Home Forums Hunting & Shooting Gunsmithing Adhesive for bonding to blued steel?

Is there an epoxy or other adhesive that will bond properly to a blued barrel? A friend of mine recently soldered a front site ramp onto a rifle barrel. He was very careful in fitting it, only removing the bluing where the mating surfaces between the barrel and the ramp were to be fitted. Good job!

Of course, when it came to doing the actual soldering, everywhere the flux ran it removed the bluing. Touched up with cold blue, it looks like you would expect.

I am wondering if there is anything out there that will bond a non-banded ramp or base to blued steel successfully?

Thanks,
Ted

I will be curious to see your responses. I am thinking about doing a similar thing. I figured what I would do is carefully mask the outline of the position of the sight base, and then rough up the surface of the barrel under the base, as well as the surface of the base itself. I think a good epoxy (Devcon) would give quite a strong bond.

I have used JB Weld to attach a front sight ramp to a S&W M/29 .44 Magnum revolver. Brownell's also has an adhesive called Black Max that they sell specifically for attaching sights.

Yukoner, 2 weeks ago I used Black Max to "glue" on 2 weaver bases on my BSA Martini Cadet to use a pistol scope, It works great! I tried ShoeGoo first, lasted about 10 shots (32-20 recoil) then a 3M product called 5200 (marine adhesive), it lasted about 100 shots but the Black Max (Loctite product)is up to about 500 rounds with a scope & mnts that probably weigh about a # and a quarter. It is basically used for sights, ribs ect.-Muddy

The important thing with the various adhesives is surface texture and cleanliness. The presence of bluing has nothing to do with it since it does not change the surface texture when it is applied. If you can mask off everything and sandblast the mounting areas with 120 grit Alox or something similar and then degrease, a modern epoxy will be amazingly strong. if you apply it to the typical polished and blued surface, it will not hold for long.

RAN

Well lessee.

Black Max is good stuff, the added rubber contributes shock resistance which can be a problem with cyanoacrylates. Manufacturer's data sheet Here. I use it to secure shotgun beads where there's not a lot of force with the itty-bitty things but plenty of shock.

Sheer strength is given as 3,770 PSI and tensile as 2,700 PSI. Note the heat degradation table, you can loose appreciable strength as the barrel gets hot.

Couldn't find a data sheet for JB Weld but they give tensile strength as 3,960 PSI and a "tensile lap sheer strength" of 1,040 PSI. Don't know if you can compare that directly with the Black Max figure. I couldn't find temperature derating info. JB Weld is supposed to be a high temperature epoxy but you know it's there.

Brownell's lists their Hi-Force 44 solder flowing at about 475F at 14,000 to 28,000 PSI tensile. They list their Hi-Force Hi-Temp 44 which flows at 650F (still easy to work with) at 38,000 PSI. For comparison 50/50 tin/lead solder has a tensile strength of around 6,000 PSI.

Silver solder has been the gold standard. Silvaloy 355 silver solder flows at 1,205F so it's hard to work with. Tensile strength is very much stronger.

How strong is strong enough I don't know, but I'd be wary of glues particularly if the bond isn't perfect.

Soldering, or sweating as used to join sight ramps, is an art learned by practice. Flux can be controlled if done carefully.

I like the mask, sandblast, and epoxy but if I was doing this to install a ramp, I would at least use a dowel to back up the bond. I have always viewed glues as fitting into two categories; those which have failed and those which have not failed yet.
BTW, that 275 Rigby is ready to blue. This was certainly a different project and sort of fun. The sights are screwed on! GD

A dowel (or screw) would clearly help in shear where the bond strength is lower but the high strength low temperature solders are so much better and really not hard to work with once you learn to make a sweated joint. And no hot tank bluing worries.

I think grit blasting would almost be a must, note that the Black Max data sheet strength figures are based on grit blasted steel. A hint, no? I have a cheap air brush type blaster that'll handle small stuff like that.

I've always been a little suspicious of screw-on ramps. Not so sure I'd trust that one little screw to not shear in a hard accidental impact. Screw and solder - belt and suspenders?

Black Max is great. It will stand bluing temps.

I just use low temp silver solder. The trick on the flux is to tin the sight first. Then just wet the sight with flux. Then set sight in place and just enough heat to flow solder. This also assumes the soldering surfaces are absolutely clean and bright.

I know that a front ramp I used JB on over15 years ago is still hanging on.

Figuring out soldering talc, and how to work with one's flux in dry or paste form, or a good silver solder paste will go a LONG way towards ensuring success.

I've misplaced my Brownells soldering talc, and have recently used plain old Welder's Soapstone in it's stead. Seems to work alright. The first application on a highly polished piece come up "spotty?". Wick a dab of hot stuff or liquid superbonder into it, and once dry, apply more talc ( or soapstone)

"Force 44" is nothing but repackaged Harris-Welco "Staybrite", a 95-5 Tin / Silver,.........the spec'd liquid flux provided is sudden death for bluing,.....adjust your sails accordingly.

Silver solder FOIL is a boon to mankind, worth scoping out, as are FIXTURES, properly used, once things go to liquidous.

GTC

Yes, and it was liquid flux with low temp, 440� I think, that he was using. Is there a dry or paste flux that can be used with that?

Thanks for all the replies, Guys. Appreciate it! Please keep them coming.

Ted

For a good solder joint you need absolutely clean steel, not just looks clean but chemically clean. That's what flux does. A primary contaminate is oxide which forms quickly on cleaned steel even if you can't see it. The flux is an acid to break down the oxide and since blue is a form of oxide it breaks that down too and very efficiently. Acid flux flows off organic contaminates too, like oil from your fingers.

Think clean, CLEAN, CLEAN. Then any contamination is at a microscopic level and you need almost no flux, not enough to run out of the joint.

I'm using Harris Welco "Stay Silv", which is for higher temp solders,.....one has to add water or isopropyl alky to it to form a paste. The dry crystaline form works pretty well, too.

Part of the problem with the liquid stuff is the cheesey containers they'd be more suitable for putting mustard on a hot dog.
.......get some parvo syringes from the feed store when precision counts,......rinse em' when your done. As noted a LITTLE goes a long way.

I would NOT put "force 44" in a hot salts tank,....

GTC

I unscrew the top on the liquid flux and use a Q-Tip. That's how little flux you need if you clean well. Brownell's doesn't claim it but published reports (Kinks and I think I've seen it elsewhere) that Hi-Force 44 is unaffected by bluing salts. They advertize that the hi temp version is unaffected. But it is mostly cadmium so care is needed.

Amen to that
I've literally used miles of the stuff at a job I used to have, and it would have been a nightmare trying to do things any other way

These coils are made from hollow copper tubing with a solid piece of copper bar soldered to the inside, and wound on an engine lathe:

I'd say the worst mistake that one can make with foil, or a "perfectly tinned' solder joint is expecting things to stay where one put them, prior to applying the final heat.

At THAT point, it's all about alignment, and holding the components aligned.

Jigs and Fixtures,.....

TAKE the time.

GTC

I used the black max a couple of times with scattergun technology shotgun sights and had it fail if it was blued steel but never had one let go on a parkarized tube. I am guessing the park gave it a more textured surface to hold on. After that if I had a blued gun I would mask and blast with 120 grit AO and never had a sight let go again. I think I put on about 30 of those on old PD shotguns and they are still going strong.