Motorcycle gas tank repair

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I need to repair two small rust holes (1/4" x 2" long) on a motorcycle gas tank.  They are near the seam at the bottom but are not part of the seam.  The areas are pretty much flat.  I was going to repair it two years ago and emptied it, cleaned it with soap and water, let it sit in the sun for 2 days and no gas smell in it.  Then I ran out of time and still needed to do research as to what is the best way to repair it.  The options I've come up with are to weld a patch over it (using 1/16" 7014 and my 50 amp welder), solder a patch over it (propane torch + plumbing solder) or rivet and JB weld a patch over it.  Regardless of the repair the tank will be getting lined with POR15 afterwards.  Maybe Permatex 12020 instead of JB Weld?So, what do you guys think is the best approach?  I was going to start with welding but have heard that even if a tank is clean and sitting for a long time it can be dangerous to weld on.  Of note, I've soldered a small 1 gallon gas tank for an old Briggs engine that had gas in it earlier that morning.  I just emptied it, cleaned it with soap and water, then with rubbing alcohol (to remove any water, keep it from rusting).  Then I let it sit in the sun, blasted it with a blow dryer and then called it good and fired up the propane torch and soldered the leaky seam.  In retrospect maybe that wasn't a good idea, but luckily I was fine and the tank hasn't leaked and it's been 2 years with gas in it the whole time after the repair.
Reply:Whatever way you go, I would advise buying a gas sank sealer kit and apply it when your done. Por 15 makes a pretty good kit. When I was working on bikes, the preferred way to fix small holes was brazing. Sounds like your going to need to open up the hole to get the rust spots out than weld a patch. If you can get hold of a MIG that would work better than the other processes you mentioned. In my personal opinion, I would TIG weld but if you don't have access to the gear, try stick welding.
Reply:Originally Posted by FireForge1Whatever way you go, I would advise buying a gas sank sealer kit and apply it when your done. Por 15 makes a pretty good kit. When I was working on bikes, the preferred way to fix small holes was brazing. Sounds like your going to need to open up the hole to get the rust spots out than weld a patch. If you can get hold of a MIG that would work better than the other processes you mentioned. In my personal opinion, I would TIG weld but if you don't have access to the gear, try stick welding.
Reply:Originally Posted by joecool85In the middle of my original post you'll notice I already said that regardless of how I fix it, the tank will be getting a POR15 coating kit.  We already have the kit actually (the bike is actually my brother's).So you don't think it will be dangerous seeing as the tank has been cleaned and empty for so long?  I don't have access to an inert gas to fill the tank with.
Reply:For the repair you need to make, an epoxy such as JB Weld is appropriate.  That's what I would do, followed by coating the inside of the tank like you already stated you plan to do.
Reply:Originally Posted by walkerweldFor the repair you need to make, an epoxy such as JB Weld is appropriate.  That's what I would do, followed by coating the inside of the tank like you already stated you plan to do.
Reply:Could I use CO2 cartridges like from a paintball gun to get CO2 into the tank and make it safe to weld?
Reply:Originally Posted by joecool85Could I use CO2 cartridges like from a paintball gun to get CO2 into the tank and make it safe to weld?
Reply:Originally Posted by joecool85Looks like I could use them.  I'm thinking of getting a bicycle adapter so that I can control the flow.  First I would fill the tank with water as much as I can, then purge the remaining space with co2 via a co2 cartridge attached to the adapter.  After one or two cartridges have been emptied into the tank I can take a third one and set it to trickle the co2 out keeping a positive charge of co2 in the tank while I weld.  If welding fails I will do the same process except I will silver solder on the patch.
