Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

Am I even close to thinking about getting a few feet of PTFE Tubing? Something like 1/8 ID with a 3/16 OD?  I am horrible at this kind of stuff.

I agree, Teflon tape is 100% messy and arduous!  Just finding the correct IDxOD diameter will be the trick.  I have some that is good for the ID but way to much for the OD.  Perhaps I could get lucky at Lowe's...

As for cleaning, yep I have that one covered.  Though on this little guy the seal was almost still rubberish - the older Empire seals are like harden clay and take ages to get cleaned out (lots of chasing the treats with my jeweler's screwdriver).

Good morning from Brooklyn...

  Sorry to hear of your uncooperative sightglass.
I tried a steamup of my latest, a Weeden 58 I
purchased on EBAY.  The boiler sightglass end has
a bit of a drip and quite a bit of steam was leaking
from the sightglass.  I'm hoping all the drips
came from the sightglass steam.

  In the past, if a proper sized bit of silicone
tubing is unavailable, I take Teflon tape and
twirl it into a string.  If the area it is for is
on the larger size you might double it over before
twirling.  Just wrap several times around the
glass tube end, pull the nut against it, tighten,
and cross your fingers.  Most times it works.
If not, try again.  I'm just waiting for my
leaker to cool so I can remove the sightglass
and see what's up.

Good Luck,
Wayne

  I suggest the 1/4" od tubing.  That is what I had laying around
the last time I fixed an Empire sightglass.  I wasn't sure it
would be ok, boiling water didn't hurt the tubing, so I gave it
a try.  Just a tiny bit of a weep that didn't even drip, so that
worked. 

  The last time I used twisted teflon tape was on a Marklin sightglass
and that worked pretty near perfectly.  I also used it as a ring on an
Elektro engine piston and valve-rod with some success.  Those Elektro's
tend to have a lot of blow-by - IMHO, bad engineering, but I love 'em.

Good Luck,
Wayne

All the tubes I got from Amazon are a bust, the Lowe's ID .170" and OD 1/4" Vinyl with reinforced with Teflon tape is the winner.

What I tried:
1. PTFE Tubing 5mm ID x 6mm OD, complete failure, I more or less expected this.
2. Silicon Tubing 3/16" ID x 5/16" OD, complete failure (as Wayne suggested no more than 1/4 OD and the ID was to big too).
3. Silicone Tubing - 1/8" ID x 1/4" OD, almost worked but it didn't seem to be 1/4 OD (smaller) and the 1/8 ID was way to tight to get on the fitting's nipple or glass.  This might have worked if the ID was a bit larger, perhaps the glass tube would have pushed it out a bit.

So I remade fresh Lowe's tube and wrapped it with some Teflon.  Fully heated up and engine running at the lowest possible speed (stack really bubbling over) zero water/steam from sight glass.  I guess this will be my go to for this size sight glass.  At least it was a under $30 experiment...

Going to try two more options, silicone O-Rings.  Which I do use doubled up O-Rings for the older engines (like B30) but their glass tube is larger and the tube slides into the fitting.  Perhaps these doubled or tripled up will work: they are 6.5mm OD, 3.5mm ID, 1.5mm Width but I think the ID might be to small - unless they stretch pretty good.  The more I think about this approach with these o-rings, the more I think it isn't going to work.

Next up is a 3/16" ID x 1/4" OD High Temp Silicone Tubing I found on a site called ZerksPlus and assuming it hugs the sight glass tube enough it could work.  For the "newer" Empire engines with the smaller tube I believe it is important for the seal to start on the glass and end on the fitting's nipple.  Since the glass rests on the fitting's nipple and doesn't go inside the fitting (like older/larger engines).

Also, I am not 100% sure you would call this sight glass 1/8.  It's just a hair over 5mm.  I am attaching photos of my calipers messuring the glass tube for US fractions, US inches, and (real people) metric.  A 3/16 diameter is 0.188 inches or 4.78 mm.  If anything I hope it is better than that hard stuff I am using from Lowe's that I have to stretch on my screwdriver first.

Okay, I did the worst Empire in my collection, this little 90 was in horrid shape.  The tank leaked and then the fittings fell out because the previous owner soldered them into the tank for some old damage - basically the sight glass area is a basket cake.

Successful seals!



PS: @St Paul Steam thank you for the whistle topper(s).