rope, fire and safety

Chit Chat
1

I spend significant time singe-ing the ends of nylon cord. When I go to the hardware or marine stores to get rope, they also “singe” the rope ends for me (nylon or polyester) usually with that cool heated element thingie. Even with lots ventilation it can still smell pretty nasty. My question is what kind of safety issues are involved with the fumes? (issues with combustion and molten nylon are kind of obvious :sunglasses:

I’m pretty sensitive and can feel asthmatic if I get too big a whiff during a session. What kind of information/warnings should be given to students?

2

I’m sure the fumes aren’t good to breathe. If you have to do a lot of it, you might want to do your melting outdoors with a fan blowing away from you. You can buy a small cheap portable electric burner and cover the burner with foil. Have a dish of water nearby to cool the molten nylon immediately to reduce the risk of burns.

With the burner, you can adjust the temperature so as to reduce excessive smoking and charring, and the foil covering will make cleanup easy and prevent additional smoking later from leftover residue. It’s also much safer than using a match which presents the danger of hot dripping nylon.

3

As for my personal setup, I used to use a candle until I managed to knock it over one day and get wax all over the tablecloth. (Two bad ideas at once 8-0 :sunglasses: Now I use an alcohol lamp (nice wide base, no danger of knocking it over) in front of the wide open window. I have no place I could do it outside that is sheltered (flickery flames: bad).

Choosing to do things like this yourself is one thing, I’m just wondering what to tell newbies.

4

See, if you use an electric burner, you don’t have to worry about flickering flames outdoors. :wink: The lower heat of a burner produces nicer-looking results, too. I’d tell newbies not to use flames, but that’s just me.

5

Hi Carol,

There is no “safe” way of using heat to melt the cord, and the fumes (coming off the melted cord) are hazardous to your health when overdone, which is the first part of the problem. Using a glue such as cyanoacrylate (superglue) also has its issues, because people misuse the glue and get themselves stuck together with it. If you tell them to use a water-based glue, they won’t thank you, because it takes a long time to dry.

Here is information from a Material Safety Data Sheet about the product of burning nylon:

When exposed to excessive heat, nylon can decompose and may release small amounts of caprolactam, volatile oligomers, carbon monoxide, nitrogen oxides, nitriles, ketones, and a wide variety of carbon, hydrogen and oxygen compounds of varying chemicals.

What to do? If you are making Chinese or other decorative knotting, I suggest you get your students advised of the products and hazards of burning, the hazards of superglue and the wait time of water-based glues and then tell them that a safer method (depending on their skill with a needle) is to sew the ends or seize the ends using a polyester-cotton thread. One final alternative would be to use “Dip-it Whip-it” plastic compound, but this is rather messy stuff to use.

Does this help? :stuck_out_tongue:

Lindsey

6

Why would anyone want to inhale the toxic byproducts of combution? (I always ask this when I see people smoking). I use a soldering iron when melting nylon ends. Like the hardware store thingie, it does a nice job in melting ends, just not as fast. I can better control where the melted goo goes, it doesn’t make a big black spot, and no open flame! Also, when I am finishing a bracelet tightened onto an ankle, it makes a smoother finish, and a calmer recipient.

Pat

7

Hi Carol,

Thank you for highlighting an issue which we should all take seriously for ourselves, but particularly so for anyone we are teaching - especially young people.

Today’s synthetic cords pose a risk that has never before been part of knotting. The compounds released when nylon (or pp or any of the synthetic fibres) are heated excessively should all be considered to range from harmful to outright toxic and even carcinogenic. While fusing the occasional end of a synthetic cord will pose little more danger than a lung full of diesel engine fumes, we should be mindful not to do this in any quantity in a closed space such as a room, and we should be mindful of the advice we give to others, particularly as they could well have breathing problems as you describe.

The solution to the problem lays in Lindseys quote

[i]When exposed to excessive heat, nylon can decompose and may release small amounts of caprolactam, volatile oligomers, carbon monoxide, nitrogen oxides, nitriles, ketones, and a wide variety of carbon, hydrogen and oxygen compounds of varying chemicals.[/i]
and the key is in the word [b]excessive[/b].

Simply melting nylon or PP does not create any of the hazardous compounds associated with burning i.e. ‘excessive heat’. A flame, even the relatively cool flame of an alcohol burner, is way too hot and easily decomposes these polymers into their dangerous by-products. Often the electric cutters used ‘in stores’ are also too hot, they are rarely thermostatically controlled and when there is no rope present to cool the element, they rapidly got ‘too hot’ and burn the polymer left sticking to the element.

