Acrylic usage

[BIGBIRD123]

I have a question about the use of acrylic...I have include a rough drawing of what I want to do. I want to put a Tee on my ball valve at the bottom of my keg that is used for draining the keg. In the Tee I want to put an acrylic tube going up for the purpose of indicating how much liquid I have remaining in my keg so that I don't go below the top heating element. I feel like this is a good idea but am not sure if/what >40% mash or low wines will do to the acrylic if anything...what do you experts think?



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[35mastr]

Good idea,But I am not sure if it's safe . If that should fail. It would be a serious mess.

[jholmz]

it shouldnt actually be needed if your running 2 elements most only use both for initial heatup then turn off top element and actually run with the bottom one through the rest of the run only using the top to reach max heat in a shorter time. if the element on bottom is as close to the bottom as you can get it about 2.5 gallons will cover it or does in mine and if you run at least a 5 gallon ferment at a time when your done you wont be low enough to run it dry. you also have to consider the heat that will be in the area where you want to mount it when running a keg it gets hot enough that you cant touch the outside with your hand, thats using electric, im sure if using gas you could expose that area to more heat causing the acrylic to melt

[BIGBIRD123]

well what you think about heat grade glass?

[jholmz]

just dont get careless and tap it with something

[steve2md]

well what you think about heat grade glass?

Although a sight glass is not a needed item on a hobby still, there's nothing wrong with a little bling if done correctly, IMO. A heat stable glass, such as pyrex, would work wonderfully for that. I might suggest adding a second ball valve though, between the keg and the sight glass, so in the event the glass is broken, you can kill the flow to it immediately.

[shadylane]

The top of the sight must be vented to the top of the boiler, not the atmosphere as shown on your drawing.
The way it's drawn the sight glass tube will show an erroneous high level, due to pressure when the pot is boiling.
I use a sight glass tube on my pot and thumper. If my memory is correct it's called red line boiler tube.
I don't know how safe acrylic is for this application but I'd bet good money the plastic police will let you know.

Edited: A quick goggle search found acrylic has many good properties. Sadly hot alcohol vapor isn't one of them.
Sorry, acrylc isn't usable for of sight glass material on a moonshine still.

[Prairiepiss]

Easy answer. Read the rules we live by.

[shadylane]

Borosilicate glass tubing can be found on ebay cheaply.

[MitchyBourbon]

shadylane wrote:

Borosilicate glass tubing can be found on ebay cheaply.

+1 shadylane,

You can also find site glass kits at your local brew shop.

[bellybuster]

I have sight glasses in all my brew kegs, not my still boiler though. I honestly don't believe polycarbonate would be an issue but I think I would go with glass. You can put a copper sleeve around it for protection.

With boiling liquids it does show a touch high, maybe 1/8" in a 13 gallon boil. Nothing to worry about.

[friendly1uk]

As it is vta it won't get hot. If you loop it back to the lid then hot liquid could circulate through it. Temperature is a big issue with materials choice.

I was recently punted a link to some expensive stills that appeared to use the loop method with silicone pipe as the sight glass. I expressed my concerns and heard nothing back. We do know these air-stills use some silicone pipe and a large silicone gasket, and over time the gasket shrinks and lab reports show plasticisers in the product. That is quite a demanding app though in terms of temp and ethanol concentration.

I won't advise anything here, I'm just laying some cards down for you to see.

[BIGBIRD123]

Well I will still pursue something this direction...I am not too concerned about any high readings, it's the low ones I am concerned about. I just want to measure the low level I can put a screw-top to release pressure only to open it when boiler is cooling. I think that as long as you don't leave it open when boiling, you can get an accurate low level. Maybe my memory of physics is not so good but I believe I am on the right track. I will use Boro glass...and maybe I can have some good results to give a small contribution to the members here...

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