Today was the first test of tack welding the exhaust pipe brackets on the bench and not in-situ on the engine. I secured the position of the respective bracket pieces and configuration with hot glue, hoping that just a tack weld on one side of the bracket wouldn’t melt the glue on the other side… so in theory I should be able to get 2 good tack welds, which is a decent start.
In general my hypothesis was correct, however I did learn something about hot glue in and around the welding process: it appears to act as a heat accelerant if directly involved in the weld. I had a couple of welds flare up in spectacular fashion when apparently the glue had melted and wicked down to the seemingly clean section that I was welding on. The result being I do have one small hole on the perimeter that will need to be filled during final welding.
Overall the op was a success, and after the cleanup I remounted the top right exhaust pipe bracket with good results.
Now, on the lower left bracket the “hot glue accelerant” characteristic really reared its ugly head in a few spots. It’s essentially analogous to going from 0-60 mph in 0.01 seconds when you’re used to 3.8 seconds (just as an example).
As I was welding the outboard sleeve to the vertical bracket plate my weld apparently hit glue towards the top outboard edge and it blew a small hole out. I left that weld alone and moved onto a “clean” (or so I thought) area near the thinner edge (bottom center), and between it just being narrow and less metal and an unplanned flair up, it literally just near-instantaneously melted the bracket in half!
The result was the inboard sleeve tack welded in place, and the outboard sleeve gooped up a good bit and the bracket plate now in 2 pieces. I cleaned up the outboard sleeve in prep for another round of welding, as well as the bigger bracket piece with the now welded-in-place inboard sleeve. I draw a Sharpie line on the back side of the weld line to ensure the pieces don’t slip out of place (and to tell if they do), so I knew the weld line on the outboard sleeve to tack weld it to the remaining half of the half circle (a quarter circle at this point) closer to the overall midpoint of the bracket.
Here we have both inboard and outboard sleeves tack welded to the major portion of the vertical bracket plate, with the very outboard free and untacked corner of the bracket simply held in place by the mounting screw.
Since I needed to do another round of cleanup and prep to weld in that last piece, and it was getting later in the evening and time for some grub, I decided to punt on any more welding for the evening and do some machining. I’ll re-engage on the welding Monday with a clearer head.
I started out machining the SC-1 canopy safety catch by first probing the part for zero-zero.
It then took me about 5 minutes to machine the SC-1 on my mill, with some action shots here.
And Voila! A per-plans spec SC-1 canopy safety catch. The first one I did, which was a bit of a test, was too thin and bent too easily. This one should work fine.
And here it is all cleaned up, ready for the metal brake!
And with that folks, I’ll bid you adieu for a few days as I take a quick break down to Florida with Jess.