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Old September 14th 05, 02:25 AM
Bob Bob
 
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Default

One of the tricks I learnt early on with RTV sealant in medical
ultrasound water tanks is if you wet the surfaces with water and a
detergent wetting agent the sealant wont actually adhere to the
prewetted surface. Kind of handy if you wanted to force the sealant into
a clearance slot and remove it later.

Or was it oil? Damn I cant remember! I know kerosene is used to pre the
surface for better adhesion...

How about paper/masking tape over the gaps and spraying with that gluggy
sealant you use on sink drains?

Probably not very useful thoughts, sorry!

Cheers Bob W5/VK2YQA

Dan/W4NTI wrote:


Maybe ... get some axle grease, or RTV sealant would be better, perhaps.
Both should peal off reasonable well.

One other thing I am concerned with tho. I always heard that the rotar
must be kept in a vertical position or the grease would drain out of the
bearings? Wives tale ??? I don't know. But I always keep mine vertical
when stored.

Dan/W4NTI


  #2   Report Post  
Old September 14th 05, 02:40 AM
Marshall Goldblatt
 
Posts: n/a
Default How to weather-seal an upside down Tailtwister rotor?

Dan/W4NTI wrote:
"Marshall Goldblatt" wrote in message
...

Hello all,

I have a Tailtwister (TX-2) rotor mounted on a Rohn 25 foldover tower.
While the tower itself appears to have survived intact, hurricane
Katrina snapped the mast and destroyed the antennas. I need to fold the
tower over to work in it, and likely leave it folded over for a fairly
extended period. This will leave the top of the tower and the rotor
upside down. Unfortunately, it is still the rainy season here, and the
last time I needed to do this, rain water got into the rotor and settled
in the bell, causing rust and other corrosion damage inside the rotor,
because it is only weather protected when it is upright. I would like
to seal the rotor to prevent this from happening again, but none of the
ideas I've had so far (wrapping it in plastic garbage bags, using duct
tape, using sealing foam) are usable, either because they don't seal
well enough to keep water out or because stuff may get up inside the
rotor where I can't get it out.

So, does anyone have any suggestions?

73, Marshall - W4EMB




Maybe ... get some axle grease, or RTV sealant would be better, perhaps.
Both should peal off reasonable well.

One other thing I am concerned with tho. I always heard that the rotar
must be kept in a vertical position or the grease would drain out of the
bearings? Wives tale ??? I don't know. But I always keep mine vertical
when stored.


Don't know about that, but there's no way to keep the rotor vertical
when lowering a foldover tower... In any case, it's been folded over
(for long periods) many times, and I've never noticed a bearing problem.
  #3   Report Post  
Old September 16th 05, 06:04 AM
Brian Kelly
 
Posts: n/a
Default


Marshall Goldblatt wrote:
Dan/W4NTI wrote:
"Marshall Goldblatt" wrote in message
...

Hello all,

I have a Tailtwister (TX-2) rotor mounted on a Rohn 25 foldover tower.
While the tower itself appears to have survived intact, hurricane
Katrina snapped the mast and destroyed the antennas. I need to fold the
tower over to work in it, and likely leave it folded over for a fairly
extended period. This will leave the top of the tower and the rotor
upside down.


Fold the tower then cut the rotator loose and store it indoors . . . ??


w3rv


Unfortunately, it is still the rainy season here, and the
last time I needed to do this, rain water got into the rotor and settled
in the bell, causing rust and other corrosion damage inside the rotor,
because it is only weather protected when it is upright. I would like
to seal the rotor to prevent this from happening again, but none of the
ideas I've had so far (wrapping it in plastic garbage bags, using duct
tape, using sealing foam) are usable, either because they don't seal
well enough to keep water out or because stuff may get up inside the
rotor where I can't get it out.

So, does anyone have any suggestions?

73, Marshall - W4EMB




Maybe ... get some axle grease, or RTV sealant would be better, perhaps.
Both should peal off reasonable well.

