Again, a couple days accounted for in this post.

With a tropical storm possibly in play for us I desperately needed to cut my out of control lawn.  The problem was my lawn mower wouldn’t start, so a day and a half of testing the battery and then charging it overnight was spent, as well as a myriad of other troubleshooting tasks to figure out what the heck was going on.  I was about ready to pull the trigger on a new battery when I worked all the safety switches on the tractor and apparently one of them was stuck open.  Finally success and I got my darn yard mowed… more domestic duties boogering up my plane-building schedule!

After a couple of hours practice back TIG welding, I felt I had enough time under my belt and was just comfortable enough that it was time to stop the playing around and time to get busy welding for real.  That being said, stainless steel can be a real sticky wicket to weld and I knew my limitations, so I proceeded accordingly.  More on that in a bit.

First off was to get my nicer blue welding helmet back online.  Again, a common hack for these mid-range price welding helmets is to crack open the sealed auto-darkening lens unit to gain access to the one or two batteries that need replaced, to then add an external battery compartment allowing for EZ future battery replacement.  I’ll note that this auto-darkening lens is one I bought as a complete assembly to simply replace the original one on this helmet that had dead batteries… yet another method of replacing dead batteries on these things.  This time around, however, I’m armed with a bit more knowledge and experience.

The battery in this lens assembly sits in the upper right corner; here it’s been removed and only the tabs that were originally “welded” to the battery remain.

Using my soldering iron I removed these battery tabs that were soldered to the circuit board and replaced them with the positive and negative leads from the new external battery holder.  I had to make a small notch in the lens assembly case to allow for the wires to exit through the edge of the lens frame.  Also note the knot in the wires for strain relief.

After some minor surgery on the lens frame of the actual helmet to allow room for the external battery wires, I then remounted the auto-darkening lens assembly back into the welding helmet and secured the external battery module to the inside of the helmet with Velcro.  I then did a final ops test: success, and… Voila!

My spiffy blue welding helmet was back online.  Now it was time to put it to good use!

I spent about 30 minutes doing some TIG practice welds to warm up for the welding of the bottom right exhaust pipe bracket and the half-moon sleeves.  The main issue is that with this thin stainless steel, simple higher amp tack welding —sans filler rod— can be a bit risky and result in blowing a hole right through the bracket/sleeve metal.  Worse yet is what is BEHIND that stainless steel, on the back side: my exhaust pipes.  I simply do NOT want to be blowing a hole through the pipes or damaging them.

The trick in all welding is heat control, and especially here as I’m tack welding this bracket in-situ on the engine.  So filler rod was definitely on the to-use list.  That being said, after a good bit of practice I noted an unseemly characteristic of this specific welding rod used for this 316 stainless steel: it prefers to ball up vs simply melt into the base metal.  I thought this might be due to contamination at first, so tried it on an extra clean blank after prepping it via grinding and acetone… same issue.  My guess is that the rod may be a bit too big in diameter for the amount of amps I’m using, but it’s all I have on hand.

This meant adding just a hair more heat to the weld junction, enough to get this finicky welding rod to work, without melting away or blowing a hole through the thin base metal.  All while working on the bottom side of the engine.  And I’m sure it goes without saying that trying to get enough lighting on the task at hand was problematic in its own right.

Above is the raw, uncleaned bottom right bracket tack welded up.  Ok, so not overly beautiful tack welds for sure, but they did hold very well and I only had a little sticking on the inboard side between bracket and actual exhaust pipe.  A thin flat bladed screwdriver provided the persuasion needed to separate the two and no real damage (i.e. “hole”) to the exhaust pipe occurred.

However, this experience is certainly pushing me to explore how to secure or replicate the positioning of each remaining bracket to allow me to tack weld it on the bench vs in-situ on the engine.  Moreover, any flirting with ideas of welding up these brackets myself is out the window… again, with stainless steel needing that razor’s edge heat control, and this being such thin metal starting out, I’m leaving the major welding up of the joints to James, a no-kidding pro at this stuff.

With the bottom right bracket tack welded, I then spent the next hour and a half measuring, cutting and dialing in the 2 top bracket half-moon pipe sleeves.  As can be seen in the pic above, the bracket plate itself needs some minor trimming to be refitted around these specific sleeves.  Moreover, before any final configuration or tach welding is undertaken, I need to install the K1000-3 platenuts in all corners to ensure I get the very good clamping pressure I need between top and bottom brackets.

And that, my friends, will come tomorrow.

Pressing forward.