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[Martin (Admin)]

Get a cheap soldering iron or a replacement tip for you current soldering iron.

 Get a hammer....

 Hammer the tip flat! 

http://www.metacafe.com/watch/854340/cut_even_thick_plastic_like_butter/

[Reade Models]

There is some recent medical research, initially reported on SKY TV, that suggests that breathing fumes from molten plastics can cause diabetes and heart disease in laboratory animals - although no conclusive work has been done to quantify the risks for humans as yet.

The plastics manufacturers add Bisphenol to some plastics (the Sky report was about PET drinks bottles) and as we've also more recently discovered to HIPS (High Impact Polystyrene) i.e. Plasticard as a flame retardant.  The Bisphenol doesn't combine with the plastic at a molecular level and can apparently leach out of the PET bottle material in normal use.

Breathing the fumes of the molten material may seriously damage your health if you do it for long enough as I've discovered having spent most of the summer in various diabetes clinics and cardiac units around the north west.  My dad and younger brother also have similar medical conditions, and we're beginning to think that operating injection moulding machines over the years MAY have caused the problems, but we can't be certain?

Until some better research is done, it's best to be very careful when melting ANY plastics and DON'T breathe the fumes.

You should be perfectly safe handling and working with plastics (cutting and glueing etc).

Malc

[tobyker]

The Weller pistol type soldering irons come with flat bits for cutting/welding plastic - and you can always cut a slot in a spare bit and silver solder a scalpel blade into the slot. Been using both on my Sovremmeny. (props promised for this week - just when the family come up over the gks half term!)

[Weeds]

There is some recent medical research, initially reported on SKY TV, that suggests that breathing fumes from molten plastics can cause diabetes and heart disease in laboratory animals - although no conclusive work has been done to quantify the risks for humans as yet.

The plastics manufacturers add Bisphenol to some plastics (the Sky report was about PET drinks bottles) and as we've also more recently discovered to HIPS (High Impact Polystyrene) i.e. Plasticard as a flame retardant.  The Bisphenol doesn't combine with the plastic at a molecular level and can apparently leach out of the PET bottle material in normal use.

Breathing the fumes of the molten material may seriously damage your health if you do it for long enough as I've discovered having spent most of the summer in various diabetes clinics and cardiac units around the north west.  My dad and younger brother also have similar medical conditions, and we're beginning to think that operating injection moulding machines over the years MAY have caused the problems, but we can't be certain?

Until some better research is done, it's best to be very careful when melting ANY plastics and DON'T breathe the fumes.

You should be perfectly safe handling and working with plastics (cutting and glueing etc).

Malc

Everything you breath into your lung either comes out, sticks to the mucus in your trachea and gets spit out, or enters the alveoli and STAYS there FOREVER. Lungs have no way of getting particles that stick to alveoli out. Even a little amount of toxic airborne particles gets into your lungs will stay there your whole life.

[Reade Models]

Everything you breath into your lung either comes out, sticks to the mucus in your trachea and gets spit out, or enters the alveoli and STAYS there FOREVER. Lungs have no way of getting particles that stick to alveoli out. Even a little amount of toxic airborne particles gets into your lungs will stay there your whole life.

Except that I wasn't discussing particulates - rather the gases generated by heating Bisphenol which is added at the time of manufacture to various plastics...

Regards, Malc

[roycv]

Hi all I use one of those plastic cutters that cuts a groove, and this works well.

However I do use a hot soldering iron to cut out sails when I am using Dacron or similar.  This seals the edge of the woven fabric and has proved effective over the years.

See attached picture taken just a few weeks ago.  The sails are for a 36 inch loa yacht.

Regards Roy

[Martin (Admin)]

The Weller pistol type soldering irons come with flat bits for cutting/welding plastic - and you can always cut a slot in a spare bit and silver solder a scalpel blade into the slot. Been using both on my Sovremmeny. (props promised for this week - just when the family come up over the gks half term!)

Funny you should mention that, last night......

[bogstandard]

I have to agree with Malc on this one.

