Must of done reasonably well at keeping the head cook on Mother’s Day. Got a few hours each arvo last weekend to cut the holes in the walls of the 4” for the sight glasses. All back together and ready for todays spirit run. For a few Looooong tense
minutes I really thought I’d wasted my time, and yours, for reading this far. All plates where loaded, but not a bubble anywhere :shock: . All vapour was blowing straight up the downcomers. Then one after the other the downcomers filled up, and in rapid succession plate after plate started bubbling. :happy-partydance:
Took bugger all pics of building the plates and weirs, so will try and keep this shorter than the last post.
I decided at this point to go with 4 caps per plate rather than 3. Purely to keep the open area percentage around 8%. If your interested in such details refer to the cap slot area in the page of scribble posted earlier.
Plates were marked out on flattened pipe. I only partially annealed these as I didn’t want them Bend In Your Fingers soft. Made it a a PITA to get flat. Not sure if it was worth the effort. Dead soft would word ok I think.
Here’s the 3 hole prototype marked out.
My build wasn’t going to be modular in the current style, I figured almost everyone uses, as a minimum, 4 plates. I drink dark and white spirits, so I figured the plate section on my build would one module of 4 plates, on a tree. Rather than threaded rod for the tree, I figured a stick of 3mm 2% silver solder up the guts would be strong enough for the job. That meant no big hole in the middle for a bolt to spin these in the drill press, so had to be done by hand. Centre punch the plates, scribe the circumference, reduce most of the perimeter with snips and the belt sander. Take down the last half millimeter to the scribe line with a file, check frequently in the actual column. If your column is squashed out of round and you can’t get it back to perfect, punch a witness mark on the edge of the plates. Don’t forget to offset your downcomers! Gently punch the column with another mark. Now file the plates to fit, align the marks each time you fit the parts together and being out of round won’t matter, just keep these clearances close.
The next job was the weirs themselves. I cut these from spare column stock, then cut a section out to reduce the diameter. These cuts I made at 45 degrees to give the solder a bit more to stick to rather than a plain butt joint. Cut a strip or two of shim stock I had, and used that as a spacer to set the clearance between weir and column. These need to be a close fit, so took a bit of fiddling to get the length and therefore diameter right. With the parts made it was time to solder them up. I just needed to hold them in position while I did it. I cut a spare ring of 4” pipe about the same height as the weirs. Lined the inside of the ring with the shims, and drop the cleaned and fluxed plate inside followed by the weir. Clamp it down so it can’t move and flatten any wobbles in the plate. Preposition solder and heat evenly until it melts and sucks into the joint. Solder the scarf joint last.
I was worried I’d solder the lot into a useless lump, but scrubbing the bits I didn’t want soldered with a carpenter’s pencil, and being very careful with where and quantity of flux, I had no issues. The solder came in contact in places, but didn’t really stick to the dirty copper ring or shims.
Note the deep centre punch hole in the plate. I did these on some endgrain pine, just drive the ouch in until the hole was a tight fit on the tree. Purpose is to give the solder a lot more purchase area on the silver solder rod.
Next up I’ll assemble the plate tree. Got some decent pictures for you too!