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Elninio
09-23-2010, 02:56 AM
Are there any etching or perhaps quenching processees that can be done to steel in order to give it some rust protection? Something that will not easily scratch off is desired. It is also of interest to discuss treatments by metric of their abilities to preserve previously existing heat treatments on the pieces in question.

Evan
09-23-2010, 03:05 AM
You have three basic choices:

Film coatings; Paint, clear varnish/laquer/acrylic, <added> powder coat
Conversion coatings; Black Oxide, Chromic acid, cold bluing, browning
Plating; Copper, Nickel, Chromium <added> zinc

The easiest of the plating coatings is copper as it doesn't require any alkaline cyanide based baths. It can be done using weak acid solutions and easily obtainable copper sulphate.

drmico60
09-23-2010, 03:30 AM
I think Evan has covered most of the possibilities with his list. However, I would like to add two comments:
1. By far the easiest and cheapest treatment for steel is to heat it to red heat and then quench in oil. This give an attactive black surface that has good abrasion and rust resistance. Any oil will do including used engne oil, or used cooking oil. It does destroy any heat treatment ofthe part.
2. Copper plating is eay and simple to do but it does not provide good rust resistance. On the copper is scratched through on a corner then the underlying steel is exposed and galvanic action between the copper and the steel will actually encourage the steel to corrode. A much better coating for steel is zinc plating. This is just as simple to do as copper plating but has the advantage that the zinc plating cathodically protects the underlying steel if the coating is scratched through. This is why steel is commonly galvanised (zinc plated or coated) for outside use.

BillDaCatt
09-23-2010, 04:15 AM
I've found that I can get really good rust protection by polishing the item. The reason this works, as I have been lead to believe, is that polishing seals or removes the microscopic fissures so rust has no locations to propagate from. A coating of furniture wax or a squirt of two of some Bosheild will add to that protection and allow intermittent moisture exposure. Of course polishing is time consuming and is not practical for all items so your mileage may vary but I have done it many times on smaller items with very good results.

Evan
09-23-2010, 05:51 AM
I can't believe I forgot zinc. Too familiar I guess. I do also find that polishing works remarkably well and I think it is simply because of the reduction in surface area and the ability of the polished item to shed water. Also, most polishing agents are suspended in wax and that wax is left behind in the remaining microscopic crevices and cracks in the surface.

x39
09-23-2010, 07:05 AM
If you're looking for something that will protect metal while it is in storage Kano Laboratories (same people who make Kroil) have a brush on product that is very effective.

Steve Steven
09-23-2010, 07:47 AM
I'm suprised no one mentioned Parkerizing, it is a conversion coating of Zinc or Manganese phosphate. Requires a bit of equipment, but is easy to do.
Steve

Michael Edwards
09-23-2010, 09:04 AM
I'm suprised no one mentioned Parkerizing, it is a conversion coating of Zinc or Manganese phosphate. Requires a bit of equipment, but is easy to do.
Steve


And Kibby did a great thread on parkerizing called Let's Parkerize Something. I liked it so much that I copied and pasted it to my files so that some day, :rolleyes: if I ever get around to it, I would like to try it.

Let's Parkerize Something (http://bbs.homeshopmachinist.net/showthread.php?t=39446&highlight=parkerize)


ME

Evan
09-23-2010, 10:05 AM
There are complete instructions in the reference section of my gallery on how to do black oxide.

http://ixian.ca/gallery

Seastar
09-23-2010, 04:46 PM
I have been parkerizing for several years with the same home made stainless tank that is similar to Kibbys. Mine is a bit bigger.
I heat with a old Turkey Fryer propane burner I picked up at a yard sale for $5.
I have used the same zinc solution to park about 20 guns and it still works the same.
Holds oil very well and stops rust.
It's also very durable.
Here are my latest guns bead blasted and Parkerized last week.

http://img837.imageshack.us/img837/192/parkerizedak47s92010004.th.jpg (http://img837.imageshack.us/i/parkerizedak47s92010004.jpg/)

My grandson made the knife so we put it in the tank while the solution was hot.
It's mild steel and came out lighter.
Bill

Forrest Addy
09-23-2010, 05:30 PM
Zinc electroplate is hard to beat for carbon steel of any alloy. If scratched the neighboring plating protects the exposed metal to some extent. There are electroless dips available.

You don't want to galvanize any work damaged by 1000F heat and the preliminary pickle.

For pure home brew convenience I use Jasco metal prep solution. Scrub the item thoroughly in kitchen cleanser (I use Comet) to remove the oil and residues then dip the article in the metal prep for a couple of hours. Scrub the surface smut off in soap and hot water with a soft bristle brush. Immediately apply any light oil. The metal will be darkened but in my experience the protection is good for a winter out doors.

A pro version of this is called "Parkerizing" Google it. It's a process you can do in the home shop if you don't mind the mess and chemicals and the finish is a handsome crystaline black.

Elninio
09-23-2010, 10:25 PM
This is a great thread; concise and to the point.

