Mig welding a fuel cell

[Just Joel]

I'm in the process of making a fuel cell for my trail truck. I'm currently planning on mig welding all the seams and would like to know if there is a particular technique or tips that would be helpful in creating an air tight seal and avoid pinholes.

Thanks
Joel

[Fat Bastard]

Got to ask ( I'm just that kind of guy) Why in the world would you be doing this? So many liabilities so much money and time when

* Dorman,
* Goodmark,
* Classic Performance,
* Summit,
* RCI,
* Putco,
* R.J.S. Racing Equipment,
* Rick's Hot Rod Shop,
* Aeromotive,
* ACDelco,
* Show All...

all these companies have gone to the trouble of figuring it all out, and then sell them for so little. You can't build them any cheaper unless your time is worth nothing.

http://store.summitracing.com/egnsearch.asp?Ntk=KeywordSearch&DDS=1&Ntt=fuel+cell&x=41&y=17&N=700+115&searchinresults=false

12 gallon tank aluminum with sending unit for $179.95


Well rant over and on to your question. HOT HOT HOT
FASTFASTFAST


Or the easy way is build it strong and buy a bladder and some foam.


TJ

[Just Joel]

Two reasons... it needs to be an extremely custom shape to accommodate the area it needs to mount in and I would like to use the stock sending unit and vent lines to retain gauge function and smog. I have researched this for quite a while and have a rock solid shape and baffle design and I understand the potential risk involved (which is rather minimal as long as the proper steps are taken). I also have a hard time paying for something I know I can do myself. In the end, truly understanding the process and better understanding a vital component of my rig is worth more than the time saved with buying a cookie cutter mass production unit. I know I can produce a better product that fits my use perfectly, rather than spending extra time adapting something that will never be perfect and always look like a universal square box in the back of my truck.

Thanks
Joel

[SundownIII]

1st Question: What material Steel, Aluminum, SS?

If you already "know" you can build it, what additional information do you really seek?

If steel is the material of choice, I'd mig it up and pressure test it. If leaks appear, I'd go back and wash the welds with tig.

If aluminum is the material, I wouldn't think of migging a fuel cell. Tig it.

If SS, warping will be a major problem.

Cold starts will be the problem with leaks. Keep them to a minimum. Backstep over your starts.

2nd Question: What machine. No fluxcore I hope.

3rd Question: Experience? Ever built a fuel cell?

[jamlit]

I don't know if their is a certain technique or not. I have made several fuel cells over the years and I used my mig for all of them until recent. I have built VW pipe rails for years and made the fuel cells from 1/16 and 1/8 mild steel. From my experience, using a little thicker material makes getting the welds liquid tight a lot easyer while maintaining good penetration and bead profile.. Also try to reduce the stops and starts of the welds. Make sure you pressure test the tank before putting gas in it. I am currently moving on to custom motorcycle tanks. While doing my home work on this I found that tig it much more preferred when dealing with light sheet metal. I purchased a Lincoln PT225 recently and started using it. All I can say now is that I can see why tig is preferred. The welds and control are amazing.

Good luck on the project and post pic's

[Just Joel]

1st Question: What material Steel, Aluminum, SS?

If you already "know" you can build it, what additional information do you really seek?

If steel is the material of choice, I'd mig it up and pressure test it. If leaks appear, I'd go back and wash the welds with tig.

If aluminum is the material, I wouldn't think of migging a fuel cell. Tig it.

If SS, warping will be a major problem.

Cold starts will be the problem with leaks. Keep them to a minimum. Backstep over your starts.

2nd Question: What machine. No fluxcore I hope.

3rd Question: Experience? Ever built a fuel cell?

I'm more so looking for specific experiences pos/neg of others that have performed a similar task. I'm not trying to come over as rude or disrespect anyone’s opinion or advise. I'm just looking at trying something new and would like some advice before I start.

1) Mild steel

2) Miller 180... no flux core ;)

3) Nope, this is a first for me but I've been building trucks for a long time...

http://i469.photobucket.com/albums/rr59/JoelToyota/100_3852.jpg

http://i469.photobucket.com/albums/rr59/JoelToyota/100_3846.jpg

Thanks
Joel

[lewray]

Hey Joel

Make sure its air tight when your done. Find a way to test it. Maybe the water test. Fill it up and leave over night and see if there are leaks. Better yet maybe try air instead.

Ive never made one personally, mine is from summit, but many of my wheelin friends have made them with no problems using Mig. Tig would be easier, but you may not have one to use....right?

As far as the welding details ...give us shout when you know what material your going to use.

I understand why you would need to make a fuel cell .;) Only us crawler guys can relate

Good luck

[Just Joel]

I don't know if their is a certain technique or not. I have made several fuel cells over the years and I used my mig for all of them until recent. I have built VW pipe rails for years and made the fuel cells from 1/16 and 1/8 mild steel. From my experience, using a little thicker material makes getting the welds liquid tight a lot easyer while maintaining good penetration and bead profile.. Also try to reduce the stops and starts of the welds. Make sure you pressure test the tank before putting gas in it. I am currently moving on to custom motorcycle tanks. While doing my home work on this I found that tig it much more preferred when dealing with light sheet metal. I purchased a Lincoln PT225 recently and started using it. All I can say now is that I can see why tig is preferred. The welds and control are amazing.

