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James Maher wrote:
For you guys that have built aluminum wing tanks and are using automotive fuel with ethanol,
which Pro-Seal did you use?
I see two types in the Aircraft Spruce catalog.
One is called Pro Seal P/S 890 Class B ad appears to be a one part sealer.
The other is called Pro-Seal Type tank sealant and is described as a two part polysulfide in a cartridge.
I'm confused.
I am making plans to build an aluminum fuel tank from 5052 sheet.
I think I'd like to use the Pro-seal for the internal flanged baffles that will be rivet in and the sump fittings plate.
The rest of the tank (perimeter) will be joined together by Tig welding.
Which one will hold up to Mogas with ethanol?
Thanks,
Jim
Hi Jim,
I'd strongly recommend contacting the sealant mfgr directly for that type of question. Here's a link to the 890 product. It states that the product has excellent resistance to alcohols. It also includes a phone # to call with questions. I'd also ask about resistance to other additives that might be in current automotive fuels, if that's what you plan to use.
http://www.bergdahl.com/baps890b.pdf
There are several other brands available (Van supplied Flamemaster brand sealant for my RV-7 tanks.) The sealant comes in several consistencies from pourable to very thick & several curing times from very short to days/weeks for full cure. I'd recommend a fairl long cure time. The stuff Van supplies begins to cure within about 20 minutes (affected by ambient temperature). If all you do with the sealant is the baffles, a small cartridge (I think most are around 3 oz) should be plenty.
FWIW, I've heard of problems with TIG welds ending up being porous, if not done perfectly. If you build the tank with flanges for each joint, it's fairly easy to use the sealant for all the joints. *Perfectly clean surfaces are essential for proper bonding.* You can get closed-end 'pop' rivets , but with proper technique, regular 'pops' can be sealed effectively. You can also use 2024, which might be a few oz lighter than a 5252 tank. :-)
Give me a call if I can answer any other questions.
Charlie
601-879-9596
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