Gunsmithing Aluminum to steel bonding?

[HSNARC]

I know the traditional method for attaching a sight base to a receiver or barrel would be drilling/tapping +/or silver solder.

What if the piece to be attached is aluminum and the barrel is chromoly? I know some wizard like C.Dixon could tig or solder it just right, but I tig like a toddler fingerpaints.

Is there an effective high strength epoxy solution? Mix it up, gloop it on and go? Maybe something a little more application specific than JB Weld? I don’t think JB weld would hold up to heat+recoil super well.

 

[Trigger Monkey]

Specifically what are you trying to do? What's the aluminum piece? What type of firearm? What caliber? Where are you trying to attach it?

We're going to need details to give any kind of competent answer.

 

[HSNARC]

Specifically what are you trying to do? What's the aluminum piece? What type of firearm? What caliber? Where are you trying to attach it?

We're going to need details to give any kind of competent answer.

Generic aluminum sight base https://www.midwayusa.com/product/1005994416?pid=453735

Stuck onto the oem barrel of a yugo 48 (already bubba’d) Mauser in 8mm where the factory rear sight was soldered on.

 

[Bantam1]

As far as I know you cannot tig weld aluminum to steel, or weld any ferrous to non ferrous metals. I could be wrong but I have never seen it done or heard about it before. I know there are some different solders out there that may allow you to solder different materials to each other. The bond will just be the solder.

 

[Taylorbok]

Why not solder?
I also wouldn't doubt if JB weld held it on just fine

 

[MAHLMAN]

https://esab.com/us/nam_en/esab-university/blogs/is-it-possible-to-weld-aluminum-to-steel/ will take you to some good information. This is not novice welder work from what I read. Way to complicated and if you can't mechanically put them together perhaps some bonding agent + screws would work. I have been tig welding since 1981 and I would not attempt any of the possible methods offered in this article on a firearm with heat treated steel and anodized aluminum and the additional coating on your barrel/receiver.

My advice would be to forget anything that requires heat.

 

[Yondering]

Obviously this depends how much of a ghetto bubba job the OP is trying to do. JB weld is pretty hard towards the ghetto end of the spectrum, not something I'd be willing to have or depend on for my rifles. Solder can work, but requires some practice to do a good job of it; if someone's wanting to go with JB weld or other epoxy solutions they may likely not have the skill or background to do a good solder job.

Of course the right way to install a sight base like that is to drill & tap the base material and screw it down. Should be two screw holes in that sight base. Fairly easy job for a competent gunsmith. Personally I'd suggest for OP to take it to someone who can do this; it shouldn't be all that expensive and will give the best end result. Even on a cheap project rifle it's worth learning to do things right rather than do bubba work with epoxy and bailing wire, IMO.

 

[Threadcutter308]

I hope the OP isn't going to put an expensive scope on this rig.........

 

[sirhrmechanic]

You won’t solder aluminum to steel either.

Best bet would be old-fashioned screws and bed in an industrial epoxy like 3m Scotchweld (scotch bond?). It’s basically the stuff they use to glue airplane wings together these days.

As said above… if you are even asking the question about tigging… take it to a ‘smith.

Drill and tap blind holes. Fit base with screws. Bed base and screws in quality epoxy. Should work. Make sure you take into account things like how massive is rifle… weight of scope and how hard does rifle kick when figuring out base screw needs. Heavy scope on light rifle with a hard recoil impulse won’t last u less very firmly attached.

Sirhr

 

[Mike Casselton]

Maybe try B-Square.

 

[HSNARC]

No scope, just a sight base for irons. I think I’ll just drill and tap with epoxy. It’s just a fun project, nothing serious.

Also there is no such thing as a “competent local gunsmith” kinda why I’m learning to bubba my own stuff. I’ve thought about it a lot and have sorta developed a theory. Central il is probably the blackest richest dirt in the world. Can’t build a range to shoot, that would cut down on valuable corn production. Nowhere to shoot guns don’t get shot. Nowhere to shoot no one cares about custom work. Everyone supports agriculture, not much work for manual machinists and gunsmiths. Plenty of big deer (see corn production above)but the state won’t let you shoot them with anything resembling a fine firearm (straight wall now but just this year). I live in a town with 150k people and not a single actual “gunsmith” maybe a few ar builders and Uber serious trap shooters but that’s it.

