Boiler is getting close

[grege]

I'm getting closer to finishing this thing!
I was waiting for more solder and bronze rod to finish the side stay-bolts so I thought I'd get all the plugs and fittings done for pressure testing.
I decided to pump it up to just 50 psi and see what leaked so I could fix at least a few spots before doing the stay-bolts. There were 4 weeps- two at brass fixture screws that I had filed flush, and one pin prick each at the front and back. They screw threads didn't have full solder penetration below the head. Later in the process I have left the screws alone, and I'll have to decide whether to file them all off flush or not.



Prelim low-pressure test 1 by gregeaster, on Flickr

[kvom]

looks good!

[daveb1]

Hi Grege, it certainly is looking good. I'm about to start the boiler on the new shay. Priced the bronze and it is expensive. Where are you getting your bronze and what type are you using. keep up the great work.

Dave

[pkastagehand]

Lookin' good! I've not bought very much of the bronze yet and have been delaying the copper purchase because of the price... guess I'll have to bight the bullet one day.

Paul

[grege]

Thanks guys.
I got some from McMaster, some from Online Metals depending on price and availability.
I too waiting until the last minute before settling on where to get the big rod for the cylinders and steam dome.
I'm more carefree with the smaller sizes, but for the big stuff- plan your use carefully. It may make sense to turn an out-of-sequence part from the same chunk so you only have one chucking allowance left over. I've been labeling my big stock with a sharpie too so I don't inadvertently use it for something else.
The big brass, bronze, and copper are expensive, but the number of hours going into some parts produces a pretty low $/hour of fun.

[grege]

I had some time on Sunday to finish making side-stays and solder the heads on both sides.


Soldered side-stays by gregeaster, on Flickr

[grege]

Done!



Success! by gregeaster, on Flickr

This has been an intense week of ups and downs trying to fix the little weeps. Each time I soldered, new ones would open up! Particularly on the front tube-sheet I think because of differential expansion it was cracking the solder joints. Probably if I would have added solder to all three the first time, they would have all melted and settled down together. The final trick to get the last couple of weeps was to use a punch or small flat screwdriver blade and lightly hammer to push adjacent metal against the weep. I read about that in Model Engineering a few weeks ago. I didn't remember though until after several rounds of soldering, and probably could have saved some heartache by using it sooner.
I had a serious heart-in-throat moment though testing it today. Everything looked great, but then a slow drip started out of the steam line on the front tube-sheet! I was sure that in all the leak fixing I had opened a gap at one of the joints inside the boiler. I let the pressure down and started to take out the plugs in despair when I realized that it could have been a problem with the gasket under the blanked-off steam dome- water creeping over to the steam line from one of the safety valve holes. I took out the gasket and sealed it up with a thin application of RTV gasket paste. I could only wait for it to dry for 3 hours instead of 24 before re-testing. It did start to dribble again at 200psi, but then stopped after a minute! Maybe the paste squeezed over and stopped it? I kept the pressure high for 20 minutes and it didn't start again so I'm assuming that was it. The throttle body is a much thicker piece and should seal more uniformly than my thinner cover.

Its been quite a trip and I'm excited to move on and talk to the club boiler tester about making this official.

[phutcheson]

Grege,


Now this is a real nice looking boiler ...

I really like your new cost analysis ... $/hour of fun. Excellent idea, put things in a much better perspective.


Hope to see more and keep up the good work and progress reports.


Thanks,

Pat H