I accidentally reversed the front and rear stock screws on my Marlin MLSS-50 and wound up breaking the tang that holds the safety button. Tried to epoxy it back together (using JB Weld), but it wouldn't hold. The surfaces that I need to glue together are very small which further complicates matters. The trigger/safety assembly looks like cast aluminum and Marlin discontinued it years ago, so finding a replacement trigger assembly seems doubtful. If I can get the mating surfaces clean I thought I would try Loctite Black Max, which has worked very well for front sight ramps. Any suggestions? Thanks in advance!

What material is this part made of? Believe it or not there are some substances that epoxy won't bond to. If JB Weld wouldn't do it I would have serious reservations regarding LBM to bond also.

It looks like cast aluminum.

Another name for that might be Pot Metal. High Zinc content. Not sure about Marlin's but it was used in several lower cost forearms. One of the metals that epoxy does not play well with. If JB weld does not work then I doubt anything will. A new part is perhaps your best choice.

Fuggetaboutit.

Replace the broken part.

Dang spell checker…. Meant firearms, not forearms. If you used JB Weld it will be hard to get off. Heat and a wire brush. I doubt anything else, epoxy of any kind would work. Welding also most likely would not work.

Clenliness is key. First I would degrease with a quality brake cleaner. That stuff removes silicone which can be used as mold release in light metal casting. Then wire brush the broken edges to remove any soft oxides. Then the brake cleaner again. No reason epoxy shouldn't stick. You do have to rub epoxy on the edges to make sure the surface is wetted with epoxy, not just sitting on top of the metal. Black Max is a cyanoacrylate, I'd have more faith in an epoxy. JB Weld is epoxy resin with powdered talc filler. For this application I'd prefer clear epoxy and not the quick set type. You don't need the filler. Epoxy continues to cure after the initial strength time so be patient.

Might work, I don't know the part and what pressures/leverages are involved.

You can braze/solder aluminum and zinc metals but tricky stuff especially with small pieces. Hard to control the heat and they tend to melt.

Oh yeah, removing epoxy. Soak in acetone or lacquer to soften, then pick or wire brush off.

(Numerich didn't have the trigger assembly in stock)

Just brainstorming:

Maybe some very small holes with pins can be put in the joint.

Grooves along the side with pins glued in.

Aluminum solder, not weld.

External piece(s) glued/pinned/screwed to hold it together.

Bruce

Thanks for all the suggestions. I'm going to try again after seeing if I can get the old stuff off. I also may try gluing the safety tang onto the trigger housing; there's a lot more surface area that way. I'm not sure they pinned it on for any reason other than ease of manufacturing.

If available, I’d replace the broken part. Not likely that any of these suggestions will provide a viable long-term fix.

There is a seller on gunbroker that sells demilled gun kits. Try that, or eBay seller Dr. Winchester

Or if there's room use a thin piece of shim steel or something to overlap and reinforce the glue joint. Glass printed circuit board material works well but I wouldn't go out of my way for it.

Some of the finest shot guns made were largely done by hand filling the block. Aluminum is easy to work. If the piece is not too complicated this might be an option. Another is to glue it together and send it to a CNC shop that has photo replication and digitizing capability. No idea of what the cost would be but the technology and equipment is becoming more common and less expensive. I live in a small town and a shop here does this for friends for art work and knife blanks so it shouldn't be that difficult to find.