AdamR
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| posted on 5/12/07 at 11:52 AM |
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fabricating a fuel tank
For a couple of reasons that I wont bore you with, I want to fabricate my own fuel tank.
I'm not set up to weld ali, so I'm limited to using my MIG and stainless or mild steel sheet as the material. I'm leaning towards
mild steel as I've not worked with stainless before.
How easy/difficult is it to get a fuel-tight seal with MIG welding? Will I have to use gallons of sealant?
How much of a problem is corrosion inside a mild steel fuel tank?
Just looking for any feedback from anyone who has done this really... I did a search and was surprised to not get any results. So maybe it's not
a job that many people attempt to do themselves?
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britishtrident
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| posted on 5/12/07 at 11:59 AM |
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Personally I would braze (bronze weld) or silver solder a fuel tank --- more chance of getting it leak tight.
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rallyingden
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| posted on 5/12/07 at 12:02 PM |
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Can you Mig weld stainless ?
I thought it had to be Tig
Then AC Tig for ally
RD 
[Edited on 5/12/07 by rallyingden]
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Hammerhead
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| posted on 5/12/07 at 12:13 PM |
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I have a lotus elise mild steel tank. I noticed that it is galvanised on the inside. So maybe using galvanised panels will be a nice solution.
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Mr Whippy
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| posted on 5/12/07 at 12:24 PM |
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oh the fumes, cough
quote:
Originally posted by Hammerhead
I have a lotus elise mild steel tank. I noticed that it is galvanised on the inside. So maybe using galvanised panels will be a nice solution.
Fame is when your old car is plastered all over the internet
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westcost1
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| posted on 5/12/07 at 12:25 PM |
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I had a go at making a mild steel tank took a long time and had to be very careful not to blow hols in it make shore you wire brush off any sooty
residue after each run of weld otherwise it will leak through the gap cased by the residue. It is also hard to get the thing to weld up straight and
not twist. I did manage to get it finished in the end but it looked a bit cr@p and started to go rusty inside so I got a Westfield ally tank instead.
Just to be on the safe side.
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UncleFista
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| posted on 5/12/07 at 12:26 PM |
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I've yet to see the inside of a mild steel tank with much rust, the petrol fumes seem to protect from rust.
SS can be welded using a MIG, you obviously need to use S/S wire (unless you want the welds to rust) but it's just like welding M/S..
Tony Bond / UncleFista
Love is like a snowmobile, speeding across the frozen tundra.
Which suddenly flips, pinning you underneath.
At night the ice-weasels come...
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Hammerhead
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| posted on 5/12/07 at 12:27 PM |
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quote:
Originally posted by Mr Whippy
oh the fumes, cough
quote:
Hold your breath! 
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BenB
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| posted on 5/12/07 at 12:36 PM |
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If you're a good welder I'm sure its definately possible. When I tried it I got lots of leaks..... but then if I took a GCSE in welding
I'd get a U grade....
If you do go for galvanised I'd be careful- a fuel tank would take a whole load of welding.... Lots of fumes....
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Mr Whippy
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| posted on 5/12/07 at 12:43 PM |
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stainless is the way to go, I have a 15 year old one in my Falcon and it still looks like new, like having a mirror under the car 
Fame is when your old car is plastered all over the internet
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AdamR
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| posted on 5/12/07 at 12:54 PM |
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Yes, not keen of galvanised steel for the reasons already stated... plus it's a bit heavier.
Stainless sounds good, but I thought it was supposed to be hard to get good results with a MIG. What sort of sheilding gas is required? Can I still
use CO2?
Will look into brazing - think I read somewhere that it can be done with a MIG.
As yet not many replies from people that have actually made their own tank. Someone on the forum must have tried this and had some success?!
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RazMan
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| posted on 5/12/07 at 12:54 PM |
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I would think about making it in ally - cut and tape the panels together and take it round to a local ally welder. The result will be lighter and
probably cheaper.
Cheers,
Raz
When thinking outside the box doesn't work any more, it's time to build a new box
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swood
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| posted on 5/12/07 at 01:02 PM |
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Fabricated Mild Steel Fuel Tank
Just finished my tank, fabricated from 1.5 CR4 M/S sheet, bit heavy but am trying to make it 'locost' and not really worried about overall
weight, just doing it cheap.
Engine is Sierra 2.0 EFI so needed swirl pot in tank.
Although not tested with petrol yet, I have pressure tested it by bunging / sealing all the inlet / outlet holes, then using a car tyre pump put about
5lbs of pressure in it and went over al the joints with a water /detergent mix applied by paint brush, had about 5 leaks, which were marked, then
dried tank off and applied good hot tack to the offending position, retested and after about 3 attemptes no more bubbles, retested with a bit more
pressure and appeared ok, so I assume all will be well.
Good Luck!
When you're up to your ass in alligators you tend to forget the initial objective was to drain the swamp !.
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nitram38
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| posted on 5/12/07 at 01:05 PM |
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I would recommend an ali tank aswell. Don't forget to put some baffles inside.
