The Stovebolt Site Forums The Shop Area Paint and Body Shop phos acid, how should it look when done

I had all my front steel blasted then Phos acid on front fenders and all other front steel except hood. looks very orange now that it is washed off with water and dry, How should it appear. Thanks in advance.

Dan

Dan,

When I have used phosphoric acid to dissolve rust the metal always comes out with a mat grey color.

I'm not sure what was applied to your metal - maybe a phosphoric paint?

Does the orange color rub off like surface rust? Maybe the washing with water has made it rust? When I use phosphoric acid (diluted to 10% with water) I don't rinse it with clear water I just let it dry.

Paul

no it was just sand blasted then the acid and i did rinse it off with water. maybe tomorrow I should do it again and just let it dry. or should I have them blast it again lightly.

Maybe I'm not understanding but if you sand blasted why did you need to use the acid?

I read on the autobody101 fourm that even though you sand blast there is small pits of rust left and the phos acid will eat it out. That what they said any way. Also it etches the metal and is fine to use expoxy over.

I don't know about any rust pits left but sandblasting will diffidently etch the metal.
Your project looks very good.

Thanks, Looks like I will just hit it again and let it dry. Man I hate rust. My moto for this project is " A truck I can trust with NO RUST".

Phosphoric acid will retard rust, not prevent it. The orange stuff is rust. Do not rinse with water, just apply a thin, even coat and let it sit. The resulting surface will be less prone to rust but if it gets wet it will rust.

I stripped my hood and treated it with phosphoric acid and left it outside... BAD mistake! It rained and just enough rain got on it that it completely rusted all the bare metal to the point of leaving an outline of the hood on the concrete floor of the car port.

My best advice is to hit it with the acid, let it sit overnight and get a coat of primer or something on it to prevent rusting. I've been using Eastwood Rust Encapsulator with excellent results. I'm absolutely sold on the product. It works as advertised, beat POR15 in an independent test and is lacquer based for quick clean up.

Thank you Czechman, I will re apply and let sit till try, then epoxy. Thank you.

There are several products on the market that will work equally well as Eastwood's and cost a bit less. Do a web search and you'll find: Zero Rust, Loctite,to name only 2.
Check this link for more information on this subject: http://www.crankshaftcoalition.com/wiki/Rust_encapsulators

i sandblasted my whole truck(UGHH!) but i did it little by little, and i used the phosphoric acid on it...don't wash it off, the acid is water soluable, then you will have bare wet steel ripe for rust.my truck is under a carport and during some of our florida thunderstorms i found out that the windblown rain had some spotty surface rust coming back. now i hung plastic sheeting on the carport and treated the surface rust again with acid.good stuff. Before i sprayed the primer, i took some fine sandpaper and green scrubpads to get the powder residue from the ospho off.I know some guys will say that's alot of extra work, but i have limited resources and time to work on my truck...i just keep chippin away at 'er! http://s48.photobucket.com/albums/f216/applebag/?action=view&current=Markspics013.jpg

Information there is suspect. They state that it must be applied over rust for proper adhesion... wrong, and NO idea where they came up with that. Can't speak for the others but the Eastwood product can be applied to any surface, over or under bondo.

I've stripped my cab down to bare metal and painted it over with Rust Encapsulator. No chipping or any signs of poor adhesion.

I'm doing mine in the carport too... I love working outdoors. I bought a couple plastic tarps and cover mine every evening when I finish up.

Your phosphoric acid experience is exactly like mine. I also give it a good light sanding and then washdown with prep cleaner before priming.

All these products are urethane resins that cure in the presence of moisture and have an affinity for iron oxide.

I just did my frame with phosphoric acid, the "metal prep" for POR-15. I sprayed it on, let it set for 10-15 minutes, keeping it wet, then rinsed. The result looks splotchy, although it feels even. Is that normal? It does feel like it gave some tooth to the metal that had been smooth. Should it appear as an even coat or does that even matter?

Scott

the visual appearance will vary depending on the condition of the metal to begin

Bill

Rinsed with what, water? That usually results in rust. You should apply it, wipe off the excess and let it dry.

Splotchy how?

I posted a couple pics of the frame after the phosphoric acid. The instructions on the "Metal Prep" from Jim Carter said "keep wet 10-20 minutes then rinse thoroughly". I followed the directions, rinsed, then blew dry with compressed air then heat gun to get all the moisture out.

The frame appear splotchy, although I'm not sure how metal is supposed to look after the metal prep. I used the prep since most of the metal had no rust whatsoever and was perfectly smooth after wire-brushing to remove the original paint and primer. The frame will be coated with POR-15.

Is this how it is supposed to look? Can you overdo the acid? Anything else I should do prior to application of the POR-15?

http://rides.webshots.com/photo/2854293210104602464GzoZvK
http://rides.webshots.com/photo/2209786390104602464NOaYtA


Thanks in advance,
Scott

looks like ya let it dry, be pretty hard to avoid unless you stayed on one little patch for the whole 10 minutes - there was paint left too, doesn't work on paint - I'd wanna scuff sand it all before paint

Bill

Your results are similar to mine when I sprayed it on. I subsequently changed my method to apply with a rag and then wipe off the excess. If I rinsed it according to the directions it left a light coating of rust.

