Floor pan rust - Temporary Penetrol?

[captspillane]

Ideally you would put "Rust Converter" on first, then primer, then high build primer for paint volume, then the actual paint in three coats. POR-15 replaces the Rust Converter and the primer and the high build primer and the first coat of paint, all applied at once. When looked at it that way it saves time and is cheaper. Then you put two coats of real paint over top of it to seal it, protect it, and provide color. On frames and underside you should use heavy abrasion resistant chassis paint and/or rubberized undercoating to further protect it.

If you use POR-15 by itself it sucks. Its not much better than Rustoleum. I'm not at all suprised the Yukon frame peeled quickly.

I use the Eastwood "Rust Encapsulator" which is the generic brand of POR-15. They come right out and say that its not intended for frame paint. Its a glorified primer that happens to look okay by itself. They recommend removing every little bit of rust you can, then using "Prep" which is a strong degreaser, light etcher, and rust converter rolled into one, then putting the "Rust Encapsulator" on, then putting their "Extreme Chassis Paint" over top of it for protection from abrasion and salt and such. That's exactly what's being done to my cars.

[Canoe]

Ideally you would put "Rust Converter" on first, then primer, then high build primer for paint volume,...On frames and underside you should use heavy abrasion resistant chassis paint and/or rubberized undercoating to further protect it....
...They recommend removing every little bit of rust you can, then using "Prep" which is a strong degreaser, light etcher, and rust converter rolled into one, then putting the "Rust Encapsulator" on, then putting their "Extreme Chassis Paint" over top of it for protection from abrasion and salt and such. That's exactly what's being done to my cars.

Far easier is Penetrol. Ideal for underside use and floor pans. Removed dirt and rust scale, leave light rust in place. The linseed oil in it cures into larger polymers, with unbonded ends taking up oxygen to complete polymers of linoyxin, both sealing and preventing that O2 from being available for rusting. Top coat with your choice. It just happens to be cheap too (Lowe's, under $10 a can). Apply by brush, roller, cloth, spray, even those stupid squeeze pump bottles (but you'll use more material than necessary with those). Just let cure before top coating.
People keep wondering why they have to revisit welded in floor pans, but the metal they're welding to is just too thin: I've yet to see a budget welder pump an inert gas through the rockers and across the back-side of where they're welding to prevent O2 getting into the metal and to cool it so the good metal just beyond the weld doesn't become brittle. Don't, and the hard weld acts like a can opener to the brittle. Every failure I've seen is this or O2 in the weld or simple rust out.

[captspillane]

I used to use epoxy primer. Now I use Penetrol or heat-treated engine enamel. They work so well, I haven't bothered with epoxy primer since, except for outer body work where I like an epoxy flash coat to seal it before colour.
Then Waxoyl Hard Body on the underside, Waxoyl Rust Inhibitor on the inside.

This is something I will check out, since I've never worked with any of these materials. I've started with my current system on one SX4 and I could do the second SX4 with the other for long term comparison.

You mentioned that you use heat treated engine enamel. Are you refering to a "poor man's powder coat" where small items are put in an oven with ceramic based exhaust pipe paint and then cured in the oven before installation?

I've never had an exhaust paint last more than a few months, but I've also never bothered to prep properly. This is something I also need to look into. There is another thread recently talking about some exhaust piper inner and outer paints that people have had good success with.

[standup650]

Ideally you would put "Rust Converter" on first, then primer, then high build primer for paint volume,...On frames and underside you should use heavy abrasion resistant chassis paint and/or rubberized undercoating to further protect it....
...They recommend removing every little bit of rust you can, then using "Prep" which is a strong degreaser, light etcher, and rust converter rolled into one, then putting the "Rust Encapsulator" on, then putting their "Extreme Chassis Paint" over top of it for protection from abrasion and salt and such. That's exactly what's being done to my cars.

Far easier is Penetrol. Ideal for underside use and floor pans. Removed dirt and rust scale, leave light rust in place. The linseed oil in it cures into larger polymers, with unbonded ends taking up oxygen to complete polymers of linoyxin, both sealing and preventing that O2 from being available for rusting. Top coat with your choice. It just happens to be cheap too (Lowe's, under $10 a can). Apply by brush, roller, cloth, spray, even those stupid squeeze pump bottles (but you'll use more material than necessary with those). Just let cure before top coating.
People keep wondering why they have to revisit welded in floor pans, but the metal they're welding to is just too thin: I've yet to see a budget welder pump an inert gas through the rockers and across the back-side of where they're welding to prevent O2 getting into the metal and to cool it so the good metal just beyond the weld doesn't become brittle. Don't, and the hard weld acts like a can opener to the brittle. Every failure I've seen is this or O2 in the weld or simple rust out.