If you can, rather than weld everything, get the corners rolled (not sharp bends) so that you end up with one seam weld "tube" with two
end caps welded on.
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robertst
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| posted on 5/12/07 at 01:38 PM |
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i tried to make a fuel tank this summer, and found out that bending the sheet was impossible, so i ended up with a tank with round corners... welding
it was a doddle though. if i get my head around it, i might opt for an ally one, welded by a pro welder...
mind you: stainless is heavier than regular steel.... also quite more expensive. the only advantage of an ally tank is its weight and anti corrosion
features, but it will be more fragile and it might break in the event of a rear-end crash...
Tom
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muzchap
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| posted on 5/12/07 at 02:35 PM |
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I made mine out of ally - I have the pics and the dimensions somewhere if you want them?
Fits perfectly into a Luego chassis.
As long as your welding is good (and the guy who did mine was like a robot) it's fine.
I've had mine for over 18 months and not even a 'sniff' of a leak.
Being ally as well - no problems with rust build up etc etc.. - BUT what is amazing is just how much 'junk' those petrol pumps stick in
your tank - I though THEY were filtered?
M
------------------------------------
If you believe you're not crazy, whilst everybody is telling you, you are - then they are definitely wrong!
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Peteff
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| posted on 5/12/07 at 02:47 PM |
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I migged my mild steel one, it's no work of art but it doesn't leak It's 18g steel and it's hidden in the boot so nobody
sees it anyway  I put 2 baffles in it.
[Edited on 5/12/07 by Peteff]
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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DavidM
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| posted on 5/12/07 at 03:26 PM |
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I MIG welded my mild steel tank. No problems, but I am a welder by trade. It's been in the car for 2 years now and the inside shows no signs of
rust. Make sure you cure any leaks before putting petrol in it, as it's a bit dangerous welding it afterwards.
Stainless steel tanks can be MIG welded, but you'll need Argon shielding gas. You'll also get much more distortion during welding.
I'm going to make an Aluminium tank for mine in the near future, but only to save weight.
David
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ewanspence
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| posted on 5/12/07 at 03:32 PM |
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por15 tank sealer
Just to be sure it is sealed you could use the tank sealant stuff for old rusty tanks..
por15 tank sealer
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Litemoth
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| posted on 5/12/07 at 03:35 PM |
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To be honest fellas, I have to question the wisdom of fabricating a tank.
Uncoated steel will shed into the fuel and galvanising would need to be done post welding otherwise joints will rust if galvanised sheet is used.
I considered this myself but it worked out a costly and possibly frustrating exercise. It may be viable if making a batch but not a one off.
The time taken will be considerable due to the lack of patterns, stainless would have to be neatly cut and folded (not easy without a big guillotine
and benders). The welds have to be faultless (sealant at £22 a pot?). the thing has to be mounted somehow too.
A swirl pot may be needed. in/out tubes have to be made and attached, hole/s cut for sender and its screws not to mention baffles, welding rods/wire,
gas etc etc.
I bought this light and durable aluminium one, swirl-potted, baffled and made to my drawings for £150 incliding aluminium mounting straps.
[Edited on 5/12/07 by Litemoth]
[Edited on 5/12/07 by Litemoth]
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mark chandler
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| posted on 5/12/07 at 05:03 PM |
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I,ve migged a few steel tanks over the years with varying degrees of success until I perfected my techique.
The trick is to be constant in your runs, then doubling back where you start and finish 9 so:
start 1/2" go the wrong way then return covering you previous weld
You do this becuase Mig suffers from cold start which leads to pin holes, so as few starts as possble and make sure the steel is really clean.
Its not an issue, certainly worth having a go, £10 worth of steel and a few hours, if in the end its pants at least you have tried.
I found you also need to design the tankl with as few welds as possible, try and get all the bottom edges folded metal.
Regards Mark
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Wadders
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| posted on 5/12/07 at 05:23 PM |
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A couple of tips if you decide to have a go.
Don't weld to or from a corner, start and finish at least an inch or so each side. To test after welding paint all the welded seams with
whitewash or similar and then pour some parrafin into the tank, swish it round so all the seams get covered and then let it stand for a while, any
pinholes will show up as a stain.
Al
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scutter
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| posted on 5/12/07 at 05:26 PM |
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I made two tanks last month, here's a picture of one, i think we had 9 leaks, which were corrected by grinding back the leak area and rewelding,
now water tight for 8hrs.
The outsides being Powdercoated, and the fuel should protect the inside.
ATB Dan.
 
off to powdercoating
The less I worked, the more i liked it.
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jacko
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| posted on 5/12/07 at 05:45 PM |
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I made mine out of m/steel welded with a mig no problems at all
no rust inside after 3.5 years
Jacko
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NS Dev
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| posted on 5/12/07 at 07:38 PM |
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as said further up, key thing with mig is remember it will always have cold starts, so you need to overlap your previous stop points by about 15 to
20mm with your next start, so that the weld is penetrating by the time it reaches the end of the previous weld.
As said by others, a migged mild steel tank will almost certainly look a bit agricultural, but it can be made to work just fine, I've done it
before!
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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