Reply:Here's a safe and very effective way to repair your fuel tank that will completely stop the rust so you won't ever have to repair it again, and it's much safer than welding.. It can fix small holes too. Go to this website and look for their fuel tank repair kit. You can repair the tank without welding it and it will be better than new when you have finished.http://www.kbs-coatings.com/orhttp://www.amazon.com/s/?ie=UTF8&key...sl_cxzn3dquz_bThis kit was recommended to me by a friend who has repaired 4 fuel tanks over the past 10 years using their kits and all of the tanks are still leak and rust free. The fuel tank that I repaired had had 1/4" of rust in the bottom after the vehicle sat unused in a forest environment for 12 years. The kit not only removed the rust, but coated the entire inside of the tank with a hard epoxy like coating that seems to be resistant to everything. It should last longer than I will now. The rust removal and coating process requires 3 steps that will only require a few hours of effort, but it will take several days to completion. Very clear instructions are included in the kit and are also available on the website so you can read them first to decide if this is what you want to do.CharleyMiller MM252Miller Bobcat 225NTMiller DialArc HF / DIY Cooler2 Victor O/A TorchsetsMilwaukee 8" Metal SawMilwaukee Dry Cut "Chop" Saw 5 Ton Wallace Gantry Various Grinders, Benders, etc.
Reply:Originally Posted by CharleyLHere's a safe and very effective way to repair your fuel tank that will completely stop the rust so you won't ever have to repair it again, and it's much safer than welding.. It can fix small holes too. Go to this website and look for their fuel tank repair kit. You can repair the tank without welding it and it will be better than new when you have finished.http://www.kbs-coatings.com/orhttp://www.amazon.com/s/?ie=UTF8&key...sl_cxzn3dquz_bThis kit was recommended to me by a friend who has repaired 4 fuel tanks over the past 10 years using their kits and all of the tanks are still leak and rust free. The fuel tank that I repaired had had 1/4" of rust in the bottom after the vehicle sat unused in a forest environment for 12 years. The kit not only removed the rust, but coated the entire inside of the tank with a hard epoxy like coating that seems to be resistant to everything. It should last longer than I will now. The rust removal and coating process requires 3 steps that will only require a few hours of effort, but it will take several days to completion. Very clear instructions are included in the kit and are also available on the website so you can read them first to decide if this is what you want to do.Charley
Reply:Originally Posted by WookieWeldingi would think some dry ice would be heaps easier then those mini co2 cartridges
Reply:If you have a Rad. repair shop where you live take it there and have them hot tank it,now you can weld or braze it without any worries.A friend of mine has been doing mods. to car and truck tanks for years,sends them out to be boiled,they come back nice and clean.My father lost a good friend who was a welder for years who was welding a tank that was flushed with soap and water then had co2 sloshed around on the inside.
Reply:x2 on what thphtm said......a good radiator shop will be able to hot tank it, braze the holes shut AND pressure check it for $35-50......I personally fix them all the time, it will definately xplode if you try to weld on it        thermal arc 252i  -  millermatic 350P -   miller XMT, cp300ts, 30a 22a feeders, buttload of other millers, handfull of lincolns, couple of esabs  -   Hypertherm 1250 G3
Reply:Originally Posted by joecool85Good idea but I haven't a clue where I could get dry ice.
Reply:Solder it. I did my car tank and it took A LOT of solder (it was beyond pin holes), but last time it had gas it was good, and its been 10 or 15 years since the repair. It's parked due to the price of gas and insurance.Miller thunderbolt 250Decastar 135ERecovering tool-o-holic ESAB OAI have been interested or involved in Electrical, Fire Alarm, Auto, Marine, Welding, Electronics ETC to name a just a few. So YES you can own too many tools.
Reply:Originally Posted by woi2ldx2 on what thphtm said......a good radiator shop will be able to hot tank it, braze the holes shut AND pressure check it for $35-50......I personally fix them all the time, it will definately xplode if you try to weld on it
Reply:Solder it using a big old soldering iron that you heat with a torch. Make sure the iron is not red as you can get a spark from a red hot iron. Clean the area well and tin the repair area and the patch. Place the patch on the repair and hold your iron on the patch. when you see the tinned areas start to flow add more solder around the perimeter of the patch and it will wick in and give you a leak free repair.
Reply:Originally Posted by lhdmechSolder it using a big old soldering iron that you heat with a torch. Make sure the iron is not red as you can get a spark from a red hot iron. Clean the area well and tin the repair area and the patch. Place the patch on the repair and hold your iron on the patch. when you see the tinned areas start to flow add more solder around the perimeter of the patch and it will wick in and give you a leak free repair.
