wheelman Posted January 12, 2006 Share Posted January 12, 2006 Last summer I welded a sump on my stock 240 tank to feed the LT1. I've had problems with pin holes and thought I got them all sealed with some stuff called Seal-ALL I found at Walmart. I was under the car last week and discovered it's leaking again so I'm looking for other alternatives. One direction is to abandon the stock tank and install an LS1 tank. I can get the tank locally for $75.00 and a used pump/sender unit from eBay for $50.00 plus shipping. Then I have to fab the mounts and cut out the spare tire well and all the attendant things that go with that project. I also already spent close to $200.00 for my current pump, filter and fuel lines. I was reading a question on another forum regarding welding on a gas tank and one poster mentioned brazing to seal the welds, which got me to thinking about using plumbers solder to seal mine. Will it work or would I just create a bigger mess than I already have (really isn't that big just frustrating)? I was thinking I would use a propane torch (I don't have an acetylene setup), heat the area real good and flow the solder over the whole seam. What do you guys think? How would it hold up to vibrations? Wheelman Quote Link to comment Share on other sites More sharing options...
JMortensen Posted January 12, 2006 Share Posted January 12, 2006 Sounds like a decent idea to me, but go get a MAP gas torch. The propane will kind of half *** work if you sit there for a long time heating up the surface. MAP works great and much quicker. Quote Link to comment Share on other sites More sharing options...
vashonz Posted January 13, 2006 Share Posted January 13, 2006 I would just reweld it, or get a radiator shop to reweld it. Anything that holds fluid should be welded without any porosity. I don't think soldering would work that well. A couple things to watch if you do. 1. If you cherry the metal (carbon steel specifically) it gets brittle and does not hold up well (someone in my class overheated their nipple on a pressure vessel, when they pressurized it it cracked in half at 200psig) 2. Solder flows to whats hot, I think that if you heated the weld bead, the surrounding sheet metal would get too hot before the entire weld was heated, causing the solder to flow to the surrounding metal rather than the weld bead like you want. 3. Don't use a propane torch, it works for thin copper pipe, but anything more substantial or with less heat transfer ability (steel) needs alot to heat, I have no idea about MAP gas, but oxyfuel can be rented easily. Quote Link to comment Share on other sites More sharing options...
Jolane Posted January 13, 2006 Share Posted January 13, 2006 I see two good ways to fix this. 1. Take it to a shop and have it TIG welded. They will basically run the torch around and remelt what weld is already there. This would be my choice. 2. Use JB Weld, or one of their other products. They have two products that will cure submersed in gasoline. This would be easy, cheap, and could actuall make the situation look nice if you use it to fillet the weld and smooth it, then paint. Joshua Quote Link to comment Share on other sites More sharing options...
wheelman Posted January 13, 2006 Author Share Posted January 13, 2006 Jolane, What are the JB weld products you're refering to? I checked thier website many moons ago and didn't see anything like what you mentioned. Wheelman Quote Link to comment Share on other sites More sharing options...
kcelectronics Posted January 13, 2006 Share Posted January 13, 2006 Re-weld, Braze or solder all 3 will do the job for you. Forget the JB Weld goop at best it is just going to patch the leak and make it harder to fix later. Welding is the hardest as it could still have pin holes. Brazing or soldering will work well to seal the weld as they both flow well and will be NON-Porous as long as they are done well. The soldering you intended to do will solve your problem very well, and you already have the equipment handy so go for IT!! just remember to clean/grind/sand the area to be sure of a good joint/flow OK I have even used a large (about 1" dia tip) electric soldering iorn to solder a patch on to a fuel tank (did'nt need to steam clean the tank for fumes so it would'nt go BANG) I hope you were going to do this!!!!!! flames and gas tanks DONT MIX, although I have been told that you can fill them with exhaust gas to allow it to be welded:icon5: dont know if I would risk it, I like my body parts where they were intended to be LOL:) Chuckie:twisted: Quote Link to comment Share on other sites More sharing options...
wheelman Posted January 13, 2006 Author Share Posted January 13, 2006 Chuckie, I used the exhaust gas method to weld this tank and have made several attempts with the welder trying to eliminate the pin holes. I plan to flush it real good with water and fill with exhaust from my pickup before getting a flame near it. Thats what I did each time I welded on it and I'm still here so I'll do it again. BTW: Thanks for bringing me back to my senses, I was looking at the JB WELD again after having tried it once already to seal these holes. The version of it I used was not gas proof and never cured, thats why I tried the Seal-ALL, which did work for a while but also doesn't seem to be gas proof. Maybe it's just me not applying the stuff correctly. So now it's off to the hardware store to get some acid core solder and a new can of propane for the torch. Thanks for the feedback guys, I'll let you all know how it turns out. If I can't get this to work then it's a swap to the LS1 tank. Wheelman Quote Link to comment Share on other sites More sharing options...
Jolane Posted January 14, 2006 Share Posted January 14, 2006 Wheelman, The products is called "Waterweld". http://jbweld.net/products/water.php The other is called JB Stik: http://jbweld.net/products/jbstik.php I like the idea of welding it though (with a TIG). Might not be too expensive. Maybe a radiator shop can fix the pin holes also... Joshua Quote Link to comment Share on other sites More sharing options...
Sparky Posted January 14, 2006 Share Posted January 14, 2006 I used "Seal all" on my sumped 240Z tank. its been almost four years since I welded that thing on and I have had zero leaks. I have a spare tank though that will be sumped with a different style pickup and then tig welded together early this summer. Quote Link to comment Share on other sites More sharing options...
AK-Z Posted January 24, 2006 Share Posted January 24, 2006 Why not just Braze/brass weld it? it should flow into the hole better than solder and it can take higher temps last longer. Quote Link to comment Share on other sites More sharing options...
SHO-Z Posted January 24, 2006 Share Posted January 24, 2006 Modern plumbers solder is 95/5 and would be hard to deal with in you situation. I have soldered up gas tank holes with 50/50 with no problem. Remember to purge the tank when soldering it or you might end up in the next county. I have used the soapy water methold a couple of times. Washing out the tank with hot soapy water 4 or 5 times. I then refilled the tank with hot soapy water so only the area where I was doing the repair was out of the water, less volume for any vapors. I used nocorode soldering flux and a propane torch for the job. Clean the area real well and then tin it first with solder and whipe with a cotton cloth. Then solder up the area. When welding or soldering on a fuel tank it is very dangerous and please take care. Quote Link to comment Share on other sites More sharing options...
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