Hot cutting on a lot of man made products (and some natural ones) puts yourself at dire risk. Some of these 'inert' plastics actually revert to more dangerous products when subjected to heat. Even small doses can become very toxic very quickly. If you feel faint, heart palpitations, numbing of fingers etc, all point to poisoning. Usually, it can be too late by the time these symptons appear. The only true safe way, is don't do it. If someone tells you to hammer a nail in your head, would you do that as well.

If it doesn't get to you straight away, it might reappear as a symptom many years later, due to cumulative effects. I know not plastic, but think of asbestos. Cutting PTFE to a hot state whilst smoking tobacco can produce phosgene gas in your lungs, a very effective snuffer gas, used during the first world war.

So be very careful, if you can smell it, it is already inside your body, and doing its best to hurt you, or even worse.

John

[Martin (Admin)]

OK to do it in a well ventilated area or outside?

[bogstandard]

if you can smell it, it is already inside your body

[Reade Models]

I wasn't advocating NOT using hot knives to cut plastic sheet, far be it for me to do so.

I was only indicating that the fumes given off by this process MAY be harmful - but probably only if you inhale enough of the stuff over a long period of time?  Actually, some grades of High Impact Polystyrene have a very nice smell when molten, but that probably only belies the dangers?

My dad starting moulding model ship fittings in the mid 1940's just after WW2 and has spent most of his life since working on bench-top injection moulding machines.  His heart problems started when he was 58 years old (My age now).  He has had a triple bypass since, but is still working on his modelling projects at 82 - and long may he continue to do so.

My brother Keith and I used to operate the same machinery as youngsters in the 1960's - we earned extra pocket money in our teens mainly by manufacturing umpteen hundreds of thousands of injection moulded model aeroplane wheels.  Keith was diagnosed earlier this year as having had a 'silent' heart attack sometime in the past - and he was a very fit ex-career soldier (RMP Special Intelligence Branch) at the end of his military career.

I too have been recently diagnosed with a 'heart condition' of some sort - they're still trying to establish what's causing my irregular ECG trace?

On the basis that there hasn't been any history of heart disease in the family previously, I'm beginning to get the feeling that the chemical Bisphenol that is added to lots of plastic compounds as a flame retardant may be the cause of the problem when heated?  It certainly causes heart disease and diabetes in laboratory animals.

It's too late for us now, you can't reverse heart disease.  I suppose that the chances of any modeller actually acquiring the same problems by using a hot knife to cut plastic sheet on the odd occasion are extremely remote, but that doesn't mean that anybody should needlessly breathe the fumes if they are potentially damaging to health?

Malc

[Weeds]

I wasn't advocating NOT using hot knives to cut plastic sheet, far be it for me to do so.

I was only indicating that the fumes given off by this process MAY be harmful - but probably only if you inhale enough of the stuff over a long period of time?  Actually, some grades of High Impact Polystyrene have a very nice smell when molten, but that probably only belies the dangers?

My dad starting moulding model ship fittings in the mid 1940's just after WW2 and has spent most of his life since working on bench-top injection moulding machines.  His heart problems started when he was 58 years old (My age now).  He has had a triple bypass since, but is still working on his modelling projects at 82 - and long may he continue to do so.

My brother Keith and I used to operate the same machinery as youngsters in the 1960's - we earned extra pocket money in our teens mainly by manufacturing umpteen hundreds of thousands of injection moulded model aeroplane wheels.  Keith was diagnosed earlier this year as having had a 'silent' heart attack sometime in the past - and he was a very fit ex-career soldier (RMP Special Intelligence Branch) at the end of his military career.

I too have been recently diagnosed with a 'heart condition' of some sort - they're still trying to establish what's causing my irregular ECG trace?

On the basis that there hasn't been any history of heart disease in the family previously, I'm beginning to get the feeling that the chemical Bisphenol that is added to lots of plastic compounds as a flame retardant may be the cause of the problem when heated?  It certainly causes heart disease and diabetes in laboratory animals.

It's too late for us now, you can't reverse heart disease.  I suppose that the chances of any modeller actually acquiring the same problems by using a hot knife to cut plastic sheet on the odd occasion are extremely remote, but that doesn't mean that anybody should needlessly breathe the fumes if they are potentially damaging to health?

Malc

just curious, what's the specific ecg trace you've got going on there..

