iquark

I wanted to post a quick safety tip regarding methylene-chloride (Dichloromethane, or IPS Weld-On #3,4,16) and Organic Vapor (OV) respirators.

I have been working on an acrylic case for a little while, and have move onto the gluing portion of the build. I am bonding multiple pieces with this chemical and I had a slight scare when after about 5 minutes of gluing I got light headed and disorientated despite using a half-face respirator. The respirator was a 3M professional 6000 series with OV rated cartridges which did not mention special needs regarding methylene-chloride in the instructions (at least anywhere I could see it). This was also despite the lack of the characteristic smell of methylene-chloride.

Little did I know, OV rated cartridges cannot withstand methylene-chloride for anymore than an extremely short period of time. According to OSHA anything besides a pressurized air system is ineffective at preventing over exposure.

I do not mean to say that Weld-On #3 is especially dangerous when used under the right conditions. I was in a garage with limited airflow relying on the OV cartridges to protect me. I have used the glue again in an open air situation since this happened, and had no issues with the fumes. However I wanted to warn everyone in case others were planning on relying or have been relying on respirators in order to protect themselves.

The reason I wanted to post this is because when researching this project on OCN I did not run across this information anywhere else. I hope that this will enlighten anyone who is thinking of using methylene-chloride in the future, and to protect from the cancer properties that it has. Hopefully others learn from my idiotic mistake!

For a little more reading:

OSHA's 1998 ruling on Methylene-Chloride: OSHA

mattliston

good to know

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CattleRustler

thanks for posting this.
I use weld on 3, and good ventilation is key

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CyberDruid

I thought that light headed feeling was just the joy of modding with acrylic

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hombredelassrtas

where do you get that as i can not find proper glue for lexan

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CattleRustler

where's Syr...

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iquark

LOL!

I'm a big fan of the respirator in the winter since having the garage open makes it too cold to work with paint/lacquer most days. Xylene's my favorite solvent for pretty much anything and I never have had issues with dizziness before!

I had only worked with MC a few times before this, and they were in a college orgainic chem class under a hood. I didn't realize how noxious it really was until this weekend.

MC based solvents such as Weld-On #3/4/16 work well for polycarb if I remember right. Check your local glass store (window companies) to see if they have any. Also you can use Chloroform (methyl-chloride/chloromethane), but it does not bond as quickly as MC.

cathode

What was the rating on your respirator? I use a P100 rated cartridge respirator, but i guess that would be insufficient for working with MC?

Syrillian

I've been using Weld #3 for years now and my drain is not bamaged.




Seriously though, ventilation is paramount.

Good post Iquark. +

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iquark

So P100 rated respirators are referring to their particulate protection. In fact they actually raise in their protection as they're exposed to more and more stuff in the air. However, this is only things like sawdust, acrylic particles, paint particles, and other 'dust' type items suspended in the air. I think it may refer to some types of mold as well, but you'd have to double check.

P100 rated cartridges do nothing for organic volatiles, things like xylene (lacquer thinner), paint thinner, mineral spirits, ethanol etc. The propellants in most spray paints, as well as the solvents in most regular paints are volatile organic chemicals, and these require special 'OV' rated respirator cartridges.

MC however saturates and moves through an OV rated cartridge in a very small amount of time (according to OSHA). If you want to work with MC in a confined space without proper ventilation, then you need some sort of pressurized air system like SCBA or a feed line mask!

Anyway, most of the cartridges sold by 3m for home/worksite use I've seen around are p100/OV rated. These are great for spray painting as they give the OV for the propellant and the p100 for the paint particles. Just don't think they'll protect you from MC exposure!

Oh the canisters I was using were 60923 I believe, I'll have to double check that though.