thats how I replaced some floorboards and other rusted out pieces on my drag car. Cut out the rust. Drill some holes in some sheet hold in place and zap every hole. Like riviting but faster with the mig. at least thats how I was taught by my grandfather

 

Dead House Employee,

Rosette welds are what I believe to be commonly called plug welds, but I think your term is technically correct. I use them for various reasons. They can be used for cosmetic reasons or to allow a smooth edge where a weld would otherwise be obstructing placement or movement of something. They can also be used to supplement edge welds on wider stock. For non-critical applications the plug weld by themselves might be ok, but on more critical items I would only use them to supplement the other welds. This is just my opinion because most of the time I really don't have a clue as to the strength of materials after they have been joined by welding. Now some of your more experienced craftsmen like Franz and others would probably know how to place the plug welds (rosettes) in all the right areas to make a very strong fabrication without running any beads. As for properly performing a plug weld, I would suggest you wait for someone with more experience to comment on this aspect. Myself I concentrate in the middle of the hole and let it burn in good before working towards the edges. I believe that the procedure used could also differ depending on if you are attaching a thicker part to a thinner one because concentrating the heat more on the thicker stuff usually brings better results........If I lead Markopolo astray someone please straighten us out.

 

Plug Welds

Markopolo,

I'm working on a project that has some thumb screws. The threads are 3/8" coarse. Instead of drilling & tapping or just welding the two pieces together, I'm using a plug weld to make the connnection. After I make the plug weld, I'll grind it flush. See attached.

 

Thank's Pat ! . . .I appreciate (and will give credence) to your reply !
Thanks, also to DH....it's clear to me now !

 

Dave, that's a nice way to do that. Thanks for the pic.

 

Also very useful in strength enhancment, like telescoping multiple pipes with random plug welds to multiply the force required to bend the pipe (handles for Whitney punches or benders).

 

plug welds

I have done quite a bit of what you call plug welds over the years but I didn't know what they were called. Some times I would drill a hole and weldin it but most of the time I would just turn up the heat to more than I need and then I would burn through the first layer and burn it into the second layer. Of course I am using a stick welder. I have never had one of these fail. I have welded auger shafts together this way,welding through a heavy steel tube into the shaft inside it.

 

I use plug welds to fasten checker plate or sheet to support angles when I cant get underneath to weld. I drill about a 3/8" hole in the sheet and fire up the Mig. Once you get the hang of it your welds will flush out nicely and reguire no grinding. BTW,regular nozzels work fine for me.

 

Reviving The Plug/Rosette Weld Conversation

I know that I am about a year and a half behind everyone that became involved on this topic but if possible I would like to revive the plug/rosette weld conversation of last year. I am working on a 1966 Mustang Fastback and if you know anything about a Mustang you know that they are literally held together with plug/rosette welds. Also, given that the aftermarket replacement panels are made of metals thinner than the original panels one is faced with welding thin metal to a thicker metal via a plug/rosette procedure. And, just for fun, the ticker metal many times is galvanized. I would be most appreciative for any an all information on how to perform this type of weld successfully under the paramaters outlined. Thanks in advance to all who lend assistance with this. :help:

 

Markpolo,I'm not 100% sure, but I think plug welds are a hole filled completely flush while a rosette weld is just a bead run around the inside of the hole without filling it all the way up........rcr-fly, if you grind the galvy off where you need to weld, and have a tight fit-up, you can probably just make like a spot welder and give it one good tack in the hole and be alright good luck