The Stovebolt Site Forums The Shop Area Paint and Body Shop Rust inside of 56 3100 Doors

Hey all,

I'm in the process of rebuilding a 56 chevy 3100 I purchased awhile ago. The truck is in great shape on the exterior and has next to no rust, but it went through a paint strip before I purchased it. I'm moving through the truck and doing body work panel-by-panel and I started working on doors yesterday. After removing the interior door cover, I discovered a ton of rust (maybe 40% coverage) on the inside (interior) of the door. It appears to be surface rust, but I was suprised since the condition of the exterior metal is in such good shape.

Any recommendations on how to remove it? It's pretty much impossible to get inside the door by hand to sand unless I want to cut the inside of the door out and weld it back into place once it's cleaned up. The last thing I want to do is to restore this thing, invest in a great paint job, only to have the door rust out in 5 years.

Help is greatly appreciated!

POR-15 needs/enjoys light surface rust (moisture) in order to cure. I sloshed around POR inside the bottom of the door and let it drain out the drain hole.

POR does not like sunshine, but there will be none inside the bottom of the doors.

https://www.por15.com/POR-15-Technical-Information_ep_62.html

Rustoleom rusty metal primer. I painted some rusty wheels with it & painted over that with grey wheel paint 3-4 years ago & they still look good.

What sort of paint strip did it go through? It could be from improper rinsing and neutralizing inside the door. If you suspect this is the case you might have trouble painting over it.

Sorry if I wasn't clear. I was referring to the exterior. All the outward facing metal on the truck is great. This is literally the guts of the door panel that 's rusty. They don't have paint from the factory.

I should add the biggest issue I'm running into is actually accessing all the rust. It's so far into the panel it's pretty much impossible to get at.

Get a small wire bottle brush and do the best you can at brushing the inside of the door to get rid of any loose stuff. Then use a craves tool on your shop vac and suck out all the dust and dirt. Then take painters tape and tape the drain holes closed on the bottom of the doors. Then pour in about 1-cup of POR-15 through the door access hole. Then use a throw-away 2" foam paint brush taped to a paint stir stick and start dabbing/brushing all the surfaces you can get to. The top edge of the brush will get under the horizontal brace.. Make sure you coat the entire bottom seam. Add more POR-15 if needed.

When done and before it dries pull the tape off the drain holes and let the excess drip out over night...

I always re-check the doors anout 2-hours later to make sure the drain holes are still open, as the POR-15 starts to dry it gets thicker and could stop up the opening. It's easy to clear the holes while it's semi soft.

That's about as good as you're going to get it and should last your lifetime.

Don't forget to wear gloves as any POR-15 you get on your skin will be there for weeks!

Mike B

Thanks, Mike. This is exactly what I needed. Much appreciated!

Or just use this every year.

https://www.3mcanada.ca/3M/en_CA/company-ca/all-3m-products/~/3M-Cavity-Wax-Plus-08852/?N=5002385+3290903372+3294529206&rt=rud