Surface Cleaners, by Brian Martin
They are commonly called 'Wax and Grease Removers' but many manufactures have changed the name to 'Surface Cleaners' or similar names. I think the biggest reason is because the name 'Wax and grease remover' implies that they will actually clean all of the wax and grease off the surface. The other reason for a name change is the simple point that wax and grease are only a few of the contaminants that you battle against while painting.
The basic idea behind these cleaners is simple, they are designed to lift the contaminant up off the surface long enough for you to wipe it away. The surface MUST stay wet and HOLD those contaminants up in the cleaner for you to wipe off with a clean/dry rag. That is mistake most make, they let it dry and the contaminant ends up laying right back on the surface. First of all let's clear up a few things; Lacquer thinner, acetone, MEK, and enamel or urethane reducers are NOT surface cleaners. Lacquer thinner evaporates too fast and doesn't give you time to wipe it off wet. It is also much to strong a solvent for most cleaning and can get under the edges of sand thrus or soften substrates. Enamel and urethane reducers often have resins and other components in them that are designed to be added to the product they were INTENDED to be used with. To put it in a nutshell, buy and use the products recommended by the manufacture of the paint SYSTEM you are using. A gallon of the proper surface cleaner runs about twenty or twenty five dollars it is money well spent. The gallon will last you through many projects, a few cars even. The pint of paint or clear to do one small redo will cost more than that.
I checked on our paint dept. at work to see how much surface cleaner they go through. We do between 100 and 150 cars a month and purchase three to five gallons of surface cleaner. We purchase about $12,000 a month in paint materials and only about one hundred bucks of that is surface cleaner. So that being said, at that rate a gallon should last a home hobbyist a lifetime, so buy the right product for the job.
One reason we use so little is how we use it. Here in the San Francisco bay area with strict VOC rules we are not allowed to pour the surface cleaner out onto a rag. We have to spray it out of a spray bottle. Like most things we are forced to do, we resist. But it has turned out to be a great way to use this product. You should give it a try, it works real well. You spray the panel and then wipe it off.
I like to have lots of clean rags when I am doing paint work. Clean rags are one of the most important item you can have in a shop. In the last few years this has gotten much easier to do. I remember having a can of paint covered rags in the corner, thinking I could wash them. I would wash them and they would be clean but the dried paint on them would be hard and make the rags unusable. Then of course you don't want to wash them in your home washer anyway, unless you want your wife's bra to smell like enamel reducer. Now a days the disposable rag is king. You can get a box of 'rags' for a pretty fair price and just throw them way when done. You always have nice clean rags. They are not 'just' paper towels, so don't think that the 'Mr. Cleanup' paper towels you get at the supermarket are going to do the job. Go to your paint store and get the real thing. There are many different kinds, from cheap wipes similar to your kitchen 'paper towels' to lint free towels for final wiping. TORX products are available at NAPA auto parts and is one source for these towels. Again, yes they cost more money than washing rags or your wife's 'Mr. Cleanup' paper towels but what kind of money are you spending on your paint products?
So let's go over exactly how you use it. As mentioned earlier, you need to keep it wet prior to wiping it off. The best way to do this is keeping your cleaning area down to a manageable size. I usually wipe no more than a half a panel at a time. About six square feet is all you can do without problems of it drying to fast, and even then you have to keep moving pretty fast. You just don't want it to dry, if you do, you have wasted your time. You haven't done what you intended to do, at all. It was not even close, you wasted your time.
When should you wipe the surface? Well first of all, BEFORE you sand. If you don't wipe the surface before you sand you will not sand off the contaminants, you will sand them INTO the surface. So a good cleaning before sanding is recommended. If the surface is really dirty, clean it a few times changing to clean rags every time. Remember, you want to wipe off the contaminants, so if you use the same rags on the subsequent wipes you can leave the contaminants you wiped off on the first wipe!
