Temp rustproofing-- application temp 40'F

[The_Jeff]

My firebird needs to sit outside this winter. Has surface rust on the floorboards I'd like to grind down and protect/ primer? before it goes out there. Temps will be mostly below freezing. I have a few days of 40'F but then a changing weather pattern will bring snow-- want to put this in its "winter bed" and free up the garage for my daily driver. I'd like to do a good-ish job of grinding/ cleaning/ protecting when it warms up but I'd also like to protect it now. Hopefully what I do now will be good prep for later.

So, for example, I don't really want to do a wax oil now if it will need a massive scrub down later for paint or undercoating.

This isn't a concourse quality car but I want it to stick around a few more years, and stop/ slow down the rust.

 

[Shannow]

Fish oil...will be slower, but much less stinky than on a hot day.

Can be primed straight over when it dries.

 

[demarpaint]

How about POR-15?

 

[Donald]

I would go with Loctite Extend if you can get the metal above 40F. POR-15 needs to be prepped with naval jelly as does Eastwood Rust Encapsulator.

The most import thing is to go to a car wash with an underbody spray and do not drive it on salted roads. The car wash near me has an additive in the underbody wash to neutralize salt also.

 

[zzyzzx]

If using oil based paint or other products I figure 40 degrees is just fine.

 

[demarpaint]

Originally Posted By: zzyzzx
If using oil based paint or other products I figure 40 degrees is just fine.


40° just about the upper limit. If it dips below that I'd suggest using some kind of nonflammable heat source to dry it.

 

[The_Jeff]

Originally Posted By: zzyzzx
If using oil based paint or other products I figure 40 degrees is just fine.


But doesn't rustoleum take months to dry?

If I used a rustoleum primer, for example, isn't that water-absorbing if not top-coated?

I painted a (different) car with the "$50 roll on" where rustoleum is diluted with mineral spirits and it flash-hardens, unlike regular rustoleum. Would a coat or two of this cure up and offer protection?

I've deftly kept this car out of the salt so far, so it's clean. I can aim a fan forced space heater under the car for a few hours and the "blanket" of the car might keep it ten degrees warmer under there.

POR15 is pricey at $40 a quart, I'd have to be really convinced it was worth it. And if I did use it, I'd want to follow the label instructions that I assume include a room temperature. Then I'd know for sure to blame myself if rust came back... due to inadequate surface prep.

 

[Donald]

Originally Posted By: eljefino
Originally Posted By: zzyzzx
If using oil based paint or other products I figure 40 degrees is just fine.


But doesn't rustoleum take months to dry?

If I used a rustoleum primer, for example, isn't that water-absorbing if not top-coated?

I painted a (different) car with the "$50 roll on" where rustoleum is diluted with mineral spirits and it flash-hardens, unlike regular rustoleum. Would a coat or two of this cure up and offer protection?

I've deftly kept this car out of the salt so far, so it's clean. I can aim a fan forced space heater under the car for a few hours and the "blanket" of the car might keep it ten degrees warmer under there.

POR15 is pricey at $40 a quart, I'd have to be really convinced it was worth it. And if I did use it, I'd want to follow the label instructions that I assume include a room temperature. Then I'd know for sure to blame myself if rust came back... due to inadequate surface prep.


POR-15 and the similar Eastwood product are very similar in that they produce a very hard surface that moisture nor air can penetrate. But you need to prep first with a rust treatment like naval jelly. They sell one for prepping for POR-15 but am pretty sure the chemical is the same as naval jelly.

Try the Extend. Easier and does a similar job in one step.

 

[Phishin]

I've had great luck with Por-15.

They make a pre-cleaner solution that any place that sells POR-15 should have on the shelf as well. All it is phosphoric acid with zinc oxide dissolved in it. Naval Jelly is just phosphoric acid.

The phosphoric acid dissolves the rust and leaves virgin metal behind. But the extra protection of the zinc in the POR-15 pre-treatment is that under those acidic conditions, the zinc will auto-plate onto the steel. Zinc is sacrificial to iron. So if any micro-corrosion takes place, it's the zinc that will get oxidized, rather than iron. When iron gets oxidized, you get rust.

When zinc oxides, you get a "white" rust. But the trick is, when zinc oxidizes, it "seals" itself tight against the metal surface, thus preventing further corrosion as well.

Most people don't have jugs of concentrated Phosphoric acid laying around and tubs of zinc oxide....but I do. And I make my own rust treating solutions.

After letting the pre-treatment stay wet on the rusty surface, you simply spray it down with a hose and let it dry. Get it good and dry, and brush on a few coats of the POR-15 paint.

 

[The_Jeff]

Thanks, it's the zinc treatment I'm looking for. I know some primers have zinc in them but am worried that they might not stick right being so cold. I feel like a schmuck grinding rust, factory paint, and factory primer off and want it going back at least as good if not better than before. This POR15 pre-treat sounds snazzy.

 

[Phishin]

eljefino,

Primers can have all the zinc in them they want. But what kind of zinc is it? If it's colloidal zinc, it won't do much good. If it's ionic zinc, the paint better be acidic somehow (it's not) for the zinc to auto-plate onto the steel. It won't, believe me.

When zinc oxide is dissolved in phosphoric acid, it's ionic zinc. Ionic zinc then can electro-deposit onto the steel/iron in acidic conditions....and it will hold. It's going to be in DIRECT contact with the metal that it's going to protect....not floating around in the primer.

It's the phosphoric acid/zinc pre-treat that really sets POR15 apart from the rest. I've run out of POR15 before, and treated rusty metal with my phosphoric acid/zinc solution and then paint the zinc treated metal with oil-based enamel and have gotten good results 3 years/salty winters later. This is how I stopped the rust on my 3/4 ton hitch on my truck. It's still spotless.

 

[The_Jeff]

GREAT INFO, thanks.

 

[cchase]

Originally Posted By: Donald
POR-15 and the similar Eastwood product are very similar in that they produce a very hard surface that moisture nor air can penetrate. But you need to prep first with a rust treatment like naval jelly. They sell one for prepping for POR-15 but am pretty sure the chemical is the same as naval jelly.

Try the Extend. Easier and does a similar job in one step.


I've used Rust Encapsulator a fair amount. You do not need to prep the surface with Naval Jelly or anything like that. Just remove loose rust, clean with a degreaser (like any paint or primer), and apply.

It is very different from POR-15 in its consistency and application.

 

[Papa Bear]

About 25 yrs ago I had a guy paint our TV tower which was beginning to rust. He used galvafroid and the tower still looks great today.