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

I have had this discussion before it probally  is not dezinc. But rather leaking via desoldering .
I have had a few wilesco boiler here and repaired because of poor manufacturing design
The sight glass is held in place via  the end plate .
The problem is the piece the endplate bolts to is soldered to the boiler end cap  and the surfaces are not flat to each  other thus instead of 3 or 4 mm join only 1 mm
A easy enough fix .

I can draw a picture to explain later to show what i am talking about .