[Reade Models]

I'm no expert on ECG traces, but as I understand it, the lower part of the trace (the bit below the 'zero' line) isn't normal - the trace stays below the line for longer than is usual?  It sort of bottoms out, and then 'steps' before the next beat?

Malc

[tobyker]

Very ingenious, Martin.

[TCC]

Cutting PTFE to a hot state whilst smoking tobacco can produce phosgene gas in your lungs, a very effective snuffer gas, used during the first world war.

What was that John, if I'm cutting some PTFE pipe while smoking, the combined emittence is phosgene gas?

We've probably spent millions getting Porton Down to weaponise that process. Hell, we probably invented PTFE as a weapon... and tobbaco!!

[malcolmfrary]

Back in the early '70's we started using ptfe insulated wire.  Strict instructions were issued to the effect that it had to be wrap-terminated and not soldered due to the danger of production of a "dangerous gas" due to heating.  The gas was rumoured to be phosgene.
The ptfe was used in this case when a large number of wires had to be poked and pulled through the small apertures in pulse transformers, and it was the mechanical property of sliding easily against its mates, reducing the chance of damage due to melting insulation, rather than any electrical property that was wanted.
This in an industry where the standard for internal cables was cloth insulation, impregnated with, among other things, arsenic, as a moth preventative.

[Weeds]

I wish Martin would make a public service announcement warning people not to burn plastics.

Many plastics contain dioxin and burning them releases dioxin into the air. Dioxin => cancer. This cancer-causing poison stays in your fat cells forever.


IN CONCLUSION I WONT BE BURNING PLASTIC ON MY BONFIRE

Source: http://plasticisrubbish.wordpress.com/2008/06/02/dioxins-why-you-dont-want-to-be-burning-plastic/

[Colin Bishop]

Isn't ita bit anti social to have bonfires anyway these days? Certainly in residential areas anyway.

[bigH]

  I don't know anyfing abaht breefing in the fumes but I DO know that if the fumes get in your eyes you can have the finest case of Conjuctivitus eyes that you have ever seen from the outside and inside,   

[Damien]

Once while arc welding a few stray hot bits set fire to a white foam vegetable box, within minutes i had raging flu symptoms and a headache so bad i felt i had to hold the top of my head on, the symptoms lasted 2 weeks. Very picky where i weld now lesson learned the hard way.
Damien.

[andrewh]

While I never disagree with John (Bogstandard) and the views expressed about overheating PTFE* (and other fluoropolymers) are absolutely right in principle, but the gas produced cannot be phosgene (CoCl2) since PTFE contains no Chlorine

*(Teflon is a Dupont brand name.  PTFE is polytetraflluorethane , and the "Fluor" is the key bit)

PTFE comes apart thermally above 405 degC to release free Fluorine gas - which is lethal and dissolves in the water in our lungs to form hydrofluoric acid (HF) which is even worse.

The message is do not overheat PTFE or Viton or PVDF of any of the other plastics with an F in the name - it can be very bad.  This is the reason I would not reccommend Viton "o" rings to amateurs or general modellers

Overheating most plastics will produce, at best, acrid fumes - in some cases these are harmful or very harmful.  Overheating (burning) polyurethanes (PU) produces cyanides  - which is what kills many people in house fires.  I won't have PU in the house, or synthetic upholstery coverings for this very reason of family safety.

So please:
- breathe as little fume as possible
- don't hot-wire cut PU
-avoid PTFE if it could be overheated
-don't worry excessively - we are getting most of the exposure by handling plastics, eating out of them and gumming highly plasticised  PVC as babies

Mentioning PVC (polyvinyl chloride) reminds me that overheating any vinyl material (or neoprene) WILL produce chlorine and COULD produce phosgene - neither are healthy

andrew

[Roger in France]

Good advice about burning or overheating plastics.

However, before anyone panics about eating food and drink from plastic containers you can rest assured that the permitted levels of leaching into food is scrupulously covered under the  Materials and Objects in Contact with Food Regulations. The levels set are many degrees below any harmful effects which could result in a lifetime of consumption.

However, a good tip is always carefully wipe the neck of your wine bottle before pouring the wine if the bottle has a lead capsule.

Roger in France