[TowerTalk] Painting the fiberglass and loops on a Steppir- advice needed

[Patrick Greenlee]

Brace yourself and put on your flame proof long handles. You may be 
about to be buried in a swarm of replies reminding you that measuring no 
conductivity is NOT measuring no resistance.  Reading an open is no 
conductivity. ...just sayin'
On 1/4/2015 1:28 PM, Joe Ciarcia wrote:
> We painted a 4 ele stepp-IR with marine topside paint purchased from
> Lowe's. It was green and probably
> made by Pettit don't remember. Anyway a check with the manufacturer
> confirmed no conductive content.
> No effect on the antenna tuning was apparent (this was an older antenna).
> Paint is holding up well.
> 73, Joe K1JC
>
> On Sun, Jan 4, 2015 at 12:38 PM, Howard W6HDG <W6HDG at arrl.net> wrote:
>
>> 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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