We have eleven RV sites in our volunteer village. Of which eight are now occupied. The neighborhood is really bustling with activity. Especially on weekend firearm hunts when our volunteer outpost (community building) doubles as a check station for harvested game. Our schedules are staggered throughout the week, three days each. There's always something going on. Especially when your reputation precedes you.
When Ken found out I was an engineer, and a welder, he asked to pick my brain. He bought his fifth wheel camper used. It came with an aftermarket shock absorbing tongue to dampen out road vibration. Large fifth wheels otherwise can "pitch" a lot during some road conditions. That can be annoying to passengers. Hence, aftermarket hitch dampers.
The problem was Ken's had cracked. Twice. The first time the shock mount tore completely loose. He was traveling and stopped so a portable welding service could come reweld the shock mount back to the pin box. That repair later cracked so he had it rewelded a second time. Obviously, he paid much more attention. I met him fretting about apparent third round cracking that just started.
What I saw looked okay on the surface. The two bottom stiffeners were added during the first repair. It would've been more effective if the two pieces had been tied together. But that welder was also trying to protect the airbag. Apparently he worked against a clock on the side of the road to get Ken and Bonnie back on their way. I had the benefit of hindsight plus the luxury of time, place and weather to work.
When I felt behind the weld with my finger I found the culprit. So of course I offered to fix it for Ken. Don't all Recreation Engineers travel with a welder? Since building the car hauler last winter, I do. And boy howdy has it been worth my weight and space budgets! Not just for my own projects but for a few others along the way.
My terms and conditions we simple. It was gift - no money. And I was gonna do my best. No more band aids. That meant first grinding out both prior welds and also the cracks. Cutting it completely apart before welding it back together. So we began. Ken disassembled the mechanism - removing the airbag, shock and swing arm so I could access the underside.
Once I showed Ken the rear side cracks he understood my solution. It had to be taken apart for proper access.
And it had to be taken all the way apart to make it right.
To beef it up some rebar was welded across the front edge. Where the shock mount webbing met the new beef I added fillet welds ground hard and blended smooth. That reduces stress concentrators and also removes residual tension at the weld toe. Whereas water expands when it freezes (as in burst pipes) when steel solidifies from molten state it actually shrinks, pulling on adjacent material. For this weld geometry that's a classic initiator for fatigue failure that I wanted to avoid. Hence over welded fillets ground smooth with force to glow red for tempering.
It was after welding in the rebar that I noticed upside down markings on the left side. Given where this weld job was done Ken and I both chuckled. The unique signature seemed fitting.
To finish the job I first descaled the beads with a knotted wheel. Then Ken gave it a coat of gloss black Rustoleum. I took pride in the job. Ken gained confidence it won't fail again. Double happy.
