Epoxy versus low temp soft solder

This probably sounds like a really dumb question but I'm a bit confused, actually a lot confused, about this subject and hope someone can enlighten me.

It seems that the tensile strength is a measure of the bonding strength of either product. Temperature tolerance is another. Using JB Weld, for example, with a maximum temp rating of 550 degrees and a tin based low temp solder with a melt point of aprox. 320 degrees, it would seem that the nod would go to JB Weld for almost any application since the tensile strength rating of JB Weld is 5020 psi and the low temp solder is rated at 6000 psi. I can understand, perhaps, electrical applications where the conductivity of solder would be needed but I'm referring here primarily to shooting sports applications.

The reason for the low temp solder would be for use in "critical" heat treated areas where one would want to be very careful not to alter the heat treatment for safety.

How does tensile strength apply to bonding situations?

Can JB, or a comparable product, be used with an expectation of success equal to soft solder or is there something I'm missing?

I have a job that normally requires soldering and I have hell's own time soldering. Don't ask me why, but I have been taught by the best and I still can't do it consistently with any degree of success so I'm trying to find a viable option. Push comes to shove, I'll get the soldering done but if it goes as usual, it will be two or three tries to get even a half way decent job.

Yours is an interesting question, and one which I'm certain will get many replies. I think you pretty well have it figured out already. I believe that the key to success with solder or epoxy is proper preparation of the surfaces to be bonded. Removal of all dirt and rust, and thoroughly degreasing both surfaces. Over the last couple of years I've started using JB Weld for some small jobs. It is much less complicated and takes less time than soldering, and so far I haven't experienced any failures. I'm speaking only to JB Weld. There are many epoxies out there, and lots of guys have their favorite, but JB is what I've had success with, even better than Accra Glas. I have used it quite successfully to attach sights to barrels, and currently have a problem that I believe it will do well at if I can't find a replacement part. Specifically, a Llama pistol on which the housing that holds the slide stop and safety springs and plungers. On a 1911 the housing is riveted onto the frame, but on a Llama it is retained by two tiny screws that pass through loops that are part of the housing, securing it to the frame. In this case, one of the loops is broken, allowing the housing to swivel slightly when the stop or the safety is applied. If I can't find a suitable replacement I'll degrease the back side of the housing and corresponding area on the frame, apply some JB to the back of the housing, and screw it on. I doubt if there will ever be a problem. You will have to be the judge of what to use in each individual situation.

DG

I'm a big JB weld fan.

There's been a few odds & end projects I've done myself that a real gunsmith would have soldered.
If for no other reason than the soldering job looks more professional.

I agree with DG. I rarely solder anything anymore unless I need electrical conductivity.

I have used epoxies for a lot of things not only gun related. I rebuilt press cross heads with turcite and an epoxy ( sham bam way lock) held it on to the cross head. This epoxy was a 3 part adhesive with a .010 grit and hardener. the grit was to maintain bond thickness when clamping. This epoxy didnt reach full cure strength for 7 days. JB weld is a favorite of mine and does a great job,easy to mix, apply and use. I also like some of the long cure locktite epoxies.

While tensile strength is a good measure of the bond, and temperature is a big part. you need to take into account the brittleness of the bond material. Shock loads may brake a brittle epoxy before the low temp solder. another is flex or expansion.

metal prep is extremely important to either as is clamping pressure, you dont want to push the glue out to a to thin bond or be so tight the solder cant work in. A properly prepared and clean surface and rough enough to make a mechanical bond also.

Der Gebirgsjager use a small block of clay bush the piece into it then with a sharp exacto knife mark the broken ear and form it into the clay. fill with epoxy and let cure then drill the hole and final form with a file. glue on and the broken ear will be there also

I'm like many others who have posted above. Unless I need the electrical connection. It is faster and easier to use JB weld.
Virtually no setup and wait time waiting for an iron to get hot.

Once the JB is in place I clamp or support it so it won't move, walk away. Come back a day later and the JB is hard and set.

I took an oversized sewing needle, set it into a small wooden handle which at one time was most likely a wood carving tool.

It is my prefered tool of choice for many jobs at the fly tying table.

If the shaft gets gunked up with super glue. (I often use it to open the tip of a super glue bottle)
I just wait till its dry, scrape it with the back of a pair of scissors and lightly brush it up with a fingernail file.

JB weld is awesome stuff and most people don't have enough on hand. Or 2 part 5/10 minute epoxy either for that matter.

I try to stock things that are

A Hard, time consuming to make. String, cordage, paracord, rope. Also tapes, glues, etc.

B Anything that can be a real life saver, or time saver in a SHTF type scenario.

Which reminds me, I need to get another package of Alien tape, now stuff is HANDY!

