Went to hardware store to buy stuff. Could not figure out how to do 1/4 tubing to 1/2 pipe. Started looking at adapters and elbows and the cost started adding up. Punted the 4 1/2" copper pipes n the center.
Bought 20ft 1/4 OD tubbing for like $9, 1/4" to 1/4" for $3, and 1/4 to garden hose for $4.
Original ideal was to run 10" lengths of copper back and forth vertical in the little 1" center whole of the boiler. I used a 3/4" pvc pipe as my turn guide. Looked nice but maybe a little big. Tried it in the pipe, no way, not even close.
Have brief fealing of wasting 20ft of copper, took the copper and started coiling it around the 3/4 pvc. Was not sure it would kink or not. But it did not (for the most part(if the copper was not already bent from failed attempt above, there would be not kinks)). Made a 10" coil and then reversed direction and made an outer coil around the inner coil. The outer cable lasted about 6 inches.
Now the fun and my maybe dangerous part, putting the coil through the center whole. After a few attempts I was able to get the coil in 9" out of the 10". Wired up the compression fittings (I hate them!) and I think I have a flash boiler.
Tested it a few times to get rid of leaks. One thing I noticed is that the amount of water coming out is not allot and there did not seem to be too much pressure either (aka no 10ft streams) when maxing out the garden hose. So I might have a kink or two in coil restricting something. My concern is not the lack of water, but rather it works too well and I just get steam instead and cant regulate it. Tomorrow I need to make a hole for the garden hose 1/4" out let and maybe test it.
I am think about buying a flat paving stone and put it on top of the coils the in the stove pipe. Maybe drilling a few small holes in as well. On the bottom I will probably have to drill in some screws to support the coils then.