DIY Stainless Steel Tubular Flow Through Sight Glass 1/2" NPT

After looking at the blingy tri clamp sight glasses that are going for $80, I thought I could build one that uses 1/2" NPT for a lot cheaper. I made this assembly in google sketchup from parts off of McMaster-Carr to see how it would look and fit together:




The model can be downloaded from the 3D warehouse here:
http://sketchup.google.com/3dwarehouse/details?mid=1d0392606df439ad27cf7a67d12bc843&prevstart=0

I think the NPT fittings will work better for most people's homebrew rigs, and the price breakdown was encouraging as well.

The flanges:
http://www.mcmaster.com/#44685K11
Cost $15.73 x 2 = $31.46

I got a quote on the borosilicate tubing for about $10 per piece if I order a whole stick (18 pieces).

The nuts, bolts and silicone gaskets probably add another 5-10 bucks.

So all together it looks like these can be built for <$50 without any bulk discounts. The flanges are the most expensive part, and I figure we should be able to find a supplier that can do better than McMa$ter. I contacted Wayne at Bargainfittings to see what he could do about pricing for a bulk order of SS flanges, and I'm waiting to hear back from him. I was hoping to at least be half as expensive as the tri clamp version from St. Pats that goes for $80.

Basically the point of this thread is to gauge interest in this project and hopefully fish out a supplier for the parts that will make it cost effective.

Please reply with whether you would seriously consider purchasing a SS 1/2" NPT sight glass for about $40 or let me know how much you think is a reasonable price point. Extra credit to anyone who can find the flanges cheaper.

Thanks

This is a great idea klyph, especially if you add an inlet for a O2 stone for O2 injection on the way to the fermenter.
What is the diameter, length and wall thickness of the glass tubing?
My question is there an already machined pocket in the flanges to retain a "O" ring for the sight glass to seal against? This will be an added machining process plus dealing with SS material. I made a larger sight, pressure and volume chamber out of 1/2" thick aluminum plates, a groove for "O" rings with a wine bottle body as the sight glass, four rods compress the assembly. This was mounted vertical with a brass hose barb to refill, regulated at 50 psi with carb cleaner inside. Tested to 125 psi. This with a variable PWM, variable Hz (help by kladue) plus electronis timer to flush, flow check nozzles and balance fuel injectors. A fun project saving me many hundreds of dollars a DIY injector checking project. Ultrasonic cleaner I already had this cleaned them internally while pulsed.
Thanks for posting.

Why not something like the below?

https://www.homebrewtalk.com/f11/line-sight-glass-my-rims-148736/

And check this one out...

https://www.homebrewtalk.com/f51/inline-sight-glass-214608/index2.html

wyzazz said:

one out...

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Very nice. That's basically what this is, except all stainless.

BrewBeemer said:

This is a great idea klyph, especially if you add an inlet for a O2 stone for O2 injection on the way to the fermenter.
What is the diameter, length and wall thickness of the glass tubing?
My question is there an already machined pocket in the flanges to retain a "O" ring for the sight glass to seal against? This will be an added machining process plus dealing with SS material. I made a larger sight, pressure and volume chamber out of 1/2" thick aluminum plates, a groove for "O" rings with a wine bottle body as the sight glass, four rods compress the assembly. This was mounted vertical with a brass hose barb to refill, regulated at 50 psi with carb cleaner inside. Tested to 125 psi. This with a variable PWM, variable Hz (help by kladue) plus electronis timer to flush, flow check nozzles and balance fuel injectors. A fun project saving me many hundreds of dollars a DIY injector checking project. Ultrasonic cleaner I already had this cleaned them internally while pulsed.
Thanks for posting.

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There is no machined groove, but there is a large flat spot that a flat washer shaped silicone gasket will seal against, and the glass will be thick enough to form a nice wide seal.

Oh and you should send me some pictures and details about that injector cleaner, I know of a guy building one right now.

Send me your email thru the PM on this forum, i'll dig up a few photos out of my confuser and forward to you or your friends email address. I ended up with 8 injectors flowing within .75% maximum error. Beats the hell out of "up to 10% production injectors".
I've lost 90% of my digitals because of two POS Kodak "El Cheapo" cameras
as well had many card failures. I hate Kodak!!!!!!!!!!
I had many of my Brewhemoth photos to post that became "deleted" just after downloading. Daughter's $900 digital is "hands off no touch" dang 17 year olds. Carl.

klyph said:

There is no machined groove, but there is a large flat spot that a flat washer shaped silicone gasket will seal against, and the glass will be thick enough to form a nice wide

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Are the flanges available flat no bolt holes?
That would be great then machine a square ring groove plus use smaller
3/16" to 1/4" SS bolts. One flange end drilled for bolt shank clearance, the other flange tapped for the bolt then add SS acorn nuts as jam nuts.
Simple clean and positive sealing. Compressing a sheet of rubber isn't an option.

I think the glass will be thick enough to offer a sufficient % of the cross section to create a reliable positive seal on a flat gasket surface. And I'd really like to avoid added machining costs. I'm basically trying to make a practical sight glasss for as cheaply as possible, and even paying a machinist to chuck it up would probably push this past the point of cost effective. I think I might bite the $50 bullet and build a prototype to test it and see how it works out.

I think I got my triclover sightglass for $65. Not to discourage you, just sayin'.

Why not just use a McMaster PN 1138K54 1/2" NPT Brass sight glass for $33.21 and skip the rest of the parts and pieces, you only have 2 threaded joints to infect things with.

kladue said:

Why not just use a McMaster PN 1138K54 1/2" NPT Brass sight glass for $33.21 and skip the rest of the parts and pieces, you only have 2 threaded joints to infect things with.

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That's rated 180*F max for brass. Below are some nice 1 1/2" SS units but the $554 range, oops.
Lathe out the threads for a snug fit of TC stubs then solder to be totally threadless, strong and sanitary.
Pickle the brass once then go for it as it's short time use with no fear of the brass.

klyph, did the Kodak photos go thru to your email?

Klyph - at $40, I'd be in for one (maybe two).

Like ScubaSteve I only paid $65 for my triclover sight tube. I would pay $30 for one of your 1/2" FNPT sight tubes.

klyph said:

And I'd really like to avoid added machining costs. I'm basically trying to make a practical sight glasss for as cheaply as possible, and even paying a machinist to chuck it up would probably push this past the point of cost effective.

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I have a lathe in my shop, no added costs.

Klyph, you beat me to it!...We will talk when I get off Slope this week.

I'm curious where you guys are getting those 65 dollar sight glasses. $73 was the cheapest I could find.
Kladue, that unit would probably work just fine, but I was after a more elegant solution that would be more robust and be able to withstand boiling temps.
Carl, they do not come without holes, I thought about using bolt spacers, but the added cost makes it cheaper to just use the 1/2" bolts. Besides I'm fairly certain it's bomb proof.

klyph said:

Carl, they do not come without holes, I thought about using bolt spacers, but the added cost makes it cheaper to just use the 1/2" bolts. Besides I'm fairly certain it's bomb proof.

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Now that sucks I had a plan if they were solid.
BTW my email go thru with the injector cleaner, PWM with timer?

How about using 2-3/4" tri clover but weld flanged spools and use loctite to seal a piece of 5/8" gauge glass to the inside. The flange bore is .620 and the gauge glass is .625, some sand paper or emery cloth should open the inside bore enough to fit the gauge glass. Sandpaper or etch the gauge glass where it fits inside the tri clover spools and use some loctite green thread lock to seal it to together and it should work. Flanges are about $10 each and the gauge glass should be a couple bucks for 3"-4" piece to make this.

Carl, your email must not be making it for some reason.

kladue said:

How about using 2-3/4" tri clover but weld flanged spools and use loctite to seal a piece of 5/8" gauge glass to the inside. The flange bore is .620 and the gauge glass is .625, some sand paper or emery cloth should open the inside bore enough to fit the gauge glass. Sandpaper or etch the gauge glass where it fits inside the tri clover spools and use some loctite green thread lock to seal it to together and it should work. Flanges are about $10 each and the gauge glass should be a couple bucks for 3"-4" piece to make this.

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You might have to draw me a picture, but are you saying to press fit the glass into the tube end of the triclamp ferrule using loctite? And the words "weld" and "machine" especially when talking about SS puts this out of reach of 90% of the DIY community, so that's something I was trying to avoid.

My fear is glass has a lot higher expansion ratio than SS, thinking boom shattered glass should sudden temp changes happen.
Hell I think I sent kladue my injector project when it was completed back in 2010.
Back to the Kodak easy Share POS. Carl.

Hey Klyph, you get anywhere with these yet?

Not really, haven't found any screamin deals on the flanges, so it's hard to put this together at a price point that's worthwhile. I'll email Wayne again and see if he's got any leads.

klyph said:

I'm curious where you guys are getting those 65 dollar sight glasses. $73 was the cheapest I could find.

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http://www.thevintnervault.com/index.php?p=view_product&product_id=1413

What's stopping you from using a x/x" slip-on flange? All you would have to do is find the appropriate size slip-on fitting and thread the inside appropriately. You would need a tap and die set.. I found two different 1/2" stainless slip-on flanges for $12 on ebay. I found one set of two flanges for $14 but that's the "great deal" occurrence.

Any reason why this approach won't work?

I'd be in at $40

Anyone notice this one? http://www.brewershardware.com/Sight-Glasses/

That's a kick ass price but I'm rockin' camlocks not triclovers.

ImperialLover said:

That's a kick ass price but I'm rockin' camlocks not triclovers.

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Sorry, forgot that was part of the goal. I'm doing a bottom dump from a Keggle so either I'd want a 2" ($95 at St Pats) or I'd rather have the 1/2" NPT so I can camlock as well.

Still a great find! I'm sure others will be glad you linked it. Happy drinking!

Yeah with the cheap triclover sight glasses out there, this design is not cost effective.

FWIW...$56

http://cgi.ebay.com/TriClamp-Sight-...141?pt=LH_DefaultDomain_0&hash=item2eb57cbb5d