Rust prep with Acid

[Hotfoot]

As I set about to do a quicky rust "knock-down" on a part of a sculpture I am assembling, I thought I would snap a couple pictures.

Before...
http://i33.tinypic.com/2iuewhs.jpg

After a quick brush with Muriatic Acid and rinse...
http://i36.tinypic.com/2hztwnm.jpg

It doesn't remove all the crusty old rust off the pipe part, but its sure took the majority of it...also cleaned up the pressure plate very well. These parts will probably get Hot Oil or Paint when the piece is finished.

..just wanted to share.:)

[MichaelP]

What acid concentration did you use, Hotfoot?

[n8tureboy]

When you say hot oil are you referring to Lindseed oil or something else?

[usmcpop]

Linseed oil, no doubt - search around for Hotfoot's various gong projects and you'll see some nice effects using linseed oil.

(Hotfoot - I was expecting to see an "after" picture of a little nub of a nail. Oops, too much acid. :D)

[Hotfoot]

I use straight Muriatic Acid, which is (I think( 4% Hydrocloric) I just handle like any acid, wear long sleeves, gloves, face shield, then brush it on. When I use it on smaller parts, I cover them with the acid in a plastic container, then save the "used" acid in another plastic bottle to use again. I use the acid a lot to remove the shiny plating from new chain or bolts I am using that I want to make "old". On most rusty parts, the acid does an even better job than on this pipe...but I used the old "re-used" acid on that, so maybe it was touch depleted.

I use Boiled Linseed Oil, with a splash of Japan Dryer (so it loses its tackiness sooner). here is my "Secret Chemical Lab"...
http://i33.tinypic.com/optocj.jpg
..I know this all looks pretty high tech, and beyond the wildest dreams of most mere mortals...

A Gong Before the oil...
http://i37.tinypic.com/e15emd.jpg
The tools...
http://i38.tinypic.com/2ep33hg.jpg

The finished gong (Lots of practice doing this to get the colors)
http://tinypic.com/view.php?pic=2ypg8zp&s=4

[Hotfoot]

Well, the board didn't get the "finished" picture. Lots of practice to get these colors down pat.

http://i35.tinypic.com/2ypg8zp.jpg

[MichaelP]

Interesting effect! So you just cover clean steel with linseed oil and then apply flame? Or you heat the metal first and then use oil? Any protective coat or the gong will be able to withstand the elements "as is"?

As for the acid, do you find that it promotes more rusting afterwords? Also, you mentioned that after removal of the major rust scales with acid, you treat [still rusty] metal with linseed oil or paint. What effect do you get when you apply oil or paint on rusty surface? Or, maybe, I understood it incorrectly, and you remove the rest of the rust mechanically prior to oil/paint treatment?

Thank you!

[Hotfoot]

I leave the remaining rust, ten oil over it, then heat. I am after the "rusty" look, but not "actively rusting" (in which case I just leave it alone), This is that pipe after oil and heat...

http://i37.tinypic.com/izlt0h.jpg

This is what it is part of "Night Bird"...a garden piece still unfinished.:)

http://i33.tinypic.com/es8f3l.jpg

[MichaelP]

I'd love to see the sculpture when your're done with it. Looks very promising!

Hotfoot, do you use any protective coats over the oil on the clean metal and rusted sculptures? If not, how well the burnt oil protects clean metal if exposed to the elements? Do you ever need to recoat?

[Hotfoot]

It holds up very well outdoors. I tell folks here in the hot Texas sun to just brush the piece late each spring with a coat of Linseed oil if they want the deep shine to continue. The sun bakes it on, but it takes longer than the torch...plus no colors with the sun! they can put some Japan Dryer in the oil just like I do, to speed up its dry time. It takes about one or two weeks of full, hot sun to dry.so paper won't stick to it.:)

[Some Creep]

I've used Foot's oil treatment and it's a blast! There are alot of combinations of colors you can get before it goes into the 'black' range but the metal prep prior to applying the oil is critical. You simply WON'T get that bright shiny gold / yellow without a good base metal prep or you'll see every imperfection of the steel. I had the weld seam of a square tube visible in my project because I didn't prep that out before I hit it with the oil. Had to heat past it into a darker shade, unfortunately...

:(

[MichaelP]

Some Creep, how exactly do you prepare the metal? Do you mean mechanical polishing?

Thank you, Hotfoot!

Also, about those colors. Is it the regular color change metal goes through while being heated or the oil has something to do with it? I assume it's purely the oil effects, right? Let's take the gong shown on the photo. You heated it with the weed burner, right? It's hard to imagine that a weed burner could bring such a large piece of metal to the high temperature when metal glows yellow.

Let's assume I hit a small area of the gong surface with weed burner at full blast. How long will it take for the area to become as gold as it is on the picture?

[usmcpop]

Folks, keep in mind that Linoleum, the original floor covering before all the new vinyl stuff, was made from linseed oil. It is a plastic, more or less. Perhaps the old-fashioned equivalent of a powder coating process.

http://en.wikipedia.org/wiki/Linoleum

[Some Creep]

Some Creep, how exactly do you prepare the metal? Do you mean mechanical polishing?

Thank you, Hotfoot!

Also, about those colors. Is it the regular color change metal goes through while being heated or the oil has something to do with it? I assume it's purely the oil effects, right? Let's take the gong shown on the photo. You heated it with the weed burner, right? It's hard to imagine that a weed burner could bring such a large piece of metal to the high temperature when metal glows yellow.

