No rust on this one yet! Seems silly that these have to be kept in a dry garage to stay relatively rust free! I got into welding for a rotter Merc W124
Too late for this thread but I have used nyloc nuts as captive nuts in the past. As is to be expected the nyloc bit doesn't like the heat from welding but no problems with the bolt sticking to the melted plastic
Just to add, the nylocs were not a conscious choice, all I had
I must admit i did try the nyloc before i got the T nuts didnt melt the plastic but couldn't get decent penetration might be the coating, or just shy as scared i would fuse the bolt.