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Re: [TowerTalk] Recommendation for heat gun for shrink wrap

To: <TOWERTALK@contesting.com>
Subject: Re: [TowerTalk] Recommendation for heat gun for shrink wrap
From: "Roger (K8RI)" <K8RI-on-TowerTalk@tm.net>
Date: Thu, 23 Aug 2007 23:27:16 -0400
List-post: <mailto:towertalk@contesting.com>
Just a note about heat shrink tubing:

It varies widely in dimensions and quality. The cheap thin stuff is usually 
pretty fragile.  It also comes with and without flooding compound (Hot melt 
glue) which for most cases is easily removed to the point of reusing 
connectors. No, it's unlikely they will come out looking like new as some of 
the glue will probably stay behind. With practice they can come out pretty 
clean and the surface will look like new (most of the time).

It would be interesting and beneficial for people to try the tubing from 
various sources and then post the results. Most likely there is some out 
there that is as good as the MMM for less, but we won't know until some one 
finds it.

The MMM tubing is strong and rugged.   Even shrunk onto the outside of a 
PL-259 it will form a jacket considerably thicker (and stronger) than the 
RG-8, LMR-400, or 9913 jacket. It also will make a splice that is more rigid 
than even LMR-400, so don't make a splice where you plan on making a tight 
bend. Of course the connectors would prevent that anyway. It's *relatively* 
easy to remove by slitting the jacket length wise and then using a pair of 
pliers to pull it apart. Unlike the stuff from Radio Shack it will not 
easily melt, but like anything else it does take a bit of practice to apply 
correctly. You can ruin it with heat but if it gets hot the coax inside will 
probably be ruined as well.  With that practice the MMM material may be 
applied with just a straight heat gun and no special attachments. I use a 
flat nozzle about 1/4" by about 1" wide most of the time and apply the heat 
alternately from points 180 degrees apart. The MMM tubing is fairly 
forgiving so the user doesn't have to heat each side precisely the same to 
get it to look uniform. Actually you can shrink one side all way way down 
and then switch to the other making sure it is shrunk as well. Then shrink 
the next section starting with the opposite side and it'll still look good. 
Remember how hot, hot melt glue gets. That is how hot you get this stuff to 
shrink. Don't get the glue on you as it hurts like the devil and it won't 
let go. If you try to pull it off with unprotected fingers you will burn 
them too. Please don't ask me how I know<:-))  Tis a good idea to wear good 
quality, tight fitting, leather gloves.

For splices I use 3 pieces. The first are about 1 1/2 inches long  (Inch to 
inch and a half is fine, it's not critical) and applied over the rear of the 
PL-259 up fairly close to the rear of the threaded portion which is slid all 
the way forward. As long as it covers half  the rear of the connector it'll 
work fine.  This makes a good mechanical connection between the barrel and 
the coax jacket IF the metal is clean. I slip a piece over one coax long 
enough to extend about an inch beyond the first layer of heat shrink tubing 
and onto the coax jacket at each end of the splice.  I start in the center 
with the heat gun over the double female connector and work out  to each 
end, one direction at a time.

BTW I've mentioned using DC-4 or 5 as a flooding compound *IN* connectors. 
AFTER the first piece of heat shrink is applied to the rear of the 
connector, take the tube of DC-4 (or what ever you have is called) and slip 
the end over the center pin of the PL-259.  Squeeze out enough compound to 
form about an 1/8" layer over the insulator in the connector and then 
install normally. Be careful about getting any excess on the coax jacket or 
your hands. It is Silicone and nothing will stick to in...EXCEPT dirt! If 
any thing prevents reusing the connectors it will probably be dirt in the 
flooding (DC4) compound and the stuff acts like a dirt magnet. So don't drop 
the end of the coax into the dirt or grass after taking it apart. The reason 
for applying the compound after the first piece of heat shrink is applied to 
the connector is this keeps the threaded portion from slipping back onto the 
connector and exposing the grease.


73

Roger (K8RI)


> John,
>
> Harbor Freight also carries the shrink wrap.
> http://search.harborfreight.com/cpisearch/web/search.do?keyword=heat+shrink&Submit=Go
>
> They have some small assortments, a larger (48" pieces) assortment and 
> even
> a marine assortment.
>
> 73,
> Scott W5LSU
>
>
> On 8/23/07, fraz1 <fraz1@bellsouth.net> wrote:
>>
>> Hi folks.............any recommendation for a good heat gun to be used 
>> for
>> shrink wrapping would be appreciated.  Also, good known sources for 
>> shrink
>> wrap itself.
>>
>> 73 John K4NP
>> _______________________________________________
>>
>>
>>
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