I cannot seem to get an off-the-gun suitable finish. Are you supposed to buff it out? Buffing seems to give a higher gloss than satin. I am new to spraying and don't know all the tricks. I have a cheapo gun. I am spraying Defthane and have tried thinning it with mineral spirits. Narrow boards buff out ok with steel wool, but the wider boards take on the higher gloss. Is buffing necessary? Are there any other suggestions? The material flows out nicely, but there is a sprayed look when dry.
From contributor A:
It sounds as if you may be dry spraying. Open your fluid valve and try to get a little more on the piece. You certainly should not have to buff or rub the urethane.
Gun quality and cleanliness, type of coating delivery to gun (pump, cup) Can you remove air cap on gun, trigger and get solid stream of coating through fluid tip? If not uniform and full stream, hold gun triggered and remove fluid tip. Inspect cleanliness inside fluid tip where fluid needle seats in orifice.
Size of orifice in fluid tip in relation to viscosity of material being sprayed (gun mfg. should have this info).
Quality of air and its pressure to gun (most HVLP operate best @ 40-45lbs). Dry air or/and filter water with water trap.
Gun adjustment- fluid and air pattern relationship and spray technique.
Temperature of part being sprayed (are you in a cold shop?)
Rate coating dries (retarders are sometimes needed)
Air flow across part from fan or draft
Sounds like material is drying too quickly during atomization leaving a rough finish that then appears to need buffing out - and no, buffing should not be necessary. Try going to a coating company such as Sherwin Williams, Campbell, or others, and get advice. Take your problem sample with you! The formula is very important and to change it by adding spirits can cause bad effects. Try one ready to spray out of can from professional paint store as listed above. There are many knowledgeable finishers on this site and I'm sure you'll get good advice.
My suggestion would be that if you want to have professional results and make money doing it, that investing in a good gun, even one of the $80 Astro's or an $80 Porter Cable, combined with switching to a finish that sprays great while drying fast enough to prevent every speck of dust in the room to settle on it will make finishing a much more enjoyable job.