[MNWayne]

Could I get recommendations for where to purchase (via mail) accurate spunding valves.  The cheap ones I currently have allow way too much pressure swing between open and close.

[narcout]

Which one are you currently using?

[MNWayne]

I have no clue, I bought it years ago from somewhere. It came with an extra-light spring for lower pressures. If I set it to open around 10 psi it will vent to around 5psi before it shuts. There must be something more accurate out there.

[ynotbrusum]

This is a simple, yet effective spunding valve:

https://www.morebeer.com/products/blowtie-diaphragm-spunding-valve.html

They also make ones with built in gauges - both analog and digital.

[narcout]

They also make ones with built in gauges - both analog and digital.

Yeah, that's what I've been using.

https://www.morebeer.com/products/blowtie-diaphragm-spunding-valve-gauge.html

Although I just replaced the analog gauge with this digital one.

https://www.morebeer.com/products/digital-mini-pressure-gauge-090-psi.html

It's a good valve, but I don't know that it's more accurate than maybe 3-5 psi.  It could be user error though, in that perhaps I didn't allow the valve to fully close when I was calibrating it (it slows down to a very slow trickle near the end, and I may not have been patient enough).   

I don't know what kind of setup you have, but Blichman, Brewbuilt and SS Brewtech all make spunding valves.  They aren't cheap though.

[MNWayne]

I saw the Blichman.  Their prices are rather hard to swallow. I appreciate quality and realize it comes at a price, but feel that most Blichman products are just a little to far over the $$$ top.

[reverseapachemaster]

I have the spunding valve they carry that attaches to a keg post. Depending on your fermentation vessel, you might be able to find the valve without the keg fitting or attach the valve to a different type of fitting. The first run requires some experimentation to find the right setting for the PSI you desire. I don't have a way to independently test the pressure but it seems to work appropriately.

[ynotbrusum]

Just saw this new item:

https://www.youtube.com/watch?v=fO_SpNMCZRI

[MDL]

FWIW, I have a couple blichmann spunding valves that have been very reliable for years.