Topics

Cleaning Insulators (again!)


David KK7SS
 

I've just spent the last 2 hours searching the archives looking for what someone used to actually clean the insulators>
Lots of messages  (went back as far as 2019!) about cleaning but no message says how to clean the insulator and what to use !
The lower one on my HF6V has turned black an I can't get the SWR below 2.3:1 with an R of 175.
Halving the coil inductance only increases the R with the SWR staying the same.
So... what do I use to clean the crap off the insulator"

Thanks in advance :-)

Dave G.  KK7SS


Chuck W3ON
 

Hmm

 I used light sand paper to clean the gunk off of the solid fiber glass insulators. Eventually I replaced them because as you clean/sand them
then get smaller in diameter. At some point the insulators will wobble in their mounts. That's at the point
that I bit the bullet and bought new ones at DXEngineering. Some folks have access to such solid fiber glass rod.
I did not.
73 de Chuck W3ON

On 7/11/2020 6:31 PM, David KK7SS wrote:
I've just spent the last 2 hours searching the archives looking for what someone used to actually clean the insulators>
Lots of messages  (went back as far as 2019!) about cleaning but no message says how to clean the insulator and what to use !
The lower one on my HF6V has turned black an I can't get the SWR below 2.3:1 with an R of 175.
Halving the coil inductance only increases the R with the SWR staying the same.
So... what do I use to clean the crap off the insulator"

Thanks in advance :-)

Dave G.  KK7SS


David KK7SS
 

Chuck,
Thanks.. 200/400/800 grit?
Dave KK7SS


Ken WB8VTW
 

Sorry to freeload.

I need to replace mine also. what diameter are the insulators? Maybe these are causing my intermittent SWR jumps as they are very black.
 


Ken WB8VTW
 


 

I have cleaned mine using denatured alcohol.  It removes the surface crud but it won't remove the stain.  Eventually they just had signs of wear and splintering.  I was lucky at the time to find a surplus industrial supply close by that had scrap fiberglass rod.  I bought several pieces by the pound in several sizes.  Unfortunately, the place is long out of business.
Al
WB9UVJ


Barry <boat.anchor@...>
 

On Sun, Jul 12, 2020 at 11:30 AM, Ken WB8VTW wrote:

Seems cheap enough to do as a preventive action if this is the right stuff. Mine is at least 30 years old. 

https://mgs4u.com/product/1-od-round-solid-rod/?attribute_pa_length=6-inch&attribute_pa_color=white&gclid=Cj0KCQjw6ar4BRDnARIsAITGzlDsu6qWpZ7vvfLuLLKAQAezOpzQbDI4DnhgBD_Bmw8sTlwmA35j30MaAuLREALw_wcB&v=7516fd43adaa

Exactly the path I followed. They will also precut it to the length you need.
barry


Scott AC8DE
 

>>... I bit the bullet and bought new ones at DXEngineering. Some folks have access to such solid fiber glass rod.

 

I can tell you that sure, you can get the rod is longer sections and then cut and drill.  I've done it and all I can say is; "Have fun!"  It really sucks to cut the fiberglass and you have to have the right kind of blade.  Then there's the matter of drilling the holes on center.  My advice is to take the high road and just buy it ready to go from DX.

 

Scott AC8DE

 

From: Butternut@groups.io On Behalf Of Chuck W3ON
Sent: Saturday, July 11, 2020 8:46 PM
To: Butternut@groups.io
Subject: Re: [butternut] Cleaning Insulators (again!)

 

Hmm

 I used light sand paper to clean the gunk off of the solid fiber glass insulators. Eventually I replaced them because as you clean/sand them
then get smaller in diameter. At some point the insulators will wobble in their mounts. That's at the point
that I bit the bullet and bought new ones at DXEngineering. Some folks have access to such solid fiber glass rod.
I did not.
73 de Chuck W3ON

On 7/11/2020 6:31 PM, David KK7SS wrote:

I've just spent the last 2 hours searching the archives looking for what someone used to actually clean the insulators>
Lots of messages  (went back as far as 2019!) about cleaning but no message says how to clean the insulator and what to use !
The lower one on my HF6V has turned black an I can't get the SWR below 2.3:1 with an R of 175.
Halving the coil inductance only increases the R with the SWR staying the same.
So... what do I use to clean the crap off the insulator"

Thanks in advance :-)

Dave G.  KK7SS


Ken WB8VTW
 

When replacing the insulators, what is the spacing of the holes and what is the total length of the insulator? I have 4 insulators from 2 different antennas and the hole spacing on all 4 are different. 
Thank you.  


Chuck W3ON
 

Hmm

I am looking at an insulator that I removed from an older HF6V (80s). It is

Length: 7 inches
Diameter: 7/8 inch (most likely originally 1 inch)
Holes: 2 holes, 2 inches from each the end of insulator.
Hole Diameter:  3/16 inch

73 de Chuck W3ON

On 7/15/2020 1:49 PM, Ken WB8VTW via groups.io wrote:
When replacing the insulators, what is the spacing of the holes and what is the total length of the insulator? I have 4 insulators from 2 different antennas and the hole spacing on all 4 are different. 
Thank you.  


 

On my insulator original was from mid 80's.
Diameter is 1.00"
Length 7"
One hole is 2" from end and the other 2.25" from the other end.
The marks showing tube spacing is 0.5"
The holes are drillled for 8-32 screws
Al
WB9UVJ


Jim Strohm
 

Here's a hint on hole spacing.

