Polycrylic Problem

[Tom Blank]

I’m making a chessboard for my grandson. Maple and Walnut, more like a cutting board than a regular game board, with the individual pieces end grain up. Customer’s orders. Here’s the board prior to finishing with a Mineral Spirits test wipe.

11 Finish Test.jpg


As per usual, construction was enjoyable with no big problems. Finishing is not going well. I started with Minwax Polycrylic glossy since it is a reasonably tough finish, he wanted a glossy finish, and I like the water clean up aspect. I’m using a Purdy Syntex brush and having a terrible time getting a decent surface.

I likely applied the first coats too light and dried before they self leveled. I thinned the Polycrylic about 5% with water and applied heavier coats. I started sanding with Norton ProSand 220 between coats and moved to 400. All the dust is removed and I have a good flat surface for the following coat. The thinned coats look good when wet, no skips or gaps, no grey puddles. There is a good reflection across the entire surface with a raking light - but it dries full of brush marks.

I’m ready to sand it back down to bare wood and start over with a different product. I do not have equipment or a place for spraying, so I am limited to brush or pad application. I like the water clean up, but at this point that is no longer a primary consideration.

Any recommendations? I have good local access to General Finishes products and to a lesser extent to Waterlox products. The BORG has the normal BORG products, which is where I got the Minwax.

Thanks for your help,

Tom

[Jim Becker]

I've had good success spraying the Polycrylic products--I use it for a lot of things I don't want to opt for more expensive product or because of immediate need, but wasn't as happy the one time I tried brushing. (To be fair, I don't like brushing any of the waterborne clears) Because I cannot spray in my temporary shop, I've been leveraging the Varathane oil based product for both brushing and wiping (thinned for the latter) and have been quite pleased. It's readily available at the orange 'borg. I've also found it to be quite durable. If your favorite 'borg store is a Minwax source, the similar oil based product should work equally well relative to application. You can also get it at your local Sherwin Williams store.

[John TenEyck]

Thinning the Polycrylic probably wasn't a good approach. It likely would give better results brushed on generously at full strength with a foam brush. But it likely would be better to switch to an oil based or oil modified waterborne. In the later realm, MinWax Oil Modified waterborne poly goes on great with a foam brush.

John

[Tom Blank]

Gentlemen, thank you for the replies.

Jim - I presume you refer to the basic Varathane Ultimate Polyurethane Oil Based, not the 3X or spar versions. I like the idea of wiping instead of brushing. What do you use for thinning and at what ratio? The TDS calls out not to thin, but I suspect that is just to avoid VOC restrictions in some states.

John - I ran across several discussions on foam brushes, positive and negative. I have had decent luck with them in the past and will give that a try before abandoning the Polycrylic. The back face of this board has been my experimental face, so will go there first.

Thanks again,

Tom

[Jim Becker]

Yes, the regular oil based product. I use mineral spirits to thin. Naptha flashes off too quickly.