I think I am poking the bear....

I am probably starting some C%#* here but I do need to ask this. But I keep reading folks distressing about the ?GOO? when doing the tanks. So here goes.

Has anyone had the tanks welded? I live in an area that is lucky enough to have three air stations, one AF and two Navy. Two shipyards that have their own welding schools that both cater to nuclear vessels, so finding a welder with the skills wont be an issue, I happen to service the X Ray equipment at all of the locations, so finding a good person will not be an issue.

But is it possible? Has it been done? What does the panel say? Please let me know!

Not having a clue what I'm talking about, I'd say no. The tank in our wings are part of the structure and the structure needs to flex. The rivets and proseal allow this.
Ron

The skins and ribs are too thin

I'll go out on a limb here and say that you absolutely cannot weld the tanks. The skins and ribs are simply too thin for welded assembly.

Use the "GOO." It's not that bad.

Welding tanks

My humble opinion is that welded tanks would be too rigid and be subject to cracking. Proseal allows movement in the joints. 6 lbs. per gallon at 21 gallons at about 4 G's can cause a lot of movement. YMMV

Not an expert BUT...

2024 aluminum does not weld well. Welded tanks should be 5052. Since the tanks are a structural part of the wing, I'm not sure how 5052 would fare.

The tanks are 2024 alloy which is generally considered to be un-weldable. It can be done but can result in all kinds of problems afterwards. The pro-seal process isn't that bad just clean it good, scuff it a little then clean it again.

Another downside

If you did change the material so it can be welded the result of welding ribs in thin material you are going to have tell marks on the outside skins and you will have more warpage of the skins. You will end up with less than satisfactory results.

welding tanks

You would have to TIG weld it together (using a different aluminum) and it would cause way too much heat and end up warping. I also do not think you would ever get a seal on something that thin without burning a hole in the material.

Sure it could be done;
But you would have to engineer it to the new material, a 5000 series weldable Aluminum. To do that you would need some co-operation from VANs re- the original design criteria. That would be thicker, heavier material.
The welding; I'm thinking that the ribs would be spot welded, to prevent warping. That would look kind of like rivits, but need specialized equipment. Here's a link: http://www.spotweldequip.com/FFA PDF/9.pdf
The edges would be seam welded to contain the fuel. These can be dolly'd down and filler applied.
Northrop welded a fighter prototype, Here's a lift:
Russell Meredith working at Northrop Aircraft Company in 1939-1941 invented the TIG process. This new process was called "Heliarc" as it used an electric arc to melt the base material and helium to shield the molten puddle. Mr. Jack Northrop's dream was to build a magnesium airframe for a lighter, faster warplanes and his welding group invented the process and developed the first TIG torches.
It's much easier to Proseal the tanks. Thousands of sets have been sucessfully built, I did mine without assistance and they didn't leak, so you can do it too.
The avialability of disposable nitrile gloves has made this work tolerable, don't let the nay sayers get you down.

Everyone is pretty much right on with their statement. Not really a great application for the RV. That being said, there seem to be some some misconceptions as to welding tanks...

If done correctly by a person skilled with tanks warpage won't be a huge issue. Thickness of the skin is irrelevant as to whether it can be welded or not...a good welder can weld beer cans or tinfoil (the talended guys will weld 2 pop cans together to show off). I doesn't have to be Tig'd, in fact the most popular and prevalent tank welding method is gas welded Aluminum although lots of people still use Tig with good results.

Overall people are correct. The end result wouldn't be nearly as attractive as the riveted tank. Typically rosettes are used to weld in the baffles and the edge seams will be exposed...Just not attractive for an RV wing - and as others have said, 2xxx series of AL isn't friendly to the torch like 3 or 5 is.

We built a lot of tanks for the Mullicoupe (Fuel, Oil, wrong size, etc..) - I learned a whole lot during that process! Of Course there is always friction stir welding, or chemical bonding!

Just my 2 cents as usual.

Cheers,
Stein

proseal or duct tape???

Just kidding!...but no doubt, somewhere in the industrial/chemical bonding 3M world, there's a black, fuel-proof 2-sided tape, and you just roll on, add the second skin, and you're done!..no rivets, no mixing, no mess.
(It's probably in the tool-box of the guys who fix undersea fibre-optic cable relays, or the space station!)

well, I guess I won't hold my breath (until I see it in some ACS catalogue)

flyboy1963 said:

or the space station!

Click to expand...

Now I'm waiting for the NASA folks here to say they use proseal.

The USAF uses it

DCat22 said:

Now I'm waiting for the NASA folks here to say they use proseal.

Click to expand...

The Air Force uses the same type of stuff. Not sure about the manufacturer but we called it B2 and B 1/2. The numbers denote the "curing" time. We always put everything on a 24 hour cure check regardless of the curing time.

I'm on the tanks myself and have procrastinated due to the fact that once you get started you have to keep going for that session. Just my opinion but you should do it the way Van intended it. Trust me, it is not as bad as it's reputation.

tanks

Really not a hard job to build RV Tanks. Just think what you are going to do. Plan your moves,,