One other thing I am concerned with tho. I always heard that the rotar
must be kept in a vertical position or the grease would drain out of the
bearings? Wives tale ??? I don't know. But I always keep mine vertical
when stored.


Don't know about that, but there's no way to keep the rotor vertical
when lowering a foldover tower... In any case, it's been folded over
(for long periods) many times, and I've never noticed a bearing problem.


  #4   Report Post  
Old September 16th 05, 03:59 PM
John Ferrell
 
Posts: n/a
Default

I am not sure I understand the question. I think you have the rotator
upside down on the tower at the moment. If it went through some
weather, it is probably full of water now. The way I would handle the
problem is to remove the rotator from the mount and hang it on the
tower (clothes hanger wire) right side up. I would hang it there for a
few days to drain & dry out. When it comes time to reinstall the
antennas, test the rotator for proper operation. Chances are that it
will be OK. If you seal it tight, the moisture will be sealed in.
These things are intended to be able to breathe!

If removing/replacing the rotator is a major hassle, I would either
send it to one of the maintenance guys or put up a new one & sell the
old one on ebay WITH the explanation. There are lots of us who have
setups that are easy to change.

If the rotator must be left in the inverted position outside for an
extended time I would wrap it in black landscape plastic and duct tape
to prevent more water from entering while leaving the bottom of the
plastic open to dry out.

On Tue, 13 Sep 2005 20:25:25 -0500, Bob Bob wrote:

One of the tricks I learnt early on with RTV sealant in medical
ultrasound water tanks is if you wet the surfaces with water and a
detergent wetting agent the sealant wont actually adhere to the
prewetted surface. Kind of handy if you wanted to force the sealant into
a clearance slot and remove it later.

Or was it oil? Damn I cant remember! I know kerosene is used to pre the
surface for better adhesion...

How about paper/masking tape over the gaps and spraying with that gluggy
sealant you use on sink drains?

Probably not very useful thoughts, sorry!

Cheers Bob W5/VK2YQA

Dan/W4NTI wrote:


Maybe ... get some axle grease, or RTV sealant would be better, perhaps.
Both should peal off reasonable well.

One other thing I am concerned with tho. I always heard that the rotar
must be kept in a vertical position or the grease would drain out of the
bearings? Wives tale ??? I don't know. But I always keep mine vertical
when stored.

Dan/W4NTI



  #5   Report Post  
Old September 16th 05, 04:41 PM
Ted Goldblatt
 
Posts: n/a
Default

John Ferrell wrote:

I am not sure I understand the question. I think you have the rotator
upside down on the tower at the moment. If it went through some
weather, it is probably full of water now. The way I would handle the
problem is to remove the rotator from the mount and hang it on the
tower (clothes hanger wire) right side up. I would hang it there for a
few days to drain & dry out. When it comes time to reinstall the
antennas, test the rotator for proper operation. Chances are that it
will be OK. If you seal it tight, the moisture will be sealed in.
These things are intended to be able to breathe!


The tower is currently up (the mast broke above the rotor, so all the
antennas are dangling by their feedlines, but the tower itself is OK)
and the rotor is in its normal upright position. It will be upside down
when the tower is folded over to work on. As far as I know, the rotor
is fine right now.

If removing/replacing the rotator is a major hassle, I would either
send it to one of the maintenance guys or put up a new one & sell the
old one on ebay WITH the explanation. There are lots of us who have
setups that are easy to change.


Don't understand this. Yes, removing/replacing the rotor is a hassle,
largely because it has to be done with the unit upside down, and
standing at the top of a ladder. But that isn't the issue here - in
fact, there is no obvious reason to remove the rotor at all, since it
seems intact. Just remove the stub of the broken mast from the thrust
bearing and put a new one in. The issue is that while that is done, and
the new antennas are mounted, and new (or repaired) feedlines are run,
and all the antennas are tuned, the tower will need to be folded over,
with the rotor mounted, and these steps will almost certainly take
several days. Because of availability of helpers reasons, this will
likely have to be on weekends, meaning the tower will be folded (and the
rotor inverted) for a period of at least 1 to 2 weeks.

