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

I am not sure which hole, the one in the end cap or the one on top?  I think the one on top is the steam pipe and valve you mention.  The endcap one is the boiler glass like on this jensen 65 https://www.ebay.com/itm/317797614656

Bob

Thanks for providing that detail, Nick, I was really wondering what that big hole could actually be. Didn't know that the German makers made such water sight glass windows back in the day.

Mica windows at that ... WOW!!!

A couple of suggestions.  You might want to find some Borosilicate glass disks that could fit the opening with an appropriate mounting sleeve, or you could try and find a replacement disk from jensen, or other suppliers close to the opening and make a sleeve adaptor as above. 

Either way it would make a fun project, learning a lot.  Even getting a few engines with that type of glass just to see how to make an adaptor that would work correctly.  The use of an O ring might help the seal work better.

Until you had the engine in hand then the solution might follow.  It would be great if you had an actual picture of the engine complete or some who had one.

Hard to tell from the ebay listing what shape the rest of the steam plan is in.  Looks like no burner, May have been a pressure gauge in that open hole on top, and as you pointed out the steam line and stack would need to be made.  Lots small projects, and then a real cool plant, and lots of experience under you belt.

Bob

Nick's photos confirm what I thought. The Ebay one is missing not only the glass but the cover which holds it in place. Plank crimped those covers over what you see in the photo so they are very difficult to remove and replace. Would also be very lucky if an off-the-shelf glass fits. Plank also made this fitting as vertical sight glass--equally painful to deal with. But go for if you like it--maybe we can figure something out.

That's the inner receptacle; cover is gone. I guess both were stamped with the number.

When I get one of these I cringe and just hope it doesn't leak badly. I had to unsolder the whole fitting from the boiler on the long one and used a piece I cut out of lexan as a mica substitute. There should be a discussion of these somewhere on the Mamod forum but hard to search and find things there.

I had this hole saw tucked away in my Amazon cart in case I ever wanted to try and retrofit a Jensen sight glass to some future purchase: https://www.amazon.com/gp/product/B0B3XQFZTR/ref=ox_sc_saved_title_9?smid=AOAWBY89MKXUL&th=1