It kind of depends on if the seam will be seen or not. A thin line of solder on a gun will more than likely be ignored, or at least "look right", whereas a slightly thicker line of gray JB Weld looks wrong. Sometimes the fix is to use an epoxy that can be colored, I never tried to color JB Weld.

Another thing is if it has to survive a trip through a hot bluing tank. I have read that soft solder won't, and I wouldn't bet on an epoxy doing it either. I have removed epoxied on sights by heating gently with a propane torch.

I guess the real answer is: it depends.

Robert

I remember a gunsmith using a bushing to reduce the size of the face of a bolt. Soft solder so as not to affect the heat treat of the bolt. But have heard of the same bolt face bushing being held in place with epoxy. Never gave much thought to either epoxy versus solder. So excellent question. Always keep extra JB Weld, Acraglass Gel, other two part epoxies and don't forget the Titebond III great wood glue. Frank

I have used JB Weld on several bolts of mine bushing the boltface for installing a different extractor. In this case, it's just a place holder, no real pressure or stress on the joint. Never had an issue. It won't take the place of silver solder strength like a bolt handle install.

Epoxy is great stuff. It was used to hold on the heat shielding tiles of the Space Shuttle. It comes in all forms and you can add a variety of additives to it to change its color and viscosity. I think it is important to roughen the surfaces of the parts being glued, so there is more of a mechanical adhesion. Also I always try to put the epoxy on both surfaces and work it in, so it has the best contact possible.

I have used Acra Glas, to attatch barrel bands for slings. Worked great. I chose Acra Glas for this, as it is thinner then JB Weld, and isn't squeezed out as much, for snug fitting barrel bands. For other uses, JB Weld is very useful, as it bonds to just about anything.

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Originally Posted by GBertolet

I have used Acra Glas, to attatch barrel bands for slings. Worked great. I chose Acra Glas for this, as it is thinner then JB Weld, and isn't squeezed out as much, for snug fitting barrel bands. For other uses, JB Weld is very useful, as it bonds to just about anything.

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When installing barrel bands, i always heated them to expand them, then tapped them into position. Once cooled, they stay put.

I use several kinds of epoxy but when an epoxy is not indicated and I need good mechanical strength for attaching metal to metal I generally use Brownells Hi-Force 44 solder. 4% silver, 96 % tin. It flows at 475 degrees and has 14000 to 28000 psi strength. I've been using it for the past 20 some years and haven't been disappointed.

I use JB on everything that need a hard finish and bond. You can machine it on the lathe, drill it, tap it, bond just about anything with it.

I only use "soft" sliver-bearing solder (not standard solder) when the surrounding areas can withstand the heat and are not a huge heat sink!

Quote:

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Originally Posted by country gent

Der Gebirgsjager use a small block of clay bush the piece into it then with a sharp exacto knife mark the broken ear and form it into the clay. fill with epoxy and let cure then drill the hole and final form with a file. glue on and the broken ear will be there also

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Great idea, Country Gent, but I got lucky and ordered a new part from GPC. I'll keep your technique in mind for future need.
Thanks.

DG

Quote:

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Originally Posted by elk hunter

I use several kinds of epoxy but when an epoxy is not indicated and I need good mechanical strength for attaching metal to metal I generally use Brownells Hi-Force 44 solder. 4% silver, 96 % tin. It flows at 475 degrees and has 14000 to 28000 psi strength. I've been using it for the past 20 some years and haven't been disappointed.

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Do you have to reblue with Hi-Force? I'm trying to avoid a trip to the refinisher.

"Tensile Strength" is the force that tries to pull things apart at right angles to the joint. Shear Strength is the force that tries to pull things apart parallel to the joint.

The way to get around both of these is to Mechanically Reinforce the joint some how. One way is to have gouges or protrusions in the joint that give the adhesive or solder a place to collect. Another way is a screw or bead that the part fits over where there is space under the screw for the glue to build up under. This increases the amount of surface area and also makes the joint a combination of a tensile and shear resistive joint.

A perfect example is Gluing an XS Big Dot Front Sight over a Shotgun Bead. The Glue (JB weld is recommended by XS) gets under the bead as well as all around it, and I can assure you that it ain't comin' off!! period. This would work with Solder as well however it is much harder to do with solder. Also the undesirable effects of heat on a gun part like destroying the Bluing or Heat Treat aren't a factor with the glue. Also if the part is Aluminum solder won't stick to it so you are "stuck" with Glue. erf [smilie=w:

I like many others have soldered stuff all my life,,, and I can assure it is a crap shoot every time I do it. The JB weld is so much easier I don't even consider the other stuff any more. But I also will not use it in a strictly tensile joint on a smooth surface with no surface profile as a sideways toonce could easily knock it off if there is any contamination in the joint..

My .02.

Randy

I have used both with great success. That being stated I do not use epoxies for things that are to be used below zero. I don't know if its a legitimate concern or not but I have used dry ice to break the joint on various epoxied assemblies in the past.