Question For Chemistry-savvy Modelers

QUOTE: Originally posted by styrene Tho, : The butyl is less toxic than the methyl. Obviously there's more that goes into it than that, but I think you understand what I'm saying...

basically... but the one thing I didn't get is the apple to volkswagen thing... I mean they ARE about the same size huh?

kidding... I think you are right though, thinking back... the 300-600 was over a 3-4 hour span.

I can't remember the 5ppm though.. I may go back and look at it.. it's kind of interesting in a way...

Tho,
Thanks for the vote of confidence, but the NSC has access to the same information that I do (just look at the bibliography). I just think they got their reporting a little messed up. They probably simply need a few good proof readers and editors. I think the NSC can be believed; I mean it's not as if DAN RATHER is putting this stuff out...

The 5ppm Time Weighted Average you referred to is pretty low--and that's because the EGmonomethyl- and EGmonoethyl- ethers are fairly significant reproductive toxins; the methyl being worse than the ethyl. I think the 500-600ppm you reference has to do with IDLH concentrations (Immediately Dangerous to Life or Health), which is the maximum concentration one can be exposed to without a respirator, and can ESCAPE from without suffering long-term health effects (at least that's the way I kinda understand it). At any rate, a 5ppm TWA cannot be compared with an IDLH level...kinda like apples and Volkswagens. However, a 5ppm TWA for the methyl stuff can be compared to a 50ppm TWA for the butyl stuff, and a deduction made: The butyl is less toxic than the methyl. Obviously there's more that goes into it than that, but I think you understand what I'm saying...

Gip Winecoff

QUOTE: Originally posted by styrene Tho9900, Thanks for the link. I visited it, and must say that even using the sources they cited, they still managed to somehow royally screw up their report. Amazing. Gip Winecoff

seriously screwed up... after reading some of the other info out there it seemed either right on your take on it, or more on your side of thinking than theirs. One of the sites I visited listed safe inhalation level at 5ppm, while another listed it the danger level at 300-600 ppm... which is quite a big spread if you ask me... I think I tend to sway more to the safe side on this one... you would think an entity like NSC would be more inline with the rest of the community...

Like I said previously... it's always good to have someone like you to questin things like this... we might have gone on believing the NSC...

Tho9900,
Thanks for the link. I visited it, and must say that even using the sources they cited, they still managed to somehow royally screw up their report. Amazing.

Gip Winecoff

QUOTE: Originally posted by styrene Once again, I just saw this post and had to jump in...Sorry... Quite the contrary. Of all the glycol ethers, EGMBE is the safest, both from an acute (short-term), and chronic (long-term) standpoint. QUOTE: Inhaling glycol ethers can result in dermatitis with erythema, edema, and weeping; hyperpigmentation; and photosensitization. By the way, how does inhalation lead to dermatitis, which is a response to direct contact?

glad you cleared that up.. I got that off the NSC's website. good to know it's not as scary as it sounded...

As far as dermatitis, it's what they had listed, perhaps they mean a rash... like when people develop a rash after eating something etc... What you are talking about is contact dermatitis, dermatitis can also result from anxiety, allergies to foods or medicines, etc...

Here's the link, it's from the National Safety Council:

http://www.nsc.org/library/chemical/glycolet.htm

Another wierd chemical though, even the goverment websites go from saying it's the most dangerous to least dangerous chemical in it's class depending which site you visit.

It looks like the median between the two extremes is to wear skin protection and use good ventilation. And on any skin contact wash immediately...

Once again, I just saw this post and had to jump in...Sorry...

QUOTE: Ethylene glycol monobutyl ether is regarded as the most toxic glycol ether used as a solvent.

Quite the contrary. Of all the glycol ethers, EGMBE is the safest, both from an acute (short-term), and chronic (long-term) standpoint.

QUOTE: Inhaling glycol ethers can result in dermatitis with erythema, edema, and weeping; hyperpigmentation; and photosensitization.

So far, current research literature does not agree with this assertion. By the way, how does inhalation lead to dermatitis, which is a response to direct contact?

From a modeling standpoint, it's important to know that acrylic paints and solvents containing this material may have the potential to cause eye and skin irritation. In addition, this material has the ability to be absorbed directly into the bloodstream from contact with intact skin, and may also de-fat the skin, opening up the possibility of dermatitis. Therefore, if skin contact is reasonably anticipated, then a pair of rubber or nitrile gloves should be worn when handling the stuff. Of course, inhalation of this product when spraying should be avoided.

