Topic: Removing old tank sealer

[TheHulk]

I am in the process of fixing up an old CB550 tank. It was filled with an insanely thick layer of old tank sealer, that was chipping and flaking. It was tan/brown in color and really poorly done. Luckily I found this video:

He used Acetone, so that's the first thing that I grabbed. After a few rounds of Acetone almost all of the old sealer has been dissolved, except for a few stubborn areas on the walls of the tank.

I guess I have 2 questions:

1. Is there anything that is stronger than acetone that might dissolve the remaining sealer?
2. If I can't manage to remove the thin stubborn spots that are left, would it be detrimental to seal over what is left? I will be using the POR15 tank sealer.

Pictures below are of what I've been removing. Look at that thick chunk!

[ekpent]

 I've used thin water soluble furniture stripper on old Kreme liner in the past with quick results but unfortunately the EPA has now outlawed the good stuff. Wish I had kept a little stockpile.

[HondaMan]

I did this with a 750F tank. I used acetone (overnight soaking) and [new] drywall screws as shaker-scrapers to get more of it out.
Afterward, use the POR-15 kit: if there is any old liner in there it will become completely trapped under the very best tank liner made. An important tip, though: if your petcock is the type that mounts with 2 screws into the tank, grease those screws, then make a plastic (or waxed-paper) cover on the outside of the tank over the holes, then a thin sheet metal cover for that, then grease the screws and screw those screws all the way in to hold it closed. The POR-15 makes a very hard shell inside the tank: when you later remove the screws they will have a sealed shell that is longer than they will be when you re-mount the petcock. This makes a perfect tank again that will probably outlast the bike!

[TheHulk]

I did this with a 750F tank. I used acetone (overnight soaking) and [new] drywall screws as shaker-scrapers to get more of it out.
Afterward, use the POR-15 kit: if there is any old liner in there it will become completely trapped under the very best tank liner made. An important tip, though: if your petcock is the type that mounts with 2 screws into the tank, grease those screws, then make a plastic (or waxed-paper) cover on the outside of the tank over the holes, then a thin sheet metal cover for that, then grease the screws and screw those screws all the way in to hold it closed. The POR-15 makes a very hard shell inside the tank: when you later remove the screws they will have a sealed shell that is longer than they will be when you re-mount the petcock. This makes a perfect tank again that will probably outlast the bike!

Awesome. Thanks man!

[Flyin900]

MEK is like Acetone and also excellent for removing the old Creme crap which doesn't like the new gasoline formulation with alcohol. Can't speak to the new Creme stuff that is still for sale, yet I would never use it given the bad rap it has on most forums.
MEK is nasty stuff too, just like Acetone, so proper PPE is mandatory! Hopefully your repainting the tank or covering up well, as both will destroy an original finish on the outside of the tank in short order.

[Dolomite]

I had really good results using the POR15 system on two different tanks.

[ckahleer]

High temperature helps a lot. I have found gas tank crud dissolves much better in the summer than in the winter.
I am considering using aquarium heaters when I need to clean a tank in the winter.
I use Caswell tank liner when sealing a tank. It's a 2 part epoxy coating.

[TheHulk]

Hopefully your repainting the tank or covering up well, as both will destroy an original finish on the outside of the tank in short order.

Yup starting from scratch. Exterior has been stripped to bare metal. I'll be sealing, bondo-ing, and painting. Wanted to get the interior cleaning and sealing finished first.