I always seem to get a few spots like this whenever I rust blue barrels. This is after the first boiling. Usually by the time I am done they are nearly impossible to see, but sometimes I can spot them. Any idea what I may be doing wrong?
Thanks,
CHAZ

That's junk (oily/greasy water) seeping back out from between the ribs & bbls after you pull them from the water.
The void fills with boiling water and mixes with any old oil, solder flux, ect in there and comes back out the way it got in.

Very tough to get that cleaned out w/o a hole for the water to get in and out fast.
Bet those bbls ring like a church bell too.

A tiny hole in the bottom rib just ahead of the forend lug is a start. Sometimes back further by the flats. That one will get covered by the ejector stems in alot of cases when assembled.

You really need another at the muzzle end to get the water to move out quickly when you pull it out of the tank.

Sometimes the front bead hole will lead to the void. If not, sometimes you can drill a tiny hole through the solder that's in between the muzzles and into the void. Carefull you don't drill into a piece of steel filler in there.

Sometimes I just go ahead and melt the solder at the muzzle and shake it out to clear the end. Then solder it back up when done.

Much better and easier than chasing oily water spots around the tubes every pass and hoping the next coat will cover them, cause it won't.

Copper residue in the mix. What are you using as the rusting component? What process did you use to strike up the barrels and get them ready for the process? What solution?

Cheers
T

As Kutter has stated, there was some contamination possibly between the ribs. You didn't mention what type of rusting agent you were using and that would help. I use Laurel Mountain Forge's Browning Solution. It has it's own cleaner mixed in and for me has worked great. I use distilled water for my rustings and also in my etchings.

Most barrels do have some voids between the bottom rib, to check on this I use a .001-,002 feeler gage and go along the bottom rib to check. Sometimes it pays to boil first to get the contaiminants out, then clean thoroughly or in my case just start the rusting with the LMF rusting agent.

Do you pre-clean with acetone before boiling....?....Including inside the weep holes with a syringe liberally and slosh......?.....

I always boil first in a very clean tank with very clean water and check for contamination....and then double check again and make sure that all the weep holes are open and flowing.......always.......

I am using Laurel Mountain, and boiling in distilled water. Now that someone mentioned weeping from between the barrels it makes sense. After I had carded off the barrels I used compressed air to dry them off and when the air hit the weep hole water escaped from between the barrels.

So a good boiling before the first rusting would help this situation? I have not flooded the weep hole with cleaning fluid before either, I will do that as well.

Thanks,
CHAZ

Hoof, instead of compressed air, use a propane torch and run it up and down the barrels to dry them, only warm to the touch and not hot. Plus this will get the moisture out between the ribs. I do this with the barrels standing up and naturally the weep hole is at the bottom.
On some of the older "elsies", take the screw out on the short extension piece between the loop and water table to dry them.

Watch barrels for the next few hours for any residue that comes out of the hole and goes on the metal, wipe it off before it stains the barrels.

Chaz:

I don't use compressed air anywhere near the barrels, weep holes etc...I let them air dry (I live in a dry climate) then lubricate well with EEZOX when finished, including in the weep holes with a syringe....

Be very careful with compressed air around weep holes, you could blow the ribs loose IMO.......or degrade-destroy already weak areas in the solder joints on vintage barrels.......

Get them as clean inside the ribs as possible before the bluing. Otherwise the crud will just appear during the process as shown in the pic and spoil everything.

A trip through the tank with any agitation possible thru what-ever weep-holes/drain holes you can get is best.

Even then as you pull the bbls from the water and in your first coating when you pull them from the water, note if anything including clean water seeps from the ribs anywhere.

At this point, all you want to do is avoid letting it do that. You can by tipping the barrels one way or the other to dump the water inside the ribs towards the end that they will drain out the easiest and quickest.
Trapped in the slow draining end, it builds up for an instant and then decides to leak out those pin hole spots in the rib solder job.

Those small holes are very common dispite the claims otherwise. In over 40yrs of doing this, I can't think of more than a few bbls that didn't have at least a tiny break in the solder joint somewhere. Try and work around them.
The large exit at the muzzle by way of the solder removed works great.

I learned that when I did mostly hot-rust bluing and you had to work fast.

I still dry them out with a propane torch. BBls stuck onto a wooden peg pointed muzzle upwards and slightly forward in a bench vise.
Gently heat the tubes and the breech especially till steam starts to emit from the lower weep hole.
Then you may get a few spurts of hot water, so a paper towel is at the ready to catch it and wipe it from the metal.

A rag with some clean hot water from the tank is usefull for wiping over those spots to clear any spotting from residue that may exist yet in the water from inside the ribs.

At this point it hopefully dribbles down the extractor stem hole and away but you have to watch it doesn't splatter and spot the flats or bbls.

