Phosphoric acid, Rustoleum and learning the hard way.

[Delawhere Jack]

I spent the weekend breaking down my Turner mill. Mechanically it's sound, but it was not well maintained, and it was covered in rust and algae. Spent six hours Saturday wire brushing the bed, Sunday I gave it a bath in phosphoric acid. The product is called Prep and Etch, it's put out by Klean Strip. My brother sells it and insisted that it's good stuff. The directions suggested letting it dry overnight if used on heavily rusted metal, so I did.

I come back Monday and the acid has done it's work. The directions are not very detailed, and recommend wiping off any rust residue with a damp rag. The acid has left the surface white, but it appears to be bonded to the metal and old paint. So I go ahead and brush on a coat of Rustoleum, and spray the hard to reach areas. 4 more hours. It looks good, so I head home.

I return Tuesday to begin painting the head. I take a look at the trailer and my heart sinks. The acid has bled white patches through the black paint all over. On horizontal surfaces, where the acid had pooled, the paint is bubbling and pealing...... :'(

I was pretty ticked off, so I decided to go and look into some other items rather than mess with it then. Today I was able to get about half of the trailer brushed-scraped and repainted, and got the head partially painted, after THOROUGHLY cleaning off the spent acid.

I will say it is a really good product, but maybe they would have room on the label for better directions if they didn't have to put on five pages of disclaimers and government warnings....... in THREE DIFFERENT LANGUAGES!

Anyway, just got notice that Cook's has shipped my blades and they are due in Monday. I think I can still make that deadline.

[bandmiller2]

Phosphoric acid is the active ingrediant in most rust conversion coatings.The one I use is mixed with some sort of latex and I've good luck with it.Probibly would have been good form to hose off before painting.I feel your paine and hate it when you get a big owners manual and its in four languages,all dipstick cautions,and one page of scant information.Is not the USA a big enough customer to deserve an english speeking manual. Frank C.

[Robert Duval]

That is a big set back. The problem with a lot of the commercial chemicals is they are made for shops that use them day in and day out, It keeps their liability lower if they leave the label vague and market it as a chemical that you should have training to use. Hope you have better luck with the rest of the project ands get it done in the time you wanted.

[Delawhere Jack]

With so much info now required on labels, and in multiple languages, they've gone to print that is so small it's barely readable. I got some spray for bagworms to use at my parents house, I had to use a magnifying glass to read the label.

[Robert Duval]

That's the other way they get you. The worst part is it's not only labels that are like this, I am working on a JLG offroad lift at work right now and all the directions that came with the parts are tiny, in six different languages and cover three different models that are totaly different from one another.

[rmack]

The trick with that is to hose it off thoroughly and then sand before applying  primer and paint.

[Delawhere Jack]

The trick with that is to hose it off thoroughly and then sand before applying  primer and paint.

I wish they had put your 18 words above on the label................ would have saved me a days work.

[Clean Image]

I'm definitely not a chemistry major but I think this is an issue of pH levels...

I used to do a lot of concrete/brick cleaning with both Muriatic and Phosphoric acids. We would throw a box of baking soda in the rinse water to neutralize the surface pH and stop the reaction of the acid with the concrete. This was especially important if the masonry was going to be sealed afterward...seems like it would work the same with metal prep.

My .02...hope it was worth at least that  :

[eastberkshirecustoms]

IMO, you should be using a good primer under the paint, preferably a catalyzed epoxy. The primer is what makes a good paint job. I would also suggest using a catalyzed paint. I'm not a fan of the basic cheap enamels- they dry too slow and just don't have the wear and endurance as an acrylic enamel or urethane.

[Cutting Edge]

Not to take anything away from catalyzed epoxy....Excellent product IMO too.  But, Rustoleum primer workes suprisingly well.  I did a test run on both the "Rusty Metal Primer" and "Clean Metal Primer" a few years back.  Both work better than one would expect.  Sprayed the rusty metal primer over a severly rusty frame (minimal prep) and it still has yet to come back through.  Also sprayed a tractor hood that was stripped to bare metal, sprayed with the clean metal primer (2 coats) and no top coat to seal.  It has yet to show any signs of any issues, and it has never been out of the elements.  The trick I found is mixing both "just right" for spraying.  Hope this helps, and easier on the wallet.

[Magicman]

When using any acid cleaner, it should be neutralized with baking soda, etc. and then thoroughly washed and dried before any finish is applied.

I have found that if you use the Rusty Metal Primer, you need to use a Clean Metal Primer over it before the final paint job.  If not, after a few years, the paint will tend to peel off.

[Weekend_Sawyer]

Gemplers makes a good rust converter, I have used it on corroded tractor rims. the salts they put in the old tires for ballast was very corrosive.

Jon

[steamsawyer]

First of all, I am not a paint guru. In fact I try to avoid anything to do with it. :D

I will swear by Ospho for killing rust. My understanding is that the phosphoric acid converts the iron oxide to iron sulphate and that forms a crust to seal the metal.

The first time I heard of Ospho was back in the early 70s. I put it on a 20 foot flatbed steel deck trailer that I built. The old painter that gave it to me told me to apply it with a pump up garden sprayer and let it dry well, then paint right over it. Since then everything iron or steel that I paint gets a coat of Ospho. I spray it down, let it dry for several days, and never wash it. After it drys I wire brush the loose white dust off and paint... It will never rust again....

