OP, you did a great job on that Cooey metal blueing. Any further information regarding chemical supply, and your process would be appreciated!
Well first of all, if anyone tells you that bluing won't cover a single defect, no matter how minor it is, they are absolutely right. Any little scratch will show through. This particular rifle had too many dings and gouges that couldn't be buffed out, they would have had to be filed/machined out. Again, good candidate for learning as far as I'm concerned. Not worthwhile to do any serious machining for a few dings.
The whole process is actually sort of simple now that I think about it. It involved a lot of screwing around preparing beforehand. I bought my bluing tanks, but I built my burners and tank stand. So consider that I started working on all this about 2 months ago. Then I bought a small tent to set up in my back yard, because I didn't want to do this in my garage. It's hot, caustic and humid.
Chemicals: (PM me if you want the names of the suppliers in Edmonton)
- The sodium hydroxide (lye) was easy. A soap making supplier in Edmonton sells by the kg, and can ship it to you. They wanted me to actually place the order online, after I called and talked to them even.
- Distilled water, less than $2 per 4L jug for the Wal-Mart brand stuff.
- Potassium nitrate...well it wasn't hard to get, it's just a little ridiculous. The place that sold it to me could only sell it in a solution as per Natural Resources Canada rules/regulations. Need to be a blaster or some such if you want dry product. So I took them my jugs of distilled water and they just poured it into that for me, as I didn't want them to just make a solution with city water. I think I asked for 1.2kg per 4L jug. Half of it settles to the bottom of the jug anyways, but when you heat it up it all dissolves. Just add the lye to the potassium/water mixture when you're ready.....
I prepped the rifle by soaking in vinegar to remove old bluing. What I really should have done was all the sanding/polishing first. That would have taken care of a lot of the old bluing, and I wouldn't have had to worry about flash rust after the vinegar.
So the order I would do things next time:
1- Buffing/polishing.
2- Degreasing. I used a hot bath of TSP (trisodium phosphate). This might depend on the parts to be cleaned as well. If you have a lot of gunky built-up crud, you might want a good solvent and scrub brush to get rid of the heavy stuff first. Also, don't forget to degrease any wire you will be using to hang parts in the bluing tank.
3- Vinegar bath to remove any remaining bluing.
4- Another degreasing bath right when you are ready for bluing. Should be followed by a clean water rinse before jumping to the bluing tank.
5- Soak in the bluing bath. Time is dependent on the colour you're after, from my understanding. Leave it longer, it gets darker. The instructions I read said anywhere from 15-45 minutes. I just went with 30 minutes.
6- Rinse off the parts. Here's a bit of a dilemma, some suggest to rinse in cold water right out of the bluing bath, then let it soak in boiling water to dissolve any excess bluing solution. Some people say to just go straight from the bluing bath to the boiling water rinse. I didn't have a tank of cold water set up, so I just went to the boiling water rinse. We'll see how it holds up in a few days (if I get any stains or rust spots).
7- Water displacing oil. Some say to have a tank, other say just a good spray/soaking and wipe down is sufficient. Again, I didn't have a tank of oil so I just sprayed it down with WD-40. I sprayed it immediately, then I brought all my parts inside and wiped them down with more oil. After a few hours I wiped more oil on them. Make sure to soak inside everything as well, like the barrel and tube mag.
I read somewhere that you should let parts sit for a day or so before reassembling. Something about letting the new bluing cure. I'm not a chemist, so I'm not sure how true that is, but I can't imagine it would hurt to let everything sit. Good way to keep oiling it and keep an eye on anything for unusual colouring or stains.
Also, my wooden stirring spoon barely lasted through my process.....
Safety Equipment:
You're dealing with a hot, caustic solution here. I don't know what it's like to get burned by it, but it's a double whammy: heat burn and chemical burn at the same time, and apparently it's really unpleasant. That being said, the bluing tank isn't going off like a volcano or anything, but it doesn't hurt to cover yourself in the event of a few splashes. Special attention to covering the eyes, as you apparently don't get a chance to rinse before the damage takes place.
I was wearing rubber boots, a rubber apron that went from my neck down to my boots, elbow length rubber chemical gloves (I also had liners inside just for comfort from the heat) and a full face/eye covering respirator. Now I'm not sure if the mixture I was using really required the full respirator. I think it's more applicable to the ammonium nitrate mixture, which gives off a good amount of ammonia gas. Either way, I wasn't in any discomfort wearing it and I didn't have to smell anything.
Keep a jug of vinegar close by, just in case you get some bluing solution splashed on your skin. Garden hose ready to go as well.
And keep in mind that I'm not a pro at this, so if I'm doing something that seems a little out of place, or completely wrong, feel free to let me know. I'm mostly working off all the info I found online. Which, as we all know, can vary greatly.