When no more steam is showing,,you may still be getting some smoke. Give it the sniff test.
Don't over heat and ruin the solder joints. The water will evaporate at just over 200F. No real need to get above that very much.
If the tubes start to creak like a ship hull under stress,,back off. You're way over what's needed to dry them.

If you do find a spot in the blue during the bluing process such as caused by one of these leakers,,you can remove it with scotch-brite. I use a maroon colored pad,,sometimes gray to polish it out and blend into the rest of the area.

It will of course leave a steel grey area where the damaged blue came off. But the next coat will generally bring you right back even with the rest as the pores of the steel are allready filled.
No need to scrap the entire job and repolish generally. At least give it a try.

Throw that small square of scotch-brite in the trash as it has the contaminants on it that caused the problem in the first place. If you leave it lying around, chances are you'll grab it again in a moment of polishing need and ruin another job while trying to save it..

I've never used compressed air for anything in the shop,,just never had the hook up.
Some systems allow oil from the compressor into the air line, filters or not.
Something you very much can do without around rust bluing.

It's not uncommon for there to be rosin flux between the ribs/barrels. Find a solvent that will disolve that and use it to flush. Acetone seemed to work by my memory.

Get a piece of PVC pipe, put an end cap on it, fill with a mixture of TSP & water, let soak overnight, then rinse with clean water. Should get the oil/crud out and leave the barrels very clean.

I’ve tried Laurel Mountain solution; I always seem to get copper colored splotches when using it. I believe that they use copper sulfate in their solution. Guess I was doing it wrong.

Finally started making my own that I’m happy with.

To remove water between ribs & barrels use denatured alcohol, acetone will not remove water.

Mike

I have started boiling my barrels for 10-15 minutes with water and commercial degreaser before putting on the first appliction of rust blue. This has helped a lot but looking at your picture it looks like copper deposits. You can try diluting your first application or two with distilled water and be very careful to ge even coverage.

I can't tell from the pix if the barrels are brazed or soldered. If brazed, the source of the copper could be the brazed joint and the contamination could be transmitted by a leaky braze joint allowing some fluids (possibly even rusting solution) to come thru the porous joint.

If the barrels are soldered, I'd wire up that barrel and solder the porosity shut. It doesn't take long and it assures no more leakage.

The other thing to consider is that porosity could be telling you something. There could be rust brewing under the ribs. A strip and re-lay of the ribs is the only way to know. Not what you wanted to hear, but always a possibility.

Tony first, then Mike answered the copper residue spots problem in these posts I believe......I agree with their posts and conclusions.....

I have found that Mark Lee's products are superior to any other that I have tried, for blue or black or brown, damascus or fluid steel......his products also lack toxic mercury, which nobody needs......

Acetone is used to clean the barrels before any boiling is applied.......to repeat my post above more clearly:

I clean thoroughly with acetone, including inside the weep holes.........let the acetone evaporate, look for residue on the barrels and re-clean with acetone if necessary, then boil in clean water for at least 10 minutes and then look for any residue in the water or on the barrels, then change the water/clean the tank and repeat the pre-boil if necessary before applying the rust blueing........

Good pre-clean with proper preparation + using excellent rusting products = very nice professional rust blue/black/brown surfaces........

I happen to like Laurel Mountain Forge Browner, I have used it since I started rusting barrels. I only do my own and have had good results. On some of my barrels I don't give them that ultra sheen blue/black finish on the steel barrels and the same on the Damascus barrels because these are old guns that many would consider "klunkers" that I fixed. giving them more rustings to a higher level is like putting a dress on a pig........still a pig.
Good Damascus

below circa 1897 Gr. 3 l.C. Smith with Chain Damascus

Stub Twist

On the finished barrels I use boiled linseed oil, put on thin and gets a nice hard finish after drying that lasts. This was one of Oscar Gaddy's idea, this or motor oil.

There is copper sulfate (or some other copper compound,,I'm no chemist) in L/M.
You can get the copper itself to plate out onto the metal while applying the solution if you're not careful.
It usually occures on the first coating,,maybe the second. I can't recall ever having a problem later than that.

The easiest way to have it occur is to have the bbls a bit warm.
Applying the soln to warm steel will result in patches of copper wash on the steel.

Another is to go over a spot with the swab moist with the L/M in an attempt to 'give it a better coating'.
Doing that, regardless of the room temp will almost always result in a copper wash/plate on the steel,,though not as distinct as the first.

Sometimes dispite my best efforts, an area will just plate out for what appears to be no reason at all. Usually near the breech (thicker area).
I get rid of it with the scotch-brite trick after the boiling and go on.

When the oily water leaks back out from inside the ribs and covers your work, it can do so while it's still in the tank.
Some oil gets left on the steel (the rest floats up and covers the water w/a slick.
The conversion from red to black oxide doesn't complete. You get the reddish color seen.
It'll card off and only a faint blemish in the blue results,,lighter than the surroundings. But it's still contaminated and will continue to be from the same area in the rib till it's clean.

