Solution for Pinholes

309 welding rod/wire can be applied externally to stop leaks.

http://www.youtube.com/watch?v=YXj7tl0--7g

http://www.reviewstream.com/reviews/?p=52626

If possible could you tell us if the "pin holes" developed in weld bead, spot weld, or in a non-welded part of the assembly. If the item in question is located in, or can be removed and taken to an area where welding can be performed, here is what I would recommend. First depressurize the system if you have not removed the piece that needs repair. Then, assuming you have located and marked all the holes, take a 4 1/2" grinder with a thin cutting disc, or even a Dremel with a cutting disc (make sure the disc's are new, or you are sure they have not been used on ferrous steels. Using the grinder grind out a little bit of the affected area so you can lay a tack inside the groove you just made. This way it also allows you to see how extensive the problem area or weld is. Then I would personally use GMAW (mig) with 309L wire, and straight Argon for the shielding gas. SMAW would also work but you would probably want to find some small 309L rods (1/16" would work great). After filling in the groove you made with the grinder, use a flap wheel type sanding disc to smooth out your repair. This is not needed if looks are not that important.. After you have made all the needed repairs, pressurize the system and check your work for leaks. Whatever you do make sure the area you are welding in is free of any explosive or flammable items and be safe. If this repair does not lend itself to welding for whatever reason, I am sure there are others on here who may be able to advise you on some type of sealant that may be used..........I wish you luck, and a leak free repair.

BASF Consumer Division, Thoro Consumer Products, markets Waterplug. It will stop thhe leak and is not toxic. Can be applied to wet or dry surfaces. Excellent, excellent product.

If the pinholes are not at welds or other areas where a leak might be normal then I would be more worried about what is causing the pinholes in a potable(drinking) water system because the same thing causing that leak if from the inside would be very bad for your insides.

I agree with the man about available epoxy repair mediums. There are several available that work great and are non-toxic. Weld repairs often require the draining of the system in order to be done.

If corrosion has worked it's way all the way thru the walls of your plumbing, it's done, you will need new plumbing. You plug holes this week, new ones will open up next week. Find out what is eating your plumbing, it may be chemical or galvanic. I hope nobody has grounded anything electric to the pipes, that makes them anodes and they go away. If anything like a pump is connected to the plumbing, ground it to a ground rod.

Water can be very aggressive, have it analyzed for hardness, salinity, etc.