Heat Shrink Tubing Technique?

[Bob Ohler]

When using heat shrink tubing, or the electrical connectors that come with the heat shrink already attached, what method are you using for actually shrinking the tubing... heat gun, mini torch, etc? I have been using a heat gun, but this necessitates the running of the extension cord at the dock. Are the small mini-torches safe? Do you ever worry about starting a fire when using a torch?

Thanks!

[Ron M.]

without a doubt I find a heat gun does the best job. You can use a lighter, torch, or a candle, but you don't have the control,(at least I don't) and often end up scorching, even melting the tubing or wire insulation.
I'm not a fan of connectors with the shrink. I like to solder my connections. Heat shrink with adhesive is more expensive but well worth it.
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GM 54-DEGREE V6 ENGINE SPECIFICATIONS

[marv brinn]

as an "expert" in connectors solder the joint with a small butane torch looks like a lighter...an use it to shrink the tubing...just practice to keep from scortching the shrink..

[Steve Bryant]

Bob,

Ancor makes a small heat gun (torch) - Model 702027 that is described as follows:

Features Piezo electronic ignition system, providing flameless
heat, safe to use around chemicals or by wire bundles when
using deflector.
• Powered by refillable cell.
• Flame temperature up to 650°C (1300°F).
• Ideal for work in the bilge where open flame should not be used.


http://www.amazon.com/Ancor-702027-Mari ... B000NI01BW

I don't have any experience with the product, but I am contemplating purchasing one to use when power is not available for my Milwaukee heat gun.

[Oswego John]

Bob,

I use a torch similar to this.

http://www.amazon.com/Bernzomatic-ST200 ... B0000CBIJS

I fold aluminum Reynold's Wrap three times (3 ply thick) and bend it in a curved shape. Place the shield above, behind and below around the connector. This contains the flame for safety and shields it from the wind.

Good luck,
O J

[Maine Sail]

When using heat shrink tubing, or the electrical connectors that come with the heat shrink already attached, what method are you using for actually shrinking the tubing... heat gun, mini torch, etc? I have been using a heat gun, but this necessitates the running of the extension cord at the dock. Are the small mini-torches safe? Do you ever worry about starting a fire when using a torch?

Thanks!

Bob,

Ideally,and by quite a long shot, the best tool is the heat gun. You want to heat shrink the polyolefin so that it is perfectly uniform in color, no bubbles or discoloration, and the heat gun works best. I have used and do use a mini lighter stick made by Ozark Trail and sold at Wal*Mart in the camping section but flame suffers in comparison to heat. Using flame you will still ruin a few connectors though. Flame tends to flash off the adhesive un-evenly and causes voids and un-even adhesive distribution which can allow moisture or water to penetrate the crimped and heat sealed connector.

I crimp hundreds and hundreds of adhesive lined heat shrink crimps per year and 99% of the time use a heat gun. When done right the factory made adhesive lined crimps are 100% water tight. If I need to I will bring my Honda 2000 generator rather than use a flame.

These are the same type of crimps that are used in water wells world wide that keep water out of the butt connectors 200+ feet under water. Factory made heat shrink crimps are all I use. Morris Yachts uses the same brand I do, FTZ Crimp 'N Seal.

Morris M-36 Ground Buss






Most of the top shelf quality marine electricians I know in this area also only use factory made heat shrink crimps.

In the photo below the top one is shrunk using a heat gun and you can see the uniformity and the adhesive evenly oozing out the end of the polyolefin. Note that using the proper crimp tool did not violate the polyolefin. The top crimp fitting is what it should look like when complete. After it cools off, took that photo still hot, it will look more opaque than clear but you check for voids when it is still hot.



Oh and please don't waste your money on heat shrink crimps if you are going to use the wrong tool. Staking or "dimple crimpers" should never be used on adhesive line heat shrink connectors. You want a single crimp ratchet type crimper so you don't damage the heat shrink. These were found on a boat owned by an EE. Might as well have bought the cheapest dime store connectors he could find cause that's what he turned these nice heat shrink crimps into..
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[Joe Myerson]

Like Marv, I use a small butane-powered soldering gun/torch combo tool. But I have scorched my share of heat-shrink tape in the process. Maybe I'll try OJ's trick of using aluminum foil to shield the tubing in the future.

