Happy New Year.
I asked this question on the Steppir Yahoo Group but didn't get an
adequate answer. I'm probably being way too compulsive but I'll ask
it here since there are so many experienced members.
I'm going to be preemptively painting my new DB18 with the marine
topside paint recommended by several Steppir forum members. This
sounds smart since the San Diego sun can be brutal to fiberglass and plastics.
I was concerned because the light blue "Blue Ice" Pettit Easypoxy
Topside Paint color I purchased contains 35% titanium dioxide and 10%
aluminum dioxide. Both the Pettit and Interlux brands of marine
top coat in any of the light colors seem to have quite a bit of the
Ti02. Even Medium grays have Ti02 as well as carbon black. Browns
have iron oxide. In fact the only marine paint which doesn't have any
metallic sounding ingredient is Pettit 3350 Easypoxy Kelly Green
Topside Paint. Could that be why Steppir chose the green color for
their fiberglass??
So here is where I am at. I wonder if my 4 tests with "Blue Ice"
marine paint were adequate to insure minimal interaction from the
paint? Your ideas welcomed.....
Test 1) I painted 6 inches of an 8 inch piece of 1" white PVC,
allowed it to dry for a day and placed it in the microwave along with
a small cup of water. I waited until the water boiled. The coated
PVC remained cool and was the same temp as the uncoated area.
Test 2) I coated a 30 inch piece of 1" PVC and allowed it to dry. I
used a dual band VHF/UHF magnetic whip on my car and measured the
signal strength of various distant repeaters. I then placed a plain
piece of 30" PVC over the entire whip and repeated the tests. Signal
strengths were all pretty much the same with a couple of weak
repeaters showing up to one S unit less than the bare tests. I then
tested with the coated PVC. There was no difference in any signal
levels between the uncoated and coated PVC.
Test 3) I put two copper probes into water and measured
resistance. It measured between .3 and .5 megaohm. I then put the
two copper probes directly into the liquid paint and got zero
resistance on all meter scales.
Test 4) I glued three strips of copper on an 8 inch piece of 1"
white PVC. The strips had a separation of 1/4 inch. Each strip had
a wire lead soldered to it. I then painted over the entire tube and
let it dry for a day. I could get no DC resistance measured between
probes. I then placed 117VAC across the two outer probes. I tried
to measure any leakage to the center probe and was not able to
measure any voltage.
So pretty compulsive, huh? Have I proven anything here or just
created a false sense of security? I figure that paint is much less
reactive than water. We know you can get electrocuted in a bathtub
and that rainy weather changes our SWR. I figure that marine paint,
even if it has metallic sounding compounds in it (short of metallic
flakes like some auto paints!) is OK for the Steppir.
73, Howard W6HDG
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