TooMuchBoost
Comp Diesel Sponsor
During these humid and hot months any solvent based or waterbased/borne product that must 'flash off' or evaporate to dry/recoat is limited by how much water content is in the air aka humidity.
If the air is 70% humidity it's 70% full of water and this leaves only 30% of available "air" for solvents to flash off a panel that has been wax and grease removered or out of a coating that has just been sprayed.
In other words the higher the humidity the less space in the atmosphere for solvents to escape therefore they escape much slower than if the humidity was low (like 30%). The more humidity that longer you need to wait before applying you next coat of primer, base or clear.
While this is reasonably common knowledge for painters I mention this specifically for the evaporation of wax and grease removers which are used to pre-clean substrates before coatings are applied. While the proper technique for wiping a panel with W&G remover is to wet a towel, wipe a small area then dry with another clean towel before the W&G remover evaporates this technique leads to a false sense of dryness on the panel when its humid out.
The panel will look one color wet then another once it has been "dried" but due to the high humidity you typically are seeing uniform "wetness" not an actual dry panel. The panel changed color as you dried it but the high humidity hasn't allowed the panel to totally flash off the solvents from the W&G remover that are still left.
The simplest way to make sure you have totally flashed off solvent from W&G is to either let the panel sit a 1/2 hour or after you wipe the panel dry blow the panel off with clean compressed air. You will see the panel change colors again.
This is very critical for those that W&G freshly blasted/sanded bare metal because the pores of the metal really hold the solvent if serious humidity is present.
What happens if you still have W&G solvents present and apply epoxy to bare metal or apply a coating over a wiped and not quite dry panel? Typically you will get "fish eyes" in the coating or a loss of adhesion or both.
We are each averaging one call per day across the country where a problem is traced back to solvents from W&G not having enough time leave a substrate.
Needless to say an ounce of prevention is worth a pound of cure.
Hope this helps.
If the air is 70% humidity it's 70% full of water and this leaves only 30% of available "air" for solvents to flash off a panel that has been wax and grease removered or out of a coating that has just been sprayed.
In other words the higher the humidity the less space in the atmosphere for solvents to escape therefore they escape much slower than if the humidity was low (like 30%). The more humidity that longer you need to wait before applying you next coat of primer, base or clear.
While this is reasonably common knowledge for painters I mention this specifically for the evaporation of wax and grease removers which are used to pre-clean substrates before coatings are applied. While the proper technique for wiping a panel with W&G remover is to wet a towel, wipe a small area then dry with another clean towel before the W&G remover evaporates this technique leads to a false sense of dryness on the panel when its humid out.
The panel will look one color wet then another once it has been "dried" but due to the high humidity you typically are seeing uniform "wetness" not an actual dry panel. The panel changed color as you dried it but the high humidity hasn't allowed the panel to totally flash off the solvents from the W&G remover that are still left.
The simplest way to make sure you have totally flashed off solvent from W&G is to either let the panel sit a 1/2 hour or after you wipe the panel dry blow the panel off with clean compressed air. You will see the panel change colors again.
This is very critical for those that W&G freshly blasted/sanded bare metal because the pores of the metal really hold the solvent if serious humidity is present.
What happens if you still have W&G solvents present and apply epoxy to bare metal or apply a coating over a wiped and not quite dry panel? Typically you will get "fish eyes" in the coating or a loss of adhesion or both.
We are each averaging one call per day across the country where a problem is traced back to solvents from W&G not having enough time leave a substrate.
Needless to say an ounce of prevention is worth a pound of cure.
Hope this helps.
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