soldering with a paste?

admin

I have a few holes in my old John Deere tractor fuel tank.  Diesel.I went to my local LWS and they recommended I use a paste type solder.  They told me to clean the area to bare metal.  Clean with Acetone.  Use a small paint brush to wipe on the paste solder and then heat it with the torch until it spread.  Anybody ever hear of doing it this way?  Me not!  I bought what they recommended but will wait to try it until I hear something back from you all.
Reply:I have used paste many times in the past..Flux and solder all in one...Clean..coat..heat.Stuff works good..http://www.alpha.cooksonelectronics....lder-paste.asp...zap!Last edited by zapster; 06-18-2010 at 09:25 AM.I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:It is not working for me!  I am doing something wrong I am sure.  How hot of a flame should I use?  It seems as if I am not getting it hot enough sometimes so I heat it more and then it all runs away.  How thick can I put this paste on?  Then sometimes it just balls up into small little balls.I am about ready to build a whole new tank.  Problem is the tank is sort of organic shaped.Thank you for the help!
Reply:Maybe you should get some sheet metal and just make a patch to go over the bad area then use the paste.....zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:How big are the holes? How many? I used to repair old vw gas tanks by cleaning the area hit it with stay-clean, drop a penny over the hole and solder with 60/40 and a 500watt iron. It worked fine.
Reply:I just love the basturds at Team THEY.  They know and They say and They are experts on everything.For your purposes, stop at the pool store and get some muriatic acid.  Pour a couple ounces of the acid into a glass container and throw a couple roofing nails in and let it set for an hour, covered tightly.Then pour the acid into another container and hide the first container in your nasty neighbor's garage so his tools rust to hell.Sandblast or grind the tank around the hole, and paint acid on where you want to solder.  Then take a large soldering copper or even a torch and tin the area where you want to patch.  After tinning you can either solder a patch in place or pile solder on as long as the holes are small.In the alternative, Fornay sells an epoxy specificly made for fuel tank patching.  Last I used was about 3 bucks for a kit about the size of a tootsie roll.  Read the instructions and patch.  It works very well if you dent the hole into the tank a bit so you can build a button on the outside of the tank.  Remeember  there is a patch of rust inside of the tank everyplace there is a hole showing on the outside unless the holes were made by bullets.Last edited by Rojodiablo; 06-21-2010 at 01:03 AM.Reason: Just cleaning up.
Reply:I've had good luck sealing small holes in gas tanks with conventional lead free plumbing solder and flux.  I wouldn't want to seal a hole of any substantial size without a coin or similar size token to cover the hole.  Beyond obvious safety issues, small holes in fuel tanks should be relatively easy to patch.  I image that diesel poses additional difficulties in cleanliness as compared to gasoline, as it is substantially less volatile.  My guess is that you aren't /getting the patch area clean enough for the flux to do it's job.  Either that, or the tank is otherwise sealed and therefore blowing the molten solder out of the way as pressure inside the tank increases.
Reply:Old Fart,    Before I die I want to meet "they"  and I want to see a print of "the big picture" everyone keeps telling me I am not seeing!I think you have hit the nail on the head about fixing the holes.Tomorrow I will build a new tank for my tractor.Thanks for the advice from all.
Reply:What do you mean by paste flux? Is it rosin cored lead/tin solder, or the silver brazing paste flux?Tin/lead solder will work better with an active flux like 'Baker's Fluid' AKA zinc chloride flux. Old Fart tole you how to make it but it's there on the shelf if you wanna buy it. Ya still have to get the metal free of oxides an oils first. Rosin cored solder is only for electrical wires because it's non-corrosive and doesn't need nutralizing and washing off like the active flux does..Silver brazing is better but heating any part of a fuel tank to red hot is a big problem because the tank can explode in your face due to traces of diesels an fuels going boom inside the tank. Silver solder needs clean metal and a paste flux such as 'Easyflo' or 'Tenacity'.Epoxy putty is surprisingly good. I have used it for a temporary fix on a rainwater tank, a fuel tank, and a holed crank case...it holds on for many years. Clean and oil free surfaces are best. In a pinch the water tank was plugged while spouting water and it worked while wet.Last edited by AyAy; 06-20-2010 at 09:15 AM.Orion pulse-arc welderStick an O/A too
Reply:Originally Posted by Old Fart . . . Pour a couple ounces of the acid into a glass container and throw a couple roofing nails in and let it set for an hour, covered tightly.Then pour the acid into another container. . .
Reply:ANCIENT recipe for "tinner's fluid" that was around before I picked up my first soldering copper.Back in the days before OSHA and the MSDS were even dreams we made our own.  I'm not sure if you can even buy tinner's fluid any more.The acid disolves the zinc coating off the nails into the acid.  Fellow here who did millions of feet of galvanized gutters with a Johnson heater and coppers never used anything else, the tinners fluid and a rag dampened in it were all the flux he ever used with bar solder.