Kicks Korner #14 Ok,... I think I warned all you readers in the first instal-
ment of Kicks Korner,... that if you didn’t send me ques- tions, you would have to listen to me rant about whatever I wanted. Hmmmmm,... your bad! Anyway,... after spend- ing way too much time on some of the airbrush forums, I find there seems to be three recurring problems that keep haunting people that are trying to do their own clear coat- ing. The first is orange peel and I covered that back in issue 7,... the other two are fisheyes and solvent popping. Some- times people have trouble distinguishing between the two, but they are definitely different animals.When solvent pop- ping occurs, the solvent becomes trapped in the new finish because the surface of the paint has skinned over. As the solvent evaporates, the gas bubbles rise to the surface of the paint, but have a tough time escaping. Those bubbles that do escape break through the surface, causing the identifiable blisters and little craters associated with this condition, and in some cases they look like miniature fisheyes. The most likely culprit is the thinner or reducer being used. In many cases, the use of a fast-drying reducer causes the surface to skinover before the solvent can evaporate out. Another common cause of solvent popping is excessive film thick- ness. This results from applying heavy coats of paint, or not allowing sufficient drying time between coats. Either way, the paint film is too thick and the evaporating solvent can’t escape. This is most often the case when using a transparent paints like Kandys. Use a slower reducer and apply the paint in thin, wet films. Allow sufficient drying (flash) time be- tween coats, and allow each coat to flash naturally, in other words void fanning the new finish and don’t pile on or do double wet coats. Also, if using a heat source to promote curing, don’t get it too close to the new finish. Most clears need 15 to 20 min- utes when you are done spraying before you bake.
Fisheyes occur when you try and paint over a contami- nant like silicone which will not allow the paint to contact the surface, causing a crater or fisheye. Contaminants can come from so many sources that at times it can be hard to track them down. Oil coming through the air hose from your compressor, someone outside in the driveway spray- ing WD40,... or even just someone waxing a previous job in the same garage,... they take their buffing rag and give it a shake, and all those little silicone particles are airborne. Or you could have the car all prepped and ready to paint, and when you drive into the booth you pick up armoral off the steering wheel and door pads which can then transfer to the surface when you tack it off. Even starting a diesel engine in the shop can contaminate the work if the exhaust settles on it.If you are using an automotive soap to wash down your vehicle,... check to make sure it doesn’t con- tain wax,... a lot of them do these days,... and only add a fisheye eliminator to your paint as a last resort. Basically what this does is add silicone to your paint, which will release the tension and allow the fisheye to close over,... but any overspray from this paint job will contaminate any other jobs that it lands on, then you end up adding it to the next job, and the next, etc. If fisheyes show up after your first coat,... allow it about 10 or 15 minutes to flash off,... then turn your air pressure up, and your material knob in,... and dry dust a little base coat over the fisheyed area. You don’t want this coat to flow,... you want it to seal. Dust on a couple of coats, tacking between coats, then reset your gun and start spraying normally again. Nine times out of ten, this will solve your problem with no additives. Don’t spray your clear coat if you still have a problem with your base coat.Prevention is the way to go. When you have your job ready to spray,... dust blown off and the air al- lowed to settle,... rewash the whole surface with a good silicone and wax remover making sure that you use a damp cloth, and immediately wipe dry with a clean dry cloth. Never allow the wax remover to dry on the surface. This will work well over two stage primers,... just be careful over lacquer primers. If the silicone remover that you’re using is a strong one,... there is always the possibility of it melting and smoothing out your 400 or finer grit sand- ing, this smoothing of the surface will mean that your base coat doesn’t have any tooth to hang on to anymore, and delamination could be a problem if you intend to mask and airbrush later. Stick to a quality primer and you’ll have no problems.
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