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Trouble spraying clear

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Old 01-20-2015, 07:49 AM
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Trouble spraying clear

Hi gang,


Awhile back I posted my experience spraying clear. I received some helpful tips, but I am still having difficulties spraying clear. I am trying to get to the appearance section of the site but can seem to find it.


I seem to be getting dry spots and well as heavy spots. I cant figure out what I am doing incorrectly. Now I have a section that I have to rework and I am not familiar how to rework it. Any advice would be appreciated.


Thanks all
 
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Old 01-20-2015, 08:36 AM
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What type of gun are you using ? Many factors in spraying .... air pressure, pure air system, gun clogged...temp . For dry spots ,after the clear cures you can carefully wet sand with 1000 to 1500 grit sandpaper on a soft block careful not to sand through the clear coat to the color coat. After that you can either respray the area of use buffing compound to bring the desired gloss. Long steady strokes when spraying works best. I use an old sharp #75 gun, very adjustable .The hvlp guns deliver lots of paint at a time so faster strokes are needed. There is less overspray with them.
 
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Old 01-20-2015, 08:46 AM
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thanks "Ibuildmyown"


Using a devbliss straight line entry gun, 1.3 tip. Temp around 60 degrees. Air pressure tried at 10 lb with gun opened, also 28 lb with gun open.


Sprayed better with higher peasure, but still not consistent. Product is wide open, fan is wide open. At this point it appears that I may be getting to much product ( few sags) Product being mixed according to mfg specs
 
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Old 01-20-2015, 08:47 AM
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Do not know weather I am going to fast or to slow. About 6" away from panel
 
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Old 01-20-2015, 09:05 AM
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Too slow will get you sags and runs, too fast will get you dry spots. Some brands of paint spray differently also. There are some reducers you can use to make the paint do the work for you . I don't like to use reducers in clearcoat because the finish will not last as long. there are retarders to slow the drying process ,reducers to speed up the drying process. Medium overlapping wet coats work best. Also, be sure to let the coat flash dry 20 to 30 minutes between coats. Gun adjustment 6 to 8 inches of spray top to bottom when trigger pulled on test paper pattern should be oval and full, too much pressure will look like an 8. More air pressure atomizes the liquid for a better flow onto surface.
 
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Old 01-20-2015, 09:25 AM
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Thank you. My particular clear does not use a reducer. It is a 4 to 1. Any thoughts on "flow" Is my product adjustment open to much?


As far as wet sanding out my goofs, Is it advisable to reshoot the panels after I wet sand or try to get the dry sections eliminated.


Also, How soon may I recoat without wet sanding everything. Example: Some of the sections came out ok, say like a pillar. but the adjoining section is bad. Can I wet sand the section and then shoot everything including the pillar, say like the next day or do I have to wetsand everything before I recoat?


thanks for your help
ps My gun is a DeVbiss Stating line
 
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Old 01-20-2015, 09:52 AM
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Jim,

If you google SPI urethanes - their sight has an excellent forum on products, set up, and spraying. Not to mention their products are some of the best I've used.

Good luck
 
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Old 01-20-2015, 10:02 AM
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Thank you towd56
 
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Old 01-20-2015, 10:41 AM
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The variables are endless when it comes to describing paint application. I have found that it is best to understand the basics of how paint reacts when sprayed on a surface. When paint spray hits the surface it is comprised of small droplets of atomized paint. As the spray is applied these droplets can stand on their own or they can merge with other droplets. If the droplets stand on their own and do not flow out then they become "dry" areas...no shine. If the droplets build up with others and flow a lot then you get beautiful gloss...and perhaps runs. The thinner the paint the more flow. The higher the pressure the smaller the droplet. The higher the ambient temperature or lower the humidity the faster the dry time.

If you have dry spots and wet spots then you are most likely not staying an even distance from the panel you are painting OR your speed is erratic. That said, I always thin a little more and spray at a little higher pressure when I am having flow issues. This is an ART not a science...if you cannot control your environment then every time you paint you have new variables to deal with. How you react to these changes usually dictates the quality of your final paint job. I can't tell you how many hours I have spent color sanding to correct a mistake I made in a few minutes of spraying! Good luck...
 
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Old 01-20-2015, 10:45 AM
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Thank you Charlie
 
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Old 01-20-2015, 02:49 PM
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If you are holding your gun 6 inches from the surface you are too close. I usually paint about 18 inches away from the surface. You have to use even strokes. Staying the same distance and speed from the time you start on the panel until you release the trigger. Pull the trigger to air only as you approach the panel and when you get to the place you want to start the paint flowing pull the rest of the way to start the paint flowing. release the trigger back to just air before you raise the gun up. That way it is easier to keep your paint stroke the same speed and distance.
Good luck
Larry
 
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Old 01-20-2015, 03:43 PM
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Thanks Larry, Appreciate it
 
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Old 01-20-2015, 05:18 PM
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Originally Posted by JimG1098
Thanks Larry, Appreciate it
When you get to end of your stroke be sure not to wave your gun before you release the trigger. That will give you dry spots. Try to keep you spay at a right angle to the surface and not as close as you were.
 
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Old 01-20-2015, 05:30 PM
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Thank you mytbtruck
 
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Old 01-20-2015, 06:26 PM
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What brand and product # of clear are you using? One of us may have actual experience with that product.
 


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