boiler testing

the burrell i am building is a few years old  so the boiler is out of ticket  i have the origional paperwork   and the boiler is new as not fiddled with  
i am going to get it tested prior to building     does anybody know the sizes of blanks to seal it up   and i presume i will have to fit the cylinder block to seal it up for hydro testing regards tony

You wont need to fit the cylinder to hydraulically test the boiler, the cylinder steam outlets are 7 off 4mm threaded holes so you can fit bolts to seal them as we do at the factory, we use socket cap heads with thinned down heads due to the close location of the holes to each other, do not over tighten these bolts they are threaded into 3mm thick soft copper and you will strip the threads, (apply sealer and leave to set overnight).
The 2 top steam outlets, fusible plug and the water gauge bush are all 3/8" x 32 tpi.
The bushes around the firebox base ring are 5/16" x 32 tpi.
And finally the tube plate bush (we use this bush for applying the test pressure) is 1/2" X 26 TPI
The working pressure of the boiler is 100 psi and we normally test them to 200 psi for a period of around 20 minutes.

Note that a change in pressure reading doesn't always mean your boiler is leaking, a change in temperature like letting the cold in from outside will reduce the pressure inside your boiler as it cools slightly, placing the boiler in sunlight will show an increase in boiler pressure, a drop in pressure can also be your test pump leaking back, so dry your boiler off thoroughly then examine it for water leaks after 20 minutes if you cant find any water on the external surfaces then it isn't leaking, however your boiler inspector may take a different view to this.

Hi, You say it's out of ticket so presumably it had ticket at some point which should have been at twice working pressure. The initial shell test of twice working pressure is only needed once, after that when the engine is built a hydraulic test of 1.5 times working pressure will be needed. Hydraulic testing is stressful on the boiler at the best of times and I wouldn't do it more often than required. Also build the pressure up slowly & release it slowly, with a small engine it would be very easy with some test rigs to put it up to 100psi in a couple of pumps and that won't do the boiler any good. 20psi increments with say a 5 - 8 second gap between would be kinder.