What's everyone's favorite gas tank sealer?

I've got this Mark 2 Jaguar that I'm trying to put back on the road.  It came with no gas tank, so I bought 2 more Mark 2's for parts.  I now have a good gas tank that has some of the worst smelling gas I've ever been around.  Since I have to clean it anyway, I might as well try to do all I can to make sure it doesn't have to come out again.  Eastwood has a kit for around $50, or POR 15 has a kit that looks very similar for $105.  Does anyone have any experience with either kit, or any other good one that I overlooked?  

I paid a rad shop 200$ to do my datsuns fuel tank after trying and failing to do it myself. I think they used redkote

My only experience with tanks that were sealed over the rust and tar is pulling them out when they leak to do the job properly.  I probably repair 3 redkote/Kreem "sealed" tanks a year.

If you can get a clean, acid etched bare steel surface on the interior of the tank then most of the sealers will work. The 17 year old POR15 I put in my Fiat tank is still perfect.

Professionally, I use Caswell's epoxy tank sealer. I have done around 50 tanks in the last decade without a failure. For some reason their "petrol blue" color is more viscous,  yet flows better giving a thicker, more even coating. 

I send all tanks to be acid dipped before rust repair and sealing. I am lucky to have a local company that specializes in this and realize not many folks do elsewhere. 

You can do a driveway version with a gallon of Muriatic acid from home depot and hot water if you have a way to clean up afterwards.  

I have seen so, so many cars in the shop with leaky tanks or flakes of sealant clogging carburetors and fuel pumps from sealing dirty tanks. It isn't a risk we can take.

Not sure about gas tank cleaners, but I've used the Bill Hirsch gas tank sealer successfully in the past for a couple home made gas tanks:

https://www.hirschauto.com/Gas-Tank-Sealer-Repair/products/4/

In reply to Trent :

Hi Trent,

It sounds like you know what you are talking about!  Hoping to get your fast feedback.

I have spent weeks researching - I want to get this right...

I have a 1993 Dodge Stealth fuel tank (same as Mitsubishi 3000GT).  It is a challenging tank with a raised vapor capture area, 2 partial baffles/walls with pass through holes on upper portion, some kind of open small capture tank on bottom portion, and finally 2 pipes half in and out of tank (small vapor pipe, larger gas full pipe).

My thoughts are:

1) Clean all rust (tank and pipes) with diluted Phosphoric Acid and swirl with large washers/bolts etc.

2) Etch with Muriatic Acid

3) Seal with Caswell "petrol blue" or perhaps KBS Gold Standard 5200 (great reviews and much more cost effective).

Any fast feedback or thoughts?

KBS also has a kit to cover 1) to 3) above with strong pos reviews.  Says up to 25 gal.  With all extra walls in tank, perhaps I need 2 kits if I go this route.

I am in USA - Texas

Thank you!

I did the home-made kit - vinegar, water, baking soda route - fail.

I bought this kit - success!

I'd defer to Trent, but I've used KBS on several motorcycle tanks successfully. I generally etch them with muriatic acid first, though. 

I have never used the KBS product but it looks like it covers the important bases. It doesn't appear that the sealant is catalyzed (but neither is POR15, so likely less of an issue than I think)

I would caution against the "washers/chains/screws/nuts and bolts and shake" method.  It may work great for a motorcycle tank but a full sized car tank will be quite heavy and awkward to swirl around. There is no way a human of average strength and endurance will do it long enough to make a measurable difference. Plus you then have a lot more debris to remove. 

I'd suggest the KBS kit and follow the instructions included. 

Take note. A modern tank might have internal pipes that you will have to ensure are clear while sealing. I use a puff of compressed air every so often until everything is set up

Ethanol is ruining a lot of older liners and I've never seen a liner that didn't fail and end up sending gunk through the fuel system.

Sure. It's fine for gas today but what about whatever junk they put in fuel 10 years from now?

Have a rad shop boil it out, solder or braze the pinholes shut and run it.

Tank won't rust if it's stored full.

Trent said:

I would caution against the "washers/chains/screws/nuts and bolts and shake" method.  It may work great for a motorcycle tank but a full sized car tank will be quite heavy and awkward to swirl around. There is no way a human of average strength and endurance will do it long enough to make a measurable difference. Plus you then have a lot more debris to remove. 

Seconded. Years ago I had a motorcycle tank that needed cleaning and sealing. I asked a friend who does custom builds and motorcycle restoration for a living about shaking it with bolts/screws/chains inside the tank. He suggested getting a quantity of beer, and inviting over 6-12 buddies, preferably young and strong ones. He said each guy shakes it until he thinks his arms are going to fall off, then shakes it for another 5 minutes after that point before passing it to the next guy and grabbing a beer...by the time everyone has taken multiple turns shaking, it might be close to clean. At that point I thanked him for the advice and took it to a radiator shop. I can't imagine doing it to the motorcycle tank, let alone doing the same with a heavier and bigger car tank.

When I had a rusty car tank, I packed it up and shipped it to Moyer's in Pennsylvania. They cut it in half along the seam, media blasted the inside and outside, welded up any holes, welded the tank back together, and then coated it inside and outside. It was a couple hundred bucks if I remember correctly, which was money well spent IMO as new tanks were impossible to find for this particular car. It worked great; no leaks, and no more struggles with clogged filters.

In reply to ShawnG :

Mine does/will get rust at top, even with a full tank, as it has a big hump for "vapor" :/  I am redoing entire fuel system and lines and hoping this will help keep moisture out of hump.