The universe must not have wanted the barrel to get blued over the weekend. I got 4 iterations of express blue done. Everything was good except the finish had a a very noticeable copper brown tinge to it. Some reading pointed me to copper plating from combination of the copper sulfate in the rusting solution and the metal possibly taking on a static charge when carding or sanding. So, I lightly sanded it off, put on the initial couple coats, and went to get my boil going again, but noticed a drip on the floor. The element was leaking at the threads. I tightened down a bit, and couldn't get it to stop. So I dumped the hot water outside. there is only about 3 threads of engagement. the plastic softens loosing the seal, and when I tightened down again it stripped this first couple threads. Should have watched the guys video and put massive amounts of teflon tape on the threads to prevent this. So dumping and diagnosing took me 5 min. I had a toilet flange and the rest of the drain pipe, so I quickly created a steam tube and plywood lid for my pot. put 2 inches of water in it, set on the hot plate. Took 15 minutes to get it boiling, another 10 to pre-heat the pipe. The express solution sat on the barrel for ~30 minutes while I worked through all this...there was some light pitting already. I put it in the steam for 20 min. came out very mottled with some lightly frosted/etched areas that wouldn't shine up when carding. I tried 4 more iterations trying to get it to even out and no dice...the damage was done when it sat for so long while I changed rigs.
I had to sand in 2 directions with 150 grit to knock the etching back. I'm going to get another pipe...3 inches this time to use less water. try my heating element again. I have a spare PID controller somewhere I might hook it up to keep it at barely a simmer, or maybe I'll just use the stove to boil water and pour it in. Others have reported success pre-heating the metal to over 200F and letting it sit in the scalding water for 20 minutes instead of actively boiling.
barrel got blued yesterday. I thought the barrel would be easier than the receiver. It's a bit more challenging to get even color across large areas with the express blue solution. So, in my final attempt starting from bare metal yesterday, I started with the slow rust solution to produce a nice, even etching - it acts slow enough that it's easy to get nice-n-even. After 2 hours drying for the pickling coat, I wiped again and a nice even layer of rust formed. The trick to getting an even blue in the end is in this first application. If you wait to boil until everything is fully rusted, you may get some areas perfect, some areas etched a bit more. I found that it was best to boil as soon as one area was perfect...the others will catch up in subsequent iterations. For the barrel...the last third seemed to rust faster than the thicker diameter at the chamber...of course it got more overlapping passes with the solution because it's narrower.
Once I had the first rusting boiled off and carded, I switched to the express blue - took about 9 iterations before no more discernible progress was made. Pictures forthcoming today after I get my shop space cleaned up from last night's work.
By the sound of things, if I attempt to blue my Marlin this way it'll take me a year.
Well, I dunno what your day job looks like. If it's like mine right now than maybe. On the other hand, I hope I've taken some of the witchcraft out of it. The science of it all really is as simple as every written instruction makes it sound. The practice is an art.
This video is really nice. If I every do more than just one barrel, the airbrush is likely the way to go for guaranteed even results - not just for the express blue but for slow ones as well. What made the barrel challenging was it was hard to not have any water spots after degreasing and rinsing. Keeping the water on cold for the final rinse, then straight to the boiler solved that problem.
My rig worked perfectly this time. Had the boiler going all afternoon. PVC gets a touch flexible, but works just fine. I had a spare temp controller that I set to 208F in between boils. Attachment 119170
I also soldered a lead onto the metal to attach a ground wire., then shrouded the terminals in spring tubing and vinyl tape. Screw the metal nipple into the plastic fitting till it bottoms out and seals. Lots of teflon tape.
