Chapter 23 – Exhaust pipes welded!

I started off this morning by pulling the now cured #2 cylinder baffle —with the fin/baffle standoff support curve integrated into it— off of the aft side of cylinder #2.  I had put a heat lamp on it since the weather (and shop) was much cooler overnight.  I assessed the baffle a bit —all looked pretty good— and then set it aside to remove the bottom cowling to allow removal of the left outboard/cylinder #3 exhaust pipe.

I commenced to remove the tape securing the halves of the exhaust pipe together at the near-center cut and then cleaned all the tape gunk off with Acetone.

While I was doing all these shop tasks, I had already pre-heated my kitchen oven to 400° F and was baking my previously “super-soldered” brass oil sump standpipe fitting.  My goal was to separate the fitting from the standpipe tube to allow James to braze it with some 1/16″ Silicone Bronze welding rods I picked up to allow TIG welding brass. Well, an interesting thing happened, or didn’t happen… whereas at 400° F previously I was able to remove the soldered pipe from the fitting, now it wasn’t budging. Hmmm?

I threw the standpipe assembly in the truck as well and headed out to James to weld the exhaust pipe, and also have a discussion on the standpipe.  My thoughts, in composite parlance, is that I had essentially post-cured this sucker and that it was now battle-tested to withstand 400° F without any issue… very interesting.

Again, it’s a good hour over to James’ shop and since Jess had a light work day I brought her along.  Unbeknownst to me, Jess’s mom is from the same area (“out in the sticks”) where James’ shop is… so after James had welded up the pipe an elderly friend stopped by and a whole conversation of who-knows-who ensued.   Combine that with a late lunch/early supper in Jacksonville and we didn’t get back to my house until very late afternoon.

And here we have the final piece of the puzzle (better be!) with the left outboard/ cylinder #3 exhaust pipe welded back together.  Now I can start on the final configuration of the tips in earnest.

BTW, James confirmed my theory on the soldered brass standpipe.  He also quipped that if I’m seeing over 300° in my oil sump that I’ve got lots worse issues than the standpipe… good point James, good point! <ha>

Back in the shop I got to work on the cylinder #2 aft baffle with it’s new integrated standoff bump.  I cut a ply of CF to fill just where the standoff support form was located and another full ply of CF to hold it all together on the interior of the baffle.  I then mixed up some HTR-212 epoxy and laid in the small filler ply of CF (pic 1) before laying up the interior ply of CF (pic 2).

I then of course peel plied the layup.

I let the baffle cure for nearly 2 hours to tack up before then setting it back onto the aft side of cylinder #2 (which I taped up completely to protect from any errant epoxy).  I taped the baffle securely in place to the cylinder since this will be the final cure and set a heat lamp on it while it cured overnight (much colder tonight than last night).  I’ll also note that the cylinder #2 fin/baffle standoff support mold was still in place on the cylinder to ensure the final shape is as optimized as possible.

And with that, I called it a night!


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