Small ally tank

[Tinbasherdan]

Neighbour appeared with some sly the other day and asked it I could make him a small fuel tank out of it for his stationary engine. The plate was an eBay buy and I'm not impressed with the quality, welds ended up sooty and untidy as no matter what I cleaned it with, it just didn't want to run very well, hence the less than impressive run round the filler neck, and the rest being cleaned up

 

[The_Yellow_Ardvark]

You did your best, I bet he was happy with it.

 

[MattH]

I'd be happy with that.

 

[Tinbasherdan]

He was happy with it, I would have preffered nice runs rather than ground back and polished up , not very chuffed with it myself if I'm honest, but apparently the sheet cost him 5 quid for a 3 ft square so it can't be that nice a quality

 

[Richard.]

Was it satin anodised?
I have some that I used to build the last tank I made on the cooler project. It is just a case of removing the anodising where you intend to weld. Reason I used it for that particular job is the anodising on the inside of the tank protects against corrosion if the correct solution isn't used.
It looks like there is some sort of coating on it and where you have removed it looks like bright Alu.
What did you remove it with? It's hard to tell from the photo but they look very much like linishing marks. That could very well be your problem. As pointed out in another thread sanders, linishers , grinders are not good for cleaning Alu or removing anodising prior to welding. They smear the coating into the soft Alu impregnating it with contamination which will give you the symptoms you describe. Unstable arc, sooty scabby welding that doesn't flow to great.

 

[Chris Stevens]

Looks like welds on the corners linished off, which is fine if you have good full pen welds, but that may well not be the case if material was anodised, and difficult to weld? Problem with non full pen welds on tanks is vibration related cracking.

 

[Tinbasherdan]

Edges were filed then scotchbrited to clean them up, linishing marks are from cleaning the welds up

 

[Tinbasherdan]

Looks like welds on the corners linished off, which is fine if you have good full pen welds, but that may well not be the case if material was anodised, and difficult to weld? Problem with non full pen welds on tanks is vibration related cracking.

Welds had good pen all round, that was my first check

 

[Richard.]

Edges were filed then scotchbrited to clean them up, linishing marks are from cleaning the welds up

Anodising or not?

 

[Tinbasherdan]

Anodising or not?

Yeah I think so, thought I'd got it off, evidently I hadn't!not a fan of welding ally that's had any sort of coating, you never seem to get it all off properly

 

[Chris Stevens]

[QUOu TE="Tinbasherdan, post: 744622, member: 22607"]Welds had good pen all round, that was my first check [/QUOTE]
Should be fine then, but every difficult to check if all welds on a tank are full pen, unless you have some sort of camera to look inside.

 

[Richard.]

Yeah I think so, thought I'd got it off, evidently I hadn't!not a fan of welding ally that's had any sort of coating, you never seem to get it all off properly

A chemical approach is best. Sodium hydroxide based seems to do the job.

 

[Tinbasherdan]

[QUOu TE="Tinbasherdan, post: 744622, member: 22607"]Welds had good pen all round, that was my first check

Should be fine then, but every difficult to check if all welds on a tank are full pen, unless you have some sort of camera to look inside.[/QUOTE]
El cheapo bore scope to the rescue

 

[Tinbasherdan]

A chemical approach is best. Sodium hydroxide based seems to do the job.

I'll keep that in mind for next time, although next time I'll be supplying the ally myself I think

 

[Richard.]

I'll keep that in mind for next time, although next time I'll be supplying the ally myself I think

Best way. At least you can supply nice clean new sheet

 

[Tinbasherdan]

Best way. At least you can supply nice clean new sheet

Indeed i can

 

[Chris Stevens]

Wonder did you make that tank using a folder? Folding up two "U" sections and then welding them together, would have been less work than welding out of sheet, especially sheet thats nasty to weld. If annealed you can easily fold 1050 using pieces of wood, so no need for a folder even.

 

[Tinbasherdan]

Wonder did you make that tank using a folder? Folding up two "U" sections and then welding them together, would have been less work than welding out of sheet, especially sheet thats nasty to weld. If annealed you can easily fold 1050 using pieces of wood, so no need for a folder even.

It was formed out of two "u" sections Chris. I'm a sheet metal worker by trade, although my garage is sadly lacking all the lovely expensive machines I used to have access to :/

 

[Chris Stevens]

Quite straightforward to make then, but shame customer supplied dodgy material, which made things more difficult. Wonder if you have had any experience of forming aluminum with male and female tools? Need to make some small alloy tanks, and looks like thats the way to go to make the parts, but last time I did anything along these lines, used cast aluminum tools which took ages to make, and were quite costly.

 

[Tinbasherdan]

Quite straightforward to make then, but shame customer supplied dodgy material, which made things more difficult. Wonder if you have had any experience of forming aluminum with male and female tools? Need to make some small alloy tanks, and looks like thats the way to go to make the parts, but last time I did anything along these lines, used cast aluminum tools which took ages to make, and were quite costly.

Not massively to be fair, most of what I did were either on a press brake or box and pan folder. If you can send me a drawing I can have a think on?