Building A Sight Gauge Or Sight Glass

[mobrien]

Hi all,

I've had a PM asking me for photos of the sight gauge I built a while back, and since I bought ozbrewers big 80L kettle, I thought I'd build a new sight gauge and document the process.

First step is to get the right equipment.

The general idea is to get a pipe compression fitting to fit the sight glass. In my case I am using a 1/2" polycarb sight glass, so need to get a 1/2" compression fitting. I suggest that you ring around first and found out what you can get - I used 1/2" because that was the ONLY size I could get a polcarb tube AND a compression fitting.

I am going to assume that you have some kind of threaded connection into the HLT or kettle that you want to add a sight guage to. If you don't you need to add one somehow! Either get a weldless fitting, or weld (or get a tame engineer to) weld a fitting to the HLT or kettle.

In my case I have a 3/4" BSP threaded fitting (male) coming out of my new boiler attaching to the thermometer. The HLT also has a 3/4" BSP threaded fitting coming out to attach the tap. My old boiler (in which the old sight glass imploded) as a 3/4" BSP socket (female). In all we're going to do three sight gauges today!

So off to the store. I came back with 3m of 1/2" polcarb tube ($28) and three fittings.

The fittings are a little more complex. For the tap and the thermometer, I need a three way T piece with three BSP female fittings. In the top of the T, got a 3/4" BSP male to 1/2" compression fitting. For the tap it needs a 3/4" BSP to 3/4" BSP adapter, so we screw the tap on. The thermometer doesn't need this, as the thermometer has a 3/4" BSP male fitting.

For the old boiler, a simple elbow does the job - 3/4" BSP to 1/2" compression.

All the fittings were $22.

Because a picture is worth a thousand words, here are the fittings - on the left, the T piece with the 3/4" BSP adapter for the tap, and the 3/4" BSP to 1/2" compression adapter for the sight glass. Notice the little nylon olive that makes up part of the compression fitting.

On the right is the elbow for the old boiler - very straight forward.

 

[mobrien]

Because it is easy to mix up the adapters, I'll show a photo of the BSP to compression adapter. Notice the PARALLEL threads of the compression fitting, compared to the TAPERED thread of the BSP fitting.

 

[mobrien]

OK - so next step is to screw everything togther, with the exception of the sight glass. I use pink plumbers tape, as this is thicker and better than the white bunnings crap. This seals the threads, and means no leaks!

Make sure you get the top of the T pointing up - you need the sight glass to be vertical!

Here is the T piece all attached to the outlet valve of the HLT.

 

[mobrien]

Now for the sight glass. Cut it to length, and sand the ends. I always wash everything at this point - any extra dust/shavings will create a leak.

Slide the cap (brass bit) of the compresion fitting onto the polycarb tube, followed by the olive. This should be a REALLY tight fit. If its not, you've got the wrong sizes.

 

[mobrien]

Now the sight glass sits into the top of the compression fitting. It should hit the bottom of the fitting and you will need to slide the olive down so it rests on the brass. Now its just a matter of tightening up the nut, which compresses the olive sealing the sight glass!

I've also add the outlet tap in the photo.

 

[mobrien]

The next step is to make a scale (and test it doens't leak!). I do this using a fermenter, as its the scale on the fermenter I use when calculating stuff. But its up to you as your source of volume measurements.

With the HLT empty, I fill a fermenter to full at the 30L mark. Then just drain it in until the water shows in the sight glass. I used a piece of white plastic electrical conduit covering as the board for my scale, and at the first sign of water, placed a grey pencil mark, recording the volume.

Then every 5L, I marked the scale in grey pencil.

 

[mobrien]

Now using the grey marks as a guide, I did some quick maths to work out the number of mm for every L. Then did the scale properly in perminant marker, and labelled the 5L incriments using my wifes labeller

 

[mobrien]

And thats it!

The same process was used for the three way T piece on the temperature port - it just looks a little different.

 

[sqyre]

Looks good mate, Wish i knew about that polycarb tubing when i built mine..