Reply:Originally Posted by lhdmechSolder it using a big old soldering iron that you heat with a torch. Make sure the iron is not red as you can get a spark from a red hot iron. Clean the area well and tin the repair area and the patch. Place the patch on the repair and hold your iron on the patch. when you see the tinned areas start to flow add more solder around the perimeter of the patch and it will wick in and give you a leak free repair.
Reply:Originally Posted by joecool85Great idea, I like soldering anyway and have always wanted to try this type of repair...now is as good a time as any right?  Where can I get an iron like that?  Or is it something I could make?  Maybe a piece of rod with some 1/4" steel welded to the end?
Reply:Any way to do this without buying the soldering coppers and that special ammoniac block?  I was hoping I could heat up a large bolt lets say and then use that to heat the area soldering and use plumbing solder to solder it together like I did that other tank seam (though that was done with an open flame).
Reply:Originally Posted by shovelonAll it takes is one time for the tank to blow on you. Long ago I let a customer do the clean and prep a steel gas tank. He assured me that all was well. Half way into adding custom bungs it blew, and that rectangular tank became a ball, and knocked me half way across my shop. Never again.Go buy a disposable balloon cylinder from the party store, and get it done.
Reply:Originally Posted by joecool85Great idea, I like soldering anyway and have always wanted to try this type of repair...now is as good a time as any right?  Where can I get an iron like that?  Or is it something I could make?  Maybe a piece of rod with some 1/4" steel welded to the end?
Reply:Alright, picked up a soldering copper and sal-ammoniac block (thanks eBay).  What type of solder should I use?  I have plumbing solder in lead and silver and also lead based electrical solder.  Will one of those work?use the plumbing solder.and you'll need flux or acid to tin the tank.miller thunderbolt 250vlincoln square wave tig 175 prolincoln idealarc mig sp250everlast tig 210EXTeverlast power plasma 50chicago electric (hf) 130 tig/90 arcchicago electric 90 amp flux wire3 sets oxy/acet
Reply:Originally Posted by boatbuoyuse the plumbing solder.and you'll need flux or acid to tin the tank.
Reply:Originally Posted by shovelon and that rectangular tank became a ball, and knocked me half way across my shop. Never again.
Reply:Originally Posted by joecool85Can I just use my plumbing flux?  Also, how do I tin the tank?  Just flux it then melt on some solder?  Or do I use the Sal-Ammoniac block?I'm assuming to tin the copper solder I will heat it then rub it on the Sal-Ammoniac block, am I right?  That's how I do it when I tin my electrical soldering iron.
Reply:Another safe way to do a low pressure test is to adapt a shop vacuum cleaner hose to the tank from the DISCHARGE outlet (blowing) of the vac.
Reply:Or you could wash, flush and dry the tank, then braze it.Do you want to be a solderer your whole life?SqWave 200Millermatic 190Airco 200 ACHypertherm PM45Boice-Crane Band SawVictor O/A
Reply:Thanks for the help guys, excellent tips.  Can't wait to try this repair.  I'll be sure to post pics.
Reply:Alright, I've started this project.  I have all the old rusty stuff cut off the tank.  The largest hole is now a triangle measuring about 5" on the longest side and the "height" of the triangle is probably about 2", so it's a fairly large hole.  I have made a patch out of 22gauge sheet steel and plan on tinning the tank and the patch, then pop riveting the patch in place.  Heat the patch with the soldering copper till the tinned areas on the patch and tank melt together, then add more solder as necessary.  After that I will fare it out with JB weld (less messy and stronger than bondo).Does this make sense?  My only concern is the size of the hole I'm patching, I'm hoping this will be strong enough. Note:  The tank will be treated with a POR15 liner kit after all repairs are complete.
