Harry736 posted:Does anyone know the temperature that smoke units operate at? I'm considering buying a 3 D printer to make funnels and tubes to retrofit TAS smoke units to my 8776 C/NW GP 20. I wonder if 3 D printers can make a these parts that will tolerate the heat put out by a smoke unit.
I used the plastic or nylon goal post shaped tubes I made shown here, and they worked well, but after time, they get burned by the heat where they attach to the smoke unit. The gloppy stuff in pic 2 is the glue I used.
The heating elements get between 350f and 500f as the fluid boils off. I bet a 20 ohm resistor running lean on 18v may go over 500f. As the fluid boils off and the temp goes up the percent of carcinogenic compounds created goes up but the volume of VOCs are going down at the same time such that you see less smoke from the stack. So time to refill. We need a chemist to step in here.
While I generally don't use silicon around electronics RTV silicone used for auto gaskets can easily stand the temps generated by our smoke units. silicone tubing is available on eBay in sizes from 1mm to around 20mm it can also withstand the temps in smoke units. I found the 7mm tubing will sit in the brass fitting on top of a MTH smoke unit. I cut the tubing off so that it forms a good seal with the boiler at the stack opening. If using RTV make sure it is completely cured before installing in a loco. You might even want to wash it before installing to remove any acetic acid that might be remaining on it's surface. You can make molds for molding RTV with common modeling clay and scrape the clay away after the RTV cures. What you can't scrape off soap and water and a stiff brush will get off. j
