Tank repair

[Matt Brown]

I have a tank that seems to have sprung a leak or it was there from the beginning and I just never noticed it.
I need to clean it out real good so I can re-solder it. I’m mostly concerned with getting all the oil out of the seam where it is leaking. What type solvent or cleaning solution works best for this?


Thanks, Matt

[Perry Rose]

Clean the outside with alcohol then rinse the inside with alcohol and drain it. Put some more in and pressurize the tank so alcohol comes out of the hole. Re clean the outside abrade the area, flux then solder. Re pressure test under water you may find other leaks.

[Tim Wescott]

Consider popping an end off and fixing it from the inside, then re-soldering the end.  If it's leaking around an end, then just pop that end off, clean everything, and re-solder.

[Dennis Toth]

Matt,
I have done this type of repair, it can be done. First flush the tank with either methanol or de-natured alcohol at lease two flushes. Clean off the outside between flushes with the solvent you use (you can also use de-greaser from the auto paint shop). Once clean and dry you can use a staybite pad to clean the area to be repaired then do a final wipe down with solvent.

Use rosen flux (not acid!!!), get the iron or gun (I use a Weller gun and found out that the two step trigger is hottest on the first click not pulled all the way back) to it's hottest setting, ligthly tin the tip. Heat the repair area then touch the solder to the part, it should melt and flow into the repair area, if it doesn't its not hot enough. Clean off rosen with solvent and flush tank do a pressure test under water, if good go fly.

Best,   DennisT

[Dave Harmon]

I have a tank that seems to have sprung a leak or it was there from the beginning and I just never noticed it.
I need to clean it out real good so I can re-solder it. I’m mostly concerned with getting all the oil out of the seam where it is leaking. What type solvent or cleaning solution works best for this?


Thanks, Matt

Lacquer thinner works best.

[Dan McEntee]

  If you have a typical metal tank that is leaking at a crack in a bend or at a seam, I just wipe the tank off with a clean rag and some airplane cleaner. Make sure the tank is completely empty. Wire brush the area or scotch brite it clean and shiny. Apply a tiny little bit of flux to the area, neat it with a soldering iron. After it burns off the initial application of flux, apply another small amount and solder away. The heat of the iron and the hot flux will dispel any fuel in the crack. Makes no difference what the inside is like. Use .030" electrical (rosin core) solder. It will flow like butter into the cracks a crevices.  When cool, check for leaks in your favorite manor. I have done repairs this way at the field, as long as I have a good 110VAC source for the soldering iron, or gas fuel soldering tool. I helped fix a tank for a young and up coming Chris Rudd who was with his Dad at the SIG contest many years ago in this manor.I think it was him???
  Type at you later,
  Dan McEntee

[Brett Buck]

It will flow like butter into the cracks a crevices.  When cool, check for leaks in your favorite manor.

   I know you are being figurative, but the solder has to be heated to the point that it is the viscosity of *water*, fully-liquid. With anything other than 63/37 solder, there is a temperature range in which is really does have variable viscosity, from toothpaste to soft butter, to honey to water, etc. I say this because I have seen people install, say, a tube in the side of the tank, and wind up with a little volcano 1/2" in diameter and 3/4" inch high of solder, sort of blobbed on at low temperature, and not only did it weigh a ton and look ugly, it still leaked and fell apart while we were testing it. . I don't even know if I could manage to replicate it. The solution, of course, was to suck it all off with a Soldapult (about 5 minutes and much cleaning and clogging), then solder it with a 1/16" length of .040 solder, nice fillet with about a 1/64" radius, shiny and clean.

    Brett

[Matt Brown]

The leak was in a seam. I had used alcohol in the past but know it doesn’t cut oil all that well. I had asked looking for a more effective solvent. Yesterday, I went ahead with some iso alcohol and rinsed the tank as best I could and pressurizing it to force alcohol through the leaky spot. Cleaned and dried off the tank real well. A few minutes with the soldering iron and the tank is sealed up like it should be. Just need some decent weather so I can test it in action.

Thanks, Matt

[Dan McEntee]

   I know you are being figurative, but the solder has to be heated to the point that it is the viscosity of *water*, fully-liquid. With anything other than 63/37 solder, there is a temperature range in which is really does have variable viscosity, from toothpaste to soft butter, to honey to water, etc. I say this because I have seen people install, say, a tube in the side of the tank, and wind up with a little volcano 1/2" in diameter and 3/4" inch high of solder, sort of blobbed on at low temperature, and not only did it weigh a ton and look ugly, it still leaked and fell apart while we were testing it. . I don't even know if I could manage to replicate it. The solution, of course, was to suck it all off with a Soldapult (about 5 minutes and much cleaning and clogging), then solder it with a 1/16" length of .040 solder, nice fillet with about a 1/64" radius, shiny and clean.

    Brett

     I agree entirely, and that is why I always stress using .030" rosin core solder for just about everything I solder on any model airplane. i typically use a 40 watt Weller iron with a 1/4" wide chisel tip.  Keep it clean, before and after each use, and I prefer Ruby Fluid soldering flux. On items like a tank, this makes more than enough heat, and the heat transferred to the tank is what melts the solder and makes it flow. Heat the material, not the solder, that is what makes the solder go where you want it to go. A situation like you describe is usually the result of someone that doesn't know what they are doing, and trying to use a soldering pencil and 1/8" acid core that they saw their dad use on the kitchen plumbing with a torch. I have done this stuff for a living since I was a teenager,(I'm 62 now) and have taught it in adult education classes, and fixed more than my fair share of messes like you describe. 100% of the time it's from too big solder size, not clean enough, and not enough of the right kind of heat. Most of the problems guys post on here are from the same thing. Practice makes perfect also. I've made plenty of mistakes on the job and have had to fix them also! That's the way you learn. I didn't learn it the first time some one showed me how to do it, it took time and practice. Most guys on here don't get that much opportunity to do this stuff, so they don't develop the techniques and skill. I have sweat soldered literally miles of copper pipe installing air lines and water line and such, and you just get to understand the animal. i under stand metal and working with it in a lot of different ways. Math is what scares me!!
  Type at you later and HAPPY EASTER!
  Dan McEntee