Question about cutting PVC

[Brent Ramsay-Boyd]

Hi All

I was asked recently by a client to cut a small amount of PVC backed reflective perspex. After reading up, I agreed to do it because it was a small Job and I thought it would not cause any problems. It ended up being about an hours worth of cutting.

After cutting I have decided I will definitely not be doing that again. After cutting I had a headache and felt nauseous. I have not had a chance to vent the room properly, so even going back in a day later I can the symptoms again. I will try vent it well this weekend.

Also while cutting I noticed that the power required to perform the cuts kept increasing. When I went to clean the focal lens this morning there was a white deposit all over the lens, and after cleaning it the lens now has a rough texture on the surface, so I think I have have to replace it.

My question is, what do I need to do to ensure there is no further damage to the machine. I am very worried that I have damaged my machine, I may be stressing for nothing, but I would really like some guidance. I cannot afford major repair work on the machine or even worse have to replace the whole thing.

Thanks in advance

Brent

[Dan Hintz]

Frankly, I would be more concerned about the damage to my HEALTH than the machine... if you cut that stuff and vented back into the room without a proper carbon filter setup, I would suggest setting up a doctor's appointment and looking at getting a breathing test done with a specialist.

[Brent Ramsay-Boyd]

I am definitely worried about my health. I did try and spend as much time outside as I possibly could, but I did still feel some ill effects. I am even anxious to continue using the machine now until I am sure it is safe to do so.

I am a bit of a hypochondriac, so I don't want to over react, but I am not prepared to put myself at risk. I do not have a carbon filter and some of the fumes were definitely coming back into the room.

[Dan Hintz]

The off-gas byproducts of PVC burning (hydrogen chloride) combines with moisture in the air to create hydrochloric acid. This stuff does permanent damage to sensitive lung tissue (not to mention what it will do to your machine... expect a heavy rust to cover any steel parts in short order if you cut thick sheets of it). You should not be using anything in your machine with PVC in it.

I cannot stress enough how bad it is to work with these machines without proper ventilation (and that does NOT mean just ventilating the room the machine is in). You need proper filtration if it is venting back into the room.

[Brent Ramsay-Boyd]

Well now I am terrified of the damage I may have done to myself. I wish I had asked this question earlier. I though I had done my research, and people had seemed to think that a one off small job like this would not be a problem.

The material was not thick, it was 3mm reflective perspex, with a pvc backing, less than 1mm thick. I really hope I have not cause serious harm to myself.

Thanks for you feedback, I wish everyone was as well informed as you are.

[Mike Null]

A small job like that shouldn't have been a problem. Pay attention to what Dan says about ventilation. You will, no doubt, have similar issues with other materials.

I recently engraved some horn mugs. The smoke and odor gave me a real problem for a couple of hours (throat irritation and coughing). I finished the order the next day using a cheap respirator and had no problems.

[Brent Ramsay-Boyd]

Mike thanks for the input, it has put my mind at ease a little. I will however be booking a doctors appointment for tomorrow just to make sure.

I will definitely not be cutting anymore pvc at all. I do have a 3m face mask, but I stupidly wasn't wearing it at the time. I will definitely be looking at getting a proper filter system in the near future, unfortunately I have not had the finances to do so.

Should I be worried about any lingering off-gases from the cutting, ie, could they have soaked into anything in the garage where they could stay and continue to be harmful, or will a good ventilation of the room be enough to make it safe to work in again. I unfortunately cannot do it at the moment as we have unknown workers on the property at the moment, so I cannot leave the garage open.

I will do so this weekend, and I will also be giving the laser machine a good cleaning after to get rid of any residue left behind.

I am a very anxious person generally, so I am very weary of doing anything to put my health at risk. This has even made me consider just getting rid of the machine, but it is something I invested in as a business so I do not want to act rashly because I am probably over reacting.

Thanks again for all the advise.

[Mike Null]

I haven't experienced any health issues as a result engraving any material in my 18 years years of engraving.

MY machine is in my basement and I exhaust the fumes outside with a blower that seems to work quite well. At times I can still smell some odor and there is a lingering odor from wood and plastics but it disappears quickly.

In all of the thousands of posts on this forum I can't recall any that identified a permanent health issue related to laser engraving.

[Dan Hintz]

In all of the thousands of posts on this forum I can't recall any that identified a permanent health issue related to laser engraving.

I'm also unaware of anyone who has cut plastic and vented directly back into the room with no filtration...

[Scott Shepherd]

It could very well be the Perspex that caused your symptoms as well. Some people are very sensitive to it. One of our customers walks into our office when cutting acrylic and almost instantly gets a headache and we're vented fairly well.

My guess is the PVC doesn't cause your symptoms, but rather breathing the Perspex cutting for 1 hour with no ventilation. I'm not suggesting cutting the PVC was okay, or possibly not harmful, but just letting you know that cutting Perspex without ventilation is also shouldn't be done. I don't think 1 hour worth of exposure to Perspex cutting did any permanent harm, but I'm not a doctor, so that's just my gut reaction.

