Let me start with a couple off-topic comments.
1) I've been making hoops, mostly fire hoops, for more than 10 years. I started with irrigation tubing, and switched to HDPE as soon as it was made available to me. I now sell two types of HDPE hoops: thick wall for fire hoops and thin wall for featherweights.
2) I have watched with dismay as people tried to describe their tubing using PSI, color, place of purchase and a myriad of other unrelated attributes. None of these things actually define the material. The type of plastic, the Outside Diameter (OD) of the tube, the wall thickness and Inside Diameter (ID) are usually all that truly matters. Fortunately other pertinent issues like fiber reinforcement and chirality have not yet come into play.
Recently I was asked if i was planning to switch to polypro hoops; like so many others since an oft repeated article on how to make your own hoops. As with everything that hits my desk, I took this seriously and put some research into this. I decided to put these two materials through a fair, side-by-side test.
First, I purchased 10' of High Density Polyethylene (HDPE) and 10' of Polypropylene (PP, or Polypro) from the same online location. Both are listed as pure materials, both are 1" OD tubing with 1/8" thick walls (3/4" pipe size). Upon arrival, i found the actual products to have wildly different lengths, so I cut them both down to 9.5 feet circumference and split them into 3 parts (as if for shipping).
The first thing I noticed was a distinctive chemical smell when heating the PP tubing. Generally, this is an indication that toxins are being released. The HDPE only released a smell when actually convinced to burn. In mass production, this toxin could start building up.
The Polypro feels a bit stiffer, but ultimately has less resistance to bending. The clearer walls mean that internal hardware (like wires and such) will be more visible, but so should any light sources.
Weight (with 3 nylon connectors): [US postal scale, legal for trade to 0.1 oz]
HDPE: 1lb 6.1 oz
Polypro: 1lb 5.6 oz
The site does not list the temperature limits for the PP tubing, so I will use descriptions from neutral sources instead.
According to wikipedia, HDPE can resist 248(f) for short periods and 230(f) for duration. PP melts at a wider range of temps ranging from 266(f) to 340(f) depending on the form of crystallinity.
PP is used in a few things and can be recycled into a limited number of goods. However, it has a major drawback of being a UV degrader. Photo degrading plastics contribute to serious environmental issues. This may also have an impact on overall lifespan. Hazardous chemicals are a byproduct of PP production, and some Canadian research indicates that it may leak toxins under certain conditions. And the nail in the coffin for use as a fire hoop material: it's vulnerable to aromatics (a type of chemical found in cheaper grades of petrol fuels)
HDPE is used in many many things and is commonly recycled into a variety products. It does not photo degrade, nor are any biotoxins released or used in it's creation. It's completely resistant to aromatics and other petrol byproducts.
I don't see Bearclaw ever switching to polypro. The miniscule weight savings and extra heat resistance do not warrant the 3-4x cost of the tube. The environmental impact of this tubing is poor enough to veto it alone. But since the bulk of my hoops are fire hoops, the chemical vulnerability is a complete deal breaker.
However, for LED hoops, I can see the clear walls being a juicy pick over the translucent white of the HDPE. Time will tell if the UV vulnerability reduces the lifespan of PP hoops not completely covered in tape. I have no idea how long the average hoop stays in use, nor do I know the rate of degradation. [FWIW, Kevlar also has a UV vulnerability, discoloration is evident in as little as a week in sunlight.]
I will say that if you have a polypro hoop, it's probably in your best interest to keep it away from UV lights, and out of direct sunlight (unless completely taped). Also, if you have a PP fire hoop, you should make very sure to use very pure fuels (like Coleman's camp fuel, crystal K, or UPLO) and wipe it down religiously after fueling and spinout.
A lot of people do sand their hoops, though I rather doubt this is why. Might get a few more doing it, though....
Right but I'm not talking about sanding with heavy grit paper for increased grip. I'm talking very low grit just to remove the mold release and antistat on the surface, then cleaning it to do your burn test again. You might have been smelling other stuff besides polypro or polyethylene.
Yeah, I get ya, but the heavy grit would also do that job, right? And since the inside of the hoop is the most likely to come in contact with the body, Inside heavy grit sanding would clear up most of the issue, n'est-ce pas?
Are you 100% positive HDPE doesn't release toxins in its creation? This has been a serious issue on my mind for some time now because I started going to school for Sustainable Living. My adviser has been an advocate on no PVC use because of its toxins released in creation and destruction. How different are HDPE (polyethylene) and polyvinylchloride (PVC)? I've attempted research and I end up reading dense documents where I get lost in chemical names. Basically I'm looking to start making wooden hoops (naturally not for fire hooping) and there is almost no information on how to do it online... so naturally I'd like to figure it out and educate anyone who wants to know. After 5 months of working towards this project (while being in school) I realized I can't be the only brain working on it, either. So... what is your opinion? Is the first step to "eco-friendly" hoops using HDPE (polyethylene)... perhaps already recycled? And have you any idea or tips on making wooden hoops? I tried willow branches woven together yet it's too flimsy, it has been suggested to me to use lamenations of wood and steam bend them. Thanks for your info on the polypro! Much appreciated! FINALLY someone discussing the ecology of hooping!
Am I "sure"... no. I wouldn't be "sure' until I made my own HDPE and tested all the byproducts myself. Could I find anything saying that HDPE was a polluter? No. HDPE is mostly used for gallon Milk bottles. Any kind of production intensive use like that seems like it should have had some attention paid to it if it were creating toxins.
This is not to say that some research hasn't been done and got suppressed, ignored, or just hasn't reached the areas that I covered an my searches. and nothing to say a new research won't turn up saying it's bad.
I like the wood hoop idea. look into "steaming" wood for chairs and such. that'll get you started. And if you pick a dense wood, like Oak or Teak, I would think that fire hoops wouldn't be a bad idea... built properly.
When I was on holiday overseas and didn't take a hoop with me, I borrowed my sister in laws cane hoop (like the ones you have in school, you know?). It wasn't half bad - why doesn't anyone use cane hoops?
Cane? As in sugar cane? or wood hoops?
No, kind of like bamboo?? http://thevintagewall.com/0911KEMP05.html I wonder if they would snap too easily? but I enjoyed playing with my SILs one with no problems (for only about a week albeit).
I think it's a function of availability. bamboo is more prevalent in some places than others, same for plastics. If it's a shorter drive to get to Home Depot than it is to get to the nearest green bamboo patch, then people will probably go with irrigation tubing. Plus, there's a bit of skill required to form bamboo into a circle without cracking, not to mention tempering, lacquering, and making custom joints. Irrigation tubing is easier to use, consistent in quality, ready made joints, and easily understood.
I could see someone making bamboo hoops for a kitch market and doing pretty well at them, but shipping might be a problem and any competition would pretty much kill it for everyone. Plus, I can see a lot of issues trying to make LED hoops out of cane, and nobody in their right mind would trust one as a fire hoop. that leaves the available options to "very few".
LOL, yeah, that makes sense. But for someone wanting to do a natural hoop it might be an option - don't know how old everyone here is or what its like in Canada/US, but in NZ the hoops we had when I was in primary school (around 1985-1990) were all cane. They were joined with more thin strips of cane wrapped around lots of times to bind, not with plastic or whatever is showing in that photo I linked to.