coffeemods Senior Member Joined: 8 Feb 2011 Posts: 13 Location: Santa Cruz, California Expertise: I love coffee
Posted Fri Feb 25, 2011, 3:09pm Subject: Starbucks Barista Steam tip mod and OPV mod
Hey all, I am in the middle of modding my steam tip from 1 hole to 3 hole. I am keeping the same total area of the holes. I also removed my vibe pump and OPV and placed a pressure gauge on it and adjusted it to 9-10 Bars. I will post photos tonight on both. And an update on how it has worked.
Update: Here are photos of my mods: In the first photo I took out the vibe pump and OPV and attached a pressure gauge to the output side of the OPV and turned it on. On my first try I was getting about 30 Bars max on the pump. Then I backed out the relief valve to weaken the spring on the OPV until the gauge read 9-10 Bars and more water was flowing out of the relief side. Then I marked it, disassembled it, wrapped it in Teflon tape, re-threaded it and checked it again. Next I took the steam wand tip and calculated the area of the hole and divided it by three and calculated the new hole sizes. I think the new ones are about .024 diameter. I believe the original was .056 diameter. I will need to look at my numbers to confirm.
I can taste a difference in the espresso and the microfoam is crazy easier. These are definite must.
brain_ninja Senior Member Joined: 9 Oct 2012 Posts: 1 Location: MI Expertise: I like coffee
Posted Tue Oct 9, 2012, 8:54pm Subject: Re: Starbucks Barista Steam tip mod and OPV mod
Just stumbled across this mod, very cool! I'm thinking of doing a very similar mod to my Barista -- except instead of making it temporary I'm planning on putting the gauge off a t-fitting and add a needle valve to adjust pressure that way (with the OPV taking care of the excess).
Could you share the size / type of the tubing and the size / type of connectors you used? They look like some sort of compression fitting and a reinforced hose, but not the same as the original fittings. I'm having a surprisingly hard time finding fitting info on the internet for this machine and it's a bit too tight to get a caliper in there (not to mention, I don't have a BSP thread gauge to figure out the thread). Do you think your setup would be reliable enough for permanent installation? Going this route seems easier than finding all the right BSP threaded parts.
Also, I like the steam tip mod. How'd you fabricate the plug for the existent hole? And for the new holes, did you just clamp it in a drill press and go to town with a tiny drillbit?
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