Tuesday, 09 February 2010 14:45

What is the Best Spray Gun on the Market? No Easy Answer ...

Written by  Stefan Gesterkamp
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A frequent question I get on an almost weekly basis is as old as our industry itself and the answer is still “it depends.”

What is the best spray gun on the market? Sounds cut and dry, but the answer to this question is much more complicated than it first seems. Besides the obvious technical aspect of this question, there are also emotional considerations that are weighing heavily in the decision-making process of a painter.

Personal preferences are important in this matter and vary from technician to technician. If a spray gun doesn’t feel right in a technician’s hand, chances are it will not become a natural extension of the applicator’s hand. This could result in less than superior finishes and often leads to a technician second-guessing his or her ability to produce what is expected of them.

 

Esthetics also has a larger impact than most would expect. Yes, painters do care what their equipment looks like. Just as some bodymen will purchase colorfully anodized tools, painters are also interested in unusual spray equipment. Personal preferences are an amazing thing. If a painter really likes a particular tool, even if it is not the ideal choice for the task, his or her performance is likely to be better than with a gun they don’t truly care for. Spray gun manufacturers are aware of it and have continued to produce special edition guns. From gold-plated equipment with Swarovski crystals to Pininfarina or Foose designed spray-guns, the options are plentiful.

The weight of a spray gun, as well as the feel of the trigger pull is a personal preference a painter would and should consider when purchasing a new gun. Remember that both are directly related to a technician’s fatigue. Of course, all of these attributes mean nothing unless the equipment is suitable for the job and therein lies the problem. What is the most suitable spray gun for your operation? How are you determining your needs and requirements?

Consider the following variables: the type of work routinely performed in your shop, the environment in which it is used, a painter’s personal spray style (a big one) and the paint technology on hand.

It is my personal experience, and I am confident you will come to a similar conclusion, that no one gun is likely to do it all perfectly. For the sake of argument, I assume that we all agree that a painter should have at a minimum of one dedicated gun for primer, clearcoat, solid basecoat, and metallic basecoat applications. Although this is a good start, it will hardly cover all of the scenarios a painter is facing during the course of the year. Let’s take a closer look at the different types of spray-guns we are using on a daily basis.

When it comes to primer guns, most paint manufacturers will agree that a 1.7mm primer gun is a perfect workhorse for most collision repair facilities. It should do a good job 90% of the time. What about the rest of the jobs?

Well, primer surfacer applications are in most cases performed on the shop floor and not in a climate controlled booth. This by itself is generally not a problem until the weather turns cold. Primer performance is greatly dependent on the proper application of the product. Film build and flash-off is critical in preventing primer shrinkage and mapping weeks or even month after the vehicle’s delivery. As the temperature on the shop floor drops, film build per coat should be reduced and flash-off time increased. A reduction in fluid tip size is a very effective way to facilitate the necessary changes in application technique. Plus there is the added desire by many of today’s painters that a primer gun should also function as a sealer gun. Maybe not the most realistic request, but reasonable enough to consider.

For sealer application a 1.7 mm tip is anything but ideal. Sealer attributes compare closer to the once of topcoats then they would to primers. The task of being an outstanding primer gun and also to function as a decent sealer gun at the same time is a difficult compromise. An alternative fluid tip would be the bare minimum requirement to make this happen. In all reality, a dedicated sealer gun would be a preferred option.

Basecoat guns are the most critical choice for any painter. They are impacting everything from color match, metallic control, basecoat texture to film build and blending abilities. They can make a painter’s life easy or miserable. Finding the right gun requires some homework and a thorough assessment of the shop environment. In order to determine what gun to buy, consider the paint technology at your shop. The ideal choice for solvent-based paint is in all likelihood not the same as it would be for water-based paint.