RobbieKnobbie
09-23-2010, 10:53 PM
If your more concerned with rust prevention than looks, there's a spray paint called Zinc Rich that is, predictably, very high in zinc. I think I've also seen it under the name 'Cold-Galvanize' or some such.

Sure, it doesn't look as nice as a well polished surface, and it's not as durable as real zinc plating, but it's as easy as spraypaint and I've had fantastic results with it on things left outside.

Zinc Paint vs Hot Dip Article (http://www.azom.com/details.asp?ArticleID=1289)

lazlo
09-23-2010, 10:59 PM
Cold blue is almost purely decorative. It does very little to prevent rust.
Hot blue isn't a particularly good rust preventative either, as any gun owner knows -- you have to keep the gun oiled to prevent rust.

Of all the conversion coatings available to a HSM'er, parkerizing is, by far, the most effective in preventing rust.

Elninio
09-23-2010, 11:29 PM
Evan,

I took your black oxide .rtf file and merged it with the black oxide jpg's into one 6-page pdf file, here: http://ompldr.org/vNW1sOQ

firbikrhd1
09-23-2010, 11:53 PM
It is surprising how well a coat of boiled linseed oil works to prevent rust. It dries to a hard clear film that is fairly tough and easily reapplied as needed. If applied over rusted areas it seems to stop further rusting. I have used it on my garden tools, shovels, axes, picks with good result.

Evan
09-23-2010, 11:59 PM
Of all the conversion coatings available to a HSM'er, parkerizing is, by far, the most effective in preventing rust.


Chromic acid (chromating) is even better but it isn't something you want to do at home. Chromic acid contains hexavalent chromium which is a powerful carcinogen. It is chromic acid that produces that bright yellow finish on items like chassis for electronic devices. It is still possible to buy chromic acid treatment solutions here but I am not interested since there is no legal way to dispose of the used solutions unless you have the right permits.

lazlo
09-24-2010, 12:25 AM
Chromic acid (chromating) is even better but it isn't something you want to do at home.

How does that work Evan? Do you just immerse the item in chromic acid? Or do you have to boil it?

The boiling lye mixture is what scares me away from hot bluing. I ordered the DuraCoat Manganese Phosphate (Black) Parkerizing solution and followed Kibby's setup, and it was dirt simple. Comes out a deep black, is very tough, and so far the parts have been completely rust-proof.

Evan
09-24-2010, 01:27 AM
Chromating is an electrolytic process. It resembles electroplating but isn't quite the same. The chromic acid chemically combines with the iron so that makes it a conversion coating.

flylo
06-27-2012, 08:47 AM
A trick we use for aircraft exhaust is to get them hot then coat them with olive oil fire up the engine & "cook" it on. Just like seasoning cast iron cookware. Works well.

moe1942
06-27-2012, 09:14 AM
Coat with fluid film.

caveBob
06-27-2012, 09:34 AM
Mutton tallow (http://www.dixiegunworks.com/product_info.php?products_id=3686) ?

cuemaker
06-27-2012, 10:32 AM
Coat with fluid film.

cant stand the smell of fluid film. Plus I find it to be messy....

Euph0ny
06-27-2012, 11:32 AM
I am very partial to the various coatings from KG (http://www.kgcoatings.com/). "Gunkote" is probably the best known, but I have also seen them give excellent rust-protection results on steels in salt-water marine environments.

lazlo
06-27-2012, 12:13 PM
A trick we use for aircraft exhaust is to get them hot then coat them with olive oil fire up the engine & "cook" it on.

Hah! That's a high-tech version of the old blacksmith's hot oil treatment. It blackens the steel and is somewhat rust resistant.

Bob Fisher
06-27-2012, 01:18 PM
I have had good luck with "tool Black" available from McMaster Carr. Not sure how well it would work in a more humid atmosphere however, my humble little shop is in the basement and is AC'd and heated. Bob.

lazlo
06-27-2012, 03:14 PM
I have had good luck with "tool Black" available from McMaster Carr.

The "Tool Black" that McMaster sells is Precision brand cold blue. It will turn the metal blue/black, but it's extremely fragile, and not rust resistant at all.

Forrest Addy
06-27-2012, 03:47 PM
For long term storage of bare steel parts I prefer LPS3 rust preventative. It's both a greasy barrier and an active rust inhibitor. It's a PITA to remove if it interfers with part function. Good for months in wet weather and a year or more in dry open shelter.

There are vapor phase rust inhibitors for use when the article is packaged as in a plastic bag. It comes either impregnated in the packaging film or in special paper you cut slips for inclusion in the package. The goodies dissipate quickly in open air and doesn't last long in closed drawers. The military makes extensive use of this material in their spare parts packaging system.

Was camphor mentioned? Old time machinist used to keep mothballs in their tool boxed to ward off rust.

Platings and coatings have been adressed but the coating I mentioned earlier my preference for a dip in a phosphore acid paint prep solution like Jasco for short term protection. It puts a dark smutty film on bare steel that offers extended protection in all environments except acid fumes. The surface treatment is dry but not very pretty. However, it's an excellent adhesion coat for subequent paint systems. Make up a hot solution and you can get a more durable near black surface treatment nearly as handsome and effective as Parkerizing.

