Monday, 21 July 2008 16:51

Automatic Gun Washers and What you put in them

Written by Jim Stubert
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In California, most of the productive shops have gotten used to using gun washers because they were required to use them 12 or 15 years ago. They now understand the benefit of using a gun washer versus doing it manually but now they come out of the waterborne paint school and they’re not really sure how to clean their equipment.  They’ve been told just to “Dump your guns in a bucket of water.”  You can ruin an $800 spray gun by getting water in the air chambers. Even if your gun is stainless steel or anodized.
Autobody News asked Jim Stubert of B-TEC North America, to explain how you should use your automatic gun washer, and what to put in it. Stubert started out as a painter and he has been in the refinish coatings industry for 40 years. He has seen a lot of products. Says Stubert:
“B-TEC Systems is based in Northern Germany and manufactures a variety of products, but you asked about gun washers.
Four years ago there was so much more waterborne paint usage over in Europe than here; I became interested in how they were cleaning water-borne products. They’re don’t behave like solvent-based products. You can’t just put any kind of thinner or water in your gun washer and expect it to clean reasonably well. The Europeans had to figure this out 8-10 years ago when they were having difficulty cleaning waterborne paint from their spray guns.

Basically a spray gun washer is a dishwasher, and it doesn’t matter whether you’re using the most expensive dishwasher in the market or the least expensive. If you don’t use an appropriate dishwasher soap or detergent, you’re not to make your dishes clean. Or you will have to clean in multiple steps.  
Our goal at B-TEC is to show a shop how to minimize waste water streams by using the right cleaning solution, and doing it in one step, quickly and effectively.
A couple of paint companies offer a cleaning product developed for manual cleaning, which are primarily water with some solvent. You don’t want to use these products in an automatic gun washer, just as you wouldn’t put manual dishwashing soap in an automatic dishwasher. When you take these products and put them in an automatic gun washer, under pressure and friction, you can create some real problems and you can damage both spray guns and gun washers.
A product developed for waterborne cleaning and for use in automatic gun washers is a specialty formula and is a blend of solvent, water, anti-foam agents, and surfactants to keep it wet, to minimize the friction, and do no damage to your expensive spray guns.
Our product AQUAMAX 1 + 3 is a patent-pending formula and process for cleaning water-borne coatings in automatic gun washers. In addition, we market ours as a concentrate to save the shop money… you just add tap water!    
If you think you have a correct gun wash cleaner you have to ask yourself this question: Does the product I have clean in one step and is it for automatic spray gun washers? Obviously there are soaps that hand-wash dishes but you wouldn’t put those in an automatic dishwasher. The same is true of your cleaning solutions for your waterborne gun cleaning.

The Do’s and Don’ts

* don’t submerge your gun in water
* don’t let them soak in water or cleaning solutions because aluminum is very reactive to oxygen in the water
* read the manufacture instructions and product information first
* If you’re using an automatic gun washer make sure the product which you are using clearly states “for automatic gun washers.”

B-TEC gun washers

B-TEC gun washers have a unique and very important feature—a hose which slips on the spray gun air fitting. As soon as you put your gun in the washer and turn your wash cycle on, it puts a positive air pressure and fills all of your spray gun air chambers with air. No solvent, no water, nothing can get behind the air cap, let alone into the air chambers. This is critical in waterborne coatings. You should never see contamination in your air chambers or behind your air cap, and if water invades these air chambers, corrosion can occur. You’ll start getting what looks like dirt in your paint as particles of corrosion move from the air chambers through the air cap, on to your beautiful paint job.
One of the processes being taught today is the use of disposable cups, and the painter is told to squirt a little bit of something—they don’t necessarily make a recommendation—into the fluid chamber.  Most shops squirt water and then some solvent. Some of the pigments, particularly in solid color water-based, are very heavy and they’re hard to get out of there just with a squirt bottle. You see guys having to spend a lot of time trying to get them clean, or—in frustration—they’ll take their air cap off, pull their fluid needle out, and manually clean those items. Then they put it back together and go to the next color.         That’s the typical manual process that we’re seeing. That is very time consuming! In the automatic gun washers (assuming you do not use a proper cleaning solution), it’s a two-step process. You have to put the spray gun in your water-based gun washer first, and then you have to put it in the solvent-based gun washer.  That also is time consuming and uses a lot of product!!
B-TEC teaches a one step process…. Two minutes. 100% clean. You can also use  our Aquamax 1 + 3 Cleaning Solution manually in a one-step process, to clean your spray guns, mixing cups, measuring sticks, etc.  If you don’t have the right cleaning solution for one step process, you will always have to do it in two steps, water rinse, and then solvent clean.
Here is a good example of choosing the correct product. Twenty years ago, when we introduced urethane-based products, it took awhile to realize that we needed a quality urethane solvent to proper clean our spray guns. The cheapest recycled thinner did not get the job done properly or quickly.
In waterborne coatings we can’t just put thinner and water in there. It’s now clear that the cleaning solution is the most important part.
As we say about Aquamax 1 + 3, “the solution is the solution.” If you travel to paint training centers in Germany, you will most likely see B-TEC equipment and cleaning solution in use. Together they solve the waterborne cleaning problem.
There is another huge advantage of waterborne coatings (over solvent) and choosing the correct cleaning solution. As your solution gets dirty, you have the option of “cleaning” your dirty solution through a coagulating process. This process allows the shop to remove the pigment and resin from the solution and minimize your waste water stream. With solvent based cleaners, once your cleaning solvent is dirty you have to put it into your waste stream.
Once you have coagulated (cleaned up your dirty solution) you have the option of refreshing with more mixed solution and continue to use the product. You can use it until the water literally takes on an odor. The more frequently the shop uses their gun washers, the longer the water lasts because it’s being recirculated and used, so the least productive shop will actually have to put solution into the waste stream more often, because they’re not using his cycles as often.  
B-TEC product can easily achieve two to three coagulation cycles—all based on the productivity of the shop. You do not have to coagulate every day if you use the proper solution. If we were starting fresh, with a dedicated waterborne automatic gun washer, AquaMax 1 + 3 cleaning solution, we ask the shops to benchmark about 60 gun wash cycles. Maybe that’s three days in one shop or maybe a week in another. When they get to around 60 washes, the solution will be getting dirty. At that point, you would want to get your B-TEC Coagulating Kit  and Coagulating Compound and coagulate or clean up the solution, add more mixed AquaMax 1 + 3  and continue again through another 60 wash cycles. But at some point, the water will take on an odor and the shop will move this waste to a water waste stream.
There are still some people who say you can coagulate and dump the remains down the drain. but it’s getting frowned on more and more in Europe because is the water actually clean?” In many communities here it is illegal to do this.
Our standard statement is: The shop must have a waste water stream once they move to waterborne basecoats. We have companies (PCL or Safety-Kleen) today to pick up your water waste stream. Our goal is showing the value of coagulating your waterborne coatings, so you can minimize
your costs.
If we continue to put the same amount of water into the waste stream as we do solvent the cost of the water is going to go sky high. Because it has to be incinerated, only a small percentage of water can be added to solvent waste streams to be incinerated inexpensively.
One other standard feature on B-TEC Gun Washers is an automatic exhaust system. In most European countries they require an exhaust system.
It’s illogical to require a closed gun washer, but not require any kind of exhaust
system. Who enjoys getting “blasted” by solvent when you open your gun washer? Contact: Jim Stubert at 480-661-8799,

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