How does one blacken bolts & nuts?

[PineRidge]

Need to blacken bolts and nuts for a lathe that I am presently working on. I would rather use chemicals to achieve the required finish rather than paint.

Have heard of using phosphoric acid but was not given any detailed instructions on how to use the acid.

Another remedy was placing parts in a bath of used diesel motor oil and cooking it on the gas grill to provide a dark, rust preventative coating. They went on to say that it is important to use used motor oil from a diesel engine for the sulfur content.

Also have used cold gun blue in the past but was disappointed in the results.

Anyone here tried these methods or have any better ideas?

 

[RobS]

There are room temperature Black Oxiding kits available like this. We use something similar on a lot of parts at work. Doesn't give a great amount of corrosion protection but for use in a shop it would be just fine /forums/images/graemlins/smile.gif

 

[RobS]

Here's some more useful info on Black Oxide finishing /forums/images/graemlins/smile.gif

 

[SnoFalls]

gun blue works good, you just have to do short batches or else it'll flake.

 

[scott_vt]

Mornin Mike,
Im with Rob on this one /forums/images/graemlins/grin.gif Black oxide is the way to go. We use it quite often on our aluminum parts.

scotty

 

[MadReferee]

Check with Brownells. They are a gunsmith supply house and probably have several different chemicals and processes that will work. One nice thing about Brownells is that you can usually buy small quantities of their stuff.

Brownells

 

[PineRidge]

Rob the Caswell chemicals look like they should do the job for my application. Since you use the product at work let me ask you if you use a timer for the parts in the solution or just keep a close eye on the color change until they reach the desired deep color?

 

[RobS]

Actually Mike, we use a product called PrestoBlack by Birchwood Casey but for some reason our firewall wouldn't let me into their site. I don't use the stuff myself, only have seen it in the shop. There is a hot plate under one of the "tanks" (more like a metal bucket) but I don't think it's as hot as the hot black oxide process uses.

I'm also under the impression that the times in the various baths are not that critical. If you want, I'm sure I could find out more about it, let me know /forums/images/graemlins/smile.gif

 

[hbarski]

Mix a little lemon juice in with a tablespoon of mayonnaise. I use it to blacken knife blades and such. Just let it react for a few days. Gives a kind of case hardened look.

 

[Inspector507]

Birchwood Casey's website

 

[RobS]

Thanks Inspector but they must have some really hot material on their site as I can't get there from your link either /forums/images/graemlins/confused.gif

Now I'm more curious than ever, may have to check from home /forums/images/graemlins/smile.gif

 

[Inspector507]

Rob,
It must be on your end. I posted that link from my laptop hours ago. I just hit it from my PC and it still works fine.

 

[kossetx]

Mike, All gunblue solutions are not alike. They react differently with different metals. I've had good luck with Oxpho Blue from Brownells.

 

[RobS]

Ah, mystery solved. The Birchwood Casey website mentions firearms and gun blueing. That tickles our work firewall due to potential for violence in the workplace. Good thing no one is using tractors to get even /forums/images/graemlins/smile.gif

 

[PineRidge]

We actually went to the Caswell site earlier and purchased the system that makes up 1.25 gallons of blackening solution. I'm sure that there will be plenty of solution to blacken all the nuts and bolts for the project at hand. Thank's for all the recommendations guys, I'll let you know how the chemicals actually work.

Here's a peek at the bare lathe bed after being stripped, pressure washed, etched, primed, and painted. Ain't it purdy, just can't seem to get enough blue. Actually, Confederate gray-blue.

 

[scott_vt]

Mornin Mike,
Sorry about my post yesterday, I meant to say we black " anodize" our aluminum parts, my mistake.

By the way nice lathe, watcha gonna be makin?

scotty

 

[PineRidge]

<font color="blue"> By the way nice lathe, watcha gonna be makin?</font>

Scotty according to my wife, trouble. Other than that I'm not going into the machine shop business, just playing around a bit. Thanks for the complement.

 

[RobS]

That is impressive Mike! Are the ways/gibs and such tight? Looks like a pretty good sized machine, can't wait to see it back together /forums/images/graemlins/smile.gif

 

[3RRL]

PineRidge,
That sure will look nice all freshly painted.

There should be adjustment to tighten up the gibs and ways. Most critical is to check the headstock bearings for any run-out. Turn a long piece up to check if it's cutting a taper. You can adjust the headstock to square it up if needed. Don't forget to indicate your tailstock windage and elevation centered to your headstock after that too.

 

[Inspector507]

<font color="blue"> The Birchwood Casey website mentions firearms and gun blueing. </font>

Rob,
I'm surprised you can even view this thread with that software filter in place. Pineridge, the original poster is "who got me in trouble". It seems his website sells "weapons". All non-firing but hey no one at IT cared /forums/images/graemlins/grin.gif
I was not allowed to access TBN at work anymore, I was labled a terrorist seeking weapons.......

Sorry Mike, I just had to bring it up again