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jd99
08-01-2018, 02:57 AM
I have 2 one-trip 20 foot seacans that got cooked in last years wildfire. One is
pretty well rusty brown all over with roof and sidewalls bulged out from stuff going boom while the other is structurally straight and has quite a bit of good paint on the
outside, with bubbled and worse in some areas. Inside is totally black. While not in the best shape, they are too expensive to replace and are still weather tight [no floor in one] so painting the outside [and inside of one] is appealing, however a proper prep job, sanding off rust etc. is out for me. I'm thinking of pressure washing both then
painting them with...what? Any suggestions for a paint that will cover tight surface rust
and/or tight but imperfect paint and last for a while? I plan on using a spray gun.

rzbill
08-01-2018, 05:45 AM
Perhaps investigate rust conversion paint. Google it for leads on brands and supply. I used some decades ago on a rusty vehicle. It worked fine. Color painted over the 'rust primer'. That vehicle is long gone but the coating did its job for a number of years.

dmartin
08-01-2018, 08:19 AM
I was reading recently that Penetrol is a good additive to add to oil based paint when painting rusty metal.
From what I read it helps penetrate tiny pores in the metal which helps coverage and adhesion.
Never used the stuff myself but apparently it is used a lot with good results.

https://www.google.com/search?q=Penetrol&ie=utf-8&oe=utf-8&client=firefox-b-1-ab

https://www.lowes.com/pd/Flood-Penetrol-Exterior-Paint-Conditioner-Actual-Net-Contents-32-fl-oz/3376246

Good luck with it.

Dwight

Doozer
08-01-2018, 08:36 AM
Get a sandblaster tip for your pressure washer
and wet blast them. Also get a soap injector
for the pressure washer and inject phosphoric
acid while wet sand blasting. This will convert
any iron oxide to iron phosphate, which is a
passive surface coating. Then use an alkyd
(alcohol-acid) based paint.

-Doozer

Black Forest
08-01-2018, 08:37 AM
I have used a pump up garden type sprayer to spray phosphoric acid on rusty steel and then used an airless sprayer with oil based paint for a finish coat.

projectnut
08-01-2018, 08:51 AM
If you really want the paint to last try using POR 15. If you prep it according to the instructions and use 2 coats it will never come off. I have used it to paint 2 permanently mounted LP tanks on motorhomes. The tanks were extremely rusty with the original paint peeling off in sheets. I followed the instructions and both turned out excellent. One was painted about 12 years ago the other about 3 years ago. The paint forms a hard shell. It's almost impossible to chip even when hitting it with a hammer. I used the silver mainly because it has more metal content and will make a smoother finish over rough areas. For the finish coat I used Krylon machinery grey.

Here's a link to their website: https://www.por15.com/Rust-Preventive-Coating_c_11.html

It's some pricey stuff so make sure you're sitting down when you check the prices.

CreakyOne
08-01-2018, 11:12 AM
What are "one-trip 20 foot seacans"? Is that slang for travel-trailers/motor homes?

I second the phosphoric acid treatment, although I don't know that spraying it on is the safest way, even for such large surfaces. A quick search found the acid available in quantity on the sites below, although I'd check the MSDS for any I considered buying, just to be sure exactly what's in the product. Shipping might be another concern.

https://www.globalindustrial.com/p/janitorial-maintenance/paint/accessories/cleaner-etch-phosphoric-acid-5-gallon-pail-1-case-cp-1512e?infoParam.campaignId=T9F&gclid=EAIaIQobChMIleOa3YrM3AIVizRpCh2HYQRxEAQYAyAB EgLhXvD_BwE

https://www.speedclean.com/product/speedybright-5-gallon-pail/

Loose rust and scale needs to be mechanically removed first. Pressure washing/sand blasting of thin metal should be done carefully, as too much force will distort the metal more. Superficial rust doesn't require either, but cleaning off the remains of paint, dirt and other accumulations would.

As for painting, the best I've seen is the Rustoleum 9100 series; I've used it for large tanks subject to both mechanical and chemical damage with very good success:

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=2ahUKEwjygbvki8zcAhUIgK0KHdabA3gQFjAAegQIAhAC&url=https%3A%2F%2Fwww.rustoleum.com%2Ftds%2FV9100% 2520System_RO-50_206348.pdf&usg=AOvVaw38_ySlsWEHhKwc7L3aevb_

If your county has a Toxic Waste program, it may also have a Giveaway operation for reusable materials which have been separated from the true waste ; this may include exterior house paint and even the H3PO4, so might be worth checking into. What State are you in, california? Others have had large fires too, although not as many or as large.

Bob La Londe
08-01-2018, 11:17 AM
Yup! A million years ago... or 25ish anyway when I worked at Tool & Supply we had a huge paint department. One of the products we sold a lot of was called Extend. Scrape, sandblast, sand, or whatever all loose rust, dirt and scale away, and then turn the rest into a rust preventative.

Mark Rand
08-01-2018, 11:23 AM
Aren't containers normally made from COR-TEN???

Yondering
08-01-2018, 11:44 AM
What are "one-trip 20 foot seacans"? Is that slang for travel-trailers/motor homes?



I think he means 20 foot shipping containers; the kind that can be hauled on a semi truck and stacked in a ship.

