fiberglass mast question
 

Anyone have suggestions on a method I might try to "twist" and collapse
some sections of my telescoping fiberglass mast? I put it up several days
ago with perhaps a bit too much "vigor" in making sure it would not
collapse on its own and now that I want to stow it away there are a couple
of sections I can not unlock. My grip is good, but the sections are really
tight. I hate to use something mechanical for fear of cracking the
fiberglass and I hate to use a lubricant since the locking requires
friction.

Thoughts ?

Ed K7AAT

fiberglass mast question
 

Ed wrote:
Anyone have suggestions on a method I might try to "twist" and collapse
some sections of my telescoping fiberglass mast? I put it up several days
ago with perhaps a bit too much "vigor" in making sure it would not
collapse on its own and now that I want to stow it away there are a couple
of sections I can not unlock. My grip is good, but the sections are really
tight. I hate to use something mechanical for fear of cracking the
fiberglass and I hate to use a lubricant since the locking requires
friction.

Thoughts ?

Ed K7AAT

======
Immerse outer end (only)in hot water. Hopefully it will expand slightly
,but not the inner mast part .

Alternatively cover outer end with insulation material and 'cool' inner
mast tube with evaporating CO2 'ice' hopefully causing it to shrink
slightly.

Of course success is not guaranteed but worth trying .....at least it is
non-destructive.


Frank GM0CSZ / KN6WH

fiberglass mast question
 

On 27 Aug 2008 19:04:14 GMT, Ed
wrote:

Anyone have suggestions on a method I might try to "twist" and collapse
some sections of my telescoping fiberglass mast? I put it up several days
ago with perhaps a bit too much "vigor" in making sure it would not
collapse on its own and now that I want to stow it away there are a couple
of sections I can not unlock. My grip is good, but the sections are really
tight. I hate to use something mechanical for fear of cracking the
fiberglass and I hate to use a lubricant since the locking requires
friction.

Let me guess. You extended the pole when the air temperature was cold
and are now trying to collapse it when the air temperature is hot? The
coefficient of thermal expansion is about the same as glass or
1.1x10^-5 inch/inch/F which is enough to expand the inner tubing into
the outer sleeve almost permanently. After a few field days of having
exactly the same problem, I sorta learned my lesson.

The easiest is to wait until it cools down at night. You can also
splash cold water on the joints, which might help. If you want to
prevent the problem in the future, I found that ordinary Ivory soap
smeared on the joint, makes a decent lube that will not cause
premature collapse. If you apply too much, just wash it off.

Also, do NOT beat on the ends in an attempt to release the seized
joint. The twist type telescoping locks will just lock even harder.

If brute force is your forte, you might try a rubber pipe strap wrench
as used to remove an automobile spin on oil filter. Wrap the strap
around a few times and put something under the gripper teeth to
distribute the force. I've never tried this but it seems like it
might work.

Also, make sure you're turning in the correct direction. I did that
once with a window washer pole with predictable results and
embarrassment.


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

fiberglass mast question
 

Jeff Liebermann wrote in
:


If brute force is your forte, you might try a rubber pipe strap wrench
as used to remove an automobile spin on oil filter. Wrap the strap
around a few times and put something under the gripper teeth to
distribute the force. I've never tried this but it seems like it
might work.

Those strap wrenches work pretty well, Jeff.

- 73 de Mike N3LI -

fiberglass mast question
 

On Aug 28, 3:52*am, Mike Coslo wrote:
Jeff Liebermann wrote :

If brute force is your forte, you might try a rubber pipe strap wrench
as used to remove an automobile spin on oil filter. *Wrap the strap
around a few times and put something under the gripper teeth to
distribute the force. *I've never tried this but it seems like it
might work.

Those strap wrenches work pretty well, Jeff.

* * * * - 73 de Mike N3LI -

You could try holding the pole vertical and let the whole lot drop a
few feet so that the base falls onto a hard surface (assuming it has
some sort of bump cap on the base).

This inertia and rapid deceleration usually releases even the most
stubborn joints.

UKM

fiberglass mast question
 

If brute force is your forte, you might try a rubber pipe strap wrench
as used to remove an automobile spin on oil filter. *Wrap the strap
around a few times and put something under the gripper teeth to
distribute the force. *I've never tried this but it seems like it
might work.

Those strap wrenches work pretty well, Jeff.

* * * * - 73 de Mike N3LI -

You could try holding the pole vertical and let the whole lot drop a
few feet so that the base falls onto a hard surface (assuming it has
some sort of bump cap on the base).

This inertia and rapid deceleration usually releases even the most
stubborn joints.

I have used these poles a lot, and the 'bump' method usually works for
me. Start on grass to cushion the blow, and gradually increase the
impact force until the joint comes free.

Twisting usually does not work, though a little soapy water and heating
might help.

