The Accurate Reloading Forums
Rust blue cycles?
07 January 2012, 23:59
montea6bRust blue cycles?
OK, I know the right answer is probably "until you get the color you like", but what is a typical number of blueing/carding cycles? I am making my first run using "Gun Godess", and I was very impressed by the amount of color achieved even on the first pass. It was a very pleasing dark gray that I would have been happy to put into a stock right then and there. After two cycles they compared very favorably to the matte black Leopold bases I am planning to use. The parts are back in for a third cycle now, but I don't want to waste time with dimishing returns if they look good the next time I take them out.
Will they continue darkening a little each cycle? How many cycles do others typically use? (I was expecting to have to go 5-6 cycles, and I saw a website advertising rust blue services that claimed 8-10.)
08 January 2012, 01:22
craigsterThis is 4 cycles with Gun Goddess:
08 January 2012, 03:41
montea6bLooks good to me!
08 January 2012, 04:00
NakihunterI like a real deep finish. I plan to try rust bluing with a home made brew of HCL, steel wool & Nitric acid.
BTW, how did you get the rifle "in the white"?
"When the wind stops....start rowing. When the wind starts, get the sail up quick."
08 January 2012, 04:49
craigsterI wet sand with backed paper or stones if needed, mineral spirits for the wet. A trick I learned (can't remember where) is that the cold blue can be applied directly over an existing blue and it will take the same as the bare polished steel. I don't make a practice of it, but it does indeed work.
08 January 2012, 15:38
Gadgequote:
Originally posted by Nakihunter:
I like a real deep finish. I plan to try rust bluing with a home made brew of HCL, steel wool & Nitric acid.
That can work extremely well [the classic Zischang/Niedner formula is based on these components], but you need to get the proportions and concentrations right. What info do you have? And have you made a boiling tank up?
I have done some conversions of a couple of the Angier/Dunlap formulas to modern units of measurement. PM me an e-mail addy, if you'd like the writeup.
Back to the OP, the effect of each cycle is totally dependent on the steel alloys and their metallurgical history. So it's a 'keep going 'til it looks right to you' situation.
09 January 2012, 09:44
dellorowhere do you buy nitric acid?
10 January 2012, 11:23
NakihunterI had a lot of difficulty getting nitric acid. Finally I got some concentrated nitric & hydrochloric acid from a chemical dealer friend - about 100 ml each.
This was my first sttempt & I added the two acids together first (a mistake I understand).
Thank I took the steel wool (weighed the proportion) and washed it with dish washing soap and then acetone. After drying it, I put the steel wool into the acid in small quantities. the 350 mm bottle was not big enough and the whole thing boiled over & spilt on the wood plank I was using outdoors. I allowed the whole thing to settle for a few days and there was a lot of sludge in the botton third of the bottle. I used a glass rod to take out the solution and put it into one of the acid bottles.
THEN - it rained for a few days the the big bottle some how got rain water into it!
Now I know that it is better to just use laboratory frade iron powder / filings.
PM me with your email if you want the formula & information. I got it by Googling.
"When the wind stops....start rowing. When the wind starts, get the sail up quick."
10 January 2012, 11:36
BoxheadSDH writes of his desire for six cycles in the latest Sports Afield.
11 January 2012, 05:33
Gadgequote:
Originally posted by Nakihunter:
I had a lot of difficulty getting nitric acid. Finally I got some concentrated nitric & hydrochloric acid from a chemical dealer friend - about 100 ml each.
This was my first sttempt & I added the two acids together first (a mistake I understand).
Thank I took the steel wool (weighed the proportion) and washed it with dish washing soap and then acetone. After drying it, I put the steel wool into the acid in small quantities. the 350 mm bottle was not big enough and the whole thing boiled over & spilt on the wood plank I was using outdoors. I allowed the whole thing to settle for a few days and there was a lot of sludge in the botton third of the bottle. I used a glass rod to take out the solution and put it into one of the acid bottles.
THEN - it rained for a few days the the big bottle some how got rain water into it!
Now I know that it is better to just use laboratory frade iron powder / filings.
PM me with your email if you want the formula & information. I got it by Googling.
Well, for a start, there is a lot of dodgy info on the Web. Sounds like you might have found some of it.
