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I will just add my two cents to this. When I split my tanks open, I take them to an automotive machine shop. They have a giant, horizontal belt sander. It’s very purpose is to true up slightly warped parts. I give the guy twenty bucks and the tank halves are as true as the day they were made, in about five minutes. Also, the last tank I did was a WD3S Wizard. Rather than fuss with a gasket, I tried an experiment and used that red, jelly donut-like, anaerobic sealant, the same stuff used on crank case halves. It is known to stand up to ethanol, at least as good as anything can. I let it set up for a week, just to be sure to give it the best chance at success. I ran the motor at the Lowell Mass meet in September, for at least an hour straight, with no leaks evident. Going forward, I think I will do this again. It was much easier than the gasket method.. It “seams” to work, if you’ll pardon the pun.
I sandblasted the gas tank halves today, and will try to lap them tomorrow.
Decided to read up on Anaerobic sealants. Found this article that makes
me nervous about using anaerobic sealants on the Mercury tank.
What’s your favorite “gas proof sealant”?==============================
4. Using an RTV or anaerobic gasket maker on an application that is exposed to gasoline-
Only solvent-based gasket makers have the ability to stand up to repeated direct contact to gasoline. Powersports vehicles, antique cars, gas-powered tools, and equipment all tend to have their gaskets exposed to gasoline. Gas weakens RTV and anaerobic flange sealants. If your assembly will have direct exposure to gasoline, you should use a solvent-based gasket maker.
https://www.enginebuildermag.com/2017/06/10-common-gasket-maker-mistakes/
===================Prepare to be boarded!
I know my “test” of anaerobic sealant on a Mercury tank is not very conclusive because it was more a vibration test than a time endurance test. As I said, it was an experiment…..but it was based on the fact that manufactures have been using this sealant on crank case halves for many years, now, to replace the old “Type M,” 847-type sealer, that was failing due to ethanol. That sealer used to work GREAT, before ethanol came along, it would seem; but not anymore. Also, I don’t know what they mean, exactly, by “solvent-based sealant?” If there truly IS something that stands up to ethanol based fuel, even better than the anaerobic type, I would sure LOVE to know what it is! The article doesn’t name an actual brand.
Note: I tried “Yamabond” one time, in direct contact with gasoline and it turned promptly to mush.
Long live American manufacturing!
Louis, Seal-All is on my list of “good as any”. Just bothers me that there’s
not a product that says something more convincing than “resistant to fuel”.
The gasket I took out was about .019 thick….. closer to 1/64″ I believe,
but after much lapping of the halves today, I can still see a gap on the outside
seam when I hold the two halves together. I didn’t bolt them together dry yet to see
how it looks. I did quit a bit more lapping after the photos were taken.
The old window pane I used was 1/8″ thick, laying on my workbench that’s
made from a solid oak door. It all seemed pretty flat, but perhaps not perfect.
I glued 4 sheets of sand paper on each side of the glass. 60 grit on one side, 100
on the other. I first duct tapped the window to the work bench to hold it steady, but
ended up screwing a board along each side of the mirror. It didn’t wiggle around then.
The original machining on the tank half seams was rather crude, with
lots of machining grooves, but perhaps that helped hold that 70 year old “mystery” sealer in place.
The Karropak I have on hand is only 9″ wide, so I’ll check out your part number.
Thanks again!
Prepare to be boarded!
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