Monday, September 18, 2006
Trimmer line progress (or lack thereof)
The trimmer line got a bit sticky after a few seconds, but after 30sec, still not fully liquified. It had the consistency of marshmallow fluff.
With the soldering iron test, the line was basically pressed against the body of the iron. The line immediately turned mushy and melted, however it also started emitting plenty of wierd smoke. After removing the line there was also a bit of black residue on the metal. I'm not sure if this was because the iron was too hot or because of the trimmer line's composition (pvc fumes?).
At any rate, I am definitely liking the idea of using alternative, higher temp materials in an extruder. Soldering iron element can easily break 200degC and can be mounted without too much effort to an extruder barrel. It would give us a bigger variety of source-material, whether CAPA or recycled material.
Here's some possible sources of polymer with unknown melting points and composition. If anyone knows the composition and whether any of these will make viable sources, please respond:
Lawn Trimmer line (still testing)
Styrofoam / Packing peanuts
Plastic shopping bags (lots of them)
Plastic cups / dishware (many varities)
Plastic bottles (water, soft drink)
Melted-down junk? (computer equipment plastics
Maybe it's a pipe-dream, but the idea of being able to recycle 'junk' and turn it into usable parts/products sounds pretty inticing.
PVC, when it decomposes creates Chlorine and Hydrogen Cloride gas. When this enters your lungs, it reacts with moisture to create hydrochloric acid. This tends to irritate best case, and destroy, worst case, any lung tissue it encounters. Needless to say, this is not a good situation to be in.
Other plastics can create other compounds that can also affect your health.
Just be careful and make sure if you are going to do experiments like this, that they be in well ventilated areas, preferably, outside.
Oh, and probably goes without saying, avoid breathing any fumes that happen to be created. :)
1 = PET or PETE (260 C)
2 = HDPE (120-130 C)
3 = PVC (212 C)
4 = LDPE (105-115 C)
5 = PP (165 C)
6 = PS (240 C)
7 = mixed/other
Clear plastic shopping bags (fruit and vegetable bags) tend to be LDPE; regular plastic shopping bags and milk cartons tend to be HDPE. Soda bottles tend to be PET. Packing peanuts tend to be PS (Styrofoam is PS - Polystyrene, and air). I've seen type 5 in some food packaging. Printer parts and other non-food containers tend to be types 3, 5, or 7 (and they usually do not label them with recycling symbols because, I suppose, they don't get recycled as often as food containers.)
Dont worry about that. Anyone that intentionally burns plastic indoors without wondering about health effects isnt going to be around long anyway.
Beagle, of those materials you graciously listed, which ones might be viable, safe sources of polymer?
HDPE seems to oxides before it turns liquid (though some disagree with me) . It is an amazing plastic though and it worth trying to overcome the problems.
LDPE was the easiest as beaglefury's table suggests.
PET is pretty much out because it reacts with water when heated.
PP and PS both discolored slightly and didn't form a uniform solid. PP distorted badly when cooled.
Didn't do PVC.
My interest is HDPE. It could be possible to make filament at lower temps using higher pressure or keeping the O2 away.
Extrusion aside - I'd like to make blocks of the stuff for machining.
Perhaps there are dyes/inks that are breaking down?
If you can maintain a temperature of 180 C on a metalic container filled with HDPE, I suspect you will not see see much (if any) oxidation.
Is there a particular type of bag that is made of PVC (Those more commonly used in craft/gift stores, maybe?) I seem to recall food packaging being possibly PVC based?
In any case, as long as you tune the temperature for HDPE, PVC shouldn't decompose too quickly (It starts decomposing ~200 C, melts at ~210 C, and rapidly decomposes at 250 C)
Herr Beagle, about spray on nylon, apparently it is not easy to get the ratio of diamine and a dicarboxylic acid. Well, that's what Wikipedia says anyway. ;-) In the same article they mention a prepared correct ratio "paste" approach, now that could be interesting.
Now this link to a "Nylon in the Comfort of Your Own Home". Sounds like fun.
A quick look through their help files didn't help me much. Does anyone know a good way of pasting an url into a reply?
In any case, for those wanting to click the link to making nylon at home I found it at the bottom of the Wikipedia article on nylon.
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