In general, solvent-based paint is more forgiving in its application and your choice of spray gun may not be quite as critical. Painters using water-based paints have to make a more informed decision.  Water-based paint requires non-corrosive construction. Stainless steel components and special gun bodies with corrosion resistant coatings are employed to make the gun last and to prevent corrosion of the aluminum pigments in the paint itself.

The climate is another critical part of making an informed decision. For example, my gun recommendation for shops in warm dry climates would be different then for a shop in either humid or cold conditions. For the most part, water dries at one speed and equipment choices and application techniques are a very effective way to control basecoat performance. The ultimate goal is to keep the basecoat wet long enough to achieve maximum metal control properties and then have the coating dry as fast as possible. A larger fluid tip may be of benefit in hot, dry climates while cold and wet areas would do better with a smaller tip. This choice is magnified during the blending process. A wrong gun or tip size could greatly impact the painter’s ability to create an undetectable blend.

And then there is the issue of size of the object you are painting. My preference for a particular spray gun changes depending on whether I’m doing a complete paint job on a SUV verses a fender job on a Honda Accord. Besides the gun tip size itself, there is another critical factor frequently overlooked or underestimated. Fluid output is not consistent from manufacturer to manufacturer. In other words, not all 1.5mm guns are created equal. Stepping up or down in tip size may be needed if a painter transitions from one brand to another.

Clearcoat gun choices are more than any other type of spray gun driven by personal preferences. They are also the only spray guns where a technician could overcome the side effects of a poor choice with color sanding and buffing. Some painters do better with conventional HVLP equipment, while others prefer the RP style spray guns. As long as the painter achieves the proper texture, gloss level and the necessary film build to protect the basecoat from harmful UV rays, without wasting product or time, everybody is in general happy. To make the proper choice for a clearcoat gun, a painter needs to be aware of his personal spraying style. The biggest difference in style is speed. Some painters like to get around the car as if they were on rollerblades. Others are more methodical and take their time applying coatings. Based on the personal style, fluid output and atomization is of importance. Obviously the faster an applicator, the higher the fluid output should be. At the same time, the density of the spray pattern should be considered. High fluid output with a dense pattern will better suit the rocket man.

You also need to consider the shop’s compressed air situation. There is a direct correlation between air supply, air quality and the final appearance of your paint finish. I still find shops today that are under-compressed and the best spray gun in the world will be insufficient if the compressor can’t support the equipment. Knowing how much CFM (cubic feet per minute) of compressed air is available to the painter during the shop’s peak consumption is a must in picking the right equipment. Keep in mind that there is a big difference between CFM and PSI (pounds per square inch). A shop may easily display over 100 PSI on the regulator and still run out of air during the application process. My favorite example to showcase the difference would be a fire situation. If you try to extinguish a fire in your shop and you have two different water hoses available: A standard 1-inch garden hose as well as a 3-inch fire hose. Both are pressurized at 120 PSI. Which hose would be more effective? The 3-inch hose of course! Although both have the same pressure, the volume is different and that is your CFM. Just like a carburetor on a car, spray guns are engineered for peak performance at a set CFM level. CFM consumption varies by brand and knowing how much you have to work with makes for a better informed purchase. The spray guns in my toolbox consume anywhere from 8 to 18 CFM. A big spread and some compressors may struggle with equipment on the upper end. Lower CFM consuming guns don’t automatically translate into better equipment though; it simply means they may be a better fit for your shop.
All major spray equipment manufacturers have greatly stepped up their R&D and produce very capable equipment. Their products are as different and unique as the technicians using them. I randomly asked 20 painters if they have read their gun’s owner’s manual and only one answered ‘yes’. These are precision instruments and you’ll be surprised what you can learn by actually reading the manual. It is the technician’s job to  analyze his or her unique situation and choose  equipment accordingly. Try before you buy. Most vendors will let you try their equipment prior to purchasing so take advantage of this opportunity. Any gun you purchase today will only be as good as your choices!

Read 13279 times Last modified on Tuesday, 13 April 2010 14:52
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