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Discussion Starter · #1 ·
My glass beaded screen paint experiments continue, and I can clearly say that spray painting rules dealing with HVLP GUNS don't necessarily apply with this weird formula of clear matt paint / flow medium / water and 100 micron high index beads !

HVLP dictates that one needs to keep the gun about six inches from the surface and movement of the gun should be around one foot per second.

Yeah, right,.......not with this stuff ! What we have here is a water based material with a high solids make up that has been thinned to be sprayable.

The material flow adjustment on the gun has to be opened up a fair whack to ensure that the beads are exiting the nozzle and due to this factor, runs and uneven application are virtually guarenteed if you follow the ''golden rules of hvlp''??

It is now becoming obvious that in order to successfully apply the beaded paint the gun needs to be kept back from the surface considerably so that application is much more diffuse than normal. Naturally, the coats will be thin and there will need to be more of them until the surface is correctly and evenly coated in the correct fashion as a screen surface demands.

I have come to this conclusion due to the fact that I noticed the overspray area behind my testing area showed better surface uniformity than all my test samples to date! This area is about a foot further back than my normal spray test area.

So, the testing will continue with the following known factors :


IT IS POSSIBLE TO MAKE A GLASS BEADED SCREEN PAINT.

IT CAN NOT HOWEVER BE ROLLED OR BRUSHED.

POSITIVE AND GRADUALLY IMPROVING RESULTS SHOW THAT IT CAN PROBABLY BE SPRAYED USING HIGH VOLUME LOW PRESSURE SPRAY SYSTEMS.

STANDARD HIGH PRESSURE SPRAY SYSTEMS ARE NOT RECOMMENDED.

BREATHING RESPIRATOR MASK AND EYE PROTECTION APARATUS IS ABSOLUTELY NECESSARY!

EXPENSE SO FAR HAS BEEN KEPT TO A MINIMUM.


YOU HAVE TO BE COMPLETELY NUTS AND HAVE AN UNDERSTANDING OR EQUALLY NUTS WIFE TO BE ABLE TO CONTINUE WITH THIS FOR SO LONG!


Cheers.
 

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Zig,


Upon reading your thread, one thing came to mind, the "drop coat" procedure for automotive metallic or pearlescent basecoat. This is where the pressure is dropped to approximately 20-25psi (conventional gun), the gun position is cocked at 45 degrees to the surface and the trigger is pulled back halfway. What this does is atomize and drop the flakes evenly so as to prevent striping and/or mottling. I don't know the specifics regarding the mixture you're using, but it's definitely worth a try. This procedure was printed in Akzo Nobel Sikkens technical books in the mid-nineties as the final coat application when using Autobase metallics or pearlescents prior to clearcoating.


Good luck to you!
 

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Discussion Starter · #3 ·
Thanks vdelauz, interesting information. I can understand the dropping of pressure, but cocking the gun at 45 degrees is curious as doing this under normal circumstances would lead to uneven paint application.

I will contact some auto spray shops and discuss the various application methods.


Cheers.
 

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Zig,


Nobody was more amazed at this procedure than myself. After seeing it performed and then doing it myself, I turned into a believer.


I was trained on this procedure at the Akzo Nobel Atlanta CRIC (Car Refinishes Instructional Center) here in the US. We sprayed panels with this procedure exactly as I've explained and also with variations (no 45 degree cocking, different pressures, etc.). The only procedure that yielded a flawless end result was this one. The basecoat back then (Autobase) needed this "dropcoat" to get the metallics or pearlescents to lay down evenly. The new generation basecoat (Autobase Plus) does not need this procedure because it has been designed to be more user-friendly.


Since what you're trying to accomplish doesn't exactly sound user-friendly, I figured I'd give you the heads-up on the "dropcoat" procedure. I certainly hope it works for you (or at least gets you on a closer track) because it sounds like your frustration factor is increasing.


As always, best of luck to you!
 

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Discussion Starter · #5 ·
Thanks again, vedelauz. I will definately look into the method you have described.

In the meantime, I can report on my latest tests done last night.

I sprayed 3 light coats on to a white painted board measuring 3 feet by 2 feet. Each coat was applied with alternating gun movement ( horizontal followed by vertical ). The gun was held back from the surface at almost 2 feet at all times.

The result ?........the best so far !........ no striping, no blotchy patches. There will be a need for an additional two more light coats as far as I can see. I am hoping that with all the coats that will be applied , there will be no problems with ''stacking '' of the beads which is possible if numerous coats are layed on top of each other. I guess we will soon find out.


Cheers.
 

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Ziggy, are you sure there won't be a problem with more than one coat? If the beads don't have reflecting backface anymore, how they can give the brightness back?


xblocker
 

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Discussion Starter · #7 ·
xblocker, you just beat me to my next posting on this subject.


The two final extra coats were applied last night. NO GOOD !. The surface developed dark blotches that is obviously the effect of beads stacking on top of each other.


I am sad to say that I am going to have to give up on this. I have tried virtually everything to make this work , but it just doesn't.


I gave it my best shot , I am satisfied with that part at least.


My thanks go out to all the members who offered their thoughts and advise on this endeavour.
 
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