100 mL of each acid is
way too much to use at once; it'd make up a couple of litres of the [proven and documented] Niedner/Zischang formula.
- 100-200mL is a handy batch size, as the rusting solution does not keep indefinitely. A matter of months, at most. This only requires 10-11 mL of each acid, for 200 mL of solution.
- So you need some way of dispensing small volumes of acid accurately. Either a 10 mL graduated pipette [and suction filler], or an accurate [0.1g or better resolution] metric balance, a couple of small glass sample vials, and an eyedropper, will work. I would not be keen on using a beam type powder scale, but a digital one would be fine.
- Steel wool, properly degreased, is just fine, if added slowly to the acids. Lab grade iron filings are too, but will react even more violently, unless added very slowly.
- Mixing the concentrated acids first, then adding the iron, is the usual procedure. Adding the acids to about an equal quantity of distilled water, then adding the iron, will make the reaction much less violent, though.
There are alternative ways of making the solution, that don't involve this reaction, but they require a source of some solid chemical compounds [Ferric Chloride and Ferric Nitrate], as well as Nitric Acid.
Back to the original query, somewhere between 5 and 10 cycles is the usual range. It's best to keep the rusting time as short as possible, to avoid pitting, even if it takes more cycles that way.
12 January 2012, 22:01
wildcat junkieI found that the # of cycles can vary W/diferent parts.
Some, like the Dakota Arms swivel bases only needed a few cycles (3) while others like the Neidner style grip cap & butt plate neeed as many as 7 cycles to acheive the same deep gray/black color.
12 January 2012, 22:03
wildcat junkiedouble post
13 January 2012, 05:41
Dr. Louquote:
Originally posted by Nakihunter:
I had a lot of difficulty getting nitric acid. Finally I got some concentrated nitric & hydrochloric acid from a chemical dealer friend - about 100 ml each.
This was my first sttempt & I added the two acids together first (a mistake I understand).
Yes, it's called aqua regia, which is a 3:1 mixture of nitric and hydrochloric acid, respectively.
Thank I took the steel wool (weighed the proportion) and washed it with dish washing soap and then acetone. After drying it, I put the steel wool into the acid in small quantities. the 350 mm bottle was not big enough and the whole thing boiled over & spilt on the wood plank I was using outdoors. I allowed the whole thing to settle for a few days and there was a lot of sludge in the botton third of the bottle. I used a glass rod to take out the solution and put it into one of the acid bottles.
THEN - it rained for a few days the the big bottle some how got rain water into it!
Now I know that it is better to just use laboratory frade iron powder / filings.
PM me with your email if you want the formula & information. I got it by Googling.
****************
NRA Life Benefactor Member
14 January 2012, 12:57
Gadgequote:
Originally posted by Dr. Lou:
Yes, it's called aqua regia, which is a 3:1 mixture of nitric and hydrochloric acid, respectively.
Ummm, that's a bit bassackwards. The classical aqua regia mix is 1 Conc. Nitric + 3 Conc. Hydrochloric.
The classical 1+3 mix is so called, because it is the only combination of acids which will dissolve gold [and platinum] - no single acid will do so.
These days, 'aqua regia' is used as a generic term for mixtures of these acids, with the proportions being stated.
15 January 2012, 16:03
Mike in MichiganUsing Brownell's IM system, I get some parts, like Mag tubes, screws, etc., that "get there" in only 4-6 cycles. Other parts, like receivers and some SxS barrels take as many as 12 cycles.
Mike Ryan - Gunsmith
20 January 2012, 08:36
montea6bWell, I finished up and thought I'd post results. Here's before: (D&Ted following this post:
D&T question)
During:
And after:
Anyhow, you can see the parts came out OK. I stopped at 3 cycles for the bolt handle, and ran the receiver and TG for 5. I did NOT blue the barrel or floorplate, and as you can see I got a pretty good match with the original Swede military blue. Overall I am happy with my first go at it.
P.S. Why must one have to go through such a lengthy trial and error process to resize photos to post here? Seems there ought to be a setting to size them automatically to the viewer's window. It took me a half hour of back and forth manipulation to get something that wasn't three times the size of the screen. I'm finally giving up because it is getting late... Webmaster?!
20 January 2012, 10:31
craigsterLooks good.