Rubberized undercoating on new gas tank

[Jake Wade]

I am going to get a new gas tank for my 85. I will be doing away with the plastic shield that's under there. I would like to coat the tank with something and thought about 3M rubberized undercoating.

Will that work OK?

[old Rusty C10]

I have done this myself. Its been done over three years and my truck is pretty well a garage queen but its been great so far.. I left my plastic shield on but I sprayed the entire tank to rust proof it. It looks good and hoses off well

[Jake Wade]

Thanks!

[bigd65]

I would think water could get under it nd be stuck there and rust out over time. The shields have drains on them that lets the water drain out
Posted via Mobile Device

[RandyP]

If you're getting water under the undercoating you have other issues besides possible rust developing.

Both new tanks I put under mine we cleaned and sprayed with undercoating. Just something to cover the ugly metal. If I recall the tanks were raw basically with a greasy coating of some sort on the outside. We thought about just using rattle can paint but decided undercoating would be a little tougher in the long run. My shields are in place though as well.

[tucsonjwt]

I would leave the shields on. They will take a scrape if you run over something and possibly save puncture/damage to the tank. I saw some shields at the pick and pull recently that were the full length of the tank and they seem to have done the job. I never saw full length shields before but they looked very practical.

[old Rusty C10]

MY CUCV has the full length shield I imagine it was some kind of option.... I bet Keith Seymour would know for sure

[king-918]

Originally Posted by Jake Wade

I am going to get a new gas tank for my 85. I will be doing away with the plastic shield that's under there. I would like to coat the tank with something and thought about 3M rubberized undercoating.

Will that work OK?

Hell I coated my whole frame in that stuff
Posted via Mobile Device

[Jake Wade]

I had rather leave them off as I found a lot of debris trapped between the tank and shield which led to tank rot.

[78 Bonanza]

The 3M undercoating is junk if you plan on driving the truck alot. I would go with Eastwood rust encapsulator (paint on 1 qt. can) and then some other higher end coating over that to protect the tank. We've tried rust bullet but it didn't hold up well. And we have had so many redo's with the 3M that we shy away from anything they offer now. The shield traps some junk but is there to prevent punctures, etc. from road hazards. With a good coating of a base and a undercoating you shouldn't have to worry about the small stuff that gets trapped in there. Just check ratings on whatever you buy as every company, including Eastwood, sells some stinkers. In our restoration shop we use a variety of different chemicals from a wide variety of makers. Just takes some homework. And remember to do proper prep. work, put on a nice even coat and let it cure all the way before you put the tank back on or you will have peeling and another rusted out tank (even without the shield). Hope this helps.

[v30crewcab]

what about spraying them with bedliner, a little tougher than the rubber undercoat, would protect it from rust better as well.

[old Rusty C10]

I pressure wash the bottoms of my trucks up here in the salt belt several times a year.. that eliminates the debris.... junk accumulates under the straps and mounts too

[maxxxy]

I used bedliner on my tank. It looked really good but the first time I spilled gas on it, it ate through the paint.