Let's assume I hit a small area of the gong surface with weed burner at full blast. How long will it take for the area to become as gold as it is on the picture?

Yup, 3M pad works well, and wire brush. Foot could give ya the skinny on other ways. The yellow comes first and yes, it's the oil color, not the metal color. You see thru the yellow, so the metal underneath needs to be nice cuz you're going to see it clearly. Brighter the base metal, the more true and brilliant the 'gold'.

Check his thread on it, he goes into detail how it's done. Follow his directions. I used a plastic brush and found I needed to reapply oil in some spots after I had heated it and melted my plastic bristled brush (duh). I also found by accident that brushing off the melted plastic from the metal gave me a wood-grain effect I hadn't intended but liked!

Don't get the torch too close or you'll scorch the oil to black right away. Heat slowly.

Foot's thread has it all. Search for it (or some kind soul will post the link).

:D

[MichaelP]

Thank you, CS! Very good explanations!

I'll also try to search for the thread you mentioned.

[usmcpop]

Straight Muriatic acid is generally around 30% HCl, though I did see one brand (Parks) that said 20%.

Here's a list of various "household" products that contain HCl.

http://hpd.nlm.nih.gov/cgi-bin/household/brands?tbl=chem&id=14&query=muriatic+acid&searchas=TblChemicals

[Adultoys]

Whats weird is that even tho it’s a very popular cleaner, at least it is here, "The Works Toilet Bowl Cleaner" isn't on that list & it does contain HCL. Obviously because it’s an acid most will know to be very cautious while using, but because it’s in so many "house hold cleaners" someone may not think that is as necessary to wear protective gear. HCL is dissolved in water to produce the usable/chemical that you see listed on that web site... The results are an acid that if it gets on your skin it works by pretty much removing the water from your flesh, & what is flesh mainly composed of? That’s right Water & Connective Tissues... This won’t just "Dry" your skin.. But it will more or less Dissolve it...

There is a video online I believe where the acid is poured onto some chicken skin, needless to say the results are obvious when the skin looks like it just dissolves & the fumes are just as harmful.

The bad thing about this is that while it should be there for its intended uses, many kids/teenagers/etc. (just as I used to do :p) make tinfoil bombs out of the stuff.. Or should I say they make it with Toilet Bowl Cleaner, probably not realizing that it is Hydrochloric acid they are playing with.. The result is a large boom.. but also what you don’t see is the Mist of HCL flying within a 20-30+ foot radius & most of these kids I see doing it online will sit there & shake the bottle for a long time, until they start to see the reaction. I would be positive there has been accidents because of this. I've watched videos of it on YouTube that are just crazy.. kids doing this & they will be standing with a camera what looks to be only 15' away or so.. maybe 20.. idk..

Anyways, the point is, Realize what your working with, Look at the active ingredients on the bottle then research them online, put that chemical into googles search bar & enter chemical video after it to actually see it in action, in many different ways.. Understand that if these liquids will eat metal off metal (oxidized or not) & it will eat a layer of cement off cement.. Then it will eat your skin off you..

I know I’m talking to many many many very knowledgeable people here, but this is for those of you who read this that are unaware of the actual chemical. (I have a small background in chemistry, although there’s alot I don’t remember off hand, some of it did soak in)

FYI I’m sure allot of us have purchased "Navel Jelly" in the past, & may even have some sitting on the shelve in the garage right now.. with the label partially aten off lol.. Navel Jelly is no more than thickened Phosphoric acid, this being said, it is an acid more often used on metal..

Phosphoric acid is actually a very very good metal treatment & used vary widely in the auto body field.. it’s used to strip/remove/treat rust & unlike HCL it leaves a desired phosphate coating on the metal which will help protect the metal from rusting further, the coating also works like a primer prior to finishing, Increasing the bond between metal and paint/top coats. Turning the Red Iron oxide into a water soluble phosphate compound, black iron phosphate coating which can be scrubbed off if needed.

Phosphoric acid is a better choice for metals if you plan to paint it for many reasons, if only for the primer like properties which prevent rapid surface rust from "growing".. It is also more non-toxic than HCL, specifically when mixed with water, which normally it is when used to treat metals.

This really is a product that should be in everyone’s shop, I can’t think of any better way to treat old rusted tools, if only for that reason. Just brush it on your rusted tool, wait, then rinse it off, using a plastic or brass brush if needed/wanted.. Your tool is now ready for a light coat of oil & it’s good to go..

& as an added side note, the used phosphoric acid that you used to clean your metal, dirty with black rust, is now a wonderful "fertilizer" for your garden.. Just dilute it heavily with water & pour it around your yard or garden. When diluted enough, it is nutritious to plants, containing essential nutrients phosphorus & iron.

Anyways, I just came across this thread & wanted to add a little educational & warning information to it, & if it helps only one person then I've done my job :p ...

btw, I use both & I had previously posted a thread asking where others may purchase such said items & any other shop chemicals.. I myself just normally go to the local hardware stores or the like.. But I was curious to if there was someplace online which these could be ordered at discounted prices & maybe also in different quantities & quality’s...

If I would have seen this thread first I would have just posted here but either way....

- Adultoys

[landman76]

A great chemical for removing rust is Phosphoric Prep and Etch. It is phosphoric acid (obviously) and can be found at HOME DEPOT in the paint department.

I use it straight, and for best results it is good to submerge the piece to be cleaned in the liquid if possible.