You can almost get the area to match after several coats. But oiling & wiping it down afterwards will result in a thin area right there as the bluing doesn't 'take' due to the original contaminated surface.

You can contaminate your carding brush(s) going over spots like that too.
Then you are just transfering it all over the steel and back into the water. Even a clean tank become instantly contaminated.

Gotta' clean that out of the ribs.
There's all types of oil and whatever that's been sprayed and pumped onto and into the ribs and void over the life of these old doubles.
Some must think the weep hole was labled 'oil' for all the stuff in there. How some of them have gotten wheel bearing grease pumped into the void I don't know.
A syringe perhaps. Those were probably to quiet the rolling solder BBs.
Have fun!

Hi,the leaking rib theory makes perfect sense but when I checked the picture, the marks seem to have a copper tone to them. Could it be that you have gone over some already dry rusting solution again? I use a homemade solution which contains copper sulphate and it leaves a copper coloured stain if I accidentally re cover the evaporated area or handle with solution on my gloves.
I may be well off the mark as it could just be down to colour cast of the photo but if not, I hope this helps.

May I add a couple of ideas to the mix? The first is that you can simply drop your barrels in warm to slightly hot water, before you start any work, and find out if you have any voids in the rib solder. The heat will expand the air between the ribs and create bubbles. I do this before starting any rust bluing project so as not to get any surprises later. You can then add a small hole near the forend lump, which in most cases will allow any water to leave. Removing the front bead will help this. When you remove the barrels from the boil, allow the water to drain, then tightly twist a small piece of paper towel and insert it in the hole. This will wick away any remaining water.
Another thing is that Laurel Mt. will indeed give you a copper color if applied thickly or twice, but this will still rust properly if your heat and humidity are correct. The end product, to my experience, is no different. Also, LM can be dilluted so as not to give such a course finish if desired.
Based on your pictures, it's the ribs weeping, not any copper deposits, causing the issue.
Last but not least. If the ribs are weeping, there is a problem, and it could be a very unpleasant one. A small hole or two may simply be a bad original soldering job. More than that and you've got rust issues between the ribs.
Luck,
Jim

It sounds like a lot of barrels have at least one or two small voids in the rib solder joints that could allow moisture and contaminants to become trapped inside. I've noticed small streams of air bubbles on occassion too, but I've never done a rib re-lay job to actually see what's in there. It would seem to me that a few pinholes could be just as bad as a much larger void when it comes to having rust issues. But I've always been under the impression that getting the barrels hot enough to drive off the moisture as steam would leave the interior dry, and that the area between the ribs would typically have been completely tinned before soldering. Wouldn't this tinning offer almost as much corrosion resistance as if that area was galvanized?

I also would like to ask if anyone has any good recipes for homebrew rusting solutions that do not contain mercuric chloride. The last homebrew I used had too much bite. I suppose I could have diluted it more with distilled H2O, but it took about a dozen turns to get good color at the recommended dilution.

Sometimes the entire surface is tinned,,sometimes not. No way of really knowing unless you remove a rib and see what their intention was. Then both to see if they achieved it if it was in fact to tin the entire surface.

Some used acid flux which just leaves a mess inside unless thoughly rinsed away.
If used to tin then rinsed thoughly and a non-acid flux for the joining,,you'll not run into the rust problem.

Acid flux gets used for rejoining small sections just 'cause it works so damn good even on a not so clean surface.
A bit of scrubbing with the hot acid flux and the solder will flow.
A polish & reblue leaves the job complete. But after-rust is almost surely to follow and is a nitemare to elliminate down inside.

It's been my observation that most all older bbls regardless of make have at least a pin hole or two in the solder joint somewhere.
You can chase those around trying to solder them up and create new ones I guess. A void or section of the seam that is open is what's needed to be repaired IMHO.

Drying the void with heat after bluing should leave the area safe from rust at that point.
Any red rust that was in there should now be 'rust-blue' after going thru the tank so many time. It just didn't get carded.
Now that you're done,,you have to deside if you feel the need to put oil back into the void or just leave it as-is.
I just leave them alone and solder the muzzle back up.

As far as bluing soln not containing mercury compounds,,that is the reason I went to L/M many years ago,,just to get away from the stuff.
I used to do much more quick rust/hot rust blueing than cold rust.
Nearly all those soln had merc bichloride in them. Way too many years of handling that stuff for me.
Even the 'new' Herters Belgian Blue from Brownells has mercury in it from what I can see stiking it onto warm brass or copper. That suprised me in this PC environment.

For quick rust I use Mark Lee rust blue solution.
Laurel Mtn for cold rust. I think L/M is mainly ferric chloride.

They both work well for me and I'm passed the point where I want to do alot of experimenting anymore.