what 5% alcohol fuel did to a factory sealed HD tank I had to cleanout by cutting open,.... TOTAL failure !!!
    Attached Thumbnails Attached Thumbnails 962.jpg   963.jpg   964.JPG  

  14. #14
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Sep 2012
    Posts
    12,407

    Default

    Quote Originally Posted by tzienlee View Post
    This is what 5% alcohol fuel did to a factory sealed HD tank I had to cleanout by cutting open,.... TOTAL failure !!!
    Yes sir Harley sealer sucks.... I've resealed at least 50 of them.. I have POR 15 in my bobber Panhead tanks and it's been in there 10 years with zero problems....

  15. #15
    Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Oct 2011
    Posts
    90

    Default

    No.

  16. #16
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Dec 2010
    Posts
    813

    Default

    I have redcoat in 5 scooters and run hi test, low test, and no test. No problems ever.

  17. #17
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Apr 2016
    Posts
    149

    Default

    Havent sealed my tanks and theyve lasted. i keep them full of fuel during long periods of no riding, like during the winter. i wasnt worried about leaks, more worried about rust, and the tank being full with 93 pump gas and 100ll av gas, theres been no sign of rust after 3 years

  18. #18
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Sep 2009
    Posts
    110

    Default

    If you're planning on spending time/money on a quality paint job, then some tanks should absolutely be sealed.

    Older, reworked (moved tunnel, bungs, etc), inside rust, whatever, then seal that shit or you'll more than likely wind up with bubbled paint.

    Only reason I'm even chiming in is nobody has mentioned one of the best sealers available today (just my opinion).

    CASWELL
    https://www.caswellplating.com/epoxy...k-sealer.html#

    It's two-part epoxy made specifically for fuels with high ethanol content.
    They even advertise it as a repair for other failed sealers.

    I'm sure I'll get roasted as a shill, but take it for what it's worth:
    -Use it and have peace of mind your shit is protected.
    -Don't and wonder how long until that paint fails.

  19. #19
    SamHain
    Guest

    Default

    Fuck sealing tanks. Especially fuck caswell. Trying to remove failed sealer is going to ruin any paint you want to protect. If the thing was built worth half a shit, it will last as long as a paintjob. Nothing lasts forever, make it easy to redo when the day comes.

  20. #20
    tzienlee
    Guest

    Default

    I TOTALLY agree with Samhain,...…. in 44 years of building bikes I have NEVER had a tank rot or split and leak on me,...
    I put it down to good checking of tanks before use,...
    pressure testing with Parffin (kerosene) and if a pinhole is found weld it before use,
    if not using a tank for any length of time I drain and swill out with a thin motor oil, that's easily washed out after a few years if use of the tank is needed,
    the only problems I have had has been from tanks others have ''sealed'' and have not mounted correctly and have split and those that were not tested before a ''sealant'' was used and the cry is always ''weld it up please'',... sorry ,it's full of shit, buy a new tank & start again,...

Share This



Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

Log in

Log in