I agree that isopropyl alcohol is OK to use as a substitute for EGMBE.

Hope this helps some.
Gip Winecoff

i correct myself, tamya thinner has an inhibitor that slows down drying. its not just alcohol.

i use tamiya acryls, the tamiya thinner smells and is just alcohol. what kind i know not. gunze thinner is cheaper and better........

from what I am reading this stuff should work fine.. it sounds like the acrylic version of laquer thinner:

_____________________________________________________
>>>>Ethylene glycol monoethyl ether is used in varnish removers, lacquers, and as a solvent for printing inks, duplicating fluids, and epoxy. Ethylene glycol monobutyl ether is used in hydraulic fluids, as a coupling agent for water-based coatings, in vinyl and acrylic paints and varnishes, and as a solvent for varnishes, enamels, spray lacquers, dry cleaning compounds, textiles, and cosmetics.

Propylene glycol monomethyl ether is primarily used in the manufacture of lacquers and paints, as an anti-freeze in industrial engines, a tailing agent for inks used on very high-speed presses, a coupling agent for resins and dyes in water-based inks, and a solvent for celluloses, acrylics, dyes, inks, and stains. It is also used in cleaning products such as glass and rug cleaners, carbon and grease removers, and paint and varnish removers; and in pesticide formulations as a solvent for applications to crops and animals.<<<<
____________________________________________________

the basic dangers of this:

>>Inhaling glycol ethers can result in dermatitis with erythema, edema, and weeping; hyperpigmentation; and photosensitization.

(read: a really bad rash, swelling of the body including fluid seeping out of your skin, changing skin color to a darker shade, and aversion to bright lights)

Exposure to ethylene glycol monoethyl ether can cause depression of the central nervous system, resulting in headaches, drowsiness, weakness, slurred speech, tremor, and blurred vision. Ethylene glycol monobutyl ether is regarded as the most toxic glycol ether used as a solvent. Exposure can result in bone marrow damage, headaches, drowsiness, weakness, slurred speech, tremor, and blurred vision. Exposure to vapors can result in respiratory, nose, throat, and eye irritation.

('nuff said)

Exposure to propylene glycol monomethyl ether can cause eye, nose, and throat irritation. High levels become objectionable because of the chemical's odor. <<

Mike,

I've tried just plain distilled water just a few times and so far the results have been good... I only use Tamiya thinner with Tamiya acrylics partly out of fear... I think they have some kind of secret formula for their paints that is only cut with some secret ingredient in their thinner... I tried cutting Tamiya with water and it turned out clear liquid with grains of the paint color floating around in it... MM it works fine tho...

As far as cleaning up after spraying Acryl I use either Tamiya thinner (to spray through the brush), alcohol or laquer thinner... 91% isoprpyl works good... as well as laquer thinner...


---Tom---

I agree with Scott.
I have been using Acryl for several months now and thin it with a 50:50 mixture of isopropyl alcohol and filtered water.
I spray it with 2 parts paint to 1 part of this thinner and it works good.
I have been meaning to try thinning it with just straight filtered water also as I think this may be better to cut down on tip dry. Acrylics dry very fast as it is and using isopropyl alcohol only shortens the drying time.
The cleaner that Scott mentioned works fairly well but I have found that some colors of Acryl are tough to remove from the airbrush color cup with this cleaner.
Actually it is not even that easy to remove with the Acryl cleaner from Testors!
I usually put a little lacquer thinner in it and clean it out with an old paint brush, spray that out, and then run the cleaning mixture that Scott mentioned in it afterwards as a follow-up cleaning.

Mike

QUOTE: This is not your common isoprophyl alcohol or Windex and in fact those common thinners don't work with Testors. They just don't bite into the paint.

I disagree. I use isopropyl alcohol all the time with Testors Model Master Acryl paints and have had no problems at all with it.

QUOTE: I want to find a cheap substitue for thinning and especially cleaning the airbrush. The original Testors Akryl thinner will cost a fortune if sprayed in large quantities to clean out the airbrush.

For cleaning my airbrush I use MikeV's Magic Mixture of 2 parts distilled water, 1 part Windex, 1 part Simple Green and it works fine on Tamiya, Model Master, Citadel, and Poly Scale acrylics. Not sure about others as those are about all I ever use.