ok my friend keeps talking about how, if you get a piece of steel to the right temp. you can spray it with WD40 and it will leave a cool looking blueish sheen behind. What color am i looking for before i spray it on?

I've never heard of that one you might have to experiment. Use mild steel it will react close enough to the same as HC steel as to make no difference. More importantly WD-40 is flammable so take appropriate precautions, do it outdoors, wear flame resistant clothing and face protection.

Please let us know how it goes, post pics and take notes.

There's another group to ask if someone here doesn't answer you question which I expect just about the time I hit send. Anyway, flame and oil patinas are often used on firearms you could ask those folk too.

Frosty

yeah, he said that your supposed to heat it to a black heat(how hot is that?) and then spray it on to keep from igniting it, and that i could use any light oil to do it. Then he said something about thats how they blue gun barrels. I have no idea so i was asking yall. Speaking of flames... do yall think that i i set myself on fire 7 times in less than a month that i'm doing something wrong? (My eyebrow is still growing back)

Speaking of flames... do yall think that i i set myself on fire 7 times in less than a month that i'm doing something wrong? (My eyebrow is still growing back)

Have you thought about taking up knitting!!??? The heat you are looking for is around 450-500F. If you wire brush to CLEAN and heat with a torch you can get something like this; , I then spray with a clear polyurathane once it has cooled. If you brush, heat, then spary your oil on it will turn black more than blue. As far as 'blueing' gun barrels this way I have my doubts, too inconsistant. That is usually done with a chemical blueing, IIRC.

Edited May 18, 200917 yr by Thomas Dean

Hot bluing gun barrels is a whole different thing than spraying oil on it.
Black heat is the heat you have when the last red fades from steel in a dimly lit shadow (less than 1000) down to room temp. Practicaly he means between 900deg and around 400 degree which is above the smoke point of just about all oils.
The blue sheen would be an oxide film that forms between 590 and 570 degrees on clean highly polished surfaces.

Most folks call it running the colors. Gunsmiths do something called "color case hardening" which is hardening parts in a can and then dumping in highly oxygenated swirling water which produces a rainbow of purple, dark blue, straw etc. All of the tempering colors.

I've seen the blue my self when wiping with a linseed oil soaked rag that was pretty wet and the item somewhat small

Sorry Thomas Dean, I was typing my response as you were. I don't know which one of use is right about the the color temperatue. I used the tempering temperatue which I've always assumed it was.

Is lighting yourself on fire a problem? I got used to it myself and eventually learned how not to do it very often. I guess getting the hot stuff on you is doing it wrong, I'm just not so sure what IT is.

Frosty

Is lighting yourself on fire a problem? I got used to it myself and eventually learned how not to do it very often. I guess getting the hot stuff on you is doing it wrong, I'm just not so sure what IT is.

Frosty

I just spit coffee all over my keyboard I guess we've all learned things the hard way

As far as oil finishes, I don't know about blue but I have seen a beautiful black satin finish with heated metal and boiled linseed oil. It's supposedly pretty durable but as with any chemical and heat, care should be taken to protect your skin and lungs while coating.

Spitting coffee on it is another top technique for putting yourself out for sure.

Was your keyboard on fire RcRacer? How did it catch fire? Does your forge and or anvil have a keyboard? Does it catch fire often?



Frosty

RcRacer, yes it usually turns out black but it can wind up blue looking with just the right thickness. Kind of like iridesent blue in a butterflies wing. Not a pigment just the right interference pattern

I got this blue by sanding, washing with degreaser, and heating to about
575 F in my heat treat kiln. I took it out and sprayed with wd40 while still hot.

Very nice!!

how big is that? great finish however big it is, keep at it.

Heat to about 500F, wire brush until all the scale is gone and it will turn blue all by itself. Use oil or wax to protect it. This is an oxide coating and very thin; it can be easily scratched off.

how big is that? great finish however big it is, keep at it.

The cannon barrel is about 6 inches long.

so how do you tell what temp you have it at?

Does the WD40 bring out more of the temper colour? I seem to get paler colours using the heat and oil method.

For temperatures, you can either get a setable oven, heat resistant thermometer, thermal crayons that melt at a certain temp or watch for the colours. There are many sources for tempering colour charts. Most blacksmithing books contain one as well.

To get bright colors the steel needs to be sanded, scraped, or brushed down to bare bright metal before heating. Traces of oil from handling before heating can cause uneven coloring. WD40 or other oil finish will make it look brighter. I used WD40 because it was handy and easy to just spray on.

On a lot of things I don't want to paint, I use boiled linseed oil. The toughest part is getting the temperature right. Too hot you get a lot of smoke or in the extreme a flash fire. I wipe off the excess and usually have enough heat left to melt on some parafin wax. Makes a pretty durable coating.