Jean Pat has received the 567 blower drawing files so it won't be long now for me to get that 567 done. Meanwhile, work still continues on all the engine house particulars. I printed all three of the faux roller door mechanisms. I corrected some problems with the first two by hollowing out the last, and supporting some of the tiny details that weren't growing correctly. Doesn't matter, invisible in the end...
Finished up the HVAC units and painted the details and weathered the track bumpers. Put a coat of sanding sealer on the roof upper surface in preparation for receiving its membrane roofing.
The HVAC units needed something more to connect them to the roof other than those spindly legs. I wanted to make a simple box that would sit below and serve as the ductwork leading to the interior and also provide a substantial gluing surface to the roof. I thought about scratch-building them out of styrene. Then I did a quick work/$$$ analysis in my head and decided to grow them instead. It took just a few minutes to measure the height and draw it up in SU. The first two are just coming off the machine now. I was able to grow them 2-up on the machine.
The parts grew in a little over 2 hours. I just went down and got them, and they fit perfectly. Two more are growing now as I write this. This capability continues to amaze me. I wondered how I was able to build without it. On this unit, the duct was a little high. I'll glue on the duct and then sand it until everything touches at the same time.
Here are the first two ducts. I made them hollow and fairly thin and they used only about 12 cents of resin for each one.
I learned something about the machine today. After printing the first two roller door assemblies, I started to print the next two, but decided that making them solid was wasting resin. I stopped the print and went upstairs and redrew the part, saved it on the thumb drive and then loaded the new program on the machine and pressed start. It went to the bottom and started making strange noises and the drive was moving up and down. I thought the stepper motor was failing and was very bummed out. After messing with it and seeing that it was unable to move and was acting like it was slipping, I paused it and went to manual and raised the platen and the stepper worked perfectly. Then it hit me. The aborted print had already started building up layers on the platen, when the platen was trying to go to the zero (start) position with the new print, it was being blocked by the resin that was solidified on the platen. It was trying to push past it, but couldn't. I removed the platen, scraped off the remnants of the old print, and started it again. It worked perfectly. Not only that, but I apparently didn't mess up the FEP release surface since the next roller door mech came out just fine as did the duct print that followed. The machine seems to be protected from being jammed and it didn't do any damage. Good design! I took the opportunity to lube the lead screw using some special gear lube I bought at the York Show a few years ago.
Here's the three roller doors after priming. I haven't decided what final color I'm going to use. Possibly white with a yellow control cabinet. I may go with that Coral Blue. I kind of like it.
I masked all the remaining HVAC units and the bumpers for the black detail painting. Lots and lots of masking for a very little amount of paint.
After the black, as before, I picked out the fan blades with chrome silver. I then added the protection screen (bridal tulle) and glued the ring to the body. Instead of attempting to stretch the tulle over the fan and glue the ring on top as I did with the first one, I reversed the process. I stretched the tulle flat and taped it down, applied pressure sensitive adhesive to the ring and when dry, stuck it to the tulle. Then with a brand new #11 blade trimmed the ring and its tulle out of the rest.
This technique worked well. I then used medium CA on the exposed top edge of the fan housing, applied some accelerator to the ring and brought them together. I dry brushed silver on the tulle to make it look metallic. I also added some wash to the HVAC units concentrating on the underside of the big louvers. These are done and ready to go on the roof once it's been covered.
That particular version of tulle is really useful for us O'scalers. It's perfect for grills and chain link fencing.
Here's a bumper just after the wash has been put on.
Here's the same bumper after using a Q-tip lightly soaked in Iso Alcohol to remove and redistribute the excess.
I then picked out the NBW detail with a fine brush with chrome silver first and, when dry, some Vallejo Dark Flesh to simulate some corrosion. That's a great rust color, BTW. These are ready to install.
I used a water-based sanding sealer to coat the top surface of the roof so the duct tape with stay put. I said yesterday that I'm going to try and simulate a Durolast Vinyl Membrane roofing which is quite widely used in industrial applications and its white. I'm thinking that I need some drain scuppers to take rainwater off the roof. In big roofs like this they located in various places leading to collection pipes that run into the foundation. I've already got two pipes carrying the lighting wires down.
I'm quickly reaching the point where I have to start building the gantry. I need to put the main rails into the building first. I'm going to use the actual as-built distance between the two to determine the length of the main gantry rails. I'm thinking of using some small track screws to hold the rail into position until the epoxy cures. I'm going to have to schlepp the whole deal back into the shop in order to do this accurately. On the layout, the engine house sits pretty high and I have to stand on a stool to be able to easily reach over its walls. My layout is 42" high and the almost a foot tall, putting the top of the wall at 54". I really don't like carrying it back and forth since it's more delicate now the the windows are installed.
I have to finish the machine shop roof. I need to install the lights and put some material on it. It's a shallow slope so shingles are out. I suppose it could be membrane too. I have to seal it first.
