doublegunshop.com - home Forums General Discussion DIY Gunsmithing @ doublegunshop.com Speaking of Rust Bluing....

Getting back into the shop after a too long hiatus (Partly while building the shop ...)

I'm prepping barrels for rust blueing, and I've got a few questions about managing the water exposure:

Primarily, I'm wondering how to keep water out of the rib space? The front bead hole and a weep hole (not sure what it's actually called) both seem to communicate with the space between the barrels. (Pics)

I'm also interested in what you all think about plugging the barrels vs leaving the open for the boiling?

Leave them open.
That's the only way that any water that may get inside the ribs will be able to get out.
Though it may seem strange to poke holes in the ribs to purposely allow water in in the first place, it's a fact that most all bbl assemblys have at least a small area
of leakage along the feet of soldered seam of rib and bbl.
It's a rarity that there is absolutely no break in the soldered joint anywhere.

If the drain/weep holes are not there, that water that does get in there by those small voids, and it will,, will not smoothly exit the assembly as you are bluing.

It will start to seep out of one of those small cracks or voids as the water builds up inside and you handle the assembly after taking it out of the water.
Then that crappy water from inside the ribs leaks over the new blue and spoils the finish.

With the drain holes, you can hold and tip the bbl assembly as you pull it from the tank and let the water drain out w/o running all over the new finish.

Plus after the last cycle, put the bbls on a stout peg in one of the chambers and mount the assembly nearly upright.
Let the muzzle tip forward a little and the bottom of the bbls where the rear drain hole is will be in position to allow any water still inside to drain out and down the hole that the extractor shaft
sits in.
At this point take a propane torch and carefully warm the entire assembly to dry up any trapped water.
You will see the steam start to chug out the front and rear drain holes as well as extra water 'spit' from the rear/lower one.
Keep a paper towel handy to clean up any that comes out.
Keep the heat up untill you are satisfied that it's dry inside there.

Do not over heat as you can melt the soft solder. But you have to get to 400F+/- to do that.
If you are getting close to that you will hear the bbls start to make a creaking noise. That's the metal expanding.
You only need 212F to boil out the water.

Let it cool on it's own when done.

That's what I do anyway.
Others have different ways and it's the final results that count.
The worst thing is to have a completed, finished & assembled gun in hand and have some water leak out from betw the ribs.
I've seen that many times.

I know there must be many who appreciate your thoughtful and detailed responses, Jim.

Thank you again. Stan

Count me in the list of ones who very much appreciate the sharing of knowledge that has been gained through years of experience

And me as well. I've not blued double yet, but I have one to do.

kutter, would a heat gun work as well or better than a torch? Might it be easier to control heat perhaps, at least for those of us with less practice?

As cutter said, others do it a different way, and some make an effort to repair the solder joints. When the water is allowed to come out, it will also go in during use. The main reason for ribs coming loose is rust at the inside of the joint and allowing water to enter only makes it worse. Where leakage was only discovered late in the process or was minor, I have seen a string "worried" between the ribs (with a scribe and compressed air) and "Ballistol" added to prevent or at least slow rust forming. I have been informed that in the old days the entire (or most) barrel blank was "tinned" before soldering the ribs on to avoid rust under them. Cleaning the barrels for bluing after extensive "tinning" was difficult and this process was slowly eliminated. When repairing small leaks, I noted the use of an electric soldering iron to place the heat directly at the joint, but with additional heat applied to tip with a torch and the ribs wired down on both ends of the leak to prevent more leaks.
Mike

In days past when I did Instant Rust Bluing having a 3 day turn round, on the final clean water boiling I would hang he barrels up to steam dry to keep the heat up in the barrels I used a gas torch but as mentioned a heat gun today would work very well. When the barrels stopped steaming I would put them in a final tank completely submerged in Water displacement oil. This would guarantee as far as possible no water in the rib cavities or anywhere for that matter on a set of barrels. Over time I was never able to find anything better where I could give a guarantee on no water under the ribs.

I agree with everything Kutter said. A set of 28" barrels will have at least 116" of solder joints along both barrels for the top and bottom ribs. I learned long ago that it is common to have one or more areas that either were not perfectly soldered during manufacture, or became separated at some point. So the problem of contaminants getting into the voids between the ribs and barrels may have been going on for decades. It is possible or even likely that gun oils, barrel cleaning solvents, grime, and rain has gotten in there over time. Getting any of that garbage sufficiently cleaned out and neutralized before starting the rusting cycles is just part of the job. And despite your best efforts, it is possible that something will leak or creep out after one of the boiling cycles. So after you have done the best you can, making sure that hidden void is totally dry is important before doing the next application of rusting solution. Kutter uses a propane torch. I use the same burner that is used for my boiling tank. I pass them back and forth over a low burner flame to heat them as evenly as possible (to avoid differential heating and expansion). Just getting them hot enough that they are uncomfortable to hold is hot enough to vaporize and dry out any moisture in there. There is no need to get them anywhere near hot enough to worry about melting the rib solder joints. Some instructions advise drilling weep holes where none are present to facilitate this, but I haven't needed to do so. I have to wonder if Kutter is shaking his head over the Professor's question of whether a heat gun could be used instead of a propane torch!!!But both will contribute to Global Warming, so that might keep some folks awake at night.

It is important to look for any areas that may have leaks during the cleaning process done after old blue removal and prep. There may even be existing weep holes, and there will be a hole present if the front bead is removed. My first cleanings are done with Dawn Dish soap, and then I immerse the barrels in a hot lye solution to remove any traces of oil or grease. Then they are thoroughly rinsed and dried. While in the hot water, I look carefully for any small stream of air bubbles that would indicate leaks that may cause problems later. In the event that anything does creep out during the rusting cycles, I can usually control it by spot cleaning the area with degreased 0000 steel wool and denatured alcohol. This prevents spotting, streaking, or uneven areas.

When all rusting, boiling, carding, and/or etching cycles are finished. Everything needs to be cleaned, neutralized, and rinsed again, which means more moisture in this void has to be dried out. After the blue is well cured, it won't hurt to get some thin oil, Ballistol, or corrosion inhibitor in there to prevent future rusting. An existing weep hole makes this easy to do with a syringe. Of course, all excess oil must be drained out so it doesn't leak later and oil the stock wood. I've also read that some barrel joiners tinned the entire tube assembly before soldering, but it's hard to believe anyone in their right mind would do it more than once. It would just waste tin and flux, and create a lot of extra work removing the excess tin before bluing. The area between the barrels may have been sufficiently tinned to prevent corrosion, but it isn't possible to know for sure. Attempting to repair a small area of lifted or imperfect rib solder joint can be problematic. Soldering is very easy when you have a perfectly cleaned and tinned joint, the correct solder, temperature, and flux. The only rib repair I have done was fairly easy because it was loose at the muzzles, and I was able to get some very thin abrasive paper in there to clean the joint without removing the original tinning. I then flushed it with electrical contact cleaner to remove any contaminants. Trying to clean and repair a contaminated and imperfect joint can cause a frustrating mess of things, with much swearing and gobs of solder rolling off and onto the shop floor.

damascus,
The procedure I was talking about was the slow rust process and would only use oil to "cure"(darken) the color, as the very last step and that would not be water displacing oil (WD40), for fear of removing some of the rust. After curing, water displacing oil wouldn't hurt.
Mike