Then there is galvanizing - dipping the cleaned, fluxed part in molten zinc. While the corrosion protection is very ugly it will last for years. OTH you can kiss your heat-treatment goodbye.

justanengineer
06-27-2012, 04:21 PM
A trick we use for aircraft exhaust is to get them hot then coat them with olive oil fire up the engine & "cook" it on. Just like seasoning cast iron cookware. Works well.

That reminds me of a trick an elderly former neighbor does regularly. He uses a modified paint gun to spray used engine oil underneath his and wife's trucks. He then drives down a few dirt roads to coat said oil heavily in dirt/dust and leaves it to dry a day or two into a sort of homemade undercoating before hand washing the body. It seems to work great as a rust preventative, but requires a good cleaning before any maintenance is done and it does make their trucks smell a bit after each application due to the burning oil on the exhaust system.

J Tiers
06-28-2012, 12:16 AM
Chromic acid (chromating) is even better but it isn't something you want to do at home. Chromic acid contains hexavalent chromium which is a powerful carcinogen.

Not always.

The latest version of MIL-DTL-5541F (was MIL-C-5541E) includes two "types" and two classes of chromate conversion coatings.

Type I is hexavalent

Type II is NOT hexavalent

The classes are basically just a heavier (class 1A) that is better protection, but less conductive, and class 3 which is less protection and more conductivity.

The type II may not have the classic yellow-tan color of the full hexavalent, but can be as good or better in performance.

ed_h
06-28-2012, 01:01 PM
While I don't at all dispute the nastiness of some chromium compounds, I wonder if all the hyperventilating about using them at home is really justified. Most of the studies cited are for industrial and/or occupational exposure. I've seen some of these, and they seem largely irrelavant to my maybe twice a year chromating of a few zinc plated parts with my home-made Cronak solution.

Even the separate but related problem of disposal may be overblown. The tiny quantities of Hexavalent chrome from an occasional hobby operation can be chemically reduced to much less toxic forms.

I'm really not trying to encourage anyone queasy about toxic chemicals to order a tub of chromic acid--just trying to inject a little rationality.

Most of us are around chemicals every day that could kill us if misused.

Krunch
06-28-2012, 06:34 PM
I know this isn't really what you asked, but FWIW, I just read in one of my woodworking magazines (FWW?) a review where they compared a dozen or more coatings for woodworking tools and machinery (from Boeshield to paste wax and a lot of stuff in-between) and compared their effectiveness at preventing corrosion on both cast iron and tool steel, as well as how much of a problem they presented at messing up unfinished wood and preventing stains and finishes from properly soaking in and/or adhering.

The material they chose as the "best value" for the buck (and I believe it was actually the MOST effective at preventing rust, not just "the most effective CHEAP solution") was CRC Industrial 3-36.

Spin Doctor
06-28-2012, 10:12 PM
One really good think about copper sulfate (blue vitrol) is that is IMO the best single layout fluid there is. Bar none.

Arcane
06-29-2012, 03:56 AM
You're in Canada, buy some Rust Check.

lazlo
06-29-2012, 10:35 AM
One really good think about copper sulfate (blue vitrol) is that is IMO the best single layout fluid there is. Bar none.

Copper Sulfate is cold blue. Never thought to try it for layout, but it does scratch very easily :)

J Tiers
06-29-2012, 10:45 PM
Copper Sulfate is cold blue. Never thought to try it for layout, but it does scratch very easily :)

You don't read OLD machining books..... It's a very well-known method.... I've tried it, and it works.

But I have generally found that for most purposes, a wide tip marker, black, or blue for the traditionalist, does a good job of putting down "layout film" that works.

J. Randall
06-30-2012, 01:41 AM
If you want to try the copper sulfate as a layout dye, dissolve some crystals in distilled water and add a few drops of battery acid, works pretty good.
James

jfreese
11-04-2014, 04:08 PM
When my brother was working as a carpenter he coated his hand tools with "Future". When I was doing test drilling I made my own sample tubes. Icoated them with Future as well. Never had any problems with rust during storage.

johnnyd
11-04-2014, 07:01 PM
The "Future" you mention is actually a S C Johnson floor wax. It's branded under the "Pledge" moniker. It is a liquid acrylic solution, & yes it is quite good at shielding bare metal from the elements.
It will also impart a glossy finish to an otherwise "flat" surface.
I've used it on several bead blasted steel pieces to prevent re-rust.
Look for "Pledge" floor wax/finish. Be sure the word "Future" is on the label. If it's not there, it's not the stuff you want.

John

Juiceclone
11-04-2014, 07:28 PM
Just my 2c worth. In south Florida the humidity and rain are serious to the point I have to run a dehumidifier in my shop all night. I discovered that oil based penetrating wood stain will protect against rust. I think it may be that since it's formulated to get into wood fibers, perhaps it penetrates and seals the pores in metallic surfaces.?? Not done a real study of it, but the tools I (accidentally at first) coated have not rusted in about 6 mos.