--Joe

[Oswego John]

Joe,

Do you remember back when marine engines were mostly gasoline fueled? The air horn on the carburetor, by law, had to be with a flame arrester to suppress accidental backfiring. For the most part, the suppresser was a series of patterns of screening.

I won't say always, but 99 and 44/100% of the time, flame won't pass through screen but the heat will.

I can't dispute the fact that making production quantity insulated crimps, the heat gun is the accepted and preferred way to go. I've made more than a few crimps in my day. When out in the field, electrical power is often not available.

In the past, I had done much work in the Arctic. The extreme cold had to be overcome in order for the shrink wrap to fuse. We had to rely on Lenk alcohol blow torches, propane and butane torches as well. Wind had to be shielded to allow the work to get up to working temp.

We had special low temperature "spaghetti" shrink sleeves we cut to order on site. Normal plastic would crack in the severe cold weather. I have seen -65°F. I would hate to guess what the wind chill factor might have been. We let the trucks run 24/7. No plastic seat covers, they'd crack in a heartbeat. Only cloth seat covers. Hey Robert, could you use some of that now down there in Miami?

When working for various government agencies, i.e., DEW, AEC, NRC, GSA, etc, they are very fastidious about their tools and equipment. For instance, the crimping tool had to be checked, certified, dated and labeled by an on site calibration lab. When testing nuclear devices or wiring nuclear powered generating stations, there's no fooling around, nothing Mickey Mouse. They are dead serious.

Enough of my babel.

All of this to tell you that flame is stopped by screening. Just like soldering, welding or even playing the piano, the more you do it, the better you get. Practice makes perfect. Until then, use a heat gun or gas heat through a screen

O J

[Bob Ohler]

Maine Sail,

Many thanks for a high-quality posting with excellent details and photos. I am now in search of a quality crimping tool!

Fair winds!

[Joe Myerson]

Bob,

Thanks to an earlier posting by MaineSail, I was able to get a top-notch crimping tool through Sailors Solutions. It's just like the Anchor model (probably made by the same Chinese factory), and costs less.

Here's a link:

http://www.sailorssolutions.com/index.a ... Item=WP042
--Joe

[Maine Sail]

Maine Sail,

Many thanks for a high-quality posting with excellent details and photos. I am now in search of a quality crimping tool!

Fair winds!

This one is a good value:
http://www.sailorssolutions.com/index.a ... Item=WP042


Or do a search for FTZ 94330

http://www.ftzind.com/index.php?page=sh ... active_cat



or you can buy the Ancor 702010 version and pay more:

http://www.marinco.com/product/single-c ... tchet-tool


This one is also an excellent tool and does 8 GA as well.
http://www.sherco-auto.com/tr50

I believe this is the same tool FTZ and Ancor sell. I own a number of Hanlong crimpers, mostly for coax stuff, and they are of excellent quality. They mostly private label stuff but for $22.00 it's worth a shot!
http://www.jameco.com/webapp/wcs/stores ... ctId=72996

This crimp tool:



Made this butt splice crimp (12 GA wire yellow 10-12 butt splice):

[Bob Ohler]

Wow! Great information!

Maine Sail... Have you used the one by Ancor? I may have a (discount) source for Ancor products.

Thanks again to both of you!

Bob O.

[Numbah134]

Having just heat-shrunk my well fittings, I used a hot air gun.

In the portable/no power line, I have a Portasol (I think Weller bought them out) flameless (catalytic) butane soldering iron, and the exhaust heat from that makes a nice, no-flame, source of heat for heat shrinking if AC is not available. That one actually runs a regular "tip that gets hot" to solder with, it's not a "torch" in any sense. The exhaust vents out the side of the tip. The "flameless torch" mentioned earlier is probably using the same technique for heat generation (likely on a larger scale).

Not to say I haven't shrunk things with a lighter or a propane torch, but not by choice, given better options.

[marv brinn]

I worked for AMP for 25 yrs sat thru the 2 month class on crimp theory saw thousands of applications in the field
solder if you can use a minature little torch that I mentioned before .dont use alum foil because you cant see the shrink shrinking
dont complicate it apply the heat and dont overheat the shrink. use a crimp tool designed for the terminal. if you overcrimp you will damage the crimp . undercrimp and you will have the terminal fall off
if you must crimp give the wire and terminal a tug test...

[Joe Myerson]

Marv,

Well, there goes the aluminum-foil idea.

Thanks for the advice.

--Joe