Your compressed air system is often taken for granted even though it is the workhorse of your shop;
providing power for nailers, sanders, sprayguns and other equipment. Most of the time you don’t give
it a second thought until it stops working and your operation slows to a crawl. Since compressed air is
the lifeblood of your finishing system it is imperative that you supply your equipment with clean dry air or
problems will surely follow.
Summertime’s high humidity levels can be a potential problem in your compressed air system. The
process of compressing air generates a lot of heat and this heat causes the water in the air to condense
in the tank, air lines and hoses. This water can directly enter your coating from the atomizing air at your
spraygun and cause blushing. Since there is also a fair amount of oil in the water this could lead to a hazy
bluish cast to your finish called bloom. If your tank or filters don’t have an automatic drain feature it is
a good idea to manually drain these items frequently throughout the day to help keep water out of your
finish and your tools.
Check to make sure that your piping system is pitched to one end with a drop leg fitted with a valve so
that any water that accumulates in your piping will flow downhill to this point and can be drained. Plastic
piping can be problematic because it will often droop between supports and water can accumulate in
these bellies and then suddenly blow out when they reach a high enough level. All of a sudden you have
a handful of pieces with bloom or blushing and then the problem is gone. This will happen sporadically
which makes it hard to troubleshoot the cause of the problem. Long air hoses can also be prone to this
type of problem.
During this time of year it is a good idea to take a little time and perform a little compressor maintenance.
Blowing out the compressor’s air filters and changing the oil, yes you can actually change the oil, will
make your compressor run cooler and reduce the amount of water that it produces. It will also make the
machine last longer and use a little less electricity. Write down the date that you changed the oil on a
piece of tape and stick it next to the compressor’s on/off switch. This will give you a little reminder every
time that you turn on the compressor of just how long it has been since you actually performed some
maintenance on this very important piece of equipment.
Another finishing tool that is directly affected by the quality of your air supply is your pneumatic sanders.
Yes a little bit of oil in the compressed air will make the sander run smoother, but water in the air can
spray out the exhaust port of the sander and on to the wood causing the evil fisheye. The water can
also cause the sanding dust to clog the sander’s exhaust filter which will slow the sander down and
potentially lead to swirl marks. Most sanders have either a felt cylinder or a cone shaped bronze filter
in the exhaust port. You can simply remove the filters for servicing. Blow out the felt filter with your nice
clean compressed air; the bronze filters can be soaked in a little lacquer thinner to soften any residue
and then be blown out while holding the filter in a rag to contain the overspray. Just a couple of drops of
light weight non-detergent oil in the air intake of the sander will make it run like a champ. You should oil a
sander after every couple of hours of use, but don’t overdo it.