If you work in manufacturing or have your own resin casting operation, you’ll know the all too familiar sound of pressure pots or tanks being bled and the subsequent look of agonizing pain as blood prepares to spray from the earholes… maybe it’s not that bad. Yeah, yeah it is.

Ear plugs always get lost or there’s the embarrassment of having mismatched colors of ear plugs *snicker* and it’s too much work to slap on some Ear Defense 3000 safety muffs, so leave it to Industrial Designer and SolidSmack contributor, Eric Strebel, to address the problem at the source – the pressure pot exhaust port.

Eric has a very simple solution to prevent a lifetime of mind-altering tinnitus with pipe fittings you may very well have laying around the shop. With these, a small exhaust port silencer can be constructed to deaden the sound when you’re ready to purge the pot. Here’s how he made it:

YouTube video

Exhaust Port Silencer Part List

  • 3/8″ x 2″ Steel Nipple
  • 3/8″ x 1/2″ Steel Hex Bushing Adapter
  • 1/2″ x 1-1/4″ PVC Busing Adapter
  • 1-1/4″ PVC Male Adapter
  • 1-1/4″ PVC Cap
  • Plumber’s Pipe Dope
  • PVC Primer & Sealant

Eric milled some slots in the PVC Cap, but holes could be drilled just the same. He fastened the steel pipe fitting to the pot’s exhaust port first, applying wee bit o’ the pipe dope to the threads. Then he built up the rest of the fixture using PVC primer and sealant between the adapters.

While you could use a smaller diameter fitting, he chose the 1-1/4″ PVC piping to easily jab in a couple of rolled up washcloths. Once everything is together, you can bleed your tank muff, plug and hands-free. It’s a small cost and quick solution for a big bit of added safety in the shop. Check out Eric’s other videos on his Youtube channel.





Josh is founder and editor at, founder at Aimsift Inc., and co-founder of EvD Media. He is involved in engineering, design, visualization, the technology making it happen, and the content developed around it. He is a SolidWorks Certified Professional and excels at falling awkwardly.