 

[Mike Casselton]

@Rthur

 

[hero's machine]

You could run a steel sight and solder it. You can drill and tap. Anything else is going to be less than reliable.

 

[Yondering]

No scope, just a sight base for irons. I think I’ll just drill and tap with epoxy. It’s just a fun project, nothing serious.

Also there is no such thing as a “competent local gunsmith” kinda why I’m learning to bubba my own stuff. I’ve thought about it a lot and have sorta developed a theory. Central il is probably the blackest richest dirt in the world. Can’t build a range to shoot, that would cut down on valuable corn production. Nowhere to shoot guns don’t get shot. Nowhere to shoot no one cares about custom work. Everyone supports agriculture, not much work for manual machinists and gunsmiths. Plenty of big deer (see corn production above)but the state won’t let you shoot them with anything resembling a fine firearm (straight wall now but just this year). I live in a town with 150k people and not a single actual “gunsmith” maybe a few ar builders and Uber serious trap shooters but that’s it.

Drill and tap would be the right way to do it. You could bed it with epoxy as well, but really not necessary for an iron sight base. That's a very similar style rear sight base as production Remington 700 rifles have used for many years, with just two screws holding it in place; no epoxy to be found.

I don't recommend trying to drill and tap a barrel yourself though unless you really know what you're doing. Super easy to end up with screw holes off center if you're not using a mill and very careful alignment; some sort of jig could work though if you found one or had the skills to make one. This is the kind of job where typical carpentry skills and tooling are not good enough; you'll need to be more precise and exact in the hole placement, starting, and depth.

If you have the ability to find and mark the exact top centerline of the barrel, start with a good heavy centerpunch mark at each screw hole; do not skip that part. (unless you have a mill and can mill flats for each hole location) You'll need to control drill depth carefully, and have plug and bottoming taps at minimum. Best of luck if you try it; it's a skill worth learning but I do recommend trying it on a piece of scrap round bar first.

If you need help selecting screw sizes and tap & drill sizes, let us know, several of us here can help.

 

[308pirate]

You could run a steel sight and solder it. You can drill and tap. Anything else is going to be less than reliable.

I slightly disagree. Henkel makes several aerospace and industrial adhesives under the Henkel and Loctite brands that will guarantee that sight won't ever come off the rifle if you apply and cure them correctly.

Aviation supply websites like skygeek and industrial supply places like MSC and McMaster Carr sell them.

 

[hero's machine]

My experience with epoxies and materials with different coefficient of thermal expansions are not what I would recommend. If I were to suggest epoxies I would grit blast the surfaces for adhesion.

Not arguing that I couldn't be serviceable.

 

[308pirate]

My experience with epoxies and materials with different coefficient of thermal expansions are not what I would recommend.

I'm talking about adhesives that hold structural portions of aircraft together, including CF to aluminum bonds.

They'll work fine in a rifle.

 

[hero's machine]

As long as your adhesive can have a 2x delta in your CTE....rock on.

It has to work. That's why wrapped barrels outshoot full steel barrels.

 

[Darryle]

Clean, blast aluminum, clean again, alodine, dry, adhesive prime, prep steel and adhesive prime, bond them together with any metal infused epoxy, A4 metal set, JB Weld and others

If done correctly, short of using a chisel and hammer, it will not come apart cold, heat being the best option.

 

[SLinKK]

https://esab.com/us/nam_en/esab-university/blogs/is-it-possible-to-weld-aluminum-to-steel/ will take you to some good information. This is not novice welder work from what I read. Way to complicated and if you can't mechanically put them together perhaps some bonding agent + screws would work. I have been tig welding since 1981 and I would not attempt any of the possible methods offered in this article on a firearm with heat treated steel and anodized aluminum and the additional coating on your barrel/receiver.

My advice would be to forget anything that requires heat.

Mettalurgist here...you would not ever weld those 2 materials...a tac weld is still a weld. If you needed to make the 2 materials bond like a weld then you would either you friction welding or explosion welding to create a bond between the two materials and then fab a part from the multiple materials. Any polymer based solution will use mechanical adhesion only and would always fail at some point.