# Coatings Pro Magazine



## MrPaint (Feb 19, 2012)

The free coatings calculator tool I've been working on is featured on www.CoatingsProMag.com
Check it out if you get a chance they really have some pretty stellar articles on real world paint and coatings applications.


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## Sir Mixalot (Sep 8, 2009)

Congratulations James. :clap:
I'll have to check that issue out. For now I'm going to click on the link in your signature and see whatcha got.:thumbsup:


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## bskerley (Apr 15, 2011)

Your calculator isnt working. :clap:


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## CApainter (Jun 29, 2007)

On the psychrometer, wouldn't you need the steel temp rather then altitude to complete the calculation of dew point on the substrate?

still a cool tool. I'll check it out more. Thanks


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## MrPaint (Feb 19, 2012)

Nope, the standards dictate that we're looking for the dew point. Typically manufacturers specify that coatings may not be applied if the surface temp is within 5 degrees of the dew point.


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## MrPaint (Feb 19, 2012)

bskerley said:


> Your calculator isnt working. :clap:


How is it not working? Can you be more specific? If you're viewing it on a mobile device, you'll need to click "go" at the top right after you've made a calculator selection, that may be the issue. I'd be glad to help, just lemme know.


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## CApainter (Jun 29, 2007)

If the ambient temp is 70 degrees and the RH is 65% for instance, the dew point would be 57 degrees F. As long as the "steel temp" is 5 degrees above dew point (62 degrees in this example) you would be able to coat the surface. True?

Therefore, since the coating manufactuerer recommends the surface be no less then 5 degrees above dew point, isn't it important to include surface temp?

I suppose we could gather the ambient temps from the calculator, and then find the difference of steel temp in the field to determine that 5 degree requirement.

Still an intereting tool. Thanks


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## MrPaint (Feb 19, 2012)

CApainter said:


> If the ambient temp is 70 degrees and the RH is 65% for instance, the dew point would be 57 degrees F. As long as the "steel temp" is 5 degrees above dew point (62 degrees in this example) you would be able to coat the surface. True?
> 
> Therefore, since the coating manufactuerer recommends the surface be no less then 5 degrees above dew point, isn't it important to include surface temp?
> 
> ...


The whole reason for the dew point calculator is to make it easier to determine dew point using a sling psychrometer and psychrometric tables. Typically two readings are taken with the sling psychrometer, one is the ambient temp and the other is the wet bulb temperature. Those readings are then charted on psychrometric tables to determine dew point. You are correct in that if the substrate temp is outside the 5 degree range then coating application may take place (if the specification is written for 5 degrees). Thanks, good discussion!


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## bskerley (Apr 15, 2011)

Working now, when I went to the link you posted and clicked the calculator it would not redirect me to the page.


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## MrPaint (Feb 19, 2012)

bskerley said:


> Working now, when I went to the link you posted and clicked the calculator it would not redirect me to the page.


Thanks for letting me know and giving it another shot. I'm betting it was a glitch in their original code, it had just gone live a few minutes before I posted it.


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