Spraying Poly for the first time.

[sjm1580]

Bit the bullet and ordered a gallon of General Finishes wb poly.  Sprayed a good amount of lacquer in the past, with always good results.

Suggestions on how I can keep that streak alive with poly would be greatly appreciated!

Steve

[Chestnut]

GF makes good poly. I know in the other thread i recommended Varathane WB the only reason for that is i continually get good results and it's $15 a quart. I should buy by the gallon like you did i could get a better product for the same price but i don't use a ton so I'm worried about it goign bad.

You send me a message about thinning. I don't personally thin but i use a FUji MM4 so a 4 stage turbine hvlp which has some decent power. I use the 1.3mm needle and cap set and to set the amount of material sprayed turn the needle all the way closed and then open it 3/4 to 1 full turn. Knowing your spray setup will help with some suggestions there.

I personally just sprayed some WB poly last night. I do all my spraying outside in direct sunlight and get coats to dry in about 10-15min. If i have to sand between coats i generally let them go a few hours. I don't sand between every coat. My typical approach is 3 thin coats let it sit for a few hours sand flat and spray a final thin coat.

Spraying WB poly is pretty easy. When the film builds you get a slight blue haze on the surface if it gets too blue you applied too much. Not a big deal it's just going to take longer to dry.

[sjm1580]

6 minutes ago, Chestnut said:

GF makes good poly. I know in the other thread i recommended Varathane WB the only reason for that is i continually get good results and it's $15 a quart. I should buy by the gallon like you did i could get a better product for the same price but i don't use a ton so I'm worried about it goign bad.

You send me a message about thinning. I don't personally thin but i use a FUji MM4 so a 4 stage turbine hvlp which has some decent power. I use the 1.3mm needle and cap set and to set the amount of material sprayed turn the needle all the way closed and then open it 3/4 to 1 full turn. Knowing your spray setup will help with some suggestions there.

I personally just sprayed some WB poly last night. I do all my spraying outside in direct sunlight and get coats to dry in about 10-15min. If i have to sand between coats i generally let them go a few hours. I don't sand between every coat. My typical approach is 3 thin coats let it sit for a few hours sand flat and spray a final thin coat.

Spraying WB poly is pretty easy. When the film builds you get a slight blue haze on the surface if it gets too blue you applied too much. Not a big deal it's just going to take longer to dry.

Thanks so much for the information.  I have a 1.8 mm needle so I will just have to back off a bit.  Can you let the poly sit in your gun between applying coats or do you have to break down and clean?  Also, do you just clean with hot water?

Thanks for all your help, greatly appreciated!

Steve

[Chestnut]

2 minutes ago, sjm1580 said:

Thanks so much for the information.  I have a 1.8 mm needle so I will just have to back off a bit.  Can you let the poly sit in your gun between applying coats or do you have to break down and clean?  Also, do you just clean with hot water?

Thanks for all your help, greatly appreciated!

Steve

I'm not sure how the larger needle and cap will work, if you cut down the flow it'll probably work the same. I think it's best to grab a piece of scrap and give it a few tests. I make some board games so they are 18"x18" flat surfaces and make perfect test platforms but a  piece of cheap ply would probably work the same.

For the short coats i leave the poly in the gun. I usually bring it in side some where cool and protected. I've gone as far as a few hours leaving finish in the gun. The only worry is getting a little bit of finish hardened on the tip of the needle. So when i set the gun down i make sure to clean the point where the fluid comes out. I then also spray a bit before i go back to the work piece.

[Chet]

I use General Finishes poly all the time.  Same a Drew, said I use 1.3 cap set.  I have used my gun all day, maybe 6 - 7 hours and had no problems between coats.  I have a garage shop and spray in there with the man door open and the garage for up about 8 inches just for air flow.  I haven't had a problem leaving material in the gun during this time, BUT I don't think I would stretch it over night with out cleaning.

For cleaning I spray about a pint of water with a few drops of liquid dish soap.  I shake it up some before spraying just to get the soap mixed with the water.  After that I spray a pint of clear water through the gun.  I just spray in to a bucket both times and then dump the water in the garden.  Then I brake the gun down on an old towel to let the parts dry.  I just use room temp water, warm would probably be okay, I don't think I would use hot water.

[sjm1580]

Thanks guys, this information is exactly what I needed.

I'll let you know how things go this weekend.

Steve