Silicone tubing for a sight glass?

[Funkenjaeger]

Has it been done before? I'm picturing a standard sight glass setup, but with a hose nipple in place of the compression fitting, and another hose nipple mounted in the eyelet at the top, with the tubing cut to the right length that it is held stretched somewhat tight when put in place.
Seems like given the difficulties and cost of glass sight tubes, it may be a reasonable alternative. Silicone tubing isn't that expensive (many of us already have some), and although it's not crystal clear it's certainly clear enough to see wort through, it's unbreakable and won't need any kind of protective shield, and of course it can take the heat.

The main problem would be that you may not want to mark graduations directly on the tubing since it's not rigid and won't be rigidly mounted, but you could quite easily add a metal strip (or similar) parallel with it on which you could mark the graduations, or mark directly on the side of the kettle/tun/etc.

I'm going to try ghetto-rigging this for a feasability test by just hooking some tubing to the outlet of my kettle valve and taping it to the side of the kettle, before I go buying parts to install another bulkhead for a more permanent solution. Though, that might even be a reasonable permanent solution for a budget brewer, albeit with something fancier than tape to hold the tubing on the side - just has the downside that you couldn't use the sight glass when draining the vessel, but the price sure is right - a few feet of tubing and a couple of clips to hold the tubing in place.

Thoughts?

 

[Special Hops]

Or just mark you stirring paddle at gallon and half gallon marks and dip into wort.

 

[k1v1116]

Or just mark you stirring paddle at gallon and half gallon marks and dip into wort.

that only works for mash and boil phases, you cant disturb the grain bed like that during lauter.

I like the silicone tubing idea you just need to pull it fairly tight and get the most transparent/translucent tubing you can buy. I imagine wort of a light beer might be hard to see. If you make this I would like to see some pics.

 

[Funkenjaeger]

Or just mark you stirring paddle at gallon and half gallon marks and dip into wort.

Yeah, that's what I do currently. But I've already got my paddle marked for two kettles, and would like to be able to measure in my various coolers which I can use as MLT's and HLT's, so I'd at least need a couple more paddles (and to keep track of them)...

Plus, looking down into the kettle from above, it's not quite as easy to accurately hit a particular volume - by the gallon is easy enough, but by the quart would be a little tough, at least on the lower end, and especially in a keggle where I have to keep the paddle in the center recess at the bottom, rather than off to one side where it'd be easier to see. And also, I wouldn't mind being able to see the volume during the boil, a situation where a paddle doesn't do me much good.

Marking the paddle certainly gets the job done in many cases, but I feel like sight glasses would just make the brewing process that much smoother.

I like the silicone tubing idea you just need to pull it fairly tight and get the most transparent/translucent tubing you can buy. I imagine wort of a light beer might be hard to see. If you make this I would like to see some pics.

The tubing I use is the standard mcmaster-carr thin-wall stuff, I'm using 5/16" tubing. I brewed a blonde this past weekend and even as light as it was (especially late in the sparge), it was easy enough to see in the tubing I was using to drain into the kettle.

 

[Bobby_M]

Mcmaster sells polycarbonate (rigid) tubing that is good up to 250F so I'd go that way if I didn't like my glass. In fact, if I ever break my glass and the one extra I have, polycarbonate all the way.

 

[Funkenjaeger]

Mcmaster sells polycarbonate (rigid) tubing that is good up to 250F so I'd go that way if I didn't like my glass. In fact, if I ever break my glass and the one extra I have, polycarbonate all the way.

Probably a good option. But, on my kettle, with a banjo burner, using a heat shield around it in the colder months, it gets REALLY hot on the sides - melting the plastic grip on the valve handle and anything else with the misfortune to find itself in that area. Since I haven't tried a polycarbonate tube I don't know for sure, but I feel like even with a heat rating of 250F it may still be damaged. I could be wrong of course.

One of my ulterior motives here is that if I install a second bulkhead fitting on the kettle for the sight glass, I could also add a 90 degree elbow on the inside and then during chilling, I could just pop the top of the sight glass tubing off, stick it on my pump, and use it for whirlpool recirculation during/after chilling.

 

[TerapinChef]

*paying close attention to yet another marvelous idea to see how it plays out* You guys are seriously too smart for my own good.

 

[Funkenjaeger]

Well, I'm satisfied! This is with plain water, and seeing the level is no problem, so even a very light wort would be no issue. Take my word for it, it's even easier in person, it was just hard to get decent pics of the shiny mash tun with the morning sun shining on it. Putting something white behind it (like a strip of plastic, or even some white duct tape) for better contrast would make it even easier to see.

Now I've got to think about permanent installation.

 

[Funkenjaeger]

Alright, after a couple minor setbacks, I finally got everything together and did a quick install in my smaller MLT:

Just need to stick some kind of a strip on the side next to the tubing and mark off the graduations by the quart or half-gallon.
I may fill in the area around the elbow on the outside with some expandable foam once I thoroughly leak-test it, or at least just throw some tape over it.
If I was feeling really industrious, I would carve a channel the full length of the tubing, and then stick a piece of 1/2" PVC pipe cut in half lengthwise (forming a U-channel) in there behind it, so the whole sight glass would be inset into the side of the MLT. But that'd be purely cosmetic.

The sum total of hardware for this install, with McMaster part numbers & prices:
1/4" NPT to 1/4" barbed nylon right angle fitting, 2974K154, ($5.53/pk10, so $0.55/ea)
1/4" barbed nylon Tee, 5121K761, ($4.42/pk10, so $0.44/ea)
Silicone O-Ring, dash #206, 9396K208 ($7.31/pk50, so $0.15/ea)
1/4" NPT brass locknut, 4429K122, $1.17/ea
1/4" ID silicone tubing (1-2 feet), 3038K172, ($6.60/10ft, so $0.66/ft)
1/4"x3" stainless eye bolt, ~$1 at home depot
Obviously it's not extremely cheap if, like me, you have to buy the minimum order quantities of all the items, but the per-unit price really isn't bad. Smearing some silicone sealant on the inside would be a cheaper alternative to the O-rings, especially if you've already got some.

Obviously, using a nylon right angle fitting is not going to work for anything that gets direct fired like a boil kettle, but I've got some SS fittings for a bulkhead that I will be using when I install one of these on my keggle. I went with the somewhat standard bulkhead arrangement with a full coupler on the inside, close nipple through the wall, and a right angle elbow on the outside with a straight barbed fitting in the other end.
A 1/4" NPT to 1/4" barbed right angle fitting made of brass (just a brass version of the one used on the MLT) would be even easier, so I may experiment with that as well, especially if home depot carries that particular fitting.

Anyway, I'm happy with it, especially for the (unit) price. Now that I've got all these extra parts, maybe I could put together some parts kits if anyone was interested.

 

[Ecnerwal]

If they have the fittings you need, USPlastic seems to sell by each.

Tubing is still 10ft chunks and priced very similarly for their house-brand (at a guess) silicone - the non-tygon stuff.