Hydraulic Aluminum Boat Lift Repair/Reinforcement (aluminum TIG welding) jakeru's #14

[jakeru]

I did some welding on an aluminum hydraulic lift for a boat dock today. This type of lift uses water pressure (IE: piped from a garden hose, or potable water piping), to raise and large hydraulic ram, which raises the boat up and out of the water, getting it up and out of the waves and keeping it "high and dry" for storage.


This was apparently an old lift that had some problems, which the customer had just purchased and was repairing it into a usable condition.

This was really a good test of my welding machine, as the material was pretty thick in places, and fairly good sized pieces as well. I started off doing some easy warm-up work on the bench using the footpedal for current control.


Then I switched out to my driveway for the big pieces, where I was running flat out (off and on) about ~190 amps (using the torch switch for current control) and at a pretty hefty duty cycle. You'd think in July, we'd be having sunny weather, but NOOOO, it was overcast and actually quite gusty (like a weather front was coming through) so I had the customer (my helper) hold a big piece of cardboard to block the wind. He also stayed busy prepping parts and feeding them to me for welding. It seems like weather never cooperates around here lately.
I did several linear feet of these stitch welds, (50% lap joint welds and 50% outside corner welds):

And I welded on a few of these tabs:


There were two of these rather large pieces:


I repaired a cracked section using similar crack repair techniques I perform on aluminum wheels. Grind a vee in the crack on both sides using a carbide burr, mechanically deoxidize and solvant wash, and then weld on both sides for full penetation without very wide of a weld bead or heat affected zone. (But since this crack was caused bya stress riser next to the filler weld, I feathered the filler weld out on the side with the filler, to distribute the stress out over a wider area.)
Crack prepped (top / bottom views):

Crack welded:


I went through 8.5, 36" long 1/8" diameter 5356 rods on this repair. Took me 2-3/4 hrs to do the work. The customer did a good job of prepping the parts (and bringing them substantially well-prepped... after apparently taking very good notes during a brief initial consultation) and he kept feeding me prepped pieces to weld together when he was not holding up a cardboard makeshift wind shield to keep my weld puddle clean during the wind gusts.


I actually smelled some funky smells during welding sometime (the lap welds in the large, thick material were somewhat demanding on the equipment), which anyway tend to freak me out a bit because I have noticed expensive equipment failure is almost always preceeded by funky smells. In this case, I realized towards towards the end that the cable itself of my ground clamp was getting pretty toasty from the sustained current & duty cycle! I'm thinking it might be to time to upgrade the size (wiring gage size / thickness) of my ground cable to eliminate this apparent "weakest link" of my present setup. I don't need to roast and smoke out my ground cable. The torch itself was also getting (subjectively) pretty toasty, and the torch cable was getting noticeably warm, but not excessively, and certainly not causing any problems, I was just keeping tabs on how things were running with the extended high power output. One sign the torch is getting hot: the normally "bright pink" cup turns a duller color and doesn't look as bright of a pink color as much. It's kind of hard to describe, but I've noticed a color change in the cup when I get it really hot! (Maybe hot enough to just begin to glow by itself if it were completely dark?)

I sure wish I had some helium mixed gas to try on this job, as it seems like it would have been perfect for this job. (A second tank for Helium is on my "want list".)

I welded all of the out of position work with the torch switch set to "wide open", max amps knob cranked up all the way, and minimum (20% EP) AC balance setting.

Tunsten: lanthanated, 3/32" blunted (only dipped a couple times, and the wind blew it "oxidized blue" once.) #6 stubby gas lens cup with 15 cfh argon. (higher than a usual 12 cfh that I use with this cup when the air is still.)

[Oxide00]

Awesome welds man!! Wish I was that good with aluminum.

[jakeru]

Thanks, Oxide. The customer was pretty happy with this one too.

I figured out the cause of my warm ground cable: loose screw holding the copper cable conductor to the clamp body. After tightening that up, I don't expect to be having warm ground clamp cables problems anymore.

Also, my stubby 3/32" gas lens collet body (CK worldwide) is toast. The copper piece that the collet presses against fatigue cracked, and broke completely away from the rest of the collet body. Maybe I tightened the collet one too many times, or took it through one too many heat cycle? Oh, the 3/32" stubby brass wedge collet deformed too. I guess I must have gotten it all pretty hot.