Hi Everybody
I am spraying thinned (by a third) oil based polyurethane on same 6 panel pine doors for a new house I am building.
I have sprayed three coats of semi-gloss so far and I am not happy with the finish. It looks more like a satin finish.
I have two questions? Does thinning poly change the gloss? What finish will I get if the top coat is sprayed with a gloss finish? Will it be a high gloss or a lower gloss because of the semi-satin finish below?
Your help will be greatly appreciated.
Bruce Curtis
Replies
Bruce,
Since you've already applied the semi-gloss, what you have now is the best it is going to get unless you can rub out the semi-gloss to the highest possible sheen and then spray the gloss if you still need more protective coats. Normally, semi-gloss or satin should be the last coat sprayed over the build layers of gloss. Each successive coat of a lower sheen finish further diminishes the gloss.
Doug
Thanks for the information. I will probably just be happy with what I have.
BC
He shouldn't rub it out to so high a sheen that the next coat can't stick well.
True - but I doubt that will happen.
Doug's right. But you can also cut the poly with boiled linseed oil to increase the gloss level.
Good luck.
Hey Bruce,
Often colloidal silica is added to poly to cut the gloss. It tends to settle in the can, or in your spray cup/pot. As you draw off of the bottom, you may get a disproportionate amount of the silica, if you don't keep it suspended.
This can make it difficult to get consistent results when spraying matching objects, so I usually just spray gloss, and then using a brush and pumice, knock the gloss off to whatever level I need.
Tom
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