For those of you that have windowed sight glass on a Jensen boiler such as on a Jensen 50, or a 75, or 55, etc; I have experimented with probably 20 different ways to get the “perfect” seal; while others have worked to 95-99% seal with only “slight to minor” leakage, this is a complete seal that I found works so well there isn’t even a slight steam leak.
While I find all Jensen products made well, the windowed sight glass wing nuts just don’t prove enough even with their flimsy paper gaskets… and I know we’ve all tried the dollar bill gaskets which prove very effective but not 100%.
If you follow these steps in the exact order you will achieve a perfect seal that lasts months or years.
From inside to out:
Dollar bill gasket
Paper Jensen gasket
Glass (wrapped in PFE tape around edges, 3 wraps.)
Dollar bill gasket
Paper Jensen gasket
Wing nut (wrapped clockwise with PFE tape, 3 wraps)
Tightened down until no longer able to tighten. What’s also best, is the PFE tape prevents rusting and corrosion. Can change out the PFE tape 2-3x a year for maintenance.
After doing this you’ll have alot of stringy material in the window. Just clean it up, then use a blow torch (small) to touch up the excess strings, but only for brief seconds to not crack your sight window.
Steam it up, you’ll see how amazing the seal is.
PS- put a drop of oil in the threads before placement! [ Guests cannot view attachments ]
I've had good luck with a #20 O-ring. Place it in the window seat, center the glass, then tighten the ring till you feel the O-ring give some. I've never had one leak and some have been in there for years. Also, if you have to remove the ring, no problems getting it off since it wasn't on there very tight.
A single teflon gasket from Teflon sheet also makes a perfect seal. Doesn’t burning Teflon give off a deadly fume? Oliv on the Mamod forum has posted warnings about that…
Nice discovery work there, Travis.
I have found (thanks to IndianaRog and Randy Calhoun) that making gaskets from a sheet of teflon works perfectly and will last forever or close to it.
This photo is of the Prototype Jensen 51 built by Randy Calhoun which has over 8,000 hours on it.
Randy originally called it the RC-50 Power Station #1 and when he showed it to Tom Jensen Sr. who asked him to produce a few of these as the Jensen #51 Power Station. The site glass windows don't leak and have had the teflon gaskets for decades.
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This is the Teflon gasket material I use. It's soft and seals easily. It's thicker than the paper gaskets or the hard Teflon gaskets so two of them with the sight glass will put the boiler nut flush with the edge of the threads but that's never been an issue.
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Only downside with this stuff is that it's difficult to cut with a knife so you really should punch it out. I had to make a larger punch for this set for the boiler glass.
A single teflon gasket from Teflon sheet also makes a perfect seal. Doesn’t burning Teflon give off a deadly fume? Oliv on the Mamod forum has posted warnings about that…
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As long as your Jensen boiler never runs dry, the gaskets will never burn.
I’m talking about Travis burning the strings of teflon tape off with a torch. I make the same teflon gaskets for my porthole glasses that you do as well.
The warning Oliv gave is that burning it can actually kill a person.
A single teflon gasket from Teflon sheet also makes a perfect seal. Doesn’t burning Teflon give off a deadly fume? Oliv on the Mamod forum has posted warnings about that…
.
As long as your Jensen boiler never runs dry, the gaskets will never burn.
I’m talking about Travis burning the strings of teflon tape off with a torch. I make the same teflon gaskets for my porthole glasses that you do as well.
The warning Oliv gave is that burning it can actually kill a person.
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I suppose I'd be more concerned about letting a coated frying pan on the stove with nothing in it for too long.
I missed the part about burning away excess with a torch.
Excess teflon tape is better dealt with by the use of a sharp blade.
I also thought the same thing about frying pans as I have a gas stove, but when he seen us using these gaskets for SV’s/whistles, he put out all kinds of warnings. Some of us use the teflon for whistles/sv’s on flame fired Jensens where the flame can come up around the boiler and touch the gasket. He made posts about machinists who after machining teflon had a little dust on their fingers and when lighting their cigarettes ended up dying from the powder burning, don’t know if that would happen with the teflon tape, but Oliv was sure worried about us all using it.
I also prefer to use a Hobbico (or similar) circle cutter and about .015" - .020" thick Teflon sheet to form my round Jensen sight glass gaskets. I do use punches for the smaller washers for SV, Whistle and Banjo fittings. When properly done, there's never any leaks, and they last indefinitely!
It seems like I have run across a warning to not even cook in Teflon coated pans, if you have a pet Cannery, as they probably won't survive it anywhere in the same house, so perhaps Olivier's concerns are not misplaced!
Good thing I don’t do a lot of cooking 😂
From a distant memory it was Rog (Temple of Steam) who advocated the use of US $1.00 notes as very satisfactory gasket material because they are made from cotton and silk (if I remember correctly).
The dollar bill was for tighter fitting areas like between the boiler and engine base of the 35 or under the steam domes.
The dollar bill was for tighter fitting areas like between the boiler and engine base of the 35 or under the steam domes.
Well I got that memory wrong Nick, I used to really like Rog's site and all the helpful hints he had (which was many!).
The dollar bill was for tighter fitting areas like between the boiler and engine base of the 35 or under the steam domes.
Well I got that memory wrong Nick, I used to really like Rog's site and all the helpful hints he had (which was many!).
I believe Rog got the dollar bill gasket tip from me. It is .004" thick and very strong. They are perfect for replacing gaskets on a #20 or 4 screw cylinder #10/25 cylinder. Great for all other flanges and any place a thin sturdy gasket is needed.