Barrel Browning question

[thecapgunkid]

Laurel Mtn. Forge Cold  Browning and de-greaser.  Worked like a jet on the first gun I used it on.

Here though, the barrel turns blue for a couple of hours before browning. The directions say you can brown or blue with it, but howcome both?  I follow the directions and even so de-greased with alcohol.  The room is cold, between forty and fifty five because of the weather bump, but the humidity is there as storm fronts move through.

Is the cold the which and why? I leave it over night and the blue disappears so the  browning is still deepening.

Thanks, and,
Don't shoot yore eye out, kid
The Capgun Kid

[flehto]

After the bbl is browned, a soak in boiling water blues it. The blue you're experiencing is a tip off that either there's not enough humidity or heat or both. .The temps you stated are way too cold for browning. The "blue stage" in normal browning is transitional  just before the rusting starts and is of a very short duration. .....Fred     

[D. Taylor Sapergia]

All cold browning reagents that I have used, when first applied to clean steel, immediately create a bluish grey oxide, that in time, whether left on the bench overnight, or in a 'damp box' for several hours, turn to red rust.  That's quite a sentence.  This will not create a blued finish on the steel.  It will turn into brown.  In order to make a rust BLUED finish, the browned steel must be boiled in water for a period of time, and carded heavily to remove the dusty black oxide.  In this process, you are colouring the steel itself rather than leaving a scaly rough coating on the metal, as is sometimes found on BROWNED steel.

[D. Taylor Sapergia]

Fred got his reply in before I did, but we are on the same page.  On the last rifle barrel I browned, just last week, I had an awful time getting it to 'take'.  I started out with Laurel Mountain Forge's browning reagent, which is very aggressive right out of the bottle, but could not get the colour to get much past the blue-grey.  My damp box has an internal temperature of 90 F and a humidity of only 30 %, according to the indicator in the box.  So I added a dripping wet piece of flannelette hanging alongside the barrel without touching it, obviously.  This increased the RH in the box to 65 %, and now the browning started to go.  But it still took over three days, carding, applying every three hours with the barrel out of the box on the bench overnight, to get it to brown evenly.  In the end I got a very deep plum brown but I finished it with my homemade solution, for the last few coats.  I've never had this sort of trouble before.  I have a temperature and humidity instrument (forget the name of the device) both in the box and on the wall of the shop, and during this browning job, the relative humidity in the shop was only 8 % - no wonder my thumbs are split!  The temperature outside during that time was - 28 C so the humidity was very low.  I just checked it today and it is 35 % in the shop and temperature outside is + 3 C.  These factors - temperature and humidity are key to consistent browning.

[Joe S]

A very good approximation for chemical reaction rate is given by the Arrhenius equation: 

The rate of chemical reactions doubles for every 10 C increase in temperature.

So, if you want your barrel to brown faster, turn up the heat.

[thecapgunkid]

Thanks folks.

I moved the poperation to the basement, wgere the insulation built into the house keeps the place at a muggy 69 degrees.

[Joe S]

Good.  By moving from 50 degrees to 69 degrees, your barrel should brown approximately four time faster.  Unless, of course, you live in one of those areas that has alternative facts.  If that's the case, then there is no telling what will happen.

[David R. Pennington]

I just browned one with similar results. My shop is not heated when I don't build a fire, so I expected slow results. The one thing I had forgotten about the Laurel Mtn. stuff is less is more. You want to apply in very light coats just barely wetting the surface without rubbing over areas already covered. If you leave it beaded up on a surface that part won't brown. I had to reapply a few times but ended up with a good looking job. The wrought iron I forged the furniture from was pretty low grade stuff and it shows some streaks but that is the iron's fault not the regents.

[smallpatch]

I live in AZ, temperature here is usually not a problem.  Humidity is!  Usually in single digits.  I use a sweat box with wet rags in the bottom.  In winter months. A work light shining on the side will usually brown barrel and hardware in 24 to 36 hours, total.