Ever thinned out water based poly (specifically minwax polycrylic)?

[BKHam]

there was a previous post that skirted this topic but seemed to go in a how-to and "dos & don'ts" type of direction. anyone ever thinned it out? it is just so thick and i want to apply at least a sealer coat (client doesn't want to use any shellac) of a thinned finish first. any help or experience would be appreciated.

bh

 

[Endless Pursuit]

When you add water it gets thicker at first, stir it a few minutes and it breaks back down. From past experience, don't thin more than 15% by volume.

 

[JimD]

You might want to try Floetrol.

 

[BKHam]

What happens when you go over 15%?

 

[Bryan S]

It has always been my understanding that you should not try to thin water based finishes. Trying to thin these finishes changes the chemical composition of the finish and the results are not predictable. Here is the link to Minwax's website under directions, scroll about half way down.

http://www.minwax.com/wood-products.../interior/minwax-polycrylic-protective-finish

As a general rule, if the manufacturer dose not say how, then it is not intended to be done.

 

[jrfuda]

I've thinned General Finishes water based products according to their label instructions (20% max, I think) without issue. Never tried minwax, though. GF has a very responsive customer support and I usually check with them when I try something new. Even though it says 20%, i think I have rarely exceeded 10% and have only thinned when using hvlp, though I've used it straight from the can the last few times.

Sent from my HTCEVOV4G using Tapatalk

 

[JohnW]

I've never thinned Polycrylic but have used Floetrol to thin water based paint and it worked well. Never had to go past about 10%. There's lots of good info on water based finishes found on Target Coatings web site...in the finishers forum. Target specializes in water based coatings and I've used their products on several guitars, and to finish furniture.

For a thin first coat, consider a water based sealer and/or filler coat. If your wood species is open grain and your client wants a smooth solid finish, filling would be a good thing.

 

[Jeff]

it is just so thick and i want to apply at least a sealer coat (client doesn't want to use any shellac) of a thinned finish first.

1. What's your client's objection to clear, dewaxed shellac as a sealer coat? (about a 1# cut of Zinnser SealCoat). Then the topcoats of choice for the final finishing.

2.

What happens when you go over 15%?

Disaster because the resins are not soluble in water so they begin to precipitate (think flour and water). Here's the basic chemistry in 2.5 minutes.

http://www.thewoodwhisperer.com/videos/waterborne-finishes-hvlp/

 

[BKHam]

Client is worried about yellowing. He will never know if I use shellac for a dealer coat. The shellac on the surface will get sanded anyway. Thanks to everyone for the help.