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Location:
Melbourne
Registered:
August 2003
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Steel ~ What type to use for this application?
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Tue, 17 February 2004 09:36
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Hi,
I need a sheet steel which meets the following requirements;
Must resist petrol exposure.
Must resist weather exposure (ie. water).
Must be weldable with MIG.
Any ideas what commonly available steel I should look at? Would galvanised steel sheet be okay or would it oxidise?
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Location:
Sydney
Registered:
April 2003
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Re: Steel ~ What type to use for this application?
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Tue, 17 February 2004 09:49
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No idea about what sort of steel you will need but just curious, what are you making? I saw your post before about gaskits. Are you trying to make your own drop tank or something?
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Location:
Lost in the K hole
Registered:
May 2002
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Re: Steel ~ What type to use for this application?
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Tue, 17 February 2004 09:51
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if you weld the gal, it will corrode along the weld seam, so you'd be better off welding up mild steel, and getting it gal'd (if thats what you wanted to do)
best bet would be stainless tho - but youre talking $$
what about alloy?
you making a petrol tank?
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Location:
Brisbane
Registered:
February 2003
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Re: Steel ~ What type to use for this application?
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Tue, 17 February 2004 10:08
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| SeptemberSquallIndustries wrote on Tue, 17 February 2004 19:36 |
d a sheet steel which meets the following requirements;
Must resist petrol exposure.
Must resist weather exposure (ie. water).
Must be weldable with MIG.
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stainless steel (but not the aluminised tin they use in exhausts)
any galvanic coating will burn off when you weld it so unless you grind clean and re-galv, galvanised mild steel isn't what you're after.
you could go for an exotic alloy - somthing with titanium or aircraft alloy - but you probably need TIG and the former woul need a plasma cutter.
you could look at alloys if you were able to bolt up or rivet the joins rather than weld.
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Location:
Melbourne
Registered:
August 2003
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Re: Steel ~ What type to use for this application?
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Tue, 17 February 2004 11:04
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just curious, what are you making? I saw your post before about gaskits. Are you trying to make your own drop tank or something
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you making a petrol tank?
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I'm thinking about it, yes.
Would immersion in petrol protect mild steel from corrosion?
If so, couldn't I weld/assemble the tank and then apply rust protectant/etch primer/enamel to the exterior surface to protect against exterior corrosion?
Can I weld stainless with MIG?
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if you weld the gal, it will corrode along the weld seam, so you'd be better off welding up mild steel, and getting it gal'd (if thats what you wanted to do)
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I like this idea provided galvinising the welded product isn't too expensive.
What are the implications for welding alloy? I've only welded a few times before and only have MIG available.
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: Steel ~ What type to use for this application?
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Tue, 17 February 2004 11:49
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long and short of it, 304L or 316L.
| SeptemberSquallIndustries wrote on Tue, 17 February 2004 20:36 |
Hi,
I need a sheet steel which meets the following requirements;
Must resist petrol exposure.
Must resist weather exposure (ie. water).
Must be weldable with MIG.
Any ideas what commonly available steel I should look at? Would galvanised steel sheet be okay or would it oxidise?
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afaik, most metals resist petrol exposure... unless there are acidic or basic additives to assist corrosion.
weather exposure is a bit more tricky. almost all materials are affected by weather exposure, just some more and some less. this is also a problem if you get any moisture in the inside of the tank which will sit under the petrol and cause corrosion from the inside.
good stainless steels (with enough chromium content) will do a pretty good job.
weldable with mig rules out most aluminium alloys, and you don't really need any fancy 6000 or 7000 series anyways (ie heat treated for strength) you just need thickness for strength, since weight is not imperative.
i would rule out steel to start with. galvanised is terrible to weld and it needs to be recoated.. i don't fancy dipping a whole fuel tank is liquid zinc tho... nor do i like the consequences of metal fume fever when welded 
low aluminium content steels (like in exhaust tubing, or other materials like Kanthal) are good, but weldability is a problem. the welds will be susceptible to corrosion.
what i would recommend, if you want to do it yourself, would be to use something like 304L stainless (18/8 to 18/20 chromium nickel, with low carbon) which is readily weldable IF you use the correct filler wire for 304L. it is readily available also.
