Using polycrylic

[ivwshane]

I am building an arcade machine and I've painted it black with a high gloss acrylic.
To protect it I am using Polycrylic from minwax. I'm about to do my third coat but I have some concerns. Because this stuff dries so fast I'm having trouble applying an even coat over large areas. The directions say to use a nice synthetic brush which I am but I wondering if I would get better results if I were to use either a foam roller or if I could spray it on.

Does anyone have any suggestions?

[atgcpaul]

I've sprayed Polycrylic with a $100 Wagner HVLP with success on kitchen
doors. For the cabinets that were in place, I used those flat paint pads from
HD. They are white with a thin, soft foam pad that's green in color.

[docrowan]

Ambient temperature will affect your drying time. A lower temperature will help slow the dry time which will tend to let it level out a bit more. Since I can't control my ambient very much in my shop, I've toyed with the idea of cooling the polycrylic, but haven't done it yet.

Are you sanding between coats? I used a 220 grit sanding sponge between coats and it helped out a lot.

[cabinetman]

Polycrylic, or WB Polyurethane, can be brushed on with a good synthetic brush, or a good foam brush. It can be sprayed with an ordinary syphon spray gun, or an HVLP set-up. I get best results with spraying, with a mix of about 10% water added. You can't spray too heavy. Many thin coats works best for me. I use 320x silicon carbide sandpaper (for dry use) (light grey sanding face), it's an open coat sandpaper. If you can, try to spray large surfaces vertically, as the surface will gather less airborne material. Spraying that way will also keep from puddling the spray.

Use a lot of light on your spray surface. It will allow you to see how "wet" your pattern gets as you go. Keep the spray tip and fluid nozzle clean.
.

[JimD]

I have both sprayed and rolled polycrylic successfully. I prefer Resisthane but Polycrylic is OK. It is a bit thick to spray easily, stinks, and does not get hard real fast (hard enough to sand). I like it better than oil based poly, however.

Jim

[herb fellows]

watch it carefully!

Polycrylic, or WB Polyurethane, can be brushed on with a good synthetic brush, or a good foam brush. It can be sprayed with an ordinary syphon spray gun, or an HVLP set-up. I get best results with spraying, with a mix of about 10% water added. You can't spray too heavy. Many thin coats works best for me. I use 320x silicon carbide sandpaper (for dry use) (light grey sanding face), it's an open coat sandpaper. If you can, try to spray large surfaces vertically, as the surface will gather less airborne material. Spraying that way will also keep from puddling the spray.

Use a lot of light on your spray surface. It will allow you to see how "wet" your pattern gets as you go. Keep the spray tip and fluid nozzle clean.
.

I agree, light it up like a xmas tree. After you've looked at it thoroughly, look at it again! I haven't had a lot of luck with polycrylic. Even watching it like a hawk, I had some undesirable built-up after it dried. Also, if it dries built up at all, it will yellow in the long run, maybe a couple of years down the road. At least, that's been my experience with it. Sorry for the crappy report, just wanted to make sure you were aware of all the possibilities.

[ivwshane]

Thanks guys. I have been sanding it in between coats and for the most part it's smooth enough for me but there always seems to be some spots were I either over brushed or put just a tad too much poly on it.

[drumpriest]

Spraying will give you a more even finish, but I really don't like Polycrylic personally. I did a couple of projects with it, and it seemed to work ok, but after using other finishes, I've realized it's not that great. I've linked to it on here a few times, but I'm now using this stuff.

http://www.targetcoatings.com/oxford-spray-lacquer.html

It's a water based spray acrylic like the minwax, but works a LOT better! I've had no trouble at all getting super even finishes right "off the gun", it dries quick, and when spraying it's pretty easy to cover large areas. I spray it with the cheapy Rockler HVLP, which is much the same as the HF one, and the Woodcraft one.

[eliasbboy]

I had the same troubles with a "princess" step stool I made for my daughter. I switched to a foam brush and it fixed all my problems immediately. Good luck!

[ivwshane]

Does anyone know if it's possible to "buff" polycrylic into a shine?

I've sanded down what I did before and got it nice and smooth but it's very dull. If I spray water on it it gives me the shine I'm looking for.
Is there a wax or something I can put on it to bring the shine back or is polycrylic really meant to be used as a final coat?

[cabinetman]

Does anyone know if it's possible to "buff" polycrylic into a shine?

I've sanded down what I did before and got it nice and smooth but it's very dull. If I spray water on it it gives me the shine I'm looking for.
Is there a wax or something I can put on it to bring the shine back or is polycrylic really meant to be used as a final coat?

Polycrylic can be polished out to a high gloss. There has to be a substantial build of coats. In between coats should be wet sanded with 400x to 600x wet-or-dry silicon carbide sandpaper and water. The final coats should be wet sanded up to 1800x to 2000x. It then can be polished out to a high gloss using a smooth pumice and then rottenstone. Or, ordinary automobile rubbing compounds can be used finishing with a ultra fine polish. Other compounds can be used in graduated smooth grits of rouges.

Each coat application should be cured before wet sanding.
.

[jabe]

I second what cabman suggest regarding buffing/polishing the finish. I've used a pneumatic 6" H&L RO sander with 1000 grit 1st, then 1200 grit and final 1500 grit. Next polish it with 3M Fineese II for a super smooth surface then wax with tree wax. Use the RO sander only on flat surfaces, contours/routed edges must be done by hand. You can purchase these fine abrasives from any auto parts store that sell auto body supplies. I learned this from my colleague an auto shop teacher. Make sure you have thick enough coats b4 using this method. I usually spray 3 to 4 heavy coats of WB lacquer (let dry 2 hrs between coats & sand very lightly between coats), i like to use Deft as it is very forgiving. Check the viscosity b4 spraying, you may need to thin it. Use a lot of light when spraying, like I said, I spray heavy coats, this takes a lot of practice & patience so you don't get any runs/sags. I've been spraying wood projects for over 30 yrs., patience & practice are the keys to a fine finish.