Waterborne finishes have come a long way since first introduced 25 or so years ago.   They were pretty awful then, but very good now.

 

Pros:

+ fast drying - usually, you can sand and re-coat in about an hour

+ low odor - other fast-drying finishes like lacquer and shellac can have some strong solvent odor while drying. So it works well if you are finishing in a house or baswement

+ no added color - perfect when you want a non-ambering finish such as one over a white stain (pickled finish) or other non-wood tone color

Cons:

- less chemical resistance - not quite as resistant to common solvents as some of the other finishes

- does not cure well in cold, needs at least 65 degrees or so for several days

- lacks amber color that we're used to so some woods can appear washed out, or even bluish, unless a stain or under-coat of shellac applied.

Thanks!

I always have trouble with the second coat tending to have runs even with sanding before the second application

10 hours ago, lew said:

Thanks!

I always have trouble with the second coat tending to have runs even with sanding before the second application

Runs are usually due to too thick application.

 

https://www.popularwoodworking.com/techniques/finishing/how-to-avoid-runs-sags

Edited July 17, 20187 yr by kmealy

Good stuff. That "curing in the cold" thing is the biggest drawback I see with them, although a lot of folks really grump about the grain raising (not me, no big deal).

I'm guessing WB finishes won't work well in my home brew wipe on, seeing as how it's 50% Watco.

9 hours ago, Fred W. Hargis