http://www.assda.asn.au/304.html
it is not recommended for temps above 50 or 60 degrees where it wil come into contact with chlorides (ie salt) or it can suffer from 'stress corrosion cracking'.
the next choice is 316L, (16/10 to 18/14, but with 2-3% molybdenum). it is a bit stronger and has higher corrosion resistance. it is harder to cut, but is almost as easy to weld as 304L (as long as it is low carbon version -L )
the only downside to it is extra cost (due to the moly, extra nickel, and is not used quite as much as 304)
http://www.assda.asn.au/316.html
304L and 316L will cost you around 4-7 times the same in mild steel, and you will need MIG wire that is specifically for the alloy (ie 304L or 316L wire) AND you will need a suitable sheilding gas (ask BOC or LINDE for their recommendations), AND you will need to have a bit of practice to make sure you can do consistent welds with no pore, pinholes or gaps... would suck to have a shiny tank that leaks.
really your only other option is aluminium alloy, but it would HAVE to be TIG'd for best results. it does not have the same corrosion resistance, and can have corrosion occuring inside the tank if any water is trapped below the fuel...
for my money i'd go 304L. if i was feeling fancy and wanted the tank to lats almost forever, i'd go 316L. if it was for a race app, and weight was huge factor, i might go aluminium alloy..
i will be using 304L for mine later (and for my surge tank)
Ti?? could use it, but oh the cost!! i have a sheet of 3mm thick Ti-6al-4V at uni... cost more than i'd like to mention.. too much for a fuel tank anyways and the heat treatment cost... etc etc.. ouch.
Cya, Stewart
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: Steel ~ What type to use for this application?
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Tue, 17 February 2004 12:11
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| SeptemberSquallIndustries wrote on Tue, 17 February 2004 22:04 |
I've only welded a few times before and only have MIG available.
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to be honest, learning to weld a stainless or alloy fuel tanks is not what i would recommend. it would be fun, but safety is an issue.. you will probably have to get the tank 'engineer approved'.
i would suggest that you get the sheet, cut it to the correct sizes, and then get a professional welder to put it together. it would probably cost less this way than to get the wire and gas yourself and then learn to do it, and it will be done to a much higher quality by someone who does it all day everyday... also might help to consult the welder about the construction, ie 1mm overhang, butt joints, bevelled edges etc..
not trying to rain on your parade, but might save you a lot of time and pain
Cya, Stewart
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Location:
Sydney
Registered:
January 2004
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Re: Steel ~ What type to use for this application?
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Tue, 17 February 2004 12:31
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2cents: If you want to weld with MIG bear in mind that most MIG welders are set up with something like a 15kg spool of filler wire. Usually this is pretty average quality to weld mild steel so do your homework on what you can get. You can get MIG to weld aluminium but need teflon lining through the torch...not generally done need expensive machine. As old corolla said check that you can match up the filler wire/rod to what you are welding. Stainless comes out nice with TIG. We've made a fuel tank from Aluminium I think 6 series..just be careful of the filler rods, we ended up getting these 99.9% pure aluminium rods (TIG).. I think for 2000 series or something but they seemed to be compatible with most grades (6 series etc). Other filler rods with silicon or magnesium (can't remember)added caused contamination. Cracks in welds are a real problem and is maybe the reason you should stick to steel of some kind. 4130 Chrome Molybdenum has some resistance to corrosion as already stated. British International Trading can help you out with getting sheets of 4130 but maybe chat to a few more people that have built tanks for race cars, road cars etc. Experience is everything! PS I hate welding gal..it stinks and heard its not good 4 u 
Handmade tanks are generally done with TIG I think.
Give a few welding supplies shops a call..I found a few of the old fellas in there knowledgabe and helpful, just judge which ones you listen to I guess.
If it's worth anything..with Al it is so crucial to get the pieces you are welding "clean" . Using acetone works..just keep it away from welder when welding. Also a stainless steel brush that hasn't been contaminated, or soaping up and washing at sink with a scotchbrite. As soon as you get blackness - from touching tip etc clean off using one of above.
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Location:
Melbourne
Registered:
August 2003
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Re: Steel ~ What type to use for this application?
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Tue, 17 February 2004 12:33
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That's an incredible reply, thanks for your time and input.
If the job could be completed in mild steel on a garden variety MIG rig I'd be comfortable to attack it with material at hand.
