Home Forums Hunting & Shooting Ask The Gunwriters Weld bonding

I'm reloading ignorant so let me exploit my ignorance a bit and ask, is Weld Bonding an issue with Factory ammo? this is the first i've read about it and find it interesting to say the least.

Yep, seating bullets slightly deeper is an easy way to break the bond.

Another way to prevent it is not clean brass unless necessary, and it rarely is. Aside from wiping off cases that fall on the ground, I rarely clean 'em. The inside of the necks gets a light brushing, but not enough to remove the last light layer of powder-fouling. I haven't had a problem with cold-welding in many years.

Wasn't Weld Bonding the wagon master on "Wagon Train"?

Heym

IMO it's more commonly called Cold Weld. Unless I'm mistaken and I'm pretty sure we discussed it last year, maybe not on this forum.

Last year was my first experience with cold weld. I had some 06 loads from a couple of years back. It's a load I've used a lot in the past. But I had a couple of shots where there was difficult bolt extraction. I stopped immediately and then seated the other loaded rounds deeper. There was an audible pop/crack. I reseated the bullets again and had NO problems.I normally don't clean inside necks 'other' than swab lightly with a clean Q tip.

If you're interested enuff you might search cold weld here in Ask the Gunwriters or in Hunting Rifle forum. Good luck.

Jerry

One of my buds at work is one of those unfortunates who has to wipe all fingerprints off a firearm before putting it away, otherwise corrosion sets in and permanently etches fingerprints into the finish.

It seems to be a question which comes up regularly.

The mechanism by which it occurs is diffusion: where you have two similar metals in intimate contact, with nothing between them, atoms from one can diffuse into the other, and vice versa, across the interface. Essentially they wander about and forget where they are supposed to be, until enough of them have migrated that the boundary between the the bullet and case neck is blurred, and you have a joint.

Diffusion bonding, the usual name, has some industrial applications too, especially when you want to weld really delicate or thin materials where any heating, such as is used in conventional welding, would be impracticable. I remember doing some work on just such an application many years ago, involving a miniature heat exchanger made by diffusion bonding of very thin corrugated sheets together to make a honeycomb.

If there's something between the two surfaces, it can prevent the wandering atoms from crossing the line. Something like wax for example would have such an effect. Or, as MD and I have independently found, not bothering to tumble cases and relying on grottiness seems to work too.