Solvent Waste Management, Inc.  www.solventwasher.com/solvent-distillation-machines.html
Solvent Waste Management, Inc. www.solventwasher.com/solvent-distillation-machines.html
I met a new friend courtesy of my series of three articles on lacquer thinner that were recently published on Woodworkingnetwork.com.
I made the comment that I felt that it was a very good idea to stay away from recycled thinners as one doesn’t really know what’s in them.  There may be chemicals in there that will react unfavorably with the lacquer that you intend to spray.  
 
My opinion was and remains that lacquer thinner is a chemical soup that is made up of a number of different chemicals. That’s easier to say than to explain so I will refer you to my previous articles on lacquer thinner where I discuss that in depth.
 
My friend objected to that comment on the recycled issue. You see, he represents a company that builds and sells stills that take used lacquer thinner and distill the “good stuff” out of it.  That allows one to recycle that lacquer thinner and reuse it. All the solids remain behind when the distillation process is completed.
I both stand by my original statement and support my new friend.We are both right.
The stills that he manufactures and sells are sold to shops that have a high throughput in the finish shop to generate a significant amount of waste thinner. It does make sense to do something to recover your investment as well as to reduce the amount of chemical waste that must be disposed.
But under these circumstances, painters in the shop know what chemicals they are loading into the still. Therefore, they also know the content of the output after the process is complete.  That’s the important part for me.
At this point I would like to tell a story that illustrates the other side of this issue and this frames the reason that was on my mind when I said that using recycled thinner wasn’t necessarily a good idea.
When I had my own cabinet shop, I purchased my finish products from a distributor.  At some point, my salesman convinced me to try the off-brand thinner that he was selling.  It was significantly cheaper than the name-brand product and, since a buck is a buck, I thought I would give it a try.  Well, one day down the road, after five or six pails of this thinner had been used successfully, I suddenly had a big issue.
I would always wash out my pot after I finished spraying.  Conversion coatings, being very chemically resistant after curing, require that this be done.  My last cleanup step was to run virgin thinner through the hose and gun.  When there is no more liquid in the pot to go up the hose, things kind of peter out and the gun stops squirting.  However, that doesn’t mean that the fluid hose is totally empty.  In fact, the thinner that remains in the line helps protect from lacquer buildup on the inside of the hose.  That’s a good thing.
The bad thing happened days later when I put new lacquer into the pot to spray my next project.  Unbeknownst to me, that virgin reclaimed thinner in the hose was not compatible with my lacquer.  A reaction happened inside the hose as I pushed the new lacquer through to come out my gun.  The lacquer went into the hose as lacquer and came out of the gun as cottage cheese; big yucky, sticky chunks.
That was the end of that experiment.  I had to replace my hose with a new one so that my lacquer didn’t have gunk in it.  I tried and tried to flush that stuff out of the hose but with no success.
Lesson learned.  I went back to the brand name thinner that was sold by the lacquer company.
You see, my distributor purchased reclaimed thinner from a source that collected and recycled waste thinner.  They had no idea what they were buying nor could they control the chemical content of what they input to their stills.
As the fates would have it, a few years later, I lost my ability to keep the shop open and got a job as a tech rep. for that very distributor selling those same brands of lacquer thinner.  I was responsible for all things pertaining to stains and lacquers.  One of my first jobs was to go across town and pick up a new order of their Brand X lacquer thinner.  This was the same product that I knew was not compatible with the line of coatings that I was responsible to sell.
To cut to the chase, that program was my responsibility and I decided that we were no longer going to sell anything but our brand name thinner at our branch.  That decision got rid of a lot of my service calls and problems over the coming years.  However, of all the issues that I had in my first years of working with customers, lacquer thinner compatibility continued to be a big issue.  It did take a while for me to educate my customers.
Now, let’s flash ahead to a few months ago.  I was working in a spray facility putting finish on some fixtures.  It happened to be the same conversion varnish that I have used all along.  This shop had a 50 gallon drum of thinner from another major manufacturer.  It worked great to clean up the gun and pot after I finished spraying.  But I noticed the same cottage cheese curds in the bottom of the pot.  Oh boy!  More compatibility issues.
Enough said?  I hope so.  You really need to be mindful of these things because some day they could turn around and bite you.
If you want to use reclaimed thinner, get yourself a still and reclaim your own.  I have no problem with that as long as you closely monitor what goes into the still so that you know what will come out.  Remember, thinner reclamation is like computer programming.  Garbage in…garbage out.  At the same time, if you choose to buy and use thinner that may or may not be compatible with your finishes, then you stand the chance of someday having issues.
Until next time…spray on!