Given that the job will require the purchase of stainless steel, specialised wire and gas, the cost minimisation advantages of doing the work with 'materials at hand' have been defeated.
As such, I'll look into a higher cost shop-assisted solution like you're described.
Thanks again for your time; rest assured I've read your post three times now gleaning information and direction, your effort is not in vain... 
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Location:
Finland
Registered:
November 2002
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Re: Steel ~ What type to use for this application?
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Tue, 17 February 2004 13:50
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How about plastic. It's cheap and light but how much would welding cost???
I have decided to get a plastic tank from wrecker and try to modify (bit of heat treatment) it to suit my application.
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Location:
Canberra
Registered:
May 2002
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Re: Steel ~ What type to use for this application?
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Tue, 17 February 2004 23:36
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Most factory tanks as far as I know are just painted mild steel. They rust when they are scratched and can be welded to with a MIG anyway.
They seem to work OK...
I'll second the welding GAL thing, not a good idea, the next day you have the worst hangover you've ever had and you didn't even get the fun of being drunk.....
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: Steel ~ What type to use for this application?
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Wed, 18 February 2004 00:27
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it would be interesting to find out what grade of steel OEM use for tanks, they seem to last a while.... anyone know?
mmm re Gal...
it's "metal fume fever". it's eville and bad for you...
http://www.aws.org/technical/FACT-PDF.EXE/FACT-25. PDF
definitely the worst hangover i've had , seems to be no known long term effects, but the short term are pretty nasty... more like worst migraine i've ever had......
Cya, Stewart
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Location:
Canada
Registered:
January 2004
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plastic
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Thu, 19 February 2004 13:08
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plastic might be better and easier
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Location:
Tasmania
Registered:
May 2002
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Re: Steel ~ What type to use for this application?
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Thu, 19 February 2004 14:31
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For a dependable and factory looking car part, just make it out of any cheap steel and get the finnished product yellow zink plated. Thats what most car parts are anyway, including fuel tanks.
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: Steel ~ What type to use for this application?
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Thu, 19 February 2004 15:07
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hmm, i don't think a plastic tank you welded yourself would be high regarding at rego time.... even if it is superior to steel...
Jonny i had forgotten about the zinc chromate coatings... this is often applied to bare steel parts either before painting, or to reduce surface rusting of components prior to sale . it's not really considered a good long term corrosion resistant coating, but it certainly will work for a while.
would probably be the cheapest option.. make up a steel tank, get it chromated, adn then if it dies, use that tank as a pattern to make a good staino one (if the car lasts that long)
Cya, Stewart
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Location:
Tasmania
Registered:
May 2002
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Re: Steel ~ What type to use for this application?
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Thu, 19 February 2004 15:16
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The yellow zink coating on car parts is often thin, and gives way to surface rust eventualy. But my local plated has redone some parts, and he does it thick and comes up as good a chrome. I often prefer the gold factory look now rather than show chrome. My fuel tank is a silver looking zink plate I think. Filler tubes are often yellow zink.
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Location:
Perth
Registered:
May 2003
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Re: Steel ~ What type to use for this application?
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Fri, 20 February 2004 01:44
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i just got a drop tank made up you have to get it engineered or get an enginer to make it up and then they stamp it.
it cost me $900 
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Location:
Newcastle
Registered:
April 2003
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Re: Steel ~ What type to use for this application?
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Fri, 20 February 2004 08:15
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| coronamark2 wrote on Fri, 20 February 2004 12:44 |
it cost me $900
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I must have been lucky with mine then cause it only cost me $80 to get folded and welded.Did the rest of the work myself.Drilling,marking,cutting etc.
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Location:
Finland
Registered:
November 2002
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: Steel ~ What type to use for this application?
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Sat, 21 February 2004 15:37
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sorry Jayem, i wasn't having a go at you 
i think i meant, "and that you had gotten welded yourself, rather than using an off the shelf non-welded item"
while a plastic tank is a good viable option, and in some applications, would be prefereable, our registering authorities look down on that kind of thing. they like to see things as stock as possible, even if it is not the best option..
i'd be happy to run a plastic welded tank on an offroad/race car, but i doubt it would be 'certifiable' for road use 
stoopid laws and things....
Cya, Stewart
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