QEProps
New Member
An immense shout out to Raven713 for getting this Bell 206 Mixing Valve off ebay a few weeks ago. We struck a deal where I got to make a mold of the piece for him in exchange for a few castings for myself. He'll be selling castings once the mold is back with him and he's comfortable with the process, so keep an eye out for his posts!
So, in an effort to expand the knowledge of the community I have documented my work here for anyone that is interested. And yes, this includes part numbers for the amp connectors that are used!
Catalyzer (Mixing Valve) - Bell P/N: 706-070-491-101, NSN: 1660-00-132-1038, Janitrol P/N: D55D10
28-pin Amp Connector (mounted to the flare fitting) - P/N: 206038-2 & 206070-8 (Digikey P/N: A1379-ND & A32516-ND)
You'll also need a 3/4" copper pipe cap to add to the top of the Catalyzer
Starting with the Mixing valve, it looks fairly complicated, with with a few minor changes it actually cleans up for molding really well. Raven had already removed the safety wire that was on each of the screws, I removed each of the screws to sand down the sharp and jagged edges of each of the screws to protect the silicone later. I also remove the little silver solenoid (shown on the bottom-left in this picture) and the electrical connector (shown on the top) because they are connected with this little wire between them. That was never going to mold well so the best option was to remove them both. Both of these pieces were fitted into a small box mold, the screws were left on the electrical connector during molding so it all comes out as one piece.
I cut out the shape of the part in MDF so I could make a parting plane for the mold. The blue anodized bolt head had masking tape wrapped around it to cover the safety wire holes and the mounting points for the electrical connector were covered as well. On the casting these textures can be left alone or sanded down without much work and it makes the mold much cleaner. The flare fitting on top where the Amp Connector will be mounted later is plugged with a piece of clay.
Smooth-On Mold Max 30 was used to cover the part. Thickened with Thi-vex to keep it on the vertical faces. This shot was after the second coat and before I added the registration keys.
Fiberglass cloth was then added to make the jacket. The whole thing was removed from the MDF parting plane and flipped over to repeat the process.
I tried out the mold with a quick casting. The mold for the electrical connector has very thin cavities and has issues with trapped air. You can massage the mold and work out most of the air but I've found that a vacuum chamber works better as long as you release the vacuum before the resin starts to set so that any remaining air is compressed back to very small bubbles. The main part is just slush cast to keep it lightweight.
And that's pretty much it! Just gluing the two pieces in place with a little telephone wire in place between them and add the Amp Connector! Now I just need to clean up the jacket and prep it for shipping back to Raven so he can start selling kits!
So, in an effort to expand the knowledge of the community I have documented my work here for anyone that is interested. And yes, this includes part numbers for the amp connectors that are used!
Catalyzer (Mixing Valve) - Bell P/N: 706-070-491-101, NSN: 1660-00-132-1038, Janitrol P/N: D55D10
28-pin Amp Connector (mounted to the flare fitting) - P/N: 206038-2 & 206070-8 (Digikey P/N: A1379-ND & A32516-ND)
You'll also need a 3/4" copper pipe cap to add to the top of the Catalyzer
Starting with the Mixing valve, it looks fairly complicated, with with a few minor changes it actually cleans up for molding really well. Raven had already removed the safety wire that was on each of the screws, I removed each of the screws to sand down the sharp and jagged edges of each of the screws to protect the silicone later. I also remove the little silver solenoid (shown on the bottom-left in this picture) and the electrical connector (shown on the top) because they are connected with this little wire between them. That was never going to mold well so the best option was to remove them both. Both of these pieces were fitted into a small box mold, the screws were left on the electrical connector during molding so it all comes out as one piece.
I cut out the shape of the part in MDF so I could make a parting plane for the mold. The blue anodized bolt head had masking tape wrapped around it to cover the safety wire holes and the mounting points for the electrical connector were covered as well. On the casting these textures can be left alone or sanded down without much work and it makes the mold much cleaner. The flare fitting on top where the Amp Connector will be mounted later is plugged with a piece of clay.
Smooth-On Mold Max 30 was used to cover the part. Thickened with Thi-vex to keep it on the vertical faces. This shot was after the second coat and before I added the registration keys.
Fiberglass cloth was then added to make the jacket. The whole thing was removed from the MDF parting plane and flipped over to repeat the process.
I tried out the mold with a quick casting. The mold for the electrical connector has very thin cavities and has issues with trapped air. You can massage the mold and work out most of the air but I've found that a vacuum chamber works better as long as you release the vacuum before the resin starts to set so that any remaining air is compressed back to very small bubbles. The main part is just slush cast to keep it lightweight.
And that's pretty much it! Just gluing the two pieces in place with a little telephone wire in place between them and add the Amp Connector! Now I just need to clean up the jacket and prep it for shipping back to Raven so he can start selling kits!