OP - rust converter is what you want for a durable coating and minimal prep. It converts the rust to a dark brown or black coating that is tougher and harder than most paint, and protects very well. You can paint over it if desired. The stuff is available to either brush on or spray on, and of course is available in aerosol cans too for smaller jobs.

You're supposed to brush off any loose rust scale, but if there's no scale you can just leave the surface rust in place and spray over it.

CreakyOne
08-01-2018, 11:58 AM
I think he means 20 foot shipping containers; the kind that can be hauled on a semi truck and stacked in a ship.

OP - rust converter is what you want for a durable coating and minimal prep. It converts the rust to a dark brown or black coating that is tougher and harder than most paint, and protects very well. You can paint over it if desired. The stuff is available to either brush on or spray on, and of course is available in aerosol cans too for smaller jobs.

You're supposed to brush off any loose rust scale, but if there's no scale you can just leave the surface rust in place and spray over it.

re Seacans: I guess I just had too many other things on my mind; I should have immediately realized that myself ...

Many "Rust Converters" are a mixture of phosphoric acid with some type of compatible paint or coating. They work, but for the long term, I think doing the two jobs separately is better.

J Tiers
08-01-2018, 12:00 PM
Kinda funny actually..... looking at the Penetrol SDS, it may be, as has been suggested, linseed in naptha and ethylbenzene as a solvent.

Funny because I suggested diluted linseed a few years back on another forum, and was told in great detail, with references to my probable ancestry and mental acuity, how totally impossible it was for that to work on rust in any way.

https://www.loghelp.com/images/MSDS_Penetrol.pdf

1-800miner
08-01-2018, 12:45 PM
I went through the same thing with five of the things. I had to replace floors as well
I wasn't about to sand five of them.
I pressure washed several times and painted with any paint I got my hands on.
Gave them a few weeks and pressure washed the peeling areas again, then repainted the whole thing.
It ain't pretty but I have a shop to work out of.
And a lot of it came from you guys on this forum and your generosity.
Thank you.

JRouche
08-01-2018, 12:58 PM
I agree with the other posts.

Now, for a quick and dirty method. Pressure wash and paint with an industrial coating containing red oxide. I have done it with outdoor metal sheds that I didnt want to prep correctly and it held up very well.

Some of the other coatings are very expensive (por) and I have used them and they work.
JR

wmgeorge
08-01-2018, 01:36 PM
I was going to say painting a shipping container with POR 15 would cost about the same as building a house, almost.

Yondering
08-01-2018, 01:52 PM
Many "Rust Converters" are a mixture of phosphoric acid with some type of compatible paint or coating. They work, but for the long term, I think doing the two jobs separately is better.

Having used rust converter on several environmentally exposed items, I've never seen evidence of that being true.

CreakyOne
08-01-2018, 02:51 PM
Having used rust converter on several environmentally exposed items, I've never seen evidence of that being true.

I have restored or been around the restoration of antique machinery and vehicles, buildings and new devices constructed from old materials. You may be right about some situations, but for shipping containers that went through a major fire a year before, where isolated pockets or areas of greater damage and rusting are likely to occur (but might not initially appear as bad), I think the two-step process has a better chance of not overlooking them.

ed_h
08-01-2018, 08:58 PM
I think it may be more common for true rust converters--the kind that turn red rust into a black or blue-black substance--to be based on tannic acid. It's the same chemical reaction that can produce black or dark blue stains on oak wood when in contact with iron. Many oaks are rich in tannin compounds. There is also usually a polymer component to form a more or less tenacious film.

It's best to temper one's expectations with rust converters and not necessarily embrace a product's marketing copy. Any coating applied over rust is a compromise. If the rust is not well bonded to the base metal (and it usually isn't), then the conversion products also will not be well bonded to the base metal. If the rust is thick, only the outer surface will be chemically converted.

Still, is it better than doing nothing? Well, I suppose it sometimes is.

Ed

J Tiers
08-01-2018, 10:31 PM
Is this a container, or an antique destined for the Concours D'Elegance?

Sandblast or needle scaler to remove loose rust, then paint with rustoleum primer, possibly thinned, or mixed with Penetrol if you wish, so it soaks into the tight rust. Finish coat, and use it. If it scales off in a few years, do the sandblast of needle scaler again, and repaint as before, being more careful.

Mark Rand
08-02-2018, 07:10 AM
If it's COR-TEN, just leave it. it'll still be rusty, but the rust won't do any harm to it.

BobinOK
08-02-2018, 07:38 AM
I have had excellent results with Rustoleum rusty metal primer. Have a couple items that have been outside for several years with nothing but the primer that look just like the day I painted them. I normally put something over the primer but these were for temporary use and I didn't bother. Clean off any loose rust/scale and paint it with the primer.

Paul Alciatore
08-02-2018, 03:25 PM
Seacans:

https://www.google.com/search?q=seacans&ie=utf-8&oe=utf-8&client=firefox-b-1-ab

They gotta quit inventing new words. They just gotta!

jd99
08-05-2018, 12:53 AM
Try finding a "seacan" in C-list or elsewhere. Call it a container
and you wind up seeing diaper pails etc. Some good hints here. Have to
wait until I get a water system before using a pressure washer, which
seems the first step.Is there universal type attachments so any pressure
washer can use abrasives for rust cleaning?