Hi Tom,
Here's a couple of observations regarding the condensation:
1. A 60 watt bulb will generate quite a bit of heat. It will also die an
early death IF you run it at full voltage. Try a 100 watt bulb, but instead
of connecting it directly to the line, install a 3-amp, 200 volt diode
(Radio Shack P/N 276-1143, $1.39) will work just fine) in series with the
hot (black wire or brass screw) lead. What this does, is only allow 1/2 the
voltage to flow through the bulb. The bulb burns a bit less than 1/2 bright,
and much more red in the spectrum. It also REALLY lengthens life. Had a yard
light that would blow a bulb everytime I hit the post mowing the lawn, or
even if the paper delivery person kinda bumped it with their sack of papers.
I was getting 2 weeks max on a bulb. Installed the diode, bulb was going for
over two years (may still be going, we sold that house and moved). By moving
from a 60 watt bulb to a 1/2 lit 100 watt bulb, you are losing just a little
bit of heating, but the bulb will last longer.
2. Condensation is a problem in many areas. One difficult area was on the
radar indicator on several different classes of Coast Guard Cutters and
small boats. The "old" equipment was full of tubes, and never had a bit of a
problem, but the new solid state radar indicators (well, except for the
cathode ray display) had severe condensation problems. First attempt was to
seal the indicator up ... which fails because when you heat the sealed box,
it's pressure goes up and will blow past the door seals. When it cools back
down ... yep, creates a vacuum which draws in damp air, and the effect is a
very nicely sealed box full of water.
The answer there was to install a heater strip ... looked all the world like
a power resistor, but was designed to conduct heat both to the chassis where
it was mounted, and to the surrounding air. If the light bulb test works and
you want to eliminate the dangers of a broken bulb, you may want to look
further into this possibility.
3. The simplest answer may simply be to get one of those double jointed
drafting table lamps, and simply turn the lamp on and put it close to the
top surface of the equipment you're working to protect. Put a fairly small
bulb (25 watt) and move the lamp real close ... and you'll heat the top
surface. Might need two lamps, but I think they're what ... $8.95 each (
http://www.draftingequipment.com/DEW...ombo&swing.htm )
.... that's the name ... swing arm lamp. This has several benefits ...
first, it's cheap. Second, you can use the lamps in the shop for spot
illumination when needed. Third, you won't forget that you left a lamp on
that's buried inside the cabinet. Fourth, it's cheap. Fifth, you'll be able
to adjust the lamp position for optimal heating (without overheating) ... so
you don't dry out the lubrication on the trunion and tilt assemblages.
Sixth, it's CHEAP!
It sounds like you were measuring the air temperature immediately above the
table, and not the table surface temperature. An infared pyrometer is just
the ticket, but at about $300.00 for a good one ... probably more than you'd
like to spend for a one-shot deal. If you have an electronic thermometer ...
one for cooking (it has a nice wide range as opposed to a digital
oral/rectal thermometer (1) that has a very narrow temperature range) you
can make direct contact with the surface and read the temperature. Mark
several spots on the table surface by circling the area with a pencil, and
measure the temperature at all of these points everytime you need a sample.
Averaging the temperatures will give you an overall indicator ... likewise,
mapping the temperatures will give you a reasonable temperature gradient to
help determine if you are heating a localized spot, or diffusing the heat
throughout.
HTH
Rick
Who will get back making sawdust "Real Soon Now"
(1) I don't EVEN need to go there!
"Tom Watson" wrote
Since I was going to be spending the whole day gluing up slabs for RP
doors, which is boring as hell, I decided to try a test of the idea I
had about using a light bulb inside of the machine cabinets to ward
off condensation and rust.