Sight Glass Mod


Hello first time threader here at Robobrew. Does anyone know what size hole is used for the ball valve?


It’s a standard 1/2" fitting. The hole itself is around 21mm diameter.


I bought a sightglass from Brew
It fits in the ball valve hole without a problem and no leaks. So, no drilling nessesary. Also the sightglass fitting will accept the Robobrew ball valve.


Nice find. Is that the 16" sightglass from


Yes it is from Brew


Nice find for a sight glass. How did you attach it at the top? It looks alot like the Fermentap sight gauge i have seen online and was thinking about getting. But your source has a much better price that others i have seen.


It’s not attached at the top


I picked a sightglass from Brew International and its really nice. Thanks for the heads up on those. Did you have any trouble screwing in the RB valve? I found that it goes part way in and then gets a bit hung up. Like the threads were slightly off or not cleaned out after tapping. Other 1/2 inch valve parts i have screw in easy so it must be the Robobrew Valve not quite fitting. I have read on other sites that the RB 1/2 inch is just so slightly different than ours.


Thanks for the helpful information and photos.
I am considering buying the 16inch gauge for my new Robobrew.
My only concern is the connection. You said yours went fine. Only one review on the BREWinternational site expressed the fitting “issue”. Did others get in touch with you about this?
Also, how did you do the markings on the side? Sharpie? Would pieces of black electrician tape be a bad idea since the gauge liquid would be at boiling temp. during boil?


I had no issues with the fittings. I did mark the sides with a sharpie. Good luck with the modifications


Great, I hope that will be my experience as well.
The company said if the tape is used properly it should be fine and if it doesn’t fit (and it’s only been tested with water) it can be returned.
So far, so good.


I was wondering if there is enough space between the sight glass and kettle to fit the neoprene jacket?


teve, I was hoping that I wouldn’t have to get in touch with you because my sightglass was going to install effortlessly. Wrong. I tried to screw it in today and it sounds like the same problem you had with not threading in beyond the first little bit. Not sure what to try next. Did you make any progress with this problem and was it indeed what you had read on other sites about the RB 1/2 inch being just so lightly different?


Happy holidays Spotteddogbrewing,
So my sight glass came in and I finally got around to attaching it only to fully realize the connection issue that was mentioned. Mine too didn’t thread in very far and seems to be a problem.
However, I just looked closely at your picture and it seems you didn’t thread yours in too far…? I’m guessing you used some of the tape there and you were good to go?
I should give that a try and see if it works.


Hi Fred, I found the treads they use are tapered so the snug fit. Gas piping has this type of threading but standard ss brewing/keggle hardward doesn’t. I worked the fittings together-tighten then loosen over and over again using a bench vice. Soon the part started to advance. I got to a (good enough) point and rummaged through washers,gaskets and nuts to find a combination of ones that made it all fit. I put on a s---- load of tefflon tape and tightened. Did a test fill and heat to look for the inevitable leak. Fixed a slow one then did a brew day. No leaks there but the sg tube threads at the t-fitting dripped. So more tape and test again. So far so good. I will be rigging up something to hold the top of the tube in place so no wiggle to cause leaks. I am really happy i installed the sg easy-no guess wort and sparge volume measurment anymore.
Sorry for the length of reply but the devil is in the details and RB’s have a few details to be worked through. One of a few mod’s i have done to the unit after it went off warranty.
Good luck and cheers


Thanks for getting back to me. I have since detached the ball valve and after attaching the sight glass only I put water in and marked the levels with a sharpie.There was a little leaking but under control after more teflon tape. I only seem to have lost a few ml after it sat over night. I think I’m going to go for my second brew with this setup since I have the pump for moving the liquid around anyway and will get by without the valve. I also noticed it was quite difficult to see the markings that are in black with a black neoprene jacket behind it so I inserted some white cardboard for contrast- much easier to read.


Hi Fred,
I found the marker/sharpie works but found the the marks will rub off with cleaning. I took a Dremel with a thin wheel bit and marked/notched the sg metal tube at gallon and half gallon marks. Then took a dimond tip and wrote the numbers .Easy to see and will last. Tried to etch it with salt,vinegar and a battery but the metal is some sort of tin perhaps and was a no go. It’s a tight fit for the jacket behind the sg on my rig as well. Just a bit of advice—check how open your vent slots are. I had a fair number that were almost closed or open very little. This thing needs all the air flow it can get.
Happy New Year!


Right- I’ll take a look at the vents for sure. Thanks


As far as markings go, use a small rubberbands and slide them into place. Works a treat. Cheers