Topic: Saving a tank WITHOUT lining it?

[Scott S]

 I got this CB350 twin tank from a guy over at the Honda Twins forums. It was a screaming deal; basically just pay shipping. I have $35 in it, plus the cost of a bottle of The Works.

 It looks rough, but it's VERY solid. In fact, it was so clean inside that I used a diluted The Works/water soak instead of full strength and rattling around chain, etc. It came out spotless.
 BUT..... After about 10 hours of soaking I started noticing water seeping through the Bondo at the top, left front. After draining and rinsing, I chipped off the Bondo and didn't see a thing. The tank is super thick and solid. I chucked up a wire brush in my drill and cleaned a three inch or so circle and found this:




 It appears to be leaking at the seam. That little divot in the pic is about the size of a pea or a pencil eraser, or smaller. That's a 4X zoom for the holes.

 This tank is so clean inside....I'd really hate to line it. This is right after rinsing. I didn't even finish the process with alcohol, oil, etc., yet.



 If.....IF... I have to line it, should I have this dent pulled first? It's about thumb sized and right about where the H in the HONDA badge would be. Everything else on the tank is just a smear of filler away from being ready to prime and bodywork.
 I purposely positioned the tank to make the dent appear as bad as possible for the picture.



 The tank looks rough in the pics but, again, it's not....it's VERY solid and very straight. And very clean inside.
 What's the best approach to sealing up that seam and saving this tank without having to line it?
 Also, even though it would mean having to clean it again, I'm thinking about filling it back up with water and letting it sit just so I can see exactly where it's weeping from.

[jonda500]

Braise or solder it?
John

I have no lining in this tank - before having it painted, I had to braise dozens of holes! That was over 3 years ago, still no leaks

[Scott S]

 I don't have the equipment or skills to braise it.

 I might take it to the body shop and have them pull the dent (in case they use the weld on studs) and fix the leak, then just hold off on body work and paint. This is for the next project in the queue, so I don't need it right NOW.

 I'm thinking about adding some water and green food coloring (because that's the only color I have) and seeing if I can confirm that's where it's coming from.

[beemerbum]

I don't have the equipment or skills to braise it.

 I might take it to the body shop and have them pull the dent (in case they use the weld on studs) and fix the leak, then just hold off on body work and paint. This is for the next project in the queue, so I don't need it right NOW.

 I'm thinking about adding some water and green food coloring (because that's the only color I have) and seeing if I can confirm that's where it's coming from.

Isn't that water, green or otherwise, going to bring back the rust?

[jonda500]

I used some compressed air inside and soapy water on the outside to check for/locate any holes I missed.
John

[Scott S]

I don't have the equipment or skills to braise it.

 I might take it to the body shop and have them pull the dent (in case they use the weld on studs) and fix the leak, then just hold off on body work and paint. This is for the next project in the queue, so I don't need it right NOW.

 I'm thinking about adding some water and green food coloring (because that's the only color I have) and seeing if I can confirm that's where it's coming from.

Isn't that water, green or otherwise, going to bring back the rust?

 It's so clean I can easily get that rust out.

 And the food coloring trick confirmed it. In fact, I buzzed off the Bondo on the other side too and there's a weep there as well. It was holding until I took off the Bondo. Both leaks are at the seam and nearly invisible to the naked eye.
 It looks like someone was just going for the "smooth" look on this tank, as the badges and trim strip area is filled in as well.
 I still think it can be saved if I can find someone to braise/solder it.

[przjohn]

Do all your dent repair and paint prep and then line with the Caswell Kit. Done it many times including a fiberglass Norton tank, it is the way to go IMO.

[Scott S]

 I've used POR15 to seal holes I could see daylight through and I feel strongly it would fix this. But there's just something so wrong about lining a tank this clean!!!!

[Retro Rocket]

I've used POR15 to seal holes I could see daylight through and I feel strongly it would fix this. But there's just something so wrong about lining a tank this clean!!!!

Take it to a radiator shop and get them to solder or braze it up, well worth it, They have the equipment to pressure test it as well. I HATE LINERS TOO.....

[754]

Looks like someone just ground thru the seam till the weld was gone ..
If that is the case just mig weld over those spots.