What are the benefits and limitations of the various blueing methods?

[dnepro-mike]

OK. I have the materials on order. How much each of lye and nitrate do you put into a gallon of water? If I'm reading it right, you indicated that Blinddog used too much nitrate.

Also, he instructs that the solution should boil. It looks like you're recommending a temp of 270, but no boiling. Am I correct in assuming that more nitrate will increase the boiling temp, while more water will reduce it?

Am I looking for a bath that will reach 270 without boiling - but only barely?

you are correct on all three points.
i started with blindhog's recipe and then tweaked it over the course of next half dozen sessions.

i think you can go with his proportions but use only 3/4 of what he says for the hydroxide and 1/2 for nitrate. add nitrate little by little as needed until your solution reaches 270 w/o vigorous boil. keep a bunch of prepped flat steel scraps to test solution. 10 minutes should put on a nice blue on it.
when mixing add dry chems to water, not other way around.
mixing will cause solution to heat up quite a bit, so have your pot standing on something heatproof.
it will also produce some nasty fumes that you should not breath in. so keep your nose away and wear good breathing protection.
add chems into called water. no preheating needed at mixing stage.
once chems are in and stopped fuming you can put it on the hot plate and start heating it, mixing with a stainless ladle.
if solution not over-saturated all chems should go in suspension near 250-260F if they didn't solution has become over-saturated. it won't hurt bluing, just will be hard to rinse after.
bluing solution has higher density than water and lower heat conductivity. so if you mixed a good amount of it will take longer to heat up than same amount of water.
my 6 galon tank with two electric heater cranked up to the max takes well over an hour to heat up to target temp.
as you work your solution multiple times (if you do) you will loose water to evaporation fairly quickly. so once you've achieved good concentration - mark a water level somehow. that will be your replenishing marker.
storage is easy. either keep it in the same pot if you gonna use it often, or buy yourself a white plastic pale from tractor supply and store it in that. obviously let it cool fully before transfering from a pot to a plastic pale. it has nice tight lid so solution will not crawl out of it. same goes for a pot - keep the lid tight. BTW those orange pales fro Home Depot have very crappy lids. they will brake after first use and won't seal well after that anymore.
once solution cools down all salts will fall into a sediment. scoop them out as well if you are transferring it intoa plastic pale.

 

[EddieCoyle]

I'll be using a propane burner to heat it - the same one I use to smelt lead. Obviously, I'll be doing it outside. I have an infrared thermometer, so I can check the temp pretty accurately.

 

[drgrant]

That colt will blue great. You'll just need to polish down the parkerization and do surface prep for the bluing. The parkerization is essentially a protective carbon that would resist the bluing process (oxidization).

Thanks for the responses, guys... the "Series 80 Colt" thing was more of a hypothetical thought experiment on my part- EG, I run into those types of guns periodically and sometimes the parking is marred up or whatever and I was just curious if it would be possible to turn it into a blued gun.

-Mike

 

[dnepro-mike]

propane puts out more BTU than electric so it'll heat-up quickly.
one word of caution though. controlling heat with propane flame might be hard or even impossible outside because even light breeze will ****-up any adjustments you may do to it.
huge problem for my outdoor smoker.

 

[flintoid]

Thanks for the responses, guys... the "Series 80 Colt" thing was more of a hypothetical thought experiment on my part- EG, I run into those types of guns periodically and sometimes the parking is marred up or whatever and I was just curious if it would be possible to turn it into a blued gun.

-Mike

I have blued many old parkerized parts. If I had found a old beat up parked colt, I'd do it over my kitchen stove in a heart beat. As with any bluing, the key is surface preparation. And this would be the bitch of it all.

When you read about people emphasizing this, they are not kidding. The blued surface will look just as good as the bare surface that you have prepared before the bluing. If it's scratched? You'll see it. If it's swirled? You'll see it. If there's still blotches of oil or debris? The bluing will look like ass or not take to the surface.

Sanding, polishing, and more polishing are all important. You want that surface to be mirror like. So scrubbing off all of that parked surface will take time. And your hands will hate you for a while afterwards, because grabbing emery cloth (sand paper) and rubbing a steel part with sharp edges will bang your hands up big time. Once you've used the finest emery cloth you could find, then go through the phases of steel wool. 0, then 00, then 000, then 0000. And then you'll finally be there for one shiny ass finish. Those steel slivers will be worth it when you see how mirror like the surface is after all that steel wool. And you scrubbed it in the same direction to get that nice, even gloss.

This is why people bead blast: getting parkerization out of a crevice can be impossible just by scrubbing with your hands. I've used dental tools so some degree of success. Where there's a will.... there's usually a way. But bead blasting would be preferred, with a fine media. And then possible steel wool action if you wanted to polish some of the larger surfaces. This would be the most efficient route.

Degrease it. Let the chemicals evaporate. Then go to town.

Oil can f it all up. Like fingerprints and whatnot. Nothing is more aggravating than pulling a piece of steel out of your bath to see your digit in the middle of a dark deep blued surface. Because then you have to use that steel wool again, and this time your'e taking off the bluing. An exercise in pain, for sure.

 

[EddieCoyle]

propane puts out more BTU than electric so it'll heat-up quickly.
one word of caution though. controlling heat with propane flame might be hard or even impossible outside because even light breeze will ****-up any adjustments you may do to it.
huge problem for my outdoor smoker.

Does it put out fumes after it's mixed? Is it something I can do on the stove?

 

[dnepro-mike]

Does it put out fumes after it's mixed? Is it something I can do on the stove?

yes once solution is done reacting there is no fumes or even bad smell. i did all the bluing indoors in the small room 10x10 feet. only mixing was done outside.