He hasn't posted since 2014 so you are unlikely to get an answer. For me (now that we're chatting), some of the reasons I love my IMS tanks are the low maintenance, not worrying about minor scratches and being able to see the fuel level from 10' away......so no paint for me.
Thanks Dave for your keen eye on his posting history. After scowering through various sites on the subject of painting IMS tanks, I have seen where everyone takes the same approach of scuffing the inside, some with drywall screws of all things and then lining it with a tank liner. This seems like a risky business at best to me so I decided to come up with my own plan.
The first thing I intended to do differently was to use a sand blast media (80 grit glass) to scuff the inside of the tank. I intended to fill the tank 90% with media and 10% water and then put it on a vibrating table for a day or two, moving it ever few hours to ensure that the media could do it's job in the nooks and cranies.
While I was developing this plan I found a post on another site that followed all of the "rules" only to have the tank liner chemical fail after a year. It was called Blue...... something or other. I tried to get them on the phone several times with no luck. I wanted to ask if their product was for PP CROSSLINK tanks.
I then had the "ah ha" moment that I might be able to coat the exterior of the tank with JB weld which would kill two birds with one stone. Seal the tank AND provide a paintable surface. I went to their site to check things out.
Turns out they sell a product that is super tough, bonds to PP and is impervious to gasoline called PLASTIC BONDER. (go figure on the name) Google Jb weld Plastic Bonder and you will find the stuff
I found it on line for under $6 a syringe.
I know that some folks like the look of the raw plastic of an IMS tank. I am not one of them. I intend to sand down the seams and such. I like to put stickers on my tanks as well as in this instance paint to match. It's my intention to thin the JB product with Acetone. According to the folks at JB slightly less that 1 tablespoon per syringe pack will do the trick. I'll thin it and then spray it on with a cheap (throw away) Harbor Freight gun. The stuff dries tan so whatever I miss I'll touch up by hand.
I think this is the ticket but I've wrong before. I'll let everyone know the end result. In closing, I have never had a reason to second guess a JB product. They know what they're doing but if anyone has good reason to steer me off of this coarse please speak up! I'll report back with my results.