Wiping before applying primer or paint of course is also recommended. Broom and/or blow off the sanding dust (I have bench brooms for wood working that are fine bristled and work great). Be sure to use the proper cleaner and wipe it dry really well. Then be sure that any remainder has flashed off (evaporated) before applying your primer or paint. You don't want any of the cleaner to be trapped under your primer or paint!
You use surface cleaners ONLY on cured paint, primer, clear. This means, prior to sanding the old paint, after your primer has been cured and sanded just prior to sealing and painting, that is it period. Don't use it between coats of primer, sealer, paint or clear. First off, there is no reason for that. Unless you KNOW something got on the surface, there would be no reason to use a surface cleaner at all between coats. And something happening between coats is highly unlikely. So ONLY on totally cured surfaces. The wax and grease remover is a solvent as you have learned, even the most mild WILL attack some uncured primers, sealers, paints, and clears.
Have a few rags ready to go folded in fourths. Put the rag over the opening on the can of surface cleaner and give the can a 'slosh' getting the rag wet, not too wet but wet. You don't need to have it dripping all over the floor, but it should be good and wet. Get in the habit of wiping things down like you are painting it. Use a back and forth pattern with an over lap being sure to wet EVERY square inch. The entire area should be shiny wet, then switch to a clean dry rag and wipe it dry using the same 'get every inch' procedure. If you feel it dried before you could get it off, repeat the cleaning. As a painter I worked under many years ago would make me repeat like a private in boot camp 'YOU CAN NEVER GET A CAR TOO CLEAN, SIR'
Because the term 'wax and grease remover' is thrown around so much little is said about the how different they can be. Until I had became a paint rep I didn't even know there were different kinds. After painting for twenty years I had always just grabbed the 'wax and grease remover' without a thought as to what I was using it on. When I bought a cleaner and found it worked different I just attributed it to the brand and not the fact that it was just not the type of cleaner I had been using.
Just like solvents you add to your paint products there are different 'temps' cleaners. Not that they are to be used in different temp shops but that they flash faster or slower than another. This is important in that you don't need a super slow flashing cleaner on your final wipe. Nor do you need a super fast one when you are doing your first wipe down of a greasy car prior to sanding.
There are also different 'strengths' of cleaners. Some are designed for cleaning soft substrates like lacquer while others are much more harsh for cleaning enamel substrates. Most all of them 'can' be used at most times but, there are some that are better than others for particular circumstances.
There are four common groups. I don't have every cleaner listed here but this will give you a good idea at what is available.
Examples are: Sherwin Williams R1K213, Martin Senour 6387, PPG DX330, DuPont 3939S, BASF 901.
Examples are: Sherwin Williams R7K156, Martin Senour 6383, PPG DX440, DuPont 3919S, BASF 900.
Examples are: Sherwin Williams W4K157, Martin Senour 6388, PPG DX380, DuPont 3909 or 3949, BASF 905.
If you find that you have been using the 'wrong' cleaner, don't sweat it, it is not THAT critical. As I said, there are cleaners that work better than others in certain circumstances but few would be 'wrong'.
I know of one particular mistake I made for many years. I was using one from the number 1 example. I used it all the time as I still do. The problem was I was using it wrong. Back in the days of lacquer primers and paint I had a few problems that I just couldn't figure out, till years later that is. I would see a lacquer paint job I did a year or so later and there would be water spots on it, coming from under or within the paint. It looked just like you would have when you dry a car in the sun and the water would dry in the patterns that the wet towel left. I always knew it was the surface cleaner but just couldn't figure out why it would happen. I now know that the cleaner was just too slow evaporating and some stayed on the surface to be buried under the paint. The lacquer primer soaked it up and held it. If I had waited a little while longer before painting or used one from the number 3 example I wouldn't have had a problem.
Hopefully this info will help you choose the best cleaner for the job. But most off all, I hope it puts to rest all the 'old husbands tales' of using thinner or enamel reducers as cleaners.