Fuel tank construction
Discussion
Anyone got any experience making alloy fuel tanks? Started making my own, all was going well until i tacked the baffles (well anti slosh) parts in and then it warped like mad and had to scrap it. I used heavy bits of steel to hold things in position, but I suspect i need a jumbo G-Clamp to actually clamp it to the bench. Any advise?
Never done anything like that and I wouldn't know where to start tbh, but I remember reading an article by Ian Massey-Crosse about his Grantura restoration, describing how the tank was folded, crimped and soldered out of some sort of tinned steel plate (it had a special name, but I don't remember what it was).
ETA: Perhaps foam instead of baffles would be easier to make?
>> Edited by GreenV8S on Sunday 14th May 12:03
ETA: Perhaps foam instead of baffles would be easier to make?
>> Edited by GreenV8S on Sunday 14th May 12:03
The steel was probably called "Zintec". It's a mild, weldable steel with a thin coating of zinc that is (I think!) rolled on to it in production. Unlike galvanised steel, it can be welded.
I don't think you'll prevent distortion, no matter how rigid the jig. Thin sheets just do that! Definitely use foam rather than baffles if possible. A sports car firm I once worked for had a problem for a while with the baffles fatiguing their welds as the tank expanded and contracted and this resulted in leaks!
I don't think you'll prevent distortion, no matter how rigid the jig. Thin sheets just do that! Definitely use foam rather than baffles if possible. A sports car firm I once worked for had a problem for a while with the baffles fatiguing their welds as the tank expanded and contracted and this resulted in leaks!
Done some more test welds, still keeps warping. More photo's over at www.mez.co.uk/ms13.html
Might have to admit defeat and get a pro to do it.
eliot.
Might have to admit defeat and get a pro to do it.
eliot.
What sort of welding equipment are you using? If it's gas then (IMO)it will be almost impossible to do without heat spreading and distorting... MIG/TIG might be better. Never done this myself but did some oxy-acetylene and MIG stuff way back when. That's my take on it anyway!
Have to say foam sounds sensible but if you go the baffle route why not fold an inverted U shape and spot/button weld to the roof of the tank (if you see what I mean)
Best of luck.
Just looked at your pic again and can see the gas bottles!
Have to say foam sounds sensible but if you go the baffle route why not fold an inverted U shape and spot/button weld to the roof of the tank (if you see what I mean)
Best of luck.
Just looked at your pic again and can see the gas bottles!
leorest said:
What sort of welding equipment are you using? If it's gas then (IMO)it will be almost impossible to do without heat spreading and distorting... MIG/TIG might be better. Never done this myself but did some oxy-acetylene and MIG stuff way back when. That's my take on it anyway!
Have to say foam sounds sensible but if you go the baffle route why not fold an inverted U shape and spot/button weld to the roof of the tank (if you see what I mean)
Best of luck.
Just looked at your pic again and can see the gas bottles!
I'm TIG welding it. Someone over at v8 owners has suggested anealing the metal first. Worth a try. I think the main difference is that a pro would fold and swage the majority of it, which as an amateur I cant do.
Dont bother annealing it as it wont make any difference. When you anneal it you will also get distortion. A fabricator would fold it up and insert the baffles and then tack them in.Also if the baffles had a 90 degree return on the ends then you would have a lap weld instead of a tee fillet. The lap is easier.
The top edge has distorted the most because it is free to move. This can be held with another piece of flatbar tacked to the back edge. In the welding game its called a 'strongback' and it would be removed after the tank is finished. It looks as if you have too many tack welds and also they look too big which is causing all that distortion. Also it would be much easier if you used thicker material, say 1.6 mm or 16 gauge sheet minimum and wouldnt add much to the weight.
The top edge has distorted the most because it is free to move. This can be held with another piece of flatbar tacked to the back edge. In the welding game its called a 'strongback' and it would be removed after the tank is finished. It looks as if you have too many tack welds and also they look too big which is causing all that distortion. Also it would be much easier if you used thicker material, say 1.6 mm or 16 gauge sheet minimum and wouldnt add much to the weight.
Edited by ferlin on Sunday 18th June 22:06
Thanks for that. The ally is 2mm NS4 , It has also been suggested that I create slots in the tank walls for the baffles, so they can be welded from the outside after the tank has been boxed in - so to speak. Although I like the idea of putting a 90' return on the baffles, as I know I could tack them with minimal heat input.
Having said all of that, Ive been quoted around £150 by allyfab to make the tank from scratch - So i'm trying to decide whether to spend another £50 on ally and have another go, with a high risk of me lot liking the end product but with the potential satisfaction of doing it myself - or sit back and get an expert to do it.
Ive added more photo's to my website:
www.mez.co.uk/ms13.html
eliot.
Having said all of that, Ive been quoted around £150 by allyfab to make the tank from scratch - So i'm trying to decide whether to spend another £50 on ally and have another go, with a high risk of me lot liking the end product but with the potential satisfaction of doing it myself - or sit back and get an expert to do it.
Ive added more photo's to my website:
www.mez.co.uk/ms13.html
eliot.
Edited by eliot on Monday 19th June 10:38
If someones offering to make you an alloy tank to your spec for £150 all in I would snap they're hand off!
Once you have the structure of your tank then you have to start leak testing it, having been there with my old lotus tank I'd not go there again out of choice!
The beauty of leak testing is you test it with water, it doesnt leak, then you try petrol and it pisses out, then you have to weld it again, oh tis full of petrol vapour!
Lol buy it and spend the time on another project!
Once you have the structure of your tank then you have to start leak testing it, having been there with my old lotus tank I'd not go there again out of choice!
The beauty of leak testing is you test it with water, it doesnt leak, then you try petrol and it pisses out, then you have to weld it again, oh tis full of petrol vapour!
Lol buy it and spend the time on another project!
What about making the baffles up outside the tank and having a slot fit with a small interference section to lock it in place?
The tank will remain in shape and the baffels will still work if they get out of shape?
Would probably need some use of a 'size 10 fixing tool' to make it work though.
The tank will remain in shape and the baffels will still work if they get out of shape?
Would probably need some use of a 'size 10 fixing tool' to make it work though.
It has also been suggested that I create slots in the tank walls for the baffles, so they can be welded from the outside after the tank has been boxed in - so to speak.
That method is called plug welding and it wouldnt be good practice to use it here. Its usually used where there is limited access to the plates inside, which isn't the case here. Also there's more chance of it leaking and it would still distort.
If you can get that tank made for £150 then I would recommend that. Its not really a beginners type project to be totally honest and you could end up with all sorts of problems doing it yourself.
It will take a tradesman a days work to fab it up and weld it and to check it out properly it should really be pressure tested.
That method is called plug welding and it wouldnt be good practice to use it here. Its usually used where there is limited access to the plates inside, which isn't the case here. Also there's more chance of it leaking and it would still distort.
If you can get that tank made for £150 then I would recommend that. Its not really a beginners type project to be totally honest and you could end up with all sorts of problems doing it yourself.
It will take a tradesman a days work to fab it up and weld it and to check it out properly it should really be pressure tested.
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