The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > Info Center > FAQ Truck Tech > Paint and Bodywork

Web 67-72chevytrucks.com


 
 
Thread Tools Display Modes
Old 09-18-2004, 01:51 PM   #1
MARTINSR
Registered User
 
MARTINSR's Avatar
 
Join Date: Dec 2000
Location: San Francisco Bay area Ca USA
Posts: 4,429
Exclamation "VOC" has nothing to do with safety.

What in the world is “VOC?”

After seeing the term “VOC” misused lately I thought a little “primer” if you’ll pardon the pun was due.

“VOC” stands for Volatile Organic Compound. Basically it is solvents deemed dangerous to our atmosphere (more on that later) that flashes off during and after application. It is measured by “pounds per gallon”. You will see references like “4.6 VOC” on many products. Meaning that the product has 4.6 pounds per gallon of VOC per sprayable gallon. When you see this on the front of the label it usually refers to “as applied” or “sprayable”, with all components mixed. If you look on the ingredient label you will likely see different numbers, these are referring “as packaged”. That would be the VOC in the can you are looking at, not “as applied” with them all mixed.

Theoretically if you were to mix the product with “4.6 VOC” as applied with all it’s components and set the can out in the sun, after it fully flashed off and there was just hard stuff in the can, it would weigh the 4.6 less. That 4.6 pounds went up into the atmosphere. It wouldn’t happen exactly like that, for a number of reasons but that is the basic theory behind the VOC measurement.

One of the reasons this wouldn’t happen is the fact “not all bad stuff is created equal”. Remember, I said “VOC” is the stuff that goes UP into the atmosphere? Well, the stuff that goes DOWN isn’t VOC is it? Not according to the powers that be in our Federal government. Some solvents are “VOC exempt”, meaning they have ZERO VOC.

The most obvious would be water, it is used in a number of “waterborne” and “waterbase” products. I would make sense to the layman that water is harmless (relatively) in this context. However, there are many other “VOC exempt” compounds such as acetone and chlorobenzotriflouride (oxhaul sp? trade name). Yep, that’s right, acetone is exempt, zero VOC. These two particular solvents are very heavy, they don’t go UP, instead they go DOWN as they flash off. One day they will likely be banned as well because they contaminate our ground water! But for the time being they are a freebie in the automotive paint industry.

You may not see "acetone" or "oxhaul" on the label of many of these products, but that is exactly what is in the can of many reducers these days.

I am sure I am about to loose you so let me get to the point. VOC or the lack of has NOTHING to do with the level of danger in the use of a product, NOTHING. I’m sure we can agree acetone is some nasty stuff, yet it is VOC exempt. Don’t let some one sell you a product that is low or zero VOC on the pretense it is “safe”. Even without the solvents, there is all kinds of stuff that is in the paint. I don’t care if it is waterbase house paint. If you are spraying it, atomizing it, there are particles of the stuff in the air. Do you want to coat your lungs with particles of the “Crescent Moon” off white you are painting your living room in?


Ok, if I haven’t put you to sleep and would like to know more, here goes.

Oxhaul for instance is a very heavy solvent at 9.8 pounds per gallon. That is not only 9.8 lbs of free VOC, but it actually “lowers” the VOC of a given product, here’s how.
If you had a primer that was 10 pounds VOC as packaged and reduced it 1:1 with Oxhaul it would then have a sprayable VOC of 5.1 VOC effectively, half of what it was. This is the only reason lacquer primer is still on the market, reduced with acetone 1:1 it is compliant. Reduced with lacquer thinner it is not even close. I am referring to the “National Rule”, in many areas there are local VOC regulations that restrict it’s sale.

High Solids hardeners for instance many times are zero VOC! So, you have a quart of hardener, with zero VOC, it is full of isocyanates, but it is VOC free. So again, that quart of VOC hardener will “lower” the VOC of the sprayable clear, yet make it MORE hazardous to YOU.

You will see all kinds of goofy mixing ratios like 4:1:1:1 with the first “1” being a urethane reducer and the second “1” being an exempt reducer. This is done to keep the VOC down and the product compliant. When the “National Rule” went into effect back in 1999 (?) you saw all kinds of goofy mixing ratios all of a sudden for this reason. If they didn’t add some exempt solvents (or a LOT of exempt solvents) the product would have been dead on the shelf. So they had to MAKE it compliant to keep selling it.

As I said, it won't likely say "acetone" on the label, but that is what is in the can many times. S-W for instance has three "compliant" reducers that are exempt. The fastest is straight acetone, the next is a 70/30 mix with Oxhaul which is much slower flashing than acetone. The slowest is a 80/20 mix with the majority being Oxhaul.

With these heavy solvents it is imperative that you don’t bomb on the product and give it full flash time. Many primers use acetone to keep the VOC down, if you bomb it on thinking it is “only the primer” you are going to have trouble with the product no curing. I have seen super low VOC products that were mixed correctly (at least I think they were) that were still WET days later because of this.

As a rep I dealt with this stuff all the time and in fact I worked markets in both VOC regulated and no VOC regulated before the National Rule. It has been a few years so I am certainly more than a little rusty in the area. As long as the point is clear VOC is NOT a gauge of danger to YOU, I don’t really care is some minute detail is not totally accurate.

You need to protect yourself, none of these products are “safe”, NONE of them.
__________________
1948 Chevy pickup
Chopped, Sectioned, 1953 Corvette 235 powered. Once was even 401 Buick mid engined with the carburetor right between the seats!
Bought with paper route money in 1973 when I was 15.

"Fan of most anything that moves human beings"

Last edited by MARTINSR; 09-18-2004 at 08:03 PM.
MARTINSR is offline  
 

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 12:30 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2018, vBulletin Solutions Inc.
Copyright 1997-2013 67-72chevytrucks.com