Knowing that I'll be sanding/painting an old M16A1 stock set what is the best adhesive for a large crack repair in a triangle hand guard?  I want the repair to be as strong or stronger if possible than original.

JB weld

For a larger crack is there is binding agent that can be sanded smooth that takes paint well?

Pics of said crack?

I'll post tomorrow. Wife just got home with wings so now it's time for food and drink.

Unless it's a "special" handguard (601, no drain hole, or not L/R marked), it might be easier and cheaper to buy a replacement. Generic late-pattern triangle handguard halves are still pretty cheap.

Thanks I'll go with Double Bubble or Devcon.  I have to admit when ever someone says JB Weld I tune out as that's the last adhesive I'd use on any thing I want to last. I suspect there is a specific adhesive for the type of material the early hand guards are made from but not knowing the specific composition it's a crap shoot knowing what will adhere and what will fail under stress.

Fiberglass epoxy.... You are repairing fiberglass.
Makes sense to me..  Treat it like a surfboard , boat ,  auto body..


I would go with the JB weld though.. Its a common part and JB will fix it.. Cheaply.
How much stress is on the h/g??? none unless you twist it or crush it with a truck.
Sand out the rough and repaint. Air dry Ceracoat in graphite black looks like NOS..
and it stands up to cleaning agent..

Marine tex would be a good subtitue in JB isn't going to to work.

I repaired a motor mount with duct tape once. It lasted 3 days.
a little wisdom/food for thought.. cheap fixes are cheap, but will get you out of a bind.
Hiring a mechanic at 3AM when I was out past curfew mud riding wasn't an option..

Doesnt someone here repair these?

I find myself using milliput for a lot of stuff where I need it to hold shape and not run. If I want to smooth it up I rub some hoppes over it and it glosses it over. It's a good cosmetic filler, but not sure if it will glue the parts together if stress is involved.