hey!

google was no help so ill start a thread.

I was cutting (on mitre saw) then milling pvc today and it had a horrid stench. Now ive got a bit of a headache and feel clamy.

Then again its very hot outside but can somebody give me a list of platics that are bad to inhale? Will i have cancer or is it just something i should avoid? what should i do when i am milling pvc to avoid the fumes? (perhaps just open garage doors and put fans on?)

thanks so much!

regards

Doing it once is not going to give you long term problems, but don't do it again. PVC generates a toxic gas when it is burnt or strongly heated; it can cause more than just a headache.

The vapors from nearly all plastics are bad to inhale, some are very bad such as PVC.

Doing it once is not going to give you long term problems, but don't do it again. PVC generates a toxic gas when it is burnt or strongly heated; it can cause more than just a headache.

The vapors from nearly all plastics are bad to inhale, some are very bad such as PVC.


gah... (nuts) Really appreciate the heads up. What do you guys do to avoid this?

Fan and maybe a respirator?

What about plastics such as polyethylene and polycarbonate?

thanks once again.

regards

.....Fan and maybe a respirator?

What about plastics such as polyethylene and polycarbonate?

thanks once again.

regards

Exhaust fan taking the fumes away from your work area or a rerspirator with a filter that removes organic vapors.

It is best however, to avoid generating fumes in the first place. Use coolant when milling and make sure your speed and feed are correct so you cut, not melt the material.

Polyehtylene, HDPE or UHMW are fairly benign, the fumes they generate are not much worse than a candle flame. Polycarbonate is not too bad but you should not breathe the fumes, use a mask or vent it.

google
+msds +pvc
+msds +polyethylene
+msds +polycarbonate


you will learn a LOT :)


robotic regards,

Tom

google

you will learn a LOT :)


Teyber12 had mentioned Google was no help so I decided to Google PVC fumes and see just what came up. One amusing thing was Teyber12's post was the tenth find on the first page; which shows how fast Google-bots do their stuff. I looked at a couple of finds which were posts from other forums and they did not have good accurate information, then pulled up a MSDS page which like most MSDS stuff goes on endlessly and is difficult to read. Here is an excerpt;

Chronic Effects:
Chronic exposure to fumes and vapors from heated or thermally decomposed plastics may cause an asthma-like syndrome due to the inhalation of process vapors or fumes. The onset of irritation maybe delayed for several hours. Fumes or vapors may accumulate within the facility during normal operating procedures that involve elevated temperatures. Exposure to these elevated concentrations, if not adequately ventilated, may have significant health effects.

Unless you know something about PVC this is not much help:

'thermally decomposed', does this mean burnt? It is not necessary to actually burn something for it to produce fumes, just get it very hot.

'asthma-like syndrome', what is this? Basically you have a bit of difficulty breathing and feel congested as if you had a bad cold.

'significant health effects' what do they mean by this?

Unfortunately the health effects from breathing too much of the fumes from thermally decomposed PVC can be very significant. PVC is made from Poly Vinyl Chloride, which gets some people all upset because it contains Chlorine!!! Provided the PVC is not 'thermally decomposing' that is not any problem. The problem is that when PVC is decomposed one of the chemicals produced is phosgene and this is very bad news. Too much Phosgene will kill rather nastily, it damages the lungs in such a way that they fill up with fluid and you feel short of breath; 'asthma like syndrome'. Google 'phosgene' if you want more detail.

Which is why my reply was that Teyber12 should not do it again.

What do you guys do to avoid this?

Sub contract it to China, they don't care about health and safety. I get a particular high index polymer blank from there- no- one else will melt and cast this particular plastic.

Run it cool, two flutes rather than 4, climb cut rather than conventional cut. Slower spindle speed and good chip extraction (air or coolant). You should be able to catch the chips comming off like to-nails and they should be no more than warm. If it stats clogging in clumps you're melting it.

Oh, and extraction. I use an 8 inch flexi tube right near the cutter venting to the outside. Paper masks won't help with fumes...only particles and even then they get holes in them after about 10 minutes breathing.

With PVC Hydrogen Chloride is your main problem but only if there's lots of it I think. See below. Hydrogen Chloride (HCl) is similar to Phosgene (COCL2) in that it reacts with moisture in body tissue (like lungs) to make Hydrochloric Acid. which reminds me of a poem by Wilfred Owen "Gas, Gas, Gas" or "Gas Boys Gas" can't recal which.

http://www.twi.co.uk/content/faqkg006.html

Owen's poem was "Dulce et Decorum Est" if anyone fancies seeing what gas did in WWI.
http://www.warpoetry.co.uk/owen1.html

....With PVC Hydrogen Chloride is your main problem but only if there's lots of it I think....

HCl gas does create Hydrochloric acid (Muriatic acid) in the presence of moisture, but this is a strong and immediate irritant. Anyone who has breathed the fumes from Hydrochloric acid has experienced this. The irritation encourages you to get away from the source of the gas, and inhaling a bit does not cause continuing problems.

As far as I know, HCl gas is not produced directly from decomposition of PVC, but Hydrochloric acid is produced by Phosgene in the presence of moisture and this is what makes Phosgene insidious.

