Gas resistant silicone gasket sealant? | FerrariChat

Gas resistant silicone gasket sealant?

Discussion in 'Technical Q&A' started by Etcetera, May 28, 2008.

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  1. Etcetera

    Etcetera Two Time F1 World Champ
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    Can anyone recommend the best gas resistant silicone gasket sealant? I need something to help seal old float bowls and to form a gasket between the carb and intake manifold an old Briggs.

    Thanks in advance.
     
  2. 2NA

    2NA F1 World Champ
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    A fairly thick paper gasket fitted DRY, no sealant whatsoever.
     
  3. Etcetera

    Etcetera Two Time F1 World Champ
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    Looks like that's a good idea for the carb and manifold. I still need something for the float bowls, though.
     
  4. FandLcars

    FandLcars F1 Rookie

    Aug 6, 2006
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    I went to Pep Boys last month, and they had just about every type of silicone you can imagine. Many, perhaps all are not compatible with gasoline, but you could check. Using silicone in a carb may not be a good idea... if any small bits break loose, it would not take much to plug or gum up something small and important. If your problem can't be handled with a normal gasket or kit, I guess it wouldn't hurt to try silicone, and then find a new carb or parts if that doesn't work. Good luck :)
     
  5. Etcetera

    Etcetera Two Time F1 World Champ
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    #5 Etcetera, May 29, 2008
    Last edited: May 29, 2008
    You guys are right. I'm going to skip the silicone on the float bowls...it'll just come back to haunt me. I'd order a kit, but none are available. I did find gaskets that are the correct length, but they aren't formed to the complex shapes of each bowl, and they are impossible *****ers to get seated long enough to get the bowls on. My thought was to use the silicone to hold them in place in certain areas long enough to affix the bowls, but the first set expanded shortly after coming in contact with the Permatex that I was using.

    :float bowls are on an old twin cyl motorcycle, not on an old Briggs. :p
     
  6. mk e

    mk e F1 World Champ

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    Silicone will break down and bugger up the carb. If you just want to keep the gasket in place for assembly you might try thick grease. The grease is very sticky, compatible with the gacket material and will just wash away once you add fuel.
     
  7. 2NA

    2NA F1 World Champ
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    What kind of motorcycle?
     
  8. andrewmr

    andrewmr Formula Junior

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    I used Hylomar to hold the rubber o-rings (that are used for float bowl gaskets on my bike) in place until I could get the bowls in place and the screws snugged up.
     
  9. finnerty

    finnerty F1 World Champ

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    There's really no such thing as "petroleum proof" silicone --- some blends are more resistant than others, but none of them will tolerate long term exposure to gasoline.

    Hylomar is the only way to fly when you want to seal against fuels and oils (i.e., petroleum products).
     
  10. brian.s

    brian.s F1 Rookie
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    Hylomar ROCKS!
     
  11. cavallo_nero

    cavallo_nero Formula 3

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    3bond1211 i think this is the name, completely gas resistant.
     
  12. snactolate

    snactolate Rookie

    Mar 16, 2010
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    ultra black silicon will work as a gasket and is impervious to petrolium products
     
  13. smg2

    smg2 F1 World Champ
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    Permatex Anaerobic flange sealant, no gasket needed and once cured it is impervious to attack by any conventional solvent, fuel or oil.

    pricey though. roughly $15 or so per tube of 50mL.

    Same as Loctite 515, same Co. at one time.

    The 1211 by three bond is good but I wouldn't use it on a float bowl where it's in constant contact with fuel and vapors.
     
  14. 350HPMondial

    350HPMondial F1 Veteran
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    Wow, your first Post,, #1 is so wordy......
    and, wrong. (sorry)

    Once you invent a Gasoline resistant Silicon, call me & we will patent it.
    (Not kidding.)

    Edwardo
    Chemical Engineer
    EPA/Dept. of Public Health Certified.
     
  15. wildegroot

    wildegroot Formula 3
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    Actually, Dow Corning makes a #730 RTV sealant that is "resistant to many fuels, oils & solvents" but it's expensive. I've used it on intake manifold gaskets and used it to seal the intercooler housing on my 308 as insurance, even though it's also sealed with O-ring string. I had it all apart recently and it seemed to be holding up. The way I use 730, it's not immersed in gasoline. It's only exposed to reversion spray and fumes. The instructions do say it can be used for "assembly and repair of fuel lines and tanks on small engines" so who knows?

    In a pinch, when a carburetor insists on leaking, I usually use Hylomar since you can still easily disassemble the components. Great stuff but the fact that it doesn't harden makes it useless in some applications.

    Wurth Orange Flange Sealant is anaerobic and also seams to be fuel proof. It only hardens in the joint but then it turns to concrete so it's not recommended for carburetors. Same thing - for certain applications it can't be beat.
     
  16. finnerty

    finnerty F1 World Champ

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    No such thing ---- All silicones are incompatible with gasoline, some mixtures and formulations will last longer than others, but in the end, they will all dissolve or get broken down ----- PERIOD.
     
  17. wildegroot

    wildegroot Formula 3
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    You can say "period" all you want but until you've tried it you don't really know do you?
     
  18. finnerty

    finnerty F1 World Champ

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    #18 finnerty, Mar 18, 2010
    Last edited: Mar 18, 2010
    I'll rely on the 30 years of data collected by the M&P Engineers in my industry regarding the performance and usage specs of silicone sealants (including RTV's) ---- they do really know. If the experts in the aircraft and aerospace industries all say these sealants are not compatible with hydrocarbons, I'll take their word for it ---- and, I'll borrow their "period" on the issue.
     
  19. wildegroot

    wildegroot Formula 3
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    Are you still using a dial telephone? I do admit they were more reliable.
     
  20. BT

    BT F1 World Champ
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    Permatex #1 & #2 form-a-gasket, and flexible thread sealant are all gasoline resitant. They do not have high adhesion though, they are just sealants that need varying amounts of time to cure. #1 is quick and dries relatively hard, #2 is slower and dries very flexible, threaded sealant never dries.
    :)
    BT
     
  21. ramosel

    ramosel Formula 3

    Sep 11, 2004
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    It may not be perfect, but I use the Ford Silicone they use to seal the oil pans on the diesel motors. Very sticky grey stuff. Its stands up to oil, diesel, gas and brake cleaner better than anything I've used.

    I think its Ford part number F5TZ-19G204-AB. Only comes in a short caulking gun tube.

    Rick
     
  22. speedmoore

    speedmoore Formula 3
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    Dow Corning 730

    Nothing else comes close.
     
  23. Fred2

    Fred2 F1 World Champ
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    Agreed -

    I have used this to seal fuel pumps to gas tanks.

    No problems, other than price ($$$).
     
  24. speedmoore

    speedmoore Formula 3
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    Hylomar is better application for gasline and race fuel. But for all engine, transission and other areas 730 is the ticket
    yes you might "think" it is expensive at $80 per 7oz tube unless you like resealing things three to four times over one with the 730

    I buy it buy the case, it's that good at keeping things sealed and way fewer comebacks due to leaks as compared to anything else
     
  25. Speedmade

    Speedmade Formula Junior
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    I learned of this stuff 20 years ago when I worked at a gas station. We used this to seal all the hose connections.
    They make this version that works with gaskets, threads, and sticks to just about any type of material. I used this to seal the fuel level sender on my old Falcon, which was at the bottom of the tank. Worked great.

    http://www.gasoila.com/products/items/pls2premiumthreadandgasketsealer.html
     

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