PatDucey’s method of using a soldering iron is in many ways ideal - these are thermostatically controlled and can be set to melt the end without any fumes. Unfortunately they can be expensive and not everyone is going to be able to run to that expense.

However, there is a solution which is easy, inexpensive and SAFE. It relies on the fact that you do not need to put the cord right into the flame in order to melt it - remember, the flame is always much too hot and will always burn and decompose some of the polymer.

I prefer to use a gas cigarette lighter, it gives a small stable flame.
Light the flame and bring the end of the cord close to the side of the flame. When the cord is still about half to one mm away from the flame, the fibres will start to melt.
Gently heat the end of the cord this way until all of the end has melted over.
Dowse the flame and dab the melted end onto the side of the lighter - it will stick.
Quickly drag the cord away from the lighter, this will drag off any blob from the end of the sealed cord and neck the fused polymer into a taper. It should look something like this:-

http://igkt.pbwiki.com/f/melt-sml.gif

If you have melted the fibres carefully, there should not be any discolouration and if you pulled out the blob quickly, there should not be any thickened rim around the end of the cord.

Trim off the whisker and the job is finished.

It takes a little practice, but after a few trials you should have the hang of not getting the cord too hot.

8

Hi Pat and Derek both,

You are right that for a competent adult and with proper practice it is straightforward to melt the end of a piece of plastic cord. I have done just as you suggested and had no problem at all (I can’t however promise that I am competent - LOL). You are also right in that the important word is excessive - but how much is excessive? Can a child be trusted to not use it excessively? Should someone with less than average intelligence or street smarts (I never test my students for this - I just have to take the stance that they could really foul up!) be entrusted this way? I have to err on the side of caution and that caution says - tape the piece temporarily using a piece of drafting tape, then sew it or glue it at the end of the work. We aren’t talking about practitioners of the art who do this on a regular basis and have learned through burned fingertips and perhaps a room full of smoke that heat can be a danger. If we advise, let’s advise using caution rather than advise using a potentially dangerous method, particularly when putting heat near someone’s skin!! :o

Lindsey

9

Derek, thanks for the picture. It shows the proper color of a melted, but not burned end. It’s possible that melting may emit unhealthy fumes.

Melting, because of its ease, quickness, low profile, and permanance, is always going to be an attractive method of finishing ends. From this discussion, a few points of good practice would be:

  1. Use the least amount of heat needed.

  2. Maximize ventilation, just in case.

  3. Don’t put your hands near or under melted nylon.

  4. Keep water nearby.

  5. (Others?)

P.S. Lindsey, the advice on melting ends presupposes a certain minimal level of skill and competence, as with any potentially hazardous operation.

10

Hi Roo,

You are correct that, of course, using heat presupposes - another word for which might be ASS-U-ME. Unfortunately, the world in which I live is litigious and I prefer to keep my home and chattels, small though they may be, against any outrageous claim that I encouraged the use of open flame, even with good practices (how do I know they haven’t left the gas pilot on or a bottle of solvent open - just a thought?). It is interesting to see that you needed to put in several points of good practice, even though it

presupposes a certain minimal level of skill and competence, as with any potentially hazardous operation.
:-\ - just a reminder that, even with a certain minimal level of skill and competence (which may have been gained, as with Carol, at the expense of wax on the tablecloth), we still strive to cover our position with further instruction, just in case! I would like to continue to use melting as a competent way of sealing the end of synthetic cord (unless it is resistant to low level heat, in which case I may be tempted to bring the flame closer yet than is perhaps healthy?) and I shall, given your and Derek’s good advice and leadership. I shall also continue to advise my students not to do this without having advised them of the hazards involved, which any competent instructor would do. ;D

Lindsey (not sued yet, touch wood!)

11

You are right, of course, Derek (and others :sunglasses: when finishing off ends burning is actually not the desired result. A nice melted blob is what I usually go for (the blob also having the side effect of stopping most beads I might have added from falling off the ends of the cords 8-). Sometimes, though, when you’re impatient or have an itch or something phttt it starts burning.

Some products I’ve been contemplating include the “Thread Burner” (http://www.artbeads.com/burn.html) which while perfectly good for thread might not have enough oomph for cord or the Clover Mini-Iron with Hot Knife Adapter (http://www.clover-usa.com/cat.php?k=59233). Of course, a soldering iron is probably cheaper and just as suited to the job.

The only place where I’m not sure the gentler methods might do the trick is when actually splicing cords together. I try to go for a good sized melted blob on both cords (simultaneously), touch them together then pull them apart (because you don’t actually want a blob in this instance, you’d ideally want the join to be the same thickness as the cords being joined). Blobs are needed because otherwise you end up with sharp scratchy fibres sticking out that hook onto everything and mess up your cord when you are tying your knot.

