Best way to fill pinholes

[Scoobydude]

I've got some pinholes on some 45 tanks I just cleaned out and have heard a couple different ways to fill the holes. Tig, braze ,silver solder, lead.... Are there any downsides/ upsides that I should consider on any one of these methods

I have an oxy acetylene rig, but am not averse to paying someone to do it by another method. Also no I am not interested in coating them

[flatman]

I have never done it, but the Indian tank restorer guys use brass screen and solder/silversolder, just a fyi

[ExplodingCoffinEmporium]

Brazing, although an antiquated process of repair, is useful if your planning on maintaining the period correct look of the tanks, as that’s the methodology that would have been classically used. My 45 bros almost exclusively use the technique with repairing old tins that will remain otherwise untouched. It can take some time to perfect the technique, much like properly sweating a copper pipe but it’s pretty straightforward.

If your planning on painting anyhow and your going for strength and efficiency farm the work out to a good TIG welder. The temperature control in terms of not fucking your tins is there and a good hand will make light work of your issue.

[10scDust]

I would say first off is you are dealing with fuel tanks.
That being said, I was taught that no matter how long ago, how many times rinsed with water, and whatever, you need to displace any oxygen that can become present lest at least having an explosion.

I have a 2" natural gas rubber hose that I clamped to the tank at the filler cap hole. The other end slipped over the exhaust pipe of a running vehicle. The carbon monoxide displaces the oxygen this way, just give it a couple minutes being sure it is still connected good.

This worked for me without a problem. Best to be safe than sorry.

Story: a friend wanted me to braze on a car tank removed once. I insisted no, he persisted in telling me look, rinsed with water numerous times, in fact it had about a quarter tank of water in it when he talked me into it.

I was leery, as I got started with my oxy-acetyline torch, the gases inside that tank ignited, popped, made the tank jump off the ground about 6 inches (with me on top of it). It even swelled the tank a little.

Needless to say, I was nervous, cut the torches off, and told him to take it somewhere else, not me.

Be smart, work safely. It's the gas fumes and not the gasoline itself that ignites.

[confab]

I have fixed a lot of things with silver solder. I'd absolutely use it on a pinhole in a tank.

Be careful heating gas tanks, though.. Even if they're old.

[docmel]

A discovered pin hole, AKA, rust, means lotsa things: In other words, you have lots more just waiting to breech the surface. Patching one, and then painting the tank, will just buy you a little time before you need to patch it again, meaning more labor, down time, and paint

To me, patching a tank doesnt make sense on gas tanks that are available aftermarket. Patching only makes sense on rare tanks: Just me

By coating, if you mean you dont want to coat the inside eventually, is just asking for more pinholes.

[Scoobydude]

Looks like silver solder it is. I paid a pretty good amount for these shit tanks off eBay, and I've been pretty stubborn on rebuilding and fixing everything and only using OEM parts minus the nuts and bolts so the tanks will stay. The more I put into it the more it feels like I've earned it , or something like that, so if I gotta fill some more pinholes later on, that's ok. They've got cool old paint so if like to keep them the way they are for the most part.

I never thought about the exploding gas tanks. I'm having a hard time cleaning the oil tank with all it's sludge. But I did the gas tank and it came out decent, but I didn't know what would keep it from flash rusting so I dumped some oil in there.how should I clean that out before welding and keep it from flash rusting?