Degrease steel sheets? interior finish
some one of you may have done this before.. and if not you may be interested. Does anyone know a good technique to effectively degrease and clean up spots of rust and crud on sheets of 14 gauge hot rolled raw steel?
I need a readily available cleaner and method. i.e. wipe on wipe off.. whatever.. buffer etc..no residue Its going to be then finished with “3 coats of old village 1400 rub on polyurethane paste” I have to do about 400 sq.ft. for interior wall sections. The sheets then are screwed to the walls with stainless steel screw and finish washer pattern. The sheets i have on site are all custom cut, but came with a lot more marks, rust streaks and oxidation then I wanted. .. thanks
arthur
Replies
There are many chemical rust removers available that work well, but not all will leave a uniform finish on large sections of smooth steel. Some might. You might be better off having them bead blased with a soft material such as walnut shells, or whatever they use for such things, but I can't imagine it would leave the surface suitable for what you are doing unless the grit was very fine.
It sounds like you are working off of an architechs spec sheet. If so you might give him a call and let hiim know the condition of the material as supplied (which sounds rather typical for steel sheets) and how he wants it cleaned up. I would get a sample from a bead blaster using soft media and another with a very fine abrasive and see which he goes for rather than leaving it completely up to his gut feeling. The fine abrasive would help hide the scratches and whatnot that are common on steel sheets. Before you ask the architect you should have a good solution in hand or he might demand a crazy option.
I can't imagine buffing 400 sqft of sheet steel since it won't look the same at all when you're done because of the swirls and polished effect.
Good building
Beer was created so carpenters wouldn't rule the world.
"Before you ask the architect you should have a good solution in hand or he might demand a crazy option."We've been doing this too long, you and I, methinks.......
We've been doing this too long, you and I, methinks.......
*chuckle*
Our last couple of architects have actually thanked us for coming up with good solutions and saving them from having to take the time to research odd problems. Personally I have a strong sense of self preservation that motivates me.
Beer was created so carpenters wouldn't rule the world.
Auto body shops use a product generically called Metal Prep to wipe down bare steel before painting. It cleans off any residual grease, oil, dirt, etc. and will remove light rust. It leaves a light zinc phosphate coating that protects the metal from moisture. That can be followed with Prep Sol, which is mainly mineral spirits, to get the last bits of contamination.
You should be able to find them at any auto body supply store, or maybe even a decent auto parts store like NAPA.
Metal prep will leave a whitish residue from the phosphoric acid.
It is going to take more than once on once off.
For light oxidation a scrubb down with palin white vinegar will cut the rust colour off. Then rinse and no residue.
But for oil from machines, I would be using something liek acetone on a rag. Followed by windshield washer fluid
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I don't have an answer, but would love to see photos of the finished wall when you're done.
thanks everybody.. that was all good help. We will be cleaning the sheets and installing next week. I have since seen pictures of what the expected finish is and I am being optimistic. maybe i'll get a couple pictures up. Thanks againhttp://www.thesmallbuildingcompany.com
I would probably try a naptha based ( Loctite has one but I don't have my catalouge here) cleaner with a 3 M type pad on a grinder. It is not that hard to get even polishing results.
The naptha will evaporate very efficiently and the 3 M pad will give you as even a finish as you can expect depending on your finish shedule.
If they want polished steel you should run very fast unless you have a steel fabrication facility.
I have actually done some very fun stuff with grinders and wire wheels that leave some beautifull paterns.
On a hill by the harbour
Naptha will degrease the sheets. As for the rust, Do not know.Use the naptha with ventilaton,outside would be best if you can.The fumes may be harmful and it is volatile until completely dried.
mike
I've cleaned and treated yards of plain Jane hot rolled steel. It's my material of choice for many projects. I use mineral spirits to get the worst of the oily grime if I can work outside. If not, then I use 409 cleaning solution. Other brands work also. Use lots of paper towels. The rust can be removed with vinegar, maybe. Or better, use muriatic acid tho that will take off the mill scale also. In any case after the rust is gone so will be the black mill finish because if it was still there, then the rust wouldn't be. So you may want to restore some black patina to it. This is possible but getting it to look like the surrounding areas is very difficult. But maybe you want to remove the mill scale......? That's easy to do also, but I'd not blast the steel with anything.
But maybe you want to remove the mill scale......? That's easy to do also, but I'd not blast the steel with anything.
Great points about the mill scale. Definitely a good idea to test which ever method is used on a hidden side before committing.
Bead blasted steel was used quite a bit in an art department building at a university and it looked good, but from my experience it's quite hard to get a truely uniform finish. One fellow was a metal artist and he used a wide range of patina formulas, surface finishes and techniques to make some real nice stuff.
Good building
Beer was created so carpenters wouldn't rule the world.
If you want to get rid of the mill scale, you can do it with muriatic acid. Let me know and I'll outline my procedure. What kind of finish does the architect want?
I'd love to hear the details of your muratic acid treatment. *all ears*
Beer was created so carpenters wouldn't rule the world.
The muriatic acid has to be diluted from what comes in the bottle. I get regular strength acid that's sold in paint stores for etching concrete, etc. Dilute this to about 20% of the bottled strength. I don't know why it has to be diluted, but at full strength is just doesn't work or at least not as well. Different sections of structural steel will clean with decreasing ease in proportion to their thickness. I've found 16 ga to 10 ga steel will be clean after 10 minutes soaking in the acid. Half inch or thicker takes longer. Surface texture plays a role I think. I've made shallow baths out of scrap lumber and lined them with visqueen for larger pieces that won't fit into my five gallon bucket of diluted acid. Or you can even paint it on with a brush... tho that's nastier business. A chunk of steel will emerge from the acid bath with the black still on the surface, but a grey pad will wipe it right off. Use baking soda mixed in water to nuteralize the acid. Dry the cleaned material immediately.
