Gas tank question

[Guest]

So I've got a 79GS1000N tank that I've worked on already to remove an old bubbling liner. Thought I had it all but recently noticed a few pieces of gunk in there so need to go at it again.

Also when I removed the old liner one small hole near the seam at bottom started leaking. At the moment it's plugged with epoxy but want to do something more secure.

I'm thinking reclean the tank with acetone or the like with drywall screws or similar. Then use a por 15 liner (following instructions carefully).

One question I have is what to do with the hole. I want it plugged "properly", meaning not just relying on the liner. One reason is because I plan on repainting the tank next year. Don't want the stripping process to get into the hole....

thoughts out there?

[chuck hahn]

Small pinholes can be plugged with brazing or with soldering. There is a limit as to how big the hole can be though and it also depends on the surrounding metals state. If the hole is on the bottom and unseen when on the bike, I would scrape the hole out till its all good solid metal around it and then have a patch brazed over it.

What you do also depends on if your trying to save the paint not. Any welding and fire is gonna ruin that right off. If the paint is good and you havent ruined it with any chemical spills from the cleaning, the fill small holes with JB weld and sand smooth. Then apply the liner kit.

[RobertGS]

Thanks, I'm not concerned at all about the paint as it's a mess all over the tank and I"ll be repainting next year.

The hole is very small. Larger than a pin prick. Sort of head of pin size. Metal around looks good.

I tried soldering ... couldn't get the solder to even melt, so not feeling all that optimistic about brazing either.

I'm assuming I need a better quality iron that get's hotter? Any recommendations for soldering iron specs and type of solder. Pointers on method?

[tkent02]

I'm assuming I need a better quality iron that get's hotter? Any recommendations for soldering iron specs and type of solder. Pointers on method?

A soldering iron won't do it. Flames. It takes a lot of heat to get the gas tank hot enough for solder to stick..

[Rover]

Where there is one hole there are usually more. Check around so you are sure to identify them all. Hope you just have the one though.

[tkent02]

Where there is one hole there are usually more. Check around so you are sure to identify them all. Hope you just have the one though.

/\ This /\

One hole is usually just the biggest of fifty or so.

[Nessism]

Long thread here on the trials and tribulations of rehabbing a rusty old tank...http://www.thegsresources.com/_forum...d.php?t=200230

[RobertGS]

I've had pretty good look, see one possible other spot but it's not leaking. I haven't seen any rust inside or out. So maybe a puncture? It's been full of gas for quite some time after removing the old liner. No other leaks.

Thanks for the thread. I'll read it over. Maybe ask a mechanic friend if he knows someone who can properly repair it. I'm not painting it until it's done right. And I'm pretty darn sure the epoxy I put in it is gonna fail at the worst possible time so that's gotta go.

[chuck hahn]

Solder holes with a propane torch because an iron wont get the metal hot enough. Clean and Flux the area. Then ( with a low flame ) start heating the area with the torch and wiping the solder around on the tank after a few seconds. If the base metal is hot enough the solder will melt and adhere to the tank. If not a little more heat..then rewipe till it melts to the tank. Kinda swirl it to the center and lift off the solder and let it cool real good. File or sand it down.

I would however suggest you just fill it and leave it as is and do the tank liner and then come back and file it. This will make the tank liner a good backing to file against and not knock the solder out of the hole all together..its gonna be real thin once its smoothed over. Heres my thread on Frank Zs Cooley tank. It had holes the size of a little fingers nail and I had to MIG it all shut..which is a very delicate process. Slow down and lots of creativity and patients and it can be accomplished. I used the ntorch method after I had ground and filed the weld down to be sure any micro cracks had been filled and then we did the Caswell tank kit.

http://www.thegsresources.com/_forum/showthread.php?t=192039&highlight=cooley+tank+saved

[RobertGS]

Thanks a lot Chuck. I'll go that route and read over your thread carefully. I've seen various suggestions for safety and realize it's on me.. but what do you do to prepare the tank for taking a flame.

I've heard detergent, lots of water, something about filling it with co2 or other gases.... My assumption is clean the thing repeatedly until no gas smell...?

Finally, any suggestion on the type of solder?

[Nessism]

Here is a good video showing how to derust and solder up a fuel tank. These guys have a bunch of different videos you may want to watch...http://www.youtube.com/watch?v=AT8EbHL_snA

[RobertGS]

Great thanks Nessism.

[chuck hahn]

I just wash them with a lot of Dawn dish soap and shake the heck out of them to get them free of fuel residue...never had one explode any gasses from inside yet.

I just flow over the welding with regular electronics solder that I get at Radio Shack.

[RobertGS]

Thanks, I'll report progress.

[Nessism]

Eastwood sells body solder and tinning fluid. Hardware stores also sell these supplies for doing plumbing work, but I'm not sure if the materials are the same. In the old days the solder was a mix of tin and lead, but modern body solder is going toward lead free. I recommend some research on what the best materials are (I'd go for the old type with lead if you can get it). There are various types of tinning fluid as well so research that one as well. In the end you are going to be into the materials for some money, so welcome to the joys of motorcycle restoration.