Reply:Only use the pop rivets if you are intending on drilling them out and soldering the holes shut!  I think I would rather use CLECOs for clamping if that was all I had for clamping options.  I would cut the patch over size and tack weld a rod or some other suitable handling device in the center.  Insert the patch into the hole so it lays under the tank material and solder it in place.  Before inserting the patch for soldering I would tin the edges of the tank cut out and the patch to assure good solder flow when you make it solid.  Once the patch is in place then cut/break off the handle and grind spot smooth.  Just my thoughts and remember  "Free advice is worth exactly what you pay for it".  RogerOld, Tired, and GRUMPYSalesman will call, Batteries not included, Assembly is required, and FREE ADVICE IS WORTH EXACTLY WHAT YOU PAY FOR IT!Dial Arc 250HFThunderbolt 225 AC/DCAssorted A/O torches
Reply:Ditto what Rog02 said.Patch ought to be inserted into the tank and then PULLED into place from the outside.You should try to shape the contour of the patch to fit pretty close to the contour of the tank so you have minimum gap at the overlap between the tank and the patch.Doing it as an inside oriented patch means you will have an easier time of filling and feathering the patch site so it looks like it never happened (instead of having a "bulge" above the patch).
Reply:Originally Posted by walkerweldDitto what Rog02 said.Patch ought to be inserted into the tank and then PULLED into place from the outside.You should try to shape the contour of the patch to fit pretty close to the contour of the tank so you have minimum gap at the overlap between the tank and the patch.Doing it as an inside oriented patch means you will have an easier time of filling and feathering the patch site so it looks like it never happened (instead of having a "bulge" above the patch).
Reply:You should be able to insert the patch edgewise through the hole that you describe as "roughly 3 X 5".I think you may be missing the part about welding something sacrificial onto the patch to use as a pulling attachment that would be cut off and ground smooth after the patch is in place and soldered.
Reply:leaving pop rivets in and just grinding them down will ruin any chance you have of this being a decent repair, def don't leave rivets in there  like has been said, weld a rod or 2 on the patch so you can manipulate it to inside and then pull it into place, once it's secured you can remove the rod(s)miller 330a bp TIGmiller dynasty 200DX TIGmillermatic 185 MIGthermal dynamics cutmaster 101 plasma cuttersnap-on YA5550 plasma cutterhypertherm powermax 30 plasma cutterbaileigh CS225 cold sawetc....
Reply:Well I did this first patch last night, no rivets used and the patch on the outside.  I was surprised how strong the silver solder is.  I was able to solder one side of the patch, then using vice grips finish a bend in the patch and solder the second side - pretty slick.Honestly, since this patch goes up against the seam of the bottom of the tank I don't see how I could get a good seal doing it on the inside anyway.  Regardless it came out great.I will post pics of the whole process once I'm finished.
Reply:I got a chance to get the other 3 patches on and did a leak test.  All four are leak tight, but I did find two small pin holes.  I drained the water from the tank and soldered those up, now we're good to clean the tank and coat it.  Then I can get going on the "body work" part of the tank, filling, priming and painting.
Reply:And I think right about.............now........you oughta learn how to post some pictures on here so we can share the wealth.
Reply:Originally Posted by walkerweldAnd I think right about.............now........you oughta learn how to post some pictures on here so we can share the wealth.
Reply:This is a joke, right?    How dahell do you plan on getting all of it out?   Won't take much going through to either clog the fuel filter (if you're lucky) or getting by it and causing major damage to the valve train, pistons, wall, etc. Originally Posted by joecool85Why would soldering be so much safer than welding?  Soldering you have an open flame...Also, no radiator shops within a few hours of me and as to the dry ice, the closest place here in maine is 2 hours away.I'm thinking fill the tank with sand then weld or solder it.  If it's full of sand then the vapor (if there was any, which there shouldn't be since it is clean and empty for 2 years) wouldn't have any room to expand so it should be safe, right?
Reply:Originally Posted by dellwasThis is a joke, right?    How dahell do you plan on getting all of it out?   Won't take much going through to either clog the fuel filter (if you're lucky) or getting by it and causing major damage to the valve train, pistons, wall, etc.
Reply:I see that, congrats  Originally Posted by joecool85Yeah, it would have worked as far as not blowing up, but getting the sand out would probably be nigh impossible.  The good news is as long as you got most of it out, when you coated the inside of the tank it would just seal it all up and no sand could come out.Regardless it doesn't matter because I'm done with that part and ended up soldering it with a soldering copper as opposed to welding it.