Sapwood,
Sorry to hijack the thread, but the reason muriatic has to be diluted is to liberate the Hydrogen ions in the acid. The PH scale that is referenced for the strength of acid is the Potential Hydrogen in solution. When the acid comes in the concentrated form, everything is locked into the acid molecule and it does not work very well. Add water and the acid binds to the water molecule and releases Hydrogen (H-) ions into the solution which do the actual work.
As a safety note, when diluting acids, I was taught to always add acid to water, as you otter. The other way around can cause boiling of the acid and nasty chemical burns.
And now back to your normal program.
Steve
Yeah, what you said. I figured out that the acid needs the water to do its chemical thing. Knowing that it worked is enough for me although you phrased it in a way that easily explains the process. Chemistry was never a favorite subject in high school or college...... I don't know why. I grasped all sorts of equally difficult engineering and math principles. Thanks for your response. I don't think it is outside the topic at all. Knowing how/why our tools and processes work is always germane to any discussion.
Ovolo,
20 some years ago--when I was( 20 something!)---- I spent 5-6 years working in an industrial chrome plating shop
chrome plating primarily plastic injection molds, tool & die projects, industrial bearing surfaces etc.
You have at least 3 seperate problems
1)- degreasing----typically plastic injection molds for plating were delivered to us covered in 40 W motor oil or coated in something like cosmoline to prevent rust.
initial degreasings were with petroleum naptha--which we bought by the 50 gallon drum-----naptha WILL leave a slightly cloudy oil film, even after numerous washes. THAT film was then removed with acetone.
2) rust removal--------
In the chrome shop--- typicallymolds were delivered to us already "finished"---that is the mold makers bench man had already polished the mold to the required finish.- that might range anywhere from a glass bead( blasted) finish---to an absolutely PERFECT mirror finish---
I mention this because muriatic acid has been mentioned.------we were QUITE familiar with muriatic acid---we kept a TANK of muriatic approx. 5 ftx 18ft. x 6 ft.
For us-we used the muriatic to strip industrial chrome OFF of steel---and it will also strip rust as well----but it will destroy the finish and if not carefully neutralized following stripping will cause even more rust than you started out with. We used a wash of caustic soda---and rinsed the molds with hundreds of gallons of water. It's use is an enviornmental nightmare---and it is unlikely that you have the facilities to process 400 square feet of metal in this manner.
PERHAPS--vinegar on a piece of coarse denim????? or see #3
3)Finish--------actually your most difficult problem--uniform finish on 400 sq. ft. of steel????? that's your real problem to consult with the architect on. depending on the finish--- I doubt I would suggest power anything---very difficult to get even consistant finish without a lot of experience on large areas. I would probably reccomend grey scotch bright( or perhaps red) on a large surface push stick over the entire sheet----and then wiping down with acetone immediately following and immediately prior to final coating, as the scothch bright will ALSO leave a slightly black oily film behind
Good Luck!
stephen
A lot of the chemicals others have suggested may be simple, but also can be very dangerous. Since you also want an even finish, I suggest you replace 'fast' with 'controllable.'
For small areas, a light oil (like WD-40) and a scotch-brite pad will remove light rust. Those pads come in various grits; I'd suggest the softer grades. The maroon and grey pads are almost sure to be too rough, and score the metal. The softest pad - the white one - might work, if you use it with Comet.
Someone suggested denim and vinegar; sounds good to me! Naval Jelly and Brasso are also readily controllable 'acid' cleaners.
As soon as you clean the metal, coat it with a very light oil - again, WD-40 works well - to keep the rust from immediately returning.
When the time comes to varnish the metal, you can remove the WD-40 quite readily with a detergent wash and rinse. The WD-40 ought to remove any oils as it is washed away. Should there be a spot that still beads up the varnish, it is probably silicone. Corning sells a silicone solvent; a little sprat and wipe, and the problem is solved. You can find the Corning product at places that sell bearingsm drive belts, etc.
I cant thank you folks enough for your input. As usual the great range of hands-on experience is invaluable. We have been testing the backs of the steel sheets for a couple of days now and are satisfied with the results.I found a good degreaser called simply 'Super Clean'. Then we immediately clean off residue and remaining spots with Acetone. Then we immediately seal with the Old Village Polly Paste. Looks good.They will have an organic industrial look,if there is such a thing.. with a deep black matt but very clean color variations, marbleized and storage marks but sealed and the rust will be gone. Obviously hard to describe. I will post a couple of pictures finished.I do have a remaining question though. The metal shop used the PERMANENT YELLOW marker. We cannot get it off with anything. Obviously not supposed to come off. We have tried Acetone and every scrubber.. but we are trying like hell not to scratch or damage the metal more then a natural looking scar. Any suggestions? thanks again arthurhttp://www.thesmallbuildingcompany.com
Regarding the yellow marker..... Have you tried Goof-Off. This is usually found in small cans in the paint stores. It's a combination of nasty foul smelling headache indusing chemicals. If it doesn't work, then I don't have an answer. My big bugaboo with my local steel supplier is their use of white grease pencil. This maybe the same thing you've got except yours is yellow.) This stuff is devilishy difficult to work with. I've given up on some material and had to get it remade or simply a new sheet supplied. Even after removing the surface greasey white, there's often a ghost image deep into the pores of the steel. I'm now in the habit of telling them to not mark on the steel with anything and I'll pay extra for their increased effort if necessary.
Goof Off is it. The only stuff that would take off the perm yellow marker of the unfinished steel. No Acetone nothing else worked. Amazing. Thanks!arthurhttp://www.thesmallbuildingcompany.com
Good ... now, to get the goof-off off ... use alcohol.