As for the age of people to teach, manual dexterity is a thing that improves with age, and the age you find on most kids knitting books is 8-9. At that age I wouldn’t dream of starting up a whole heat-sealing discussion (or cyanacrylic glues or…). For them I’d suggest just leaving ends as they are, or if adding beads, use a 3-4 turn capuchin knot.

12

Hi Carol,
Forgive me if I missed this suggestion on a prior post. Polution + dilution = solution. Take your smoke outside. Also, as was suggested in some prior post: do not burn the cord but melt the cord and let the fusion work for you. Very good idea, it melts way before it burns. If you work outside and use a heat that melts at your command instead in incenerating with no control I think very little noxious nasty comes to you and the expelled noxious nasty is diluted by all the air around you. Someone will say: “but it still goes into the atmospeher” to which I say “don’t exhale… ever again.. COtwo is still polution. Hold and pucker. If you puker good then no methane need escape.” Looking over the thread.. one more thought: If you decide to singe the ends with a propane tourch try to wear a shirt and tie your beard and hair behind you.. Yes Carol, no beard for you. Tie back hair or smell like burned chicken feathers. Your choice. Kidding aside the fusion temp of cord is so far below the burning temp of the same cord that it is just a matter of finding the right heat maker and there is no reason to do this inside. (of course Carol knows I ask you to do as I say an not as I do as she know I carry a Zippo). So at a show or under stress we do what it takes but at home we can find the right melter to put off almost no stinkum and still make the finished ends we love.

13

Carol,

You said ‘splice’ - do you mean that you actually fuse two cords together to join them?

Does anyone have any information on how this (inline fusing) affects the strength of cord/cable?

14

Yes, I mean fuse together when I say splice. If you do it right, you have a solid melted spot in the middle of your cord, so it’s not flexible anymore, whatever that may do to cord strength.

15

That sure is novel, I would never have thought of doing that. Technically, its a weld and provided you have not denatured the polymer, I see no reason why it should not be even stronger than the cord.

Does anyone have any references for this process?

16

Hi,
In the Telephone Industry we fuse glass fibers… but we do it for light tranmission, not strenght. I use heat to fuse the braid of synthetic cord to make it solid, often to help in tucking and end or often to finish ends when the knot is done. I just used heat to fuse the tapered yarns of a eye splice… so not long threads could stick out and no short threads could pull into the splice.. but… As an end to end joining.. a true splice… I can see no way get much tensile strength. It is an tempting idea. I may make up a long splice in some of the 7mm “stinkum” cord we have here and at the junction of two strands I try to fuse them with heat. Then I might try to destroy the splice, to see what I get. My guess is that fused ends do not transmit load up the thread, yarn and strand far enough to take advantage of the friction within a thread, yarn and strand. Have you watched rope fail? Friction is a big factor as to why rope works in the first instance. This is why there is a length where the long splice works no matter how sloppy you make your tucks. I suspect we could join two lines, carefull sheared to 90 degrees and fuse them to melt into the line for several turns and perhaps have a homonogous splice. However since the line relies on flex and transfer of forces through friction to be strong.. I think it will still break. A good avenue to explore. I am sure Carol was just fusing the end of the cord to prevent unraveling. The ever present zippo back splice. But it sent me to thinking…

17

What I missed in the replies so far, (or did I overlook it?) is that in many cases it is posible to use sticky tape. When working it will keep the ends of most kinds of string sealed. When applied right it does not need to make the string thicker by much, sometimes it even reduces the size of the string. Apply one and a bit, or two layers, of tape, well streched and under tension, before cutting the string.
It is no solution at the end of a project, but it should halve the need to melt.

Willeke

18

awesome discussion,
i will use soldering iron instead of shopping for a hot knife :slight_smile:

19

https://www.youtube.com/watch?v=Yys7isMYN5I

Here’s a video I made for a class that I was teaching to adults.

When I have just a few ends to singe or one join to make, I often (so lazy!) fire up our kitchen stove (gas) with the fan on full blast.

20

(Bold added to quote)
I find this interesting, but is “the side of the lighter” the plastic side (if it’s a Bic you mean) or the side of the metal top part? (which can get quite hot). I prefer to ask than to experiment - to avoid a damaged lighter.

Or is this the cold flat steel side of a Zippo? I had one 30 years ago when I was a smoker but I don’t think I could afford one now. In this part of the world they’re collectors’ items.