Phosgene has a sweetish smell and when inhaled it does not cause much, if any, irritation; so there is no indication that you are inhaling anything harmful. However, the inhaled Phosgene dissolves in the moisture in your lungs and slowly produces Hydrochoric acid, but this acid is produced deep in the lungs and does not cause any discomfort (initially). What it does do is cause the lungs to become inflamed and fluid starts leaking into the air spaces. This is the normal reaction to an acid burn on any part of the body. Eventually the lungs fill with fluid and it is no longer possible to breath, and you die of drowing...in your own body fluids. Google 'Phosgene Carbonyl Chloride' for some links with horrible descriptions from WW1.

Why do I know about Phosgene? One reason is I do have a couple of degrees in Chemistry. The other is my Grandfather died due Phosgene poisoning in WW1, but he did not die fairly quickly in a matter of days, he survived for a few years with enormous acid burn damage to his lungs and died over a very long time.

:( you got my sincere sympathies Geof.

My own grandfather died of pneumocossis (sp?) through working down the mines in Scotland. I was at the bedside when he finaly went, I was only a kid, and it was neither dignified nor quick. The nurses/ doctors had him on a DNR (Do Not Resuscitate). He was a fighter and it took a long, long time. The images in my head are still with me forty years later.

One good thing came of it though, I suppose. I am constantly curious about stuff that I'm machining. I will not machine Beryllium, Zinc Selenide, Zinc Sulphide, anything that contains Thorium (232), Gallium Arsenide, Aresnic TriSulphide, Chalcoginide, and many other things that folk will just go ahead and do because "Joe Blogs did it, it must be ok".

Likewise, we used to wash our hands in Napthalene to get rid of the pitch from the lens polishing, when they found out this was dodgy, it was Tolulene, then that was thought to be a little suspect so they changed it to TriChloroEthane, then TriChloroEthene, then TriChloroTriFluroEthane. In know you know, but for others... that's 2 carbon atoms, joined with a single covalent bond: The first Carbon atom has three Chlorine atoms on it, the second three Fluorine (nice for the atmosphere and your skin/ lungs). We used a LOT, ie 50 gallons a day. There was an artificial cloud above our lab as it was pumped out in vapour.

I firmly beleive that if you do not research the stuff you're working with then no- one else will.

I have honestly seen folk angle grinding lenses coated with Thorium (half of which is Th232), an alpha emitter, which is more tightly controlled from a dust point of view by Governmental agencies than Uranium or Plutonium.

Because, simply, they didn't know (I put a stop to it).

I've seen men with their arms up to their elbows in Zinc Selenide dust eating their sandwiches

Because they didn't know.

Designers don't really have the intelligence to think things through. I've personally had in my hands a lens system that was giving off very significant amounts of Gamma. Looking into it, I found that the Thorium on the coating was giving off Alpha and Beta that reacted with the lead in the glass causing what the Germans call Brehmstallung radiation (sp?)- as the alphas/ betas get slowed down by the dense medium it spits out fast neutrons. Not good if you're looking through it for a while cos your eyes are close to your brain.

Wrong! It's been kindly pointed out to me that it spits out across the whole electromagnetic spectrum from visible right up- didn't know that! thanks Geof! Oh and it is "breaking" radiation (as in slowing down), not braking. The correct spelling is: bremsstrahlung, I am dumb :) sorry for the confusion!.

Sorry to rant on, but I firmly beleive that no- one will look after your own safety more than yourself... or am I being paranoid?

I ran a lot of plastics when working for a sign shop and we went threw a form of pvc called sintra and it was really bad. Venting is important but I suggest a mask. Look at getting a mask with changeable filters and get the organic filters. The best would be to get a mask the will bring in fresh air from some where else.

Sub contract it to China, they don't care about health and safety. I get a particular high index polymer blank from there- no- one else will melt and cast this particular plastic.

Run it cool, two flutes rather than 4, climb cut rather than conventional cut. Slower spindle speed and good chip extraction (air or coolant). You should be able to catch the chips comming off like to-nails and they should be no more than warm. If it stats clogging in clumps you're melting it.

Oh, and extraction. I use an 8 inch flexi tube right near the cutter venting to the outside. Paper masks won't help with fumes...only particles and even then they get holes in them after about 10 minutes breathing.

With PVC Hydrogen Chloride is your main problem but only if there's lots of it I think. See below. Hydrogen Chloride (HCl) is similar to Phosgene (COCL2) in that it reacts with moisture in body tissue (like lungs) to make Hydrochloric Acid. which reminds me of a poem by Wilfred Owen "Gas, Gas, Gas" or "Gas Boys Gas" can't recal which.

http://www.twi.co.uk/content/faqkg006.html

Owen's poem was "Dulce et Decorum Est" if anyone fancies seeing what gas did in WWI.
http://www.warpoetry.co.uk/owen1.html


i don't make enough of these for that. just a 16 year old with a hobby.

PVC is done. i heard you guys loud and clear. safety is always #1. switched over from pvc to hdpe (hope it has the tensile strength though...)

Thanks for the fast and great responses:)

Reed

There are two things that my laser manufacturer specifically say not to laser - pvc and teflon. Both emit very hazardous gasses and can do harm to you and the machinery. PVC emits chlorine gas when burned, lasered, and that mixes with the moisture in the air resulting in hydrochloric acid - nasty stuff. As said previously, it probably won't do immediate damage but you don't want to be exposed to it for too long. It also is very corrosive, lasers can be destroyed from periodic exposure. I won't laser anything that I can't verify is not pvc.

Gary