AmericanLongRifles Forums
General discussion => Gun Building => Topic started by: rich pierce on March 06, 2024, 06:07:59 PM
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I want to make a footed tool for leveling inlets. I’ll cut off a piece of a new coarse file and braze a steel rod above it for a handle. I’d like to protect the teeth of the file from scale while doing this. Might even want to anneal the file piece and shape it w/o worrying about losing temper, then quench after the braze runs. Thoughts on how to prevent scale? Some kind of flux? Would rubbing with soapstone work?
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Brownell’s has a good product for that.
https://www.brownells.com/tools-cleaning/paint-metal-prep/metal-bluing/non-scaling-compound/
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I have made a few of those tools just by bending smaller three corner files. Since they were going to be used to clean up the inside\bottom of lock and trigger inlets I never rehardend them. I ground safe sides on one edge.
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IIRC someone here, possibly Smart Dog, suggested or recommends a coating or several of pure boric acid powder thinned with alcohol as a preventative of scale.
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Here is a write-up on using Boric Acid paste to prevent scaling:
"One of the industrial uses of boric acid was listed as "hardening steel". I thought "That's odd... I don't remember that being a step in my heat to cherry red, won't attract a magnet, quench in the backfat of a virgin slave on the harvest moon heat treat procedure." So, I did some more looking, and found that our friends in the jewelry and gunsmithing community use boric acid to prevent scaling when heating precious metals or heat treating precision firearms parts. It prevents oxidation and washes away in hot water or in alcohol, and that is the one thing that boric acid is very soluble in at room temperature.
Anyway, once I was resonably sure that anti-scale compounds were by and large just boric acid, I had to actually find a source of the stuff. Boric acid is an excellent insecticide, and is sold as a safe, natural way to decimate the local cockroach and silverfish populations
Ingredients:99% orthoboric acid, 1% other ingredients. For a little more than $6/lb with no shipping, I effectively have the same stuff that costs 3 times as much. I bought a little denatured alcohol because I wanted to just dip and go.
Now, I don't think this is going to be the have all end all, as it probably starts to chemically attack steels at high temp. Judging from PBC's website, it's about 1600 degrees. That doesn't concern me too much as I use O-1 and 1095 a lot. At those temps, it might be best to use anhydrous borax and deal with the bark, or break down and use a commercial compound. I might have to try borax and try removing it with hot water with hot vinegar or cold muriatic acid. Borax is a base, so an acid might have better luck removing it than just hot water."
I've use this before and it does work.
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Thanks! I do have borax and use it fur brazing flux. I removed it with vinegar. I’ll give it a try!
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Heck, if you have vinegar just give an old file a good soak and it will sharpen up plenty good enough to level inlets. I ordered some 45% vinegar from Amazon, and WOW does it sharpen files, and rasps. It also makes some kickass vinegaroon as well.
Hungry Horse
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Mix boric acid and alcohol. Dunk whatever you are working on and then light it on fire. This will burn off the alcohol and leave a coating of boric acid. When you heat it up the boric acid will melt and be an airtight coating.
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Bill, sounds fast and FUN!
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I second the boric acid strategy I have done that on the ends of my chasing tools to keep scale from forming when I go to quench them.
-Robert Hill
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I want to make a footed tool for leveling inlets. I’ll cut off a piece of a new coarse file and braze a steel rod above it for a handle. I’d like to protect the teeth of the file from scale while doing this. Might even want to anneal the file piece and shape it w/o worrying about losing temper, then quench after the braze runs. Thoughts on how to prevent scale? Some kind of flux? Would rubbing with soapstone work?
If you use too much flux it may cause brass to flow where you don’t want it. I would think that Kasenit or Cherry Red on the cutting face would work too and prevent decarb of that area. Especially if its an import file made of casehardened mild steel which I have head was the case with some.
And I would surely anneal and shape to suit. Polish the non-cutting edges so they will not cut or abrade So far as that goes if annealed one could drill and tap and not worry about brazing. Shape, reharden, draw back slightly, 375 maybe. Put some 271 Loctite or epoxy on the threads and screw in a handle
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Heck, if you have vinegar just give an old file a good soak and it will sharpen up plenty good enough to level inlets. I ordered some 45% vinegar from Amazon, and WOW does it sharpen files, and rasps. It also makes some kickass vinegaroon as well.
Hungry Horse
Back years ago a company I worked for bought an acid “file sharpening” system. Yeah it made them sharp again but they plugged so quickly since there was now pitting in the teeth that it was essentially just a really expensive and time consuming way to prepare a file for scrapping. So if a file gets too far gone to use I just buy a new one.
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Bill Raby is right - boric acid and alcohol, leaves a great coating for no scale. Used in most jewelry repairs. We then dumped the item (gold, silver, etc) into a pickle - a light acid, even vinegar, but kept warm, about 150 F. couple minutes, then wash in water.
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Folks are mentioning boric acid. Would straight borax as in Twenty Mule Team Borax washing powder be just as effective?
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I’ve used 20 mule team borax for braising flux. Worked fine, also for silver solder. BJH