Filling Drilled Holes in M151A2 Military Vehicle

[glcaines]

I recently purchased a 1979 M151A2 1/4 ton ex-U.S. Army jeep. Unfortunately, this particular M151A2 previously was used as a TOW missle launch vehicle. The TOW missle launcher was bolted down to the vehicle body with a very large number of bolts and once the missle launcher was removed, a large number of 1/4, 3/8 and 1/2 inch holes were left all over the body, 3/8-inch being the most common. There are even two 2-inch holes left. I intend to fill them with my newly acquired Miller Shopmaster 300 welder with an Miller 22A wire feed. I also need to replace one rusted out floor pan. Strangely enough, I have a lot of experience gas welding and brazing and a lot of previous experience TIG welding 316 stainless steel. However, I have never MIG welded. I plan on practicing filling holes in sheet metal before I start on the jeep body. The body consists of 19 gauge steel. I have a large supply of .023, .030 and .035 wire. My question is what is the best wire size and welder settings to fill the holes. I have received a lot of conflicting advice on wire size and settings from friends.

[ryanjones2150]

Looks like a bunch of Dzus fasteners used on that bad boy. Cool Jeep.

You’ll probably want to cut patches for holes bigger than 1/2”, and that’s even pushing it.

.023 or even .030 wire is fine, you’ll just have to take your time and do some peening as you go along or you’ll warp the living daylights out of your metal. 15ish volts and 140 ipm is a good place to start.

Don’t forget to clean the backside if you can too.

[aametalmaster]

Weld over a copper bar. Did thousands of holes over the last 50 years

[MMW]

Find a shop that has a punch and get them to punch out a bunch of slugs of different diameter. Easier than trying to cut little circles.

[MAC702]

Find a shop that has a punch and get them to punch out a bunch of slugs of different diameter. Easier than trying to cut little circles.

Might even be able to find a shop that has a bunch of leftovers. Most customers want the piece the slug came out of and the slugs are just piling up in the scrap bins.

[glcaines]

A little late, but thanks for all the suggestions. Due to another unexpected project, this was put on hold temporarily. I'll be starting to weld in a day or so.

[metalmagpie]

Really, your machine settings depend on the steel thickess. The diameter of the hole isn't relevant.

MIG welding sheet metal is often a series of button tacks.

Sand the area down to bare metal (ideally on both sides but for sure at least the exposed side) before you start patching.
Consider cutting out a large piece to cover a bunch of holes at once. Maybe even put some goop around the edges and set it in place and then rivet it with steel rivets, that way you don't have to weld at all and nothing will warp.

If you put too much heat into a panel and warp it it's going to be a ***** to flatten it if it's even possible.

metalmagpie