I'm not even going to ask why or how you drilled a hole in a cast iron radiator... I've used JB Weld to successfully and permanently fix cracks in radiators, both hot water and steam, but nothing quite so dramatic as a 3/8" diameter hole. Your best bet, I would think, would be a mechanical plug. Go to a heating supply store that handles goodies for radiator systems and see if they have tapered plugs used to cap holes in radiators that have been either moved or renovated or converted from steam to hot water or vice versa. My guess is that you're going to find something that will work. You'll have to ream a tapered hole to match the plug and then tap threads into it. All in all a pain in the butt, but a LOT easier than trying to braze it.

It can be done, but it really should be done by someone who knows exactly what they're doing and who has experience in working with old heating systems. Probably the easiest thing to do would be to remove the radiators, pull out the floor boards, put new over-length stubs on the pipes, and then relay the floor. When you have the final floor in place, you can have the plumber or heating person back in to trim the stubs to the proper length and reattach the radiators.

Hello to you all. I have been meaning to drop in and give you an update on the performance of our new Triangle Tube Solo 300 boiler. Having read all the posts, I can reaffirm that the cast iron rads will never be really hot as they were with our old 1919 steel boiler but the heating is very satisfactory. We have an 8 unit apartment building four storeys high and I am at the top of the building. I keep the thermostat which is installed in the hall of my unit at 21 Celsius which is the law here in Toronto for heat temperature of Apartment buildings. At night, thermostat goes down to 19 Celsius till I get up at six am. On the first, second and third floors, rads are hotter than on the top floor, This puzzles me but I figure that once the stat hits 21 Celsius, the pump or whatever kind of slows down so my long living room cast iron rads only get heated all the way across when it is really cold. We have the reset outdoors and the little boiler is a marvel. It sits on its little steel table in the old boiler pit and is so quiet. It vents a light warm vapour, no smell, out the side of the building. We are awaiting the first natural gas bill. I will keep you informed of savings over last year.

Look at the Myson toe kick heater. They have the best product out there. We took out a 6 ft cast iron radiator this past fall in our kitchen remodel. I called Myson directly and got their advice as far as sizing. You purchase the heater and the extra components from Home Depot. It is very inexpensive !! Don't let that deter you. It is amazing ! Quiet and very efficient. I love that thing and am so glad we did it. Your plumber will hook up the " in/out " to it and when your boiler kicks on and the temp of the water reaches the setting...I think 90 degrees the blower comes on. Remarkable quality for the price. c