I'm not saying that you are wrong i like your idea, its good, but i use stargon its argon and co2 mix and i have never had a problem with any replacement panels that i have welded in.

[captspillane]

I'm buyig an Eastwood TIG welder this week. TIG will give me more heat control to prevent distortion and brittle issues. That's why TIG can be used to weld tin foil, it is very controlled and precise to prevent blowouts. 

I took Wray Schelin's "coach-making" class advertised on the evil bay. It was beyond incredible. It was legendary. We made very complex fenders from sheet metal in three days. There I've personally made butt welds on fender halves that totally vanished with minimal grinding and english wheel treatment.

[standup650]

I'm buyig an Eastwood TIG welder this week. TIG will give me more heat control to prevent distortion and brittle issues. That's why TIG can be used to weld tin foil, it is very controlled and precise to prevent blowouts. 

I took Wray Schelin's "coach-making" class advertised on the evil bay. It was beyond incredible. It was legendary. We made very complex fenders from sheet metal in three days. There I've personally made butt welds on fender halves that totally vanished with minimal grinding and english wheel treatment.

Ya tig is awsome! A nice tig welder is on the wish list. whats the deal with that class that class?

[mach1mustang351]

I don't anything like that but one think I keep seeing on the POR 15 is frame and under car use.  They have several different formulas.  They have a POR 15 and a Chassis coat.  They are NOT the same thing.  Proper product per application yields the best results in any type of situation. 

[Canoe]

This is something I will check out, since I've never worked with any of these materials. I've started with my current system on one SX4 and I could do the second SX4 with the other for long term comparison.

Test this. Take a piece of scrap that's rusting. Paint with penetrol. When cured, topcoat half. When topcoat dry, put your undercoating on half the topcoat and half the only penetrol. Leave out in the elements.

You mentioned that you use heat treated engine enamel. Are you refering to a "poor man's powder coat" where small items are put in an oven with ceramic based exhaust pipe paint and then cured in the oven before installation?
I've never had an exhaust paint last more than a few months, but I've also never bothered to prep properly...

Exactly. And with proper prep (all rust & grease removed), but no primer.
I've got to run right now, but I posted before about doing my front springs and other parts that way.

[Canoe]

... People keep wondering why they have to revisit welded in floor pans, but the metal they're welding to is just too thin: I've yet to see a budget welder pump an inert gas through the rockers and across the back-side of where they're welding to prevent O2 getting into the metal and to cool it so the good metal just beyond the weld doesn't become brittle. Don't, and the hard weld acts like a can opener to the brittle. Every failure I've seen is this or O2 in the weld or simple rust out.

I'm not saying that you are wrong i like your idea, its good, but i use stargon its argon and co2 mix and i have never had a problem with any replacement panels that i have welded in.

The problem is overheating, as when welding to thin metals. Your gas protects the weld, but not the backside(s). The backside won't rust as fast as an O2 contaminated weld, but it gets second place.
And few welders will temper the brittle zone after welding. TIG's great for preventing the gross overheating, but with any melted pool, there's always that little zone between the weld pool's surrounding metal and untouched metal where the temper's been changed. It's fine if it's going to sit in a showroom, but if it's going to get the loads of flex from potholes and anything other than pavement... then the flex moves the hard weld against the next-to-it brittle zone - and fracture.
Aircraft and bicycle frames is where this issue is more known.
Explains all the floor pan repair failures I've seen, and done back in the day.

[Canoe]

I don't anything like that but one think I keep seeing on the POR 15 is frame and under car use.  They have several different formulas.  They have a POR 15 and a Chassis coat.  They are NOT the same thing.  Proper product per application yields the best results in any type of situation.  

Yup.
All the complaints and they had to change their advertising. Frame use was the major push and the majority use of their customer endorsements. Last I checked a few years ago, they still had their requirement to degrease hidden in the fine print; their major competitor at the time had it up front.
Although coloured, POR-15 is not a top coat - surface discolours in UV.

[Canoe]

You mentioned that you use heat treated engine enamel. Are you refering to a "poor man's powder coat" where small items are put in an oven with ceramic based exhaust pipe paint and then cured in the oven before installation?

One major change. I've not used exhaust or manifold paint. I use the baked engine enamel. And without primer.
Here's where I use evapo-rust (expensive) as part of the prep, then engine enamel.
If you bake indoors in your kitchen oven, use parchment paper and NOT wax paper to set the parts on.
Like the original source, I've also used a torch to bake some parts. And some while they're in place, or to touch up dings, or a quick coat to a new part before it goes in (latest, steering high-pressure line fittings) In place, watch your temp - not the most complete bake as in an oven or BBQ, but it helps set the paint.
http://forums.amceaglenest.com/index.php?topic=36270.0