Good luck on the project and post pic's


Thanks, good info. I'm going to start with mig and I'm sure, like you, eventually develop my tig skills and move that direction at a later date. I'm currently probably going to build the tank from 1/16" mild steel to try and keep the weight down compared to 1/8".

Later
Joel

[Supe]

Wrap your corners. Don't just place a tack right on the corners and weld into it. Weld at least an inch away from the corner, head into it, and wrap another inch right around the side. This should help minimize the pinhole leaks/cold starts. That was by far the most common problem I saw when dealing with MIG'd fuel cells. If you have to do a start/stop mid-way through a seam, grind the end down and feather it in. This will also minimize leaks, and make it look better to boot by eliminating the bulge of weld metal on the restart.

[Just Joel]

Hey Joel

Make sure its air tight when your done. Find a way to test it. Maybe the water test. Fill it up and leave over night and see if there are leaks. Better yet maybe try air instead.

Ive never made one personally, mine is from summit, but many of my wheelin friends have made them with no problems using Mig. Tig would be easier, but you may not have one to use....right?

As far as the welding details ...give us shout when you know what material your going to use.

I understand why you would need to make a fuel cell .;) Only us crawler guys can relate

Good luck

Nice to see there’s a few crawlers on here that know the need to build everything as well. This is step one of linking up the rear... I need to get the tank out of the way and the spot its going also needs to take care of the spare. I don't have access to a tig right now so I'm planning on building this thing out of some fairly thick material (1/16" mild steel) for ease of welding more than anything (It doesn't need to be armored because its on top)

Thanks
Joel

[Just Joel]

Wrap your corners. Don't just place a tack right on the corners and weld into it. Weld at least an inch away from the corner, head into it, and wrap another inch right around the side. This should help minimize the pinhole leaks/cold starts. That was by far the most common problem I saw when dealing with MIG'd fuel cells. If you have to do a start/stop mid-way through a seam, grind the end down and feather it in. This will also minimize leaks, and make it look better to boot by eliminating the bulge of weld metal on the restart.

Thanks, good info.

[500HpSilverado]

Also, if when you pressure test it, don't exceed about 3psi maximum, I usually do it with 1-2psi. You will need a 0-10psi pressure gauge and hose barb and some small little parts. I usually take a piece of brake line, attach it to a t connector. The gauge is on one branch of the T and then a ball valve connected to that with an air fiting on the otherside to lock the pressure in once I have filled it with my air compressor. I have used it many time on boat fuel tanks, works like a charm. I'll have to find a picture of it, sounds more complicated then it is.

Here we go, not mine but its the same deal to help the visual learners.

http://i6.photobucket.com/albums/y206/400HPSilverado/presstest3.jpg

[Rojodiablo]

Weld it up, and after you're done, when you pressure test it, use soapy suds on every weld to test for spot leaks. What can I say?? Any process of weld runs a chance of a leak. The key is to minimize the chances. That's all.

[Just Joel]

Also, if when you pressure test it, don't exceed about 3psi maximum, I usually do it with 1-2psi. You will need a 0-10psi pressure gauge and hose barb and some small little parts. I usually take a piece of brake line, attach it to a t connector. The gauge is on one branch of the T and then a ball valve connected to that with an air fiting on the otherside to lock the pressure in once I have filled it with my air compressor. I have used it many time on boat fuel tanks, works like a charm. I'll have to find a picture of it, sounds more complicated then it is.

Here we go, not mine but its the same deal to help the visual learners.

http://i6.photobucket.com/albums/y206/400HPSilverado/presstest3.jpg

I was planning on building a manifold just like that one... Should work great. I didn't know how much pressure to hit it with so that’s very helpful.

Thanks
Joel

[Just Joel]

The key is to minimize the chances. That's all.

That’s why I am asking the question now and getting advice about things to do/avoid. ;) Eventually, I'll jump in head first and just weld the thing up, but I want to have tool I can to avoid pin holes all over the damb thing.

Thanks
Joel

[dave powelson]

I'm in the process of making a fuel cell for my trail truck. I'm currently planning on mig welding all the seams and would like to know if there is a particular technique or tips that would be helpful in creating an air tight seal and avoid pinholes.

Thanks
Joel

1-Lapping the corners and seams makes for a strong tank, ditto for adding flanged baffles,
plug welded after assembly as needed.

http://weldingweb.com/attachment.php?attachmentid=26845&stc=1&d=1230662435


http://weldingweb.com/attachment.php?attachmentid=26846&stc=1&d=1230662480

IOW---especially in a 16 ga. steel tank--doing a corner weld without flanging or lapping, is very problematic.

Suggest you consider flanging and lapping in the tank design.

2-Pressure testing

-if there's no internal baffling to stiffen the tank--then just a little positive pressure, probably 0.5 PSI is all you dare do. It's very easy to permanently balloon a thin, weak tank--or explode it.

-Blow off patch---On any tank p-test I have duct tape over one opening, for a safety blow off patch. I feel and watch the tank slightly swelling and this patch--during the p-test.

3--Migging the tank, then grinding and washing over the leaking starts and stops with TIG, even if you have to pay for TIG, will save you lots of time/hassle. It's possible to MIG a tank leak tight---just takes care, patience and lots of practice. I normally just wash over with TIG.

The starts and stops of the weld as others have mentioned are major leak points.