RV Mudflap Bracket - TIG welding

I TIG welded a cold rolled steel angle for a wide, continuous mudflap onto the frame of a pretty big recreational vehicle yesterday.

Attachment 6255

This RV is used to tow a trailer for a roadrace car. The trailer was getting "sandblasted" and the purpose of the wide rear mudflap is to keep this from happening. You can see the thick rubber "mudflap" off to the right in this picture.

Attachment 6254

Attachment 6256
We figured out where it should be positioned, and clamped it.

Then I marked it's location with both a tungsten carbide scribe and also a gray sharpie that it good for writing on black things
Attachment 6257

Attachment 6260

Then it was time to prep it for welding. That includes unclamping it, then giving the cold rolled some solvent (nonchlorinated brake parts cleaner out of a spray can is what I use) and paper towels just to remove the oil (so easy!)

The paint/undercoating on the frame, however, had to be removed in the area where I would weld, however, and for that I used a 4.5" angle grinder with 80 grit flap wheel and light pressure, being careful to not remove all of the scribe lines so I would not lose the position. I did follow that up with a quick solvent wipe as well. I removed the paint about 1/2"-1" away from anywhere I'd be welding:

Attachment 6258

Attachment 6259

Then, I TIG welded the bracket onto the frame. The materials I didn't measure thickness of exactly, but guesstimate the cold rolled was about 1/8" thick and the frame was about 3/16"-1/4" thick. I set my machine (Everlast Super200P) up in DC, started at around 150 amps but eventually bumped it up to 200 amps peak current. I dialed in about 4 seconds of downslope and used my torch switch to regulate the current level. It worked just great. You do need to vary the peak current and the downslope settings a bit to get them dialed in for what you're working on, but the result was very controllable heat without having to do strange footpedal contortions while laying down doing this work.

Attachment 6261

Attachment 6262

The owner was really pleased with how the welds came out, and I was too. (clean, no spatter, good penetration, good aesthetics, etc.) Some of these welds were tricky because of being on my back, and also at times only having one or a couple of positions where I could put my head to see what I was doing.

I did this outside and it was pretty gusty, so what I did there was put on a big #8 gas lens, and pumped up the flow to about double of what I would normally use, (and eventually had to bump it up to triple, so was running about 38 cfh at the end!) It actually worked great. I felt the wind blowing pretty hard some times when I was welding and the puddle stayed shiny. The wind only "got to" the puddle once, and that was before bumping the flow up to 38 cfh.

Here's an overall shot of how it looked after welding:
Attachment 6263

The customer brought it back after he painted it and installed the mudflap, he was really happy with how it came out:
Attachment 6266

Attachment 6267

Attachment 6268

Attachment 6269

Attachment 6265

..and here is the roadracing car that gets trailered by this RV (a Porsche GT3):
Attachment 6264

That's impressive! I can barely tig weld in a good position much less on my back. What tig torch are you using?

looks good . nice Porsche

Thanks guys! It was difficult to weld on my back in contorted positions for this project. I'm still "feeling it"! Kind of like yoga, but only holding one move for a really long time and not switching the moves around to balance your muscles around, I imagine. (Actually never yoga'ed, in real life just "welder's yoga.")

Sean, I'm using a CK Trimline 210 with flex-neck and superflex cable. It can consistently dish out everything I give it using my Super200P (200 amps @ 60% duty cycle), and does so with grace. Before I got this torch, I totally melted down the cable of a WP-17 setup.

I have a thread where I adapted a torch switch into it and also a flexible loom; and there are some pictures in it, let me know if you'd like me to find it.

Oh and can't forget, a stubby gas lens collet body (WP-20 style cup), with a 1/16" tungsten on this (2% lanthanated.)

By the way, I got a ride in the Porsche (a 996 GT3 model I learned) on R-compound tires (basically street-legal racing tires) and it was sheer beauty. I am used to the lateral G-forces from my autocross racer, but I loved the sound that Porsche made accelerating onto the freeway... it was also super-stable at speed. I got invited to come to a track day and go for a ride in it on a roadrace course, and think I might take him on on it, because I've never been in a car at speed on a roadrace course before and it sounds like lots of fun!

I've got a follow-up project for this RV involving cutting an aluminum plate to fit the back area behind above the trailer hitch received to "clean it up" visually a bit, by the way. Should be pretty straightforward.