The aluminum tubes and the glas insulator rod were never precision-drilled.  So the odds of your getting the holes in mismatched pieces are slim at best, and unlikely on "matched" pieces.  My suggestion?  Using a drill press and vee blocks for positioning, fit your tubes and rod set, place them in the vee blocks, and turn them 90 degrees from the existing holes in the tubes.  Then drill and affix hardware.

Problem solved.

Alternatively and additionally, and this is what I did, since I had an elevated HF6V decades ago -- assemble the tubes and rod, then partially fill with a good grade of liquid epoxy, like West.  Tape up the joints between the tubes and the glas rod, as they'll leak until the epoxy cures.  The fast catalyst is recommended.

One you've done both ends, you'll never have to worry about re-fitting the tubes to the rod, tho you want to drill a weep hole in the upper rod just above where the epoxy stops.  And you can attach this newly indestructible structure using a couple of SS u-bolts to something that serves as a base mount, whether in the ground or in the air.  Remember to put anti-seize on all SS nuts and bolts.

73
Jim N6OTQ


Ken WB8VTW
 

I am curious, Has cleaning/replacing the insulators eliminated intermittent SWR jumps? I am pulling out what is left with my hair trying to figure it out. Sometimes just a shot of RF will fix it for a short time. I have cleaned/rebuilt/Jet-Lube'd the antenna and replaced all caps except for the 200pf. My insulators are very old and have a lot of black on them. 


Chuck W3ON
 

Hmm.

IMHO you should do everything in your power to get rid of that black gunk on the insulators. I believe that gunk can act as a conductor, under the right circumstances, and cause unwanted
shorts across the insulators. In olden days I lightly sand papered the insulators to get rid of the gunk. That worked for several rebuilds. Then the last time, two years ago, I noticed that
the antenna was wiggly at the connectors. So, I checked and found that they were about 7/8 on an inch in diameter, rather than the 1 inch in diameter. Since I had no spare insulators
rods, I ended up purchasing two new ones from DXEngineering. Now they are clean, and don't wiggle. Wiggle is your enemy. As is that black gunk, which I think is dried aluminum
oxide which leaked from aluminum tubing joints over a long period of time. Others may have other ideas. That is mine. Hi Hi.
73 de Chuck W3ON

On 7/22/2020 1:20 PM, Ken WB8VTW via groups.io wrote:
I am curious, Has cleaning/replacing the insulators eliminated intermittent SWR jumps? I am pulling out what is left with my hair trying to figure it out. Sometimes just a shot of RF will fix it for a short time. I have cleaned/rebuilt/Jet-Lube'd the antenna and replaced all caps except for the 200pf. My insulators are very old and have a lot of black on them. 


Ryan AE0JX
 

It would be very interesting to see an old and new insulator tested on a Megger. I don't have access to one but it would be able to determine the conductivity of the old insulator.

73 Ryan AE0JX

On Wed, Jul 22, 2020 at 1:08 PM Chuck W3ON <w3on@...> wrote:

Hmm.

IMHO you should do everything in your power to get rid of that black gunk on the insulators. I believe that gunk can act as a conductor, under the right circumstances, and cause unwanted
shorts across the insulators. In olden days I lightly sand papered the insulators to get rid of the gunk. That worked for several rebuilds. Then the last time, two years ago, I noticed that
the antenna was wiggly at the connectors. So, I checked and found that they were about 7/8 on an inch in diameter, rather than the 1 inch in diameter. Since I had no spare insulators
rods, I ended up purchasing two new ones from DXEngineering. Now they are clean, and don't wiggle. Wiggle is your enemy. As is that black gunk, which I think is dried aluminum
oxide which leaked from aluminum tubing joints over a long period of time. Others may have other ideas. That is mine. Hi Hi.
73 de Chuck W3ON

On 7/22/2020 1:20 PM, Ken WB8VTW via groups.io wrote:
I am curious, Has cleaning/replacing the insulators eliminated intermittent SWR jumps? I am pulling out what is left with my hair trying to figure it out. Sometimes just a shot of RF will fix it for a short time. I have cleaned/rebuilt/Jet-Lube'd the antenna and replaced all caps except for the 200pf. My insulators are very old and have a lot of black on them. 


Al AB2ZY
 

Al2O3 is an electrical insulator.

FWIW, HF6V 10 years of service, QRO, no cleaning of insulators, no problems.

Al
AB2ZY


David KK7SS
 

Our city supplied water here is quite 'hard'.
My HF6V is ground mounted - roughly in the middle of the back yard..
I have a Sprinkler system watering the grass.
The bottom insulator is Black!
Could the mineral content of the water be the cause?

Dave  KK7SS


Peter VA3PET
 

My Butternut HF9V has been in use for years, I have never bothered cleaning it's insulators and I have never had a problem.

If the "black stuff" were carbon, I'd be concerned but aluminum oxide is an electrical insulator so I wouldn't worry about it?

I do own a 600vac megger, next time I do maintenance on my antenna, I'll check it's insulated joints for lack of connectivity.

Pete
Va3hr va3pet


From: Butternut@groups.io <Butternut@groups.io> on behalf of David KK7SS <d3j452@...>
Sent: Friday, July 24, 2020 12:50:11 PM
To: Butternut@groups.io <Butternut@groups.io>
Subject: Re: [butternut] Cleaning Insulators (again!)
 

Our city supplied water here is quite 'hard'.
My HF6V is ground mounted - roughly in the middle of the back yard..
I have a Sprinkler system watering the grass.
The bottom insulator is Black!
Could the mineral content of the water be the cause?

Dave  KK7SS