I doubt that any damage has been done but by the looks of it you've got some wire brush/sanding work in your future.

I know that's too late for you but it's always a good idea to do a little experimentation with things like this before diving in.

I use it all the time and am very happy with the results. Leaving it on too long is not a problem for all but maybe delicate stuff. I soak parts in it to remove heavy rust and have not seen a problem. You can let it dry between coats with no problem. But when you have it the way you want it then do it again and let it set a few minutes but don't allow to dry. Then you can rinse or wipe it off. Be sure to dry it though or it will flash rust. You can also wipe it once done with good lacquer thinner or a good wax and oil cleaner from a paint supply place.

I wonder how much the other chemicals that may be mixed with the phosphoric acid effect the outcome? I searched every possible supplier in my area and could only find 2 phosphoric acid type products available. I am using a Jasco product. If I leave it on their suggested 20 minutes it is very sticky to try and wipe off and I realize I am leaving a coating behind. When it dries it is slightly uneven and will need to be scuffed well before primer. It does appear it would prevent rusting in the mean time. So far I have only used it on smaller parts. I am hesitant to apply it to a complete panel using my current technique because it would involve a lot of "scuffing" when I got ready to apply primer.

Chuck

when it's 'left on 20 min' it needs to be continuously applied to prevent that stickiness .... note they say keep wet, not an easy thing to do on large panels or complex shapes ... also the primary purpose of it is to neutralize rust and it is meant for bare metal

Woody - when you wipe on with a rag and wipe off the 'excess' right away you're not giving it enough time for the chemical reaction to occur, that's why they say 'keep wet for 10-20 minutes', rinsing it with water shouldn't leave a coating of rust if it's had time to change the iron oxide to iron phosphate, which doesn't rust

Bill

Thanks Bill, it sounds like you know what you're talking about and giving solid advice.

I quit using the acid quite some time ago in favor of Eastwood's Rust Converter and Encapsulator. Now that they've come out with the Converter in a spray can, it's my weapon of choice where rust is bad, otherwise I paint all my stripped panels right after stripping with the Encapsulator.

BTW, I just dropped by to check progress on "da bus"... all I can do is smile and shake my head in awe. The progress is amazing and no one will cheer louder than I when it's back on the road.

thanks Woody, I'm weary but determined

I've gone thru more than a few cans of metal prep, rust converter, high-build zinc primer and Zero Rust .... I kinda prefer the converter too mostly, but like the zinc [tho not the price!] as "encapsulation" where panels will be bolted. riveted or welded together - all the hidden spaces that have any chance of condensation are getting a coat of zinc

near to having the shell done, just doors and the big air scoop on the back yet, all the under-floor stuff is ready [I think] - don't expect it'll actually be on the road before fall, but I'm hoping it'll be liveable - still have to come up with the cash for the 454 I found and brush up on the air brake stuff to get the air ticket

Bill

Based on advice in this thread I went back and re-coated the few items I previously treated with phosphoric acid. When that surface coating loosened up I wiped the parts down right away and now have nicely coated parts without the rough surface coating they had before. They could be primed right away now without a lot of prep. That tip of re-coating saved me a lot of prep work. The big thing I was missing was keeping the surface wet and wiping it off while still wet. There is a lot of advice suggesting leaving it on overnight. I think some of my confusion comes because it is okay to leave it overnight or even soak rusty metal. Stripped shiny metal needs only a few minutes and then wiped clean. Many of my parts are going to have some areas of rust and some shiny metal. I am now comfortable enough using phosphoric acid to start treating my body panels as I finish each one and will start priming when I have a few pieces ready.
Thanks to all who contributed to this thread.

Chuck

Dgallager,

This link will take yo to a few pictures of what fresh metal looks like afer a dip.

Before
http://rides.webshots.com/photo/1414844718054402330eASBec

After
http://rides.webshots.com/photo/1418342078054402330ovysKb

Jake

I'll add a couple points to Jakes pictures - I've had quite a lot of stuff Redi-Stripped years past and have observed every part of the operation, asking as many questions as DennyG
I have some sheet metal on hand now that was done years ago and left sitting - the stuff stored indoors dry looks fine, the parts stored poorly have surface rust that hasn't changed in years .... I stopped using the Redi-Strip here [closed now anyway] when they quit using the phosphating step

the commercial operations use the phosphate bath after the rust removal step - they keep the part wet for a specific time by immersing it in a bath - they immediately pressure wash it with plain water when removed

Bill

THanks,

I had my parts lightly blasted again and sprayed on and wiped off the phos. look like yours. let dry 4 hours then coated with epoxy and all is well.

Thanks again to all