Here we go after pickling for 2 hours, and applying the first coat of slow rust and letting it sit for half an hour. At this point, I popped it in the boiler as soon as the water was at a simmer. Attachment 119171Attachment 119172
Notice the shank isn't as rusted as the end of the barrel. This happened last time too, and the express solution bites so quick, by the time the shank was even, the narrow end etched the metal more and the color after carding was noticeably cloudy there from then on while the shank inched towards perfection...brown color from static charge on the metal notwithstanding. To fix that problem, after sanding I attached a long wire to the ground post of my ceiling shop light, and wrapped the other end around the barrel threads while I wiped down with lacquer thinner. Carding with steel wool seems to build up the charge again - you can tell by the hairy bits of metal pointing out at the muzzle or breach. Re-attach ground wire and lightly brush the fuzz away with carding brush or wipe off with a dry cotton patch.
in the first couple coats, a few magic shiny spots appeared. They were dark black, with no grain showing after carding...almost like a water spot which was impossible. It was almost like the spot was fully done bluing, with nice smooth satin stop where the rest of the metal was still adding layers of black oxide one iteration at a time. By the time I was done, the spots had completely disappeared unless I shine a bright light on it and look through a magnifying glass. There was one spot, just in front of the receiver ring on top, that I can see without aid, but after oiling I have to stare pretty damn close to catch it.
Now what to do next. Suppose I can torque the barrel on and index it, and cut the chamber so I can get Doco's wrench, gauges, and reamer back to him. I have to blue the bands and the rear sight and screw and some pin heads too. Also need to decide on what to do about the rear sight screws - and whether to get finely figured wood or straight grain. Hmmm...I feel like I've crested the mountain though and am on the downhill slope now.
Polish the inside of that wrench out and break any sharp edges so you don't scratch anything!
Your not going to hurt it. Weld- grind, make it work best.
No hurry here.
Had some 8-32 screws in my kit I used to tighten the rear sight base on and then level from there in my barrel vice. the rear sight base is also dead level with the top of my front sight. 2 wraps of aluminum tape around the receiver ring to protect from rubbing with Doco's wrench. The index marks can't be seen when all is set up, I thought I'd start just leveling the rear sight base with the top bridge rear bridge or the receiver, which just so happens was dead even level with the tang. I made sure the threads inside and out were nice and dry, then I like to use barely a smidgen of nickel anti-sieze on the barrel threads. Here is how much there was left to go after hand tight. Attachment 119179
Turns out, that aint much at all and it takes far less to tighten it on than any other barrels I've done. I used my BFW as a cheater, gave it maybe 4 light tugs and...over did it I backed to off and with 1 smooth pull and a light mallet tap, it tightened up...dead on level. I've pulled and put on plenty of barrels - but only rem700 and 1903's. By comparison, I almost had a disaster on my hands, it takes a lot less to tighten the krag on with the stop inside the receiver instead of the shoulder of the barrel. Moment of truth...index marks are... Attachment 119180
PERFECT!
Now, given how little force it took to index, I think just my BFW on the receiver flats, same way I took off the old one, would have been fine and simple. But Doco's wrench sure did make it simple. So, for anyone else that reads this, has a new krag barrel to put on but doesn't have a friend like Doco, just go to harbor freight and get a 24" crescent wrench and wrap the jaws in aluminum tape.
Next up, finish reaming.
Before I put the barrel on, I tested the chamber. My hand loaded rounds with new full sized brass and hornady 220gr. round nose seated to the middle of the cannelure went all the way in. I made a case for my hornady OAL gauge... Attachment 119182Attachment 119181
With the barrel on, I stripped my bolt down...it closes all the way, falls to the bottom with just gravity, with a new round in the chamber, but comes up barely short of closing on the go gauge. Attachment 119183
I'll check the chamber for any scrapes or chatter from manufacturing. If it looks good I think I'll just leave it. If there is a bunch of chatter I can see giving a couple light turns with no pressure just to smooth it out. Otherwise, what is the point? I have a perfect chamber, on my ammo.
Next, I assembled the bolt to take some pics for ya'll. It is very sticky and requires a bit of force to open and close. It needs some fitting, likely lapping on it's camming surfaces and maybe clean up or lap the sleeve at the rear. it is very tight in the rear of the bolt, and needs polished and re-blued anyway, as does the cocking piece. Attachment 119184Attachment 119185
PM
Originally Posted by 
I backed to off and with 1 smooth pull and a light mallet tap, it tightened up...dead on level. I've pulled and put on plenty of barrels - but only rem700 and 1903's. By comparison, I almost had a disaster on my hands, it takes a lot less to tighten the krag on with the stop inside the receiver instead of the shoulder of the barrel. Moment of truth...index marks are...
