Have you heard of fixing stripped bolt holes with scrap copper wire?
 

I ran across this and thought that it was clever. It looks good, but how effective would it be? From 3:19 to 4:53: https://www.youtube.com/watch?v=soOv...youtu.be&t=199

He also mentioned using an aluminum brazing rod to fill the hole, which sounds interesting, but the threads probably failed in the first place because they were aluminum. You need to heat it to 735° and if then you would grind it down?

I am sure that would be a great solution in some circumstances, but I can think of plenty of exceptions.

Curiously, he said that replacement parts are cheaper than Helicoil kits. I wonder how much that is true. If the part were cheap I probably wouldn't be trying to fix it.

Anything that sizes the minor diameter smaller will tend to work but not at the strength as the original parent metal. Ever notice that helicoils are hardened spring steel or that they work by enlarging the bearing area? If you had a full set of taps / dies /drill bits you might NOT need helicoils for repair. If your whole engine is tapped for 8-125 metric screws, and you just stripped the 3rd manifold bolt because the idiot before you used a impact wrench on monster, helicoils are a godsend and you don't need every size.

I think his copper wire solution is cheaper than a helicoil only in the short run. I think he is delaying the inevitable: helicoil or replacing the part. If I were on the side of the road with a necessary and stripped piece, maybe I do this. Sooner or later, it needs a better intervention.

He said that replacing the part is usually cheaper than using Helicoils, but that really depends. The last kit that I bought was $25 with 12 inserts. He had three stripped holes, but if you only had one, I could totally see how using Helicoils would be preferable to buying another part. Maybe even if there were three stripped holes. If you do the job right, it is stronger than the original aluminum, so this may last longer than a replacement part.

However, I have done my own repairs for years, and have only dealt with three stripped parts:

1. My Subaru engine block.
2. My Civic oil pan.
3. My Civic cylinder head [the valve cover bolts].

I could have put a Helicoil in my oil pan. That definitely would have been easier than replacing it, even if I didn't have [ridiculously] stuck bolts.

Of course, nobody told me about bolt extractors until afterward.

The oil pan was $85. There is a cylinder head in Phoenix for $150, but is it better than the one that I would be replacing? I removed and reinstalled the head when I replaced the gasket, I would hate to redo everything to replace the head.

Twenty-five dollars seems like a bargain in comparison!

Copper and aluminum don't go together well. Copper would have lower shear strength than aluminum.