Be very careful about using any kind of wrench or vice jaws, as these
thin-walled poles are VERY vulnerable to crushing. On the other hand,
I've never damaged one by end-on impact.


--

73 from Ian GM3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek

fiberglass mast question
 

On Thu, 28 Aug 2008 12:07:01 +0100, Ian White GM3SEK
wrote:

On the other hand,
I've never damaged one by end-on impact.

I have. It split the tubing just below the locking area. The problem
is that there are many types of locking mechanisms. You need to know
what's inside and how it works before applying the traditional brute
force.

For example, some poles use external compression or cam type locking
mechanisms:
http://www.telescopingpoles.com/specs.html
http://www.briarwoodproducts.com/newtools.htm
These do not jam and will respond properly to the inertial hammer
(brute force) disconnect method. However, they add width which is
often undesireable.

Internal locks, with expanding cores, cams, or wedges are a different
story. To prevent collapse, most become tighter when loaded in
compression, especiallyl those that take advantage of a slight conical
taper in the tubing:
http://www.google.com/patents?id=78duAAAAEBAJ
http://www.google.com/patents?id=fvc5AAAAEBAJ
http://www.google.com/patents?id=i2ZMAAAAEBAJ
http://www.google.com/patents?id=_hMBAAAAEBAJ
(Look at the drawings). Banging on these internal locks will jam them
only worse.

I couldn't find a picture of the inside of the common window washer
fiberglass pole. It has partial threads molded into the fiberglass.
1/4 turn to lock. Bang on that design, and you'll split the tubing
(like I did).

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

fiberglass mast question
 

This mast is smooth all the way, no cams, locks, etc. The tubes must
be "slightly" tapered such that as you pull one out of the other it locks
in place by sheer friction.

I have tried heat on the outer, cooling the inner tube and
considerable twist/pushing force with my hands to get the stuck sections
to unlock, all to no avail.

Yesterday I resorted to applying some Teflon Lubricant ( Tri-Flo) to a
stuck joint but it would still not budge. Maybe today when I go out to
the garage the lubricant may have seeped its way down in to the
junction.... will try again....


Hate to toss the thing as junk, but its not looking very positive so
far. It was a cheap "flag / banner" type import so at least I won't be
out as much as a quality unit would have cost me.


Ed K7AAT

fiberglass mast question
 

On 28 Aug 2008 17:40:08 GMT, Ed
wrote:

This mast is smooth all the way, no cams, locks, etc. The tubes must
be "slightly" tapered such that as you pull one out of the other it locks
in place by sheer friction.

I don't think so. Such tapered devices have an irritating habit of
collapsing. There's usually some manner of locking mechanism, usually
activated by twisting.

Any way to look inside and determine the type of mechanism? If you
don't have a handy x-ray machine, perhaps a strong light will show
something.

Could you disclose the maker and model number? If there are any
patent numbers listed, that would be helpful to determine the
mechanism.

I have tried heat on the outer, cooling the inner tube and
considerable twist/pushing force with my hands to get the stuck sections
to unlock, all to no avail.

You don't want to heat the outside. That will cause the outer tube to
expand, which will increase its compression on the inner tube. You
want to cool both tubes causing both to contract. If you can remove
an end cap, pour in some ice water.

Yesterday I resorted to applying some Teflon Lubricant ( Tri-Flo) to a
stuck joint but it would still not budge. Maybe today when I go out to
the garage the lubricant may have seeped its way down in to the
junction.... will try again....

Well, that might help if you can get it into the joint. My guess(tm)
is that it will cause the uncoated parts of the joint to swell, which
might increase its grip. If you must lube the joint, perhaps
penetrating oil would be best.

Did you try the rubber strap wrench(s) idea? That should give plenty
of torque to rotate the sections.

Hate to toss the thing as junk, but its not looking very positive so
far. It was a cheap "flag / banner" type import so at least I won't be
out as much as a quality unit would have cost me.

Maker and model number? Photo?

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

fiberglass mast question
 

Jeff Liebermann wrote:
. . .
You don't want to heat the outside. That will cause the outer tube to
expand, which will increase its compression on the inner tube. You
want to cool both tubes causing both to contract. If you can remove
an end cap, pour in some ice water.
. . .

If you heat a ring of material, both the OD and ID increase in
proportion. This loosens, not tightens, its hold on an inner object.

I recall from freshman physics that if you heat two concentric rings
made of the same material (having a positive coefficient of expansion),
all dimensions increase by exactly the same proportion. A little
geometry shows that any gap, even microscopic, between them will
therefore also increase proportionally. Cooling both objects of course
has the opposite effect, reducing the size of any gap and tightening the
fit. Heating the outer one and cooling the inner one, as Ed did, gives
you the best of both, increasing the ID of the outer tube and decreasing
the OD of the inner tube.

Roy Lewallen, W7EL