[TowerTalk] [Bulk] Easy removal of Heat Shrink Tubing

[Roger (K8RI) on TT]

Preheating the connectors after the connection is made is relatively 
easy. UHF and N splices have relatively small mass so preheating  the 3 
connectors can easily be done.  There is a small learning curve, BUT the 
connection (in a splice) will be water proof if the glue bonds to the 
coax. OTOH,  If the connectors are preheated to give a good bond, then 
the connectors are chilled prior to the heat shrink removal, the glue 
will "usually", break off leaving a relatively clean connector.

"IF" the connectors are preheated too hot, the glue will likely melt 
making it difficult to properly position the heat shrink, (it may shrink 
too soon), or not enough glue will be left to seal the end(s). For a 
splice, preheat the connectors (if desired), quickly slide the tubing 
into position and then start the shrinking process FROM THE CENTER and 
move out.  If the ends are sealed first the center will form an 
unsightly bulge.     OTOH you can heat the double female connector to 
the point of melting glue and thoroughly coat the center first, but LET 
THE CONNECTORS COOL enough to allow sliding the tube into place with out 
melting the glue lining.

OTOH is it necessary to seal onto the connectors.  The water proofing 
method with the first layer of 33, or 88 tape wound with the adhesive 
side out keeps the metal clean without sealing to it.  It depends on the 
method used, but connections can be made that do not bond to the metal, 
yet remain water  proof.
http://www.rogerhalstead.com/ham_files/AV-640/AV640.htm .  Check the 
left side photo on the bottom row.  The next photo to the right is a two 
layer EPS 800 over 400 on a TV balun.  RG-6 to 300 ohm twinlead.

NOTE:  If you want the glue to adhere to a surface, degrease the surface 
with a good solvent.  Be careful when using solvents.

73

Roger (K8RI)


On 12/21/2015 Monday 6:27 PM, Grant Saviers wrote:
> Roger's heat shrink removal explanation shows one peril of adhesive 
> heat shrink, that is the adhesive is not really adhered to the 
> connector body.  Andrew specifies preheating of Heliax connector 
> bodies prior to slipping on the adhesive shrink and then shrinking the 
> tubing.  Of course the larger the connector, the more it is a heat 
> sink that doesn't get hot enough thru the wall of the tubing for the 
> adhesive to tightly bond to the metal.
>
> IMO, unless the adhesive is adhered to the connector the joint will be 
> tight, but not totally watertight.  However, there still is some 
> protection and an excellent strain relief.  I think the cable jacket 
> fairly easily gets hot enough to have the adhesive stick to it.
>
> Grant KZ1W
>
> On 12/21/2015 12:08 PM, Roger (K8RI) on TT wrote:
>>
>> If the connection is cool or cold, this approach works better than 
>> warm or hot.
>> Room temp works well, but may leave more residue.
>>
>> There is a bit of a learning curve.  Some pick it up right away while 
>> others, not so much.
>> Using a sharp knife, or box cutter with the blade extended just 
>> enough to cut through the heat shrink.
>> Make a single cut  lengthwise from one end to the other of the heat 
>> shrink. A second cut on the other side works well, but it's another 
>> chance to cut into the coax jacket.  The cut does not need to go all 
>> the way through the heat shrink
>>
>> Using a pair of pliers, channel locks / slip joint pliers grab the 
>> heat shrink at or close to the cut with the other jaw of the pliers 
>> about one third of the way around the coax and pinch the heat 
>> shrink.  If you go too far it will pinch the coax. That should pull a 
>> section away from the coax jacket Repeat on each side of the cut 
>> along the length of the seat shrink.
>>
>> Doing takes less time than explaining.
>>
>> If the connection is cool, the heat shrink adhesive "usually" breaks 
>> away from the connector, leaving the connector relatively clean.
>>  http://www.rogerhalstead.com/ham_files/connectors.htm  The splice 
>> shown in the bottom right side photo shows a N-Type connector splice 
>> after the flooded (adhesive lined) heat shrink has been removed. Some 
>> residual glue is visible on the coax jacket but the connectors are 
>> relatively clean
>>
>


-- 

73

Roger (K8RI)


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