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Brazed aluminum fuel tank

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WilliamMartin

Member
Has anyone or would it be safe to use .063 aluminum to build a fuel tank for an RV12 replacement? I can’t get my rivet one to stop leaking. No one wants to weld one for me, and my only options are to braze it or start all over. Any suggestions would helpful.
 
It wouldn't be "brazed" , but TIG welded. You would need an alloy that's weldable (6061 is common) , and the associated bungs / filler neck, ect. Nothing terribly difficult, but I wouldn't be surprised if someone out there has already done it. I'm not that familiar with the RV-12 tank, but I am familiar with the rivet/sealed tanks on the other RV's.
 
Have you checked Van's for replacement? Less labor than fabricating a new one. It's a tank kit but probably easier than scratch build
 
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WilliamMartin said:
Has anyone or would it be safe to use .063 aluminum to build a fuel tank for an RV12 replacement? I can’t get my rivet one to stop leaking. No one wants to weld one for me, and my only options are to braze it or start all over. Any suggestions would helpful.
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Purchase a factory made tank from Van's.
 
fixnflyguy said:
It wouldn't be "brazed" , but TIG welded. You would need an alloy that's weldable (6061 is common) , and the associated bungs / filler neck, ect. Nothing terribly difficult, but I wouldn't be surprised if someone out there has already done it. I'm not that familiar with the RV-12 tank, but I am familiar with the rivet/sealed tanks on the other RV's.
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What I was thinking is using the aluminum rods that melt At 730 degrees I’ve seen advertised. Says they are stronger than the aluminum with a tensil strength of 43,000 psi. Sure would save me time and money.
 
WilliamMartin said:
... Sure would save me time and money.
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Can you describe what sealing efforts you have attempted so far on the original tank? Did you install an access plate and try resealing it from the inside?
I can't see how starting from scratch fabricating a whole new tank with different materials (6061 vs 2024) & different method (welding vs riveting) will be any kind of time or expense saver.
 
WilliamMartin said:
What I was thinking is using the aluminum rods that melt At 730 degrees I’ve seen advertised. Says they are stronger than the aluminum with a tensil strength of 43,000 psi. Sure would save me time and money.
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Nope, don't do it. I'm in the business of aircraft structures, unless the metals are compatable, (I have zero details on your tank) , you may end up with a total mess. The fact you mentioned a rivet and sealant? Complicates the matter. If your looking to salvage what you have, share some detailed pictures with the braintrust.
 
Ralph Inkster said:
Can you describe what sealing efforts you have attempted so far on the original tank? Did you install an access plate and try resealing it from the inside?
I can't see how starting from scratch fabricating a whole new tank with different materials (6061 vs 2024) & different method (welding vs riveting) will be any kind of time or expense saver.
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I have only tried resealing it 5 times with Chem seal. It’s under the stiffing bar that’s riveted and screwed to the tank. I’m going to have one welded up with .063 aluminum.
 
WilliamMartin said:
Has anyone or would it be safe to use .063 aluminum to build a fuel tank for an RV12 replacement? I can’t get my rivet one to stop leaking. No one wants to weld one for me, and my only options are to braze it or start all over. Any suggestions would helpful.
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I had mine leak at the corners where the bends are. I purchased
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FLAMEMASTER CHEMSEAL 6 OZ CS3204 B2 from Aircraft Spruce and used on the outside of the tank on all the seams and rivets. It is working so far. I had used 93 octane with alcohol in it. I think the alcohol caused the leaks. Since I use 90 octane non alcohol mixed with 100LL and have no problems.
 
fixnflyguy said:
Nope, don't do it. I'm in the business of aircraft structures, unless the metals are compatable, (I have zero details on your tank) , you may end up with a total mess. The fact you mentioned a rivet and sealant? Complicates the matter. If your looking to salvage what you have, share some detailed pictures with the braintrust.
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+1

Avoid that like the plague. May be fine for lawn furniture, but even ig that stuff was any good, you are going to anneal the 6061T6 material, significantly reducing tensile strength, if that is even the material. You are also getting close to melting point at 800* and can trash the sheet or deform it, if not carefull. Nobody brazes AL, TIG welding is the standard for weldable alloys, like 6xxx. 2024 is NOT weldable, but also may not be compatible with that rod. likely designed for 3 & 6 series.

There is a reason many folks don't want to weld your tank. FAR better off mastering the art of using sealant.
 
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If you are going to attempt this, use 3003 or 1100, not 6061
The heat affected zone on 6000 series will crack in time.

For what it’s worth, making the tank two or three times heavier than it need be, doesn’t make a lot of sense.
 
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