I have used Rustoleum for most of my projects lately. It protects very well. It looks good for a while but out in the sun it fades rather quickly. It still protects well though and I still use it.

I have got to paint my boiler soon but I can't decide what to put on it. The paint on it now is rustyolum that was put on with a roller by the last owner and forum member Steamenginesmitty about 20 years ago. There is no serious rust it, it just looks bad. I am considering useing what the oldtimers used at the begining of the last century... Take boiled linseed oil and mix in some fresh soot from the boiler tubes to make black paint. A boiler really needs to be black, don't you think. You can also bet that there will be a coat of Ospho on it first.

  Your mileage may vary. ;D

Alan

[tcsmpsi]

From iron oxide (rust) to iron phosphate, an inert element.  I've not had trouble with Rustoleum over either of the phosphoric acid based 'rust killers'.  What I have run into that has caused a problem, is moisture 'hidden' in the phosphate from its application and/or, it does seem to draw moisture once it has rendered and set a spell.

[westyswoods]

Redoing frame, axle, and all rear end components on a 2001 F350 which is getting extended two feet.

I settle on a product which may not be that well known as it is fairly new. Rust Bullit is a rust prohibitor and has several products which can be used for top coating. The stuff is not cheap by any stretch although to this point I have been very impressed with the way it lays out.

I would suggest going to their website as I sure don't have the expertise to explain how it works.   Rust Bullit


Guess I won't  know long term results for years, impressed to this point.



Be Safe and Stay Well
Wesy

[submarinesailor]

A boiler really needs to be black, don't you think.
Alan

No because the black will allow for more heat to be released from the boiler walls.  Most boilers I have worked on were painted silver.  According to the people that teach infrared thermography, the silver paint actually reflects heat back into the boiler.  Flat black paint has an emissivity, http://en.wikipedia.org/wiki/Emissivity, very close to 1.  Whereas silver has an emissivity of about .25.  Meaning that it will help keep the heat in, not releasing it to the outside as quickly.

Bruce

[Delawhere Jack]

Thanks for all the tips. I would have liked to use a better paint, I know Rustoleum is consumer grade stuff, but cost was an issue. My brother suggested that I use Por-15, but I advised him what a quart of that cost, over $40 plus shipping, and that was 6 years ago. This will at least let me have a mill that doesn't cover me head to to in rust every time I brush against it. If things work out as I hope, I can refinish it down the road (or move up to an LT40 ;D).

It's funny that when I logged in, I saw that last reply to this topic was from submarinesailor. As I was working on the frame today I was reminded what an old schoolmate of mine told me about being in the Navy. He said you basically get up in the morning, eat, and then find something to scrape and paint.

[bandmiller2]

Alan,years ago I painted my boiler,I asked at a local paint manufactuter.Sounds strange but he told me to use their oil base porch and deck enamel,black of course.It lasted well,moot point now as about the only oil based paint you can still buy is rustoleum.Theirs probibly some truth to what sub sailor says but black doesn't show the soot. Frank C.

[Al_Smith]

FWIW on the job back when I've used Rustolium rusty metal primer with almost no prep and followed up with a base color of Rustolium and it never flaked off .

Some people swear at Rustolium but I swear by it .It cost's tad more but it's on there for the long haul .

[Cutting Edge]

I would have liked to use a better paint, I know Rustoleum is consumer grade stuff, but cost was an issue.

Some people swear at Rustolium but I swear by it .It cost's tad more but it's on there for the long haul .

Don't let the price fool you about Rustoleum.  May be classified as consumer grade...but you can get professional results.  I've sparayed it in the past and even added metalic once.  People swore it was high-dollar stuff.  There are a couple tricks that really improve the results.  Montana makes a catalyst that I found was compatible, sprayed in the evening, dry by morning.  5 years later....still shines great.

[LOGDOG]

This out fit has some good solutions for rust removal and paint prep. I'm about to buy their combo soda blaster/sand blaster. They've got some videos too. Not sure if there are any on phosphoric acid or neutralizing it though.
http://www.youtube.com/user/EastwoodCo/videos?view=1

[LOGDOG]

You can also use Molasses as a rust remover.
http://www.youtube.com/results?search_query=rust+removal+molasses&oq=rust+removal&aq=5&aqi=g10&aql=&gs_l=youtube.1.5.0l10.1583.5133.0.10783.12.8.0.4.4.0.71.389.8.8.0...0.0.

[steamsawyer]

I can't argue about the science and thermodinamics involved. It is common knowledge that the reason car radiators are painted black is because the black releases the heat better.  : I had a friend that painted the radiator in a Silver King tractor red and it overheated. All he did was take it out and repaint it black and it never ran hot again.... However I can't remember ever seeing a silver, locomotive, traction, or portable engine boiler... not saying it isn't so though... I have seen other dark colors on boilers like green, blue, brown, or red  ;D

I always felt weird that my engine was gray. The story is that a previous owner bought the gray Rustolium because it was cheaper than the other colors.

Sorry, I didn't mean to get us off on a tangent.  Nothing wrong with a good rust killer, primer, and paint.

Alan

[bandmiller2]

Rustoleum has a commercial line of paints available from supply houses such as Graingers,probibly as good a quality paint as you will find. Frank C.

[MotorSeven]

I've had good luck with Rustoleum & buy it by the gallon at Home Desperate. Be real careful with POR-15(even when using outside), you must use a mask with canister filters...the stuff is very nasty and will do a job on your central nervous system. Permanent damage is a real possibility.