If the rotator must be left in the inverted position outside for an
extended time I would wrap it in black landscape plastic and duct tape
to prevent more water from entering while leaving the bottom of the
plastic open to dry out.


I have done this in the past, but because of the way the rotor is
mounted on the Rohn tower, it isn't possible to seal it very well this
way - I was looking for suggestions for better ways of weatherproofing
it for this period.

Marshall



  #6   Report Post  
Old September 17th 05, 02:28 PM
John Ferrell
 
Posts: n/a
Default

Now I understand!
I this case I would get some of the soft rope like window putty from
the hardware store to seal up the rotator while it was vulnerable. I
have not bought any for years, I assume it is still available. Play
Dough does not work well, it either shrinks and falls out or hardens.

On Fri, 16 Sep 2005 11:41:56 -0400, Ted Goldblatt
wrote:



I have done this in the past, but because of the way the rotor is
mounted on the Rohn tower, it isn't possible to seal it very well this
way - I was looking for suggestions for better ways of weatherproofing
it for this period.

Marshall


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Old September 17th 05, 06:43 PM
Roger Conroy
 
Posts: n/a
Default


"Ted Goldblatt" wrote in message
...
John Ferrell wrote:

I am not sure I understand the question. I think you have the rotator
upside down on the tower at the moment. If it went through some
weather, it is probably full of water now. The way I would handle the
problem is to remove the rotator from the mount and hang it on the
tower (clothes hanger wire) right side up. I would hang it there for a
few days to drain & dry out. When it comes time to reinstall the
antennas, test the rotator for proper operation. Chances are that it
will be OK. If you seal it tight, the moisture will be sealed in.
These things are intended to be able to breathe!


The tower is currently up (the mast broke above the rotor, so all the
antennas are dangling by their feedlines, but the tower itself is OK) and
the rotor is in its normal upright position. It will be upside down when
the tower is folded over to work on. As far as I know, the rotor is fine
right now.

If removing/replacing the rotator is a major hassle, I would either
send it to one of the maintenance guys or put up a new one & sell the
old one on ebay WITH the explanation. There are lots of us who have
setups that are easy to change.


Don't understand this. Yes, removing/replacing the rotor is a hassle,
largely because it has to be done with the unit upside down, and standing
at the top of a ladder. But that isn't the issue here - in fact, there is
no obvious reason to remove the rotor at all, since it seems intact. Just
remove the stub of the broken mast from the thrust bearing and put a new
one in. The issue is that while that is done, and the new antennas are
mounted, and new (or repaired) feedlines are run, and all the antennas are
tuned, the tower will need to be folded over, with the rotor mounted, and
these steps will almost certainly take several days. Because of
availability of helpers reasons, this will likely have to be on weekends,
meaning the tower will be folded (and the rotor inverted) for a period of
at least 1 to 2 weeks.

If the rotator must be left in the inverted position outside for an
extended time I would wrap it in black landscape plastic and duct tape
to prevent more water from entering while leaving the bottom of the
plastic open to dry out.


I have done this in the past, but because of the way the rotor is mounted
on the Rohn tower, it isn't possible to seal it very well this way - I was
looking for suggestions for better ways of weatherproofing it for this
period.

Marshall


LOTS of Heavy Grease "glooped" all over every conceivable (and
inconceivable) opening. Then wrap it in plastic.

73
Roger ZR3RC



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Old September 19th 05, 03:20 AM
russ
 
Posts: n/a
Default

hi,

A large sheet of 6 mil clear plastic should be able to
cover the tower and the folded over section.

Place a container of DampRid on the rotor shelf
before you cover the tower with the plastic sheets.

Two layer of sheet should do the trick.

Drape the plastic 4 or 5 feet below the rotor,
no way for any water to get inside the rotor.

Tie it tiht with some good rope and your done.

The damp rid will absorb any moisture that it
trapped during the day from the hot sun
heating up the top of the 'rotor bag' you just made.

Or just take the rotor inside.

good luck with the repairs.

russ

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