[Brent Ramsay-Boyd]

I work from a double garage. I work with both of the garage doors open and with the vent hose blowing out of the door. Unfortunately the hose I have only just reaches outside. Most of the fumes were blowing away with the wind, but occasionally some may have blown back in. I think this combined with the fumes that escape from the lid (it is not very well sealed) of the machine were what I was smelling. I tried to stay in fresh air as much as possible while popping in every few minutes to keep an eye on the cutting.

[Dave Sheldrake]

I cut quite a bit of PVC on a laser Brent BUT it has to be done with very specific extraction systems that over here are tightly controlled by law. The normal home user extraction and filter systems simply won't do the job (the HC will mix with moisture in the extraction system and rot it out very quickly)

Scotty, Dan and Mike are all correct, cutting acrylic for an hour likely hasn't made you more healthy but I doubt you are in any immediate danger of dropping dead ;), PVC is another animal, the fumes from that don't damage all at once, the effects can build up over a few days so a quick check up may well be in order.

You may also have restrictions in your area about venting to atmosphere, especially with toxic / corrosive fumes like HC being vented.


I do have a 3m face mask

Depends on the rating for the mask, if it's a fine particulates mask that will keep out acrylic dust but will do nothing to prevent toxic fumes and gasses (In some cases a mask can make things worse not better)

If you get any odd jobs or whatever in future just drop by and ask...somebody here will have an answer..it may not always be the one you are looking for but somebody will know.

After all,all we can only say "No" and prevent a problem...there may be a time though if people don't ask that we also cannot fix what happens to them ;)

[Brent Ramsay-Boyd]

Thanks Dave

I will definitely go for a check up tomorrow, if anything just to ease my mind. The mask I have is a 3m half face mask with 6075 A1 filters for organic compounds and formaldehyde. But as I said I stupidly wasn't wearing it yesterday because I was talking to the customer while I was cutting.

The material I was cutting was 3mm perspex which I believe may have had glass bead in it for reflective properties, and the perspex was backed with a 3m 610 series reflective vinyl.

As I said before, PVC of any sort will be on my no-go list from now on.

Thanks

Brent

[Dan Hintz]

Just a side note no one seems to have mentioned yet... if you're cutting anything flammable (and acrylic fits well within those boundaries), you should not be anywhere other than watching the machine like a hawk. Too many users here have lost more than just the machine itself to major fires hat were likely preventable with someone nearby watching the operation.

Talking to a customer while the machine cuts something in the background is adequate flame-up time to see major damage to the machine itself, and if left unchecked, plenty of stuff beyond the machine (like your garage!).

[Clark Pace]

I have a CNC for cutting PVC. While the debate is still out. I Don't do ABS anymore either. I cause me headaches. Please be careful. If you are unsure contact your laser company if possible, and an MSDS is a good start as well. You might have a big job cleaning the machine now. And do a very thorough job.


Just a side note no one seems to have mentioned yet... if you're cutting anything flammable (and acrylic fits well within those boundaries), you should not be anywhere other than watching the machine like a hawk. Too many users here have lost more than just the machine itself to major fires hat were likely preventable with someone nearby watching the operation.

Talking to a customer while the machine cuts something in the background is adequate flame-up time to see major damage to the machine itself, and if left unchecked, plenty of stuff beyond the machine (like your garage!).

[Brent Ramsay-Boyd]

Hi All

I have been to the doctors and done a breathe test and the doctor has assured me that i am in the clear.

Thanks to everyone for there advise, an important if not somewhat terrifying lesson has been learnt and I will be making some significant changes wrt filter and extraction before I continue working with the laser cutter. I will also make sure I ask before I do anything I am unsure of.

Thanks Again

[Scott Shepherd]

That's great to hear Brent. I'm sure the last day or two have been quite stressful for you. Hopefully you can relax now and get the things put in place to make sure you are safe in the future. Thanks for the update, that's great news.

[Keith Winter]

Brent that sounds pretty problematic. The way your describing it a lot of the fumes will be blowing back in even if you cannot smell it they may be hurting you doing stuff like pvc. Not worth it, especially in a setup like you're describing. You may be harming your health. Get a proper setup with a blower venting to an outside wall asap is my suggestion.

[Kev Williams]

another word on blowers and venting- if at all possible you want the blower outside. If it's inside, you have positive pressure from the blower to the outdoors. if there's any leaks in the venting or the blower itself, the blower just pushes smoke & fumes thru them.

With the blower outdoors, the entire ventilation system indoors will be in a negative pressure/vacuum condition.

[Michael Kowalczyk]

I thought that the off gas produced from lsasering pvc was cyanide i would not do any PVC job unless i could do it on my CNC router. Just not worth the risk no matter how much it would pay and I have an air extraction system that would peel the paint off the laser IF trotec didn't do such a nice job painting it. It is either a 3HP or 5HP 3 phase motor which extracts at about 2000 CFM. which sadly makes the AC air disappear quickly. Blast gates help control it though.