Hard plastic is it??

If you have your tap come off the "T" piece you will lose your level reading while the tap is open due to the suction of the flow from the tank.

I did the same thing originaly but got the shits with it as had to turn the tap off and wait for it to relevel to know where i was at. I ended up making the sight glass seperate to the tap and works great now.

My 2 cents..



Sqyre...

 

[mobrien]

And finally - the lebow on the old boiler. Same deal, just using the elbow.

There you go - three sight gauges all done. Hope this helps someone!

 

[mobrien]

Finally - a pic of the new look brewery for good measure!

 

[mobrien]

Looks good mate, Wish i knew about that polycarb tubing when i built mine..

Hard plastic is it??

If you have your tap come off the "T" piece you will lose your level reading while the tap is open due to the suction of the flow from the tank.

I did the same thing originaly but got the shits with it as had to turn the tap off and wait for it to relevel to know where i was at. I ended up making the sight glass seperate to the tap and works great now.

Sqyre,

Polcarb is damn hard plastic, and supposed to be good with heat - we will see!

I have noticed the level on the tap drops - by about 1L with a full HLT and 0.5L when its half full. The eventual plan is to do it with a temp guage in there - just need to get the new BSP port to put it in. Until then. the depressed levels I will cope with - its got to be better than measuring it in 2L lots!

M

 

[Keifer]

Hey, so you have a pump? how do you get from the mash tun to the boiler?

 

[mobrien]

Keifer,

I haven't actually used the new rig yet, but....

I don't have a pump. At the moment it is gravity fed - mash tun is the blue keep cold cooler, and the outlet is above the 40L mark of the boiler boiler - its no drama to drain it from there into the boiler.

Maybe a pump eventually - for now, I'm willing to keep with gravity!

M

 

[Fents]

Finally - a pic of the new look brewery for good measure!

:beerbang: Thats mad.

 

[Pumpy]

Great Post Mobrien , Thats going to help a lot of people like me who need guidance in life to fit a low cost sight gauge

.well done !!

Pumpy

 

[Ross]

Will be interested to see how you go mobrien - i was going to fit one the same way & got advised by several people (& as Sqyre found out) that the false readings whilst drawing water from the tap make it far from desirable to mount like that. My understanding is, you'll have to keep turning it off to let the level settle to see what you've drawn off.
Rig looks good though.

cheers Ross

 

[Batz]

And finally - the lebow on the old boiler. Same deal, just using the elbow.

There you go - three sight gauges all done. Hope this helps someone!

Looks a familiar old kettle there
Did the old sight glass give it up?

Batz

 

[Pumpy]

Will be interested to see how you go mobrien - i was going to fit one the same way & got advised by several people (& as Sqyre found out) that the false readings whilst drawing water from the tap make it far from desirable to mount like that. My understanding is, you'll have to keep turning it off to let the level settle to see what you've drawn off.
Rig looks good though.

cheers Ross

Oh I see Ross is that because of the turbulance caused by using a ball valeve on the end of the Tee .

perhaps it should just be a un-interupted 90 degree bend fitting instead of the tee to the sight gaugue .

Pumpy

 

[mobrien]

Yeah - it definitley does effect it having it on the outlet. In my tests yesterday when I checked the calibration scale, I found that when the boiler is full it depresses by around 1L in the sight glass. Half full depresses about 0.5L, and when it gets low - well its almost right.

I've actually set it up so that I can just take the tap off and mount a thermometer there - then just mount the tap elsewhere. I want the tap lower on the HLT anyway - The guys that welded the fitting misread my instructions and put it 50mm from the bottom, not 5!

I'll use it as it is for now - its better than the old measuring way of 2L jug - I'm waiting for the Craftbrewer place to get stainless weldless fittings to add the new place for the tap

Figure I'll do that the same time as I build the new mash tun - no point in having a 80L boiler, 65L HLT and a 37L mash tun. 57 mash tun coming up me thinks!

M