Lining a gas tank

Has anyone in the club relined a gas tank?
What method did you use? Kreem, Vinegar or other or combination?
Any hints and tips.
I emptied out my gas tank to change out the gas and make sure I didn't have any water in there sitting at the bottom ( I didn't) and thought this might be a good time to do a reline.
I heard about Kremm and I am considering it but I want to hear from the populace (Sp?)
So give me some advise if you have same.
Thanks

Your question is addressed very nicely in the Tech Q&A section of the January 2015 edition of Rider Magazine (p.66).  Briefly, he suggests the Yamaha Fuel Tank Rust Remover and Neutralizer kit, which he says is about $25.  He also discusses some alternatives.  

On a personal level, in about the mid ’90’s, I stripped and recoated the interior of the tank I got from a R100RS.  I used a product that I got from the BMW dealer in Woodbridge, Ontario and while I do not recall the product’s name it was apparently the best one on the market at the time.  It had both the stripping mix and new coating, which was a two part epoxy mix.

Stripping of the tank interior is usually done with a solution containing phosphoric acid.  As it can be a messy procedure  and phosphoric acid is toxic to the skin I very strongly suggest wearing protective gloves, clothes and eye protection when using it.   Where most acids will burn the skin, phosphoric acid penetrates into the skin and then causes blisters, which can take quite a while to heal.  It’s a mild acid and rather insidious so you may not be aware of any on your skin until it’s too late.

It may seem obvious, but before starting, remove the petcocks, if you’re not going to replace them, and plug each hole with a cork or rubber stopper.  This procedure will destroy them otherwise.

With the BMW tank, you are not only removing rust but also the original inner liner.  This must be done if you’re going to get good adhesion of the new coating.  It had also been suggested that I also put some metal nuts in the tank, to act as an abrasive, and shake it with that to help get the coating off.  I didn’t do that because I felt that the nuts could get caught in the neck of the tank when emptying it.  I followed the procedures outlined for the stripping, making sure to swirl the tank periodically and to allow sufficient time for the stripper to do it’s work.  I seem to recall that I drained the tank after a few hours and, after cleaning the solids from the solution, poured it back in for a second soak.  This solution did clear the rust nicely and got in under the stock coating and lifted it all.  Be very careful not to get any solution on the exterior of the tank as it can also damage that paint and, if you do, spray it off quite quickly.  After everything was stripped out, I gave the tank interior (and exterior) a thorough water rinse with a garden hose.  At this point I had bare metal inside the tank so to avoid flash rusting I then rinsed the tank interior several times with methyl hydrate or isopropyl alcohol (don’t recall which) to remove all traces of water and to make sure the interior was dry.  I then blew it out with compressed air.  If you don’t have a compressor, a hair dryer (low setting) will do nicely.  I seem to recall that this took the better part of an afternoon (or longer) to make sure the tank was clean and rust free.

Once the tank was good and dry I let it sit for a bit and then mixed and applied the two part epoxy liner.  That part can also be quite messy and, again, you have to be careful not to get any on the tank exterior (particularly if you don’t have plans to paint the tank).  Depending on the coating that you are going to apply, you will likely want to do this either outside or in a well ventilated area.  

It again seems obvious, but allow the new liner to thoroughly cure for a few days before putting gas back into the tank.  

As a side note, be careful of any fuel additives that you add to the tank.  You may recall that a typical fuel additive several decades ago was methyl hydrate (methyl alcohol) which was used to address water in the gas.  Well, I added a small amount to the tank on leaving Halifax to ride to North Carolina in 1982.  Big mistake.  By the time we reached St. Stephen, NB the methyl hydrate had peeled a significant amount of the red liner on the inside of the /5 tank and it plugged the fuel filters and carbs.  I managed to creep into a service station and the owner kindly let me use his tools and facilities to take the tank and carbs off and clean everything up.  We were on the road again in about an hour or so (in the rain of course) but lesson learned.

Just a few ideas there and as it has been a few years I may have forgotten something but I hope this helps.

Alan

Thanks Alan.
This is the type of dialogue I was looking for.
Upon reflection I might not redo the liner at this point in time. A few points that led me to this realization are as follows.
The residual gas beyond the reserve level of the petcocks yielded not water or rust.
I had the tank relined about 20 years ago at a Radiator shop (I don't recall exactly but it was either 'Stan the Rad' or 'National Radiator'). the liner had a red finish to it or clear over the original red. There seems to be some rust flecks in the tank but they seem to be stable in the liner material (if that makes any sense?).
So I think I will stay with Staus Quo for now.
Thanks again for chiming in.