how to heat shrink wraps?

[jtkwest]

how do i heat the shrink tubing on my bands, that covers the tying line without damaging the tubing? heat gun seems hard to control kinda. any ideas?

 

[Mr. X]

Heat shrink on your bands?! Why/where? I would have thought a heatgun would be the right tool for the job. If you need less direct heat, a hairdryer might work. Failing that, other heat sources: warm water, soldering iron, lighter, steam,...?

 

[ReefTroll]

Although this sounds rather dangerous, a naked flame can work as you can get the wrap to shrink at a very high speed. I use this technique on certain things at work. The theory behind it is that the high intensity of the flame heats the wrap and shrinks it too fast for any damaging heat to transfer to the delicate thing you're wrapping.

 

[Bill McIntyre]

My heart gun has two settings, and the low heat seems to work just fine.

 

[strangelove]

I am curios, what would be the main reason to do that ?

 

[Bill McIntyre]

I am curios, what would be the main reason to do that ?

My main reason is that when I started to make my own bands, I was copying Riffe.

Another reason is that it protects the knot in the whipping twine.

And one more is that it just looks so damn neat.

 

[alexrom1207]

Assuming your gun doesn't have a low setting (most do) then your heat gun probably came with array of nozzles, pick one that fans out at the end, this will keep the heat mild. If you don't have any nozzles the best way to use the gun is:
1. start with the heat gun far away from the tubing and keep moving the nozzle back and forth horizontally very quickly so at to prevent putting too much heat in one place and damaging something.
2. keep moving it back and forth while gradually bringing it closer to the tubing. The tubing should start to shrink, if it does not shrink before the bands start to get damaged then ???? that really is a dilema.
I use a heat gun quite often on that type of shrink tubing and it should be made to shrink at a much lower heat than will damage the bands. If you just keep the gun going back and forth from side to side you should be able to control the heat more effectively. Good luck

 

[Magpie]

Never used heat shrink on me bands but have on lots of other things and all I do it poor boiling water straight out of the kettle on it. Means you get an even temperature distribution and I doubt it'd affect the bands.

 

[jtkwest]

My main reason is that when I started to make my own bands, I was copying Riffe.

Another reason is that it protects the knot in the whipping twine.

And one more is that it just looks so damn neat.

yes that is my reasoning also on all three counts.

 

[jtkwest]

My heart gun has two settings, and the low heat seems to work just fine.

thats what i thought, but i figured i would check with you guys before i took a chance. incidently, it seems like there is rubber cement maybe on my riffe bands, under the shrink tubing? if so, do you use it?

 

[Bill McIntyre]

thats what i thought, but i figured i would check with you guys before i took a chance. incidently, it seems like there is rubber cement maybe on my riffe bands, under the shrink tubing? if so, do you use it?

I don't. I tie a constrictor knot, go around to the other side and tie a simple overhand knot, then back to the first side and tie another overhand knot. With waxed whipping twine, it seems to hold fine. But lately, just to make sure, I've been putting a drop of liquid electrical tape or Super Glue on the last knot.

When I first started making bands, I used to put a drop of glue from hot glue gun on the knot. Then when you apply the heat, the glue melts and runs all over the whipping twine and even out from under the shrink tubing. That worked too.

BTW, a couple of times I've screwed up and used the heat gun on the high setting, and the portion of the rubber where I had tapered it started to sizzle, but it didn't seem fatal. I went back to low heat as soon as I noticed it, and the shrink tubing was OK. I went ahead and used the band with no apparent problem.

 

[jtkwest]

thanks again , bro, that is just the info i was after, incidently, isnt it interesting that so many people never heard of this? most bands even from the store seem to all have this. not just riffe.

 

[Bill McIntyre]

What kind of twine are you using?

For years I used waxed whipping twine that I got at West Marine. Its a bit on the thin side, but I double it before tying the knots and it has always held.

But then I noticed that Daryl Wong's bands seemed to have some sort of neat black twine, and I asked him what it was.

QUIK_KLIPS

Its # 802B Brim twine from this site, and I recently got a roll. Its wider and flatter, and I like it a lot. The down side is that a roll is a lifetime supply for most of us, and costs $40. Daryl says he ties about 1500 bands per year, so he goes through the stuff. Even though I tie bands for several friends, at about a yard per band I'm going to end up leaving most of the roll to someone in my will.

But still, its nice to use the good stuff, and I'll never have to worry about West Marine having the other stuff in stock again. And maybe you are young enough to use it up.

You probably already know how to taper the bands if you have an inclination to do so, and how to insert the wisbone knot in the rubber. But just in case anyone else reading this is curious-

To taper the band, stick a nail in the end to stiffen it, then turn it against the wheel of a bench grinder until sparks come off of the nail head.

You can insert the knot with needle nose pliers, but I tend to lose flesh and blood when I do it, especially with tapered bands. So these simple wishbone insertion tools make it a lot easier. The first one is just a stainless tube with a slot cut in the side of it. You put in a vise, pull the knot tight against the end, and stick the tubing onto it. The other one can be hand held, and is a Rob Allen tool. The tube had a pretty big flare on the end and the knot in the end of my Spectra wishbone would hide in it and come back out of the rubber when I withdrew the tool, so I just ground off most of the flare so that I could grab the knot through the rubber to hold it.

 

[blaiz]

I was told by a local spearfishing shop owner here in hawaii that the smaller the knot the longer it will take for the bands to crack around it. He said he uses his truck to tie his wishbones. any thoughts on this?

 

[Bill McIntyre]

I was told by a local spearfishing shop owner here in hawaii that the smaller the knot the longer it will take for the bands to crack around it. He said he uses his truck to tie his wishbones. any thoughts on this?

I don't really know, but it sounds counterintuitive. However, I tie mine as tight as possible simply to keep the wishbone knot from coming out, but I don't use a truck. I put a knot in each end to make it easier to grab, and then put one end in a vice and grab the other end with visegrips and pull as hard as I can. Or alternatively, you can wrap each end around a screwdriver or pliers handle to get a better purchase and pull as hard as you can.

 

[Mr. X]

I put a knot in each end to make it easier to grab, and then put one end in a vice and grab the other end ... wrap ...end around a screwdriver or pliers handle to get a better purchase and pull as hard as you can.

That's what I do. Nice tutorial Bill. Interesting to see how you grind the ends. Was surprised that you just use a knot at the end; the RA Dyneema wishbones that I use have a nylon toggle at both ends, sort of conicle in shape. Other homemade wishbones I've seen use round beads. Your Dyneema looks considerably thicker than the RA ones -- so I'm thinking your guns have sharkfins rather than the smoothed-out grooves of the RA spears. I don't think dyneema that thick would work with my spear.

I like the idea of using superglue to lock the cinch knot. I usually smear the knot using a soldering iron but superglue would be less likely to weaken the knot. I notice one of the Italian speargun makers puts an extra half-hitch around the rubber after the cinch knot - which strikes me as a good idea, esp if you plan to melt/smear the knot.

 

[Bill McIntyre]

That's what I do. Nice tutorial Bill. Interesting to see how you grind the ends. Was surprised that you just use a knot at the end; the RA Dyneema wishbones that I use have a nylon toggle at both ends, sort of conicle in shape. Other homemade wishbones I've seen use round beads. Your Dyneema looks considerably thicker than the RA ones -- so I'm thinking your guns have sharkfins rather than the smoothed-out grooves of the RA spears. I don't think dyneema that thick would work with my spear.

I use 3 mm Spectra, but I do have shark fins on the shafts.

However, Riffe uses some kind of much thinner cord for his wishbones, and he uses a knot. I used to use his wishbones before I started making my own, and the wishbones never pulled out.

I like the idea of using superglue to lock the cinch knot. I usually smear the knot using a soldering iron but superglue would be less likely to weaken the knot. I notice one of the Italian speargun makers puts an extra half-hitch around the rubber after the cinch knot - which strikes me as a good idea, esp if you plan to melt/smear the knot.

When I used the waxed whipping twine that I got from West Marine, I used to tie a square knot on the other side of the band from the constrictor knot, and then another square knot over the constrictor knot. But that stuck up quite a bit, and was one reason I used the heat shrink to protect it from catching on something.


But now that I'm using this Brim electrical whipping twine that Daryl Wong suggested to me, I'm not using the square knot. After I tie the constrictor knot, I just go around to the other side and tie a double half hitch. Or I guess that's what its called- I just pass one side of the twine around the other side twice before tightening it. And then I go back around and do that again over the original constrictor knot. A touch of glue insures that it doesn't start to unravel, and it doesn't stick up. On the last couple of sets of bands, I haven't bothered with the heat shrink.

This photo shows the Brim tape with no heat shrink. Also note that I didn't bother to taper, since these heavy wire wishbones hold the bands apart so that there is no concern with visual clutter where the bands pile up on each other as they do with cord wishbones.

Years ago I got turned off to wire wishbones because the ones that came on American guns such as JBL tended to break. But now I'm trying these much thicker ones made by Masahiro Mori, and I like the way they make for a clear line of sight down the shaft. The only problem is that I can't use them on my enclosed track guns because they tear up the finish on the top of the gun.

 

[foxfish]

Never used heat shrink on me bands but have on lots of other things and all I do it poor boiling water straight out of the kettle on it. Means you get an even temperature distribution and I doubt it'd affect the bands.

Nobody seemed to comment on this but surly it is the best way?

 

[Bill McIntyre]

Nobody seemed to comment on this but surly it is the best way?

Just turning on a heat gun seems a lot easier to me than boiling water and then having to have the band over a sink or outside, but whatever works.

 

[ihab]

My heart gun has two settings, and the low heat seems to work just fine.

Can I ask what type of Dyneema do you use and where to get it.


Cheers,
Ihab