sufficient, hit the pin a side blow in order to loosen it, and turn the
expander about one-quarter of a turn, and drive it up as before; loosen
up and continue to turn as before until you have made the entire circle
of flues. Then remove the expander, and you are ready for your header
or calking tool. It is best to expand all the flues that are leaking
before beginning with the header.

The header is used by placing the gauge or guide end within the flue,
and with your light hammer the flue can be calked or beaded down against
the flue sheet. Be careful to use your hammer lightly, so as not to
bruise the flues or sheet. When you have gone over all the expanded
flues in this way, you, (if you have been careful) will not only have a
good job, but will conclude that you are somewhat of an expert at it. I
never saw a man go into a firebox and stop the leak but that he came out
well pleased with himself. The fact that a firebox is no pleasant
workshop may have had something to do with it. If your flues have been
leaking badly, and you have expanded them, it would be well to test your
boiler with cold water pressure to make sure that you have a good job.

How are you going to test your boiler? If you can attach to a hydrant,
do so, and when you have given your boiler all the pressure you want,
you can then examine your flues carefully, and should you find any
seeping of water, you can use your beader lightly untill such leaks are
stopped. If the waterworks will not afford you sufficient pressure, you
can bring it up to the required pressure, by attaching a hydraulic pump
or a good force pump.

In testing for the purpose of ascertaining if you have a good job on
your flues, it is not necessary to put on any greater cold water
pressure than you are in the habit of carrying. For instance, if your