I gotta admit, building this boiler has been kicking my butt. So far this has been the most frustrating part of the build for me. But I am trying to get through it. I did learn to fill the gaps with acrylic nail polish mixture, which provides a very hard surface and when sanded gives great results.
(http://largescalecentral.com/FileSharing/user_6229/CP%20Huntington/B1.jpg)
(http://largescalecentral.com/FileSharing/user_6229/CP%20Huntington/B2.jpg)
Tommy
Rio Gracie