How to attach a sight glass?

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blockmanjohn

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Hi,

I am putting together a brass gas tank that is 1 1/2 inches in diameter. I would like to make one end out of glass. I am wondering what would be the best way to glue the glass to a brass ring that would be soldered to the tank end. I was thinking of silicone, but I don't know if it would hold up to the gasoline.

Any one have any experience with this?

Thanks, John.
 

Peter Twissell

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I wouldn't try to solder the ring in place after gluing the glass to it.
My preference would be for a mechanical joint, with an O ring sealing the glass to the tank end and the glass held in place by a retaining ring, all held in place by some studs on a PCD.
 

blockmanjohn

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Thanks for the reply Peter,

For what it's worth, I planned to glue the glass to the outside of the ring after it was soldered. Also, I'm not sure what a PCD is.

Thanks again, John
 

Brian Rupnow

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I have done this. Contrary to what you may hear, J.B. Weld is not effected by gasoline nor coleman fuel. It stands up fine and does not soften or lose it's ability to hold parts together. Machine a brass or aluminum ring and use J.B.Weld to glue the glass into it, then use it to glue the machined ring into the ends of the tank.---Brian
 
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Peter Twissell

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PCD is a pitch circle diameter. It describes a series of features arranged in a circle, such as a ring of screws.
 

cheepo45

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I glued a watch crystal to the end of the tank on my Jan Ridders Debbie engine with Gorilla super glue 4 years ago and it still doesn't leak.
Just be sure everything is really clean before you glue it.
Don't use silicone sealer-it will leak.
Scott
 

blockmanjohn

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Does anyone know where I can find a 1 1/2 inch clear glass disk? All I can find are disks that are textured on one side.

Thanks, John.
 

WOB

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IMHO Loctite 609( or similar) is a better choice for sticking the ring to the tank. You don't need any clearance for epoxy in the interface. A snug to .005" clearance fit with a short overlap will work well.

WOB
 

Brian Rupnow

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Find a local watch repair shop. They will have an assortment of clear glass discs.- You don't have to leave a large clearance for j.b. weld. A sliding fit is just fine. Loctite isn't good a filling voids or gaps. ---Brian
 

bluejets

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Hi,

I am putting together a brass gas tank that is 1 1/2 inches in diameter. I would like to make one end out of glass. I am wondering what would be the best way to glue the glass to a brass ring that would be soldered to the tank end. I was thinking of silicone, but I don't know if it would hold up to the gasoline.

Any one have any experience with this?

Thanks, John.
Instead of a complete end of glass, perhaps a couple of angle nipples soldered into the tank, one top, one bottom and a piece of clear plastic tube in between.
Did this on my scale Rivierra boat.
 

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ozzie46

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Lexan works great for the tank end gasoline will not harm it.

Randy
I used lexan,(at least thats what Lowes said it was), and it became so cloudy I can't hardly see thru it.

Ron
 

awake

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As I understand it, Lexan is a brand name of polycarbonate ... and polycarbonate has poor resistance to gasoline or other aromatic hydrocarbons. Acrylic (plexiglass) actually does better with gasoline, from what I can tell - but I hasten to say that I am no expert!
 

bruedney

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Here is my gas tank for my Rupnow IC engine



It is thick walled Ali tube - Internal thread and watch glass and thin oring captured by retaining ring

Works great
 

Balta

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Policarbonate will become brittle in the presence of hydrocarbons (gas, oil, etc).
 

R Degen

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awake

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Oh, the power of the internet - it can provide contradictory information faster than I can blink! Now I don't know what to think, since we have an apparently authoritative site saying PC has good resistance to gasoline, but I looked up several sites saying it had poor resistance to gasoline. Here's one that I found just now: http://kmac-plastics.net/data/chemical/polycarbonate-chemical.htm#.XiMQ66ZOkXA

The proof is in the pudding, as they say ... but even above we have two different outcomes when people have tried it. Perhaps each person was *sold* PC, but one of them actually received something else - ?
 
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