E3D Revo-HT Sock Mold

Mold for casting a sock for the Revo-HT heaterblock using Permatex Gold Exhaust gasket RTV.

BOM:
- M3x20 (or longer) x4
- M3x12(ish) x 10
- High temp RTV (I used Permatex Ultra Copper exhaust manifold gasket maker).
- Cup or bowl.
- Blue Dawn dish soap.
- water.

All of the parts are pre-oriented in the optimal way. Any settings should work fine. I printed mine in PLA, but I think any material should work.

After printing the file you will have to assemble the parts. Use the CAD as a reference for putting them together, it all goes together pretty simply. One thing worth noting is to attach the Inner heater block piece to the top piece first. Your two M3 screws will be so close to each other that one of the heads will end up on top of the other one, this is fine, we're working with limited space and it doesn't affect the end product. Just screw both partially in, so that the parts are properly aligned, then tighten one at a time until everything is secure. Your screwing into plastic, so don't torque it too hard.

Once you get the mold fully assembled (Remember, your screwing into plastic, so your aiming for just snug) mix up some soapy water in a cup or bowl or something large enough so that you can fully submerge your mold. Dunk it in and slosh it around for a few seconds to let the whole interior get soaked. This does two things: Firstly, it allows the RTV to cure while confined in the mold, secondly it acts as a release agent so that the RTV doesn't bond to the mold.

Once your mold is done soaking, screw the nozzle onto your tube of RTV, shove the tip into the hole in the mold, and squeeze. I recommend holding your finger over the side vent hole at first, until you see excess coming out of the three vent holes at the bottom. Once you see that, move your finger to block off those three holes and squeeze some more until you get a decent amount coming out of the side vent hole. I added this side vent hole because in the initial prototype without the hole, there was a tiny hole where the RTV didn't flow fully into the center of that side.

Once you are satisfied that you should have RTV forced into every part of the mold, set it aside for 24-48 hours. I usually wait 48 hours, but some people on the internet say it's fine to only give it 24 hours. It's up to you.

After 24-48 hours have passed, remove all the screws and carefully start wiggling things apart. There will be flashing, just tear it off with your fingers. Use some small snips to cut off the big flashing left from the injection hole. Give it a rinse in some warm water to rinse off any soap residue, then leave it sit out for another day or two to finish curing.

You will have to cut a slit for your heater and thermistor wires in order to install it.

I've included the .step files so that you can use it for reference as well as make any modifications you see fit. Cheers.

Big thanks to Stephan from CNC Kitchen for the idea, as well as tribologist on youtube for his videos on using RTV instead of the 2 part stuff that Stephan used. Those videos can be found here:

CNC Kitchen DIY Sock video
 

Tribologist RTV Video Part 1 / Part 2

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Update: 10/ 27/24

• Changed where the bodies were split in order to resolve an issue where the bottom part that covers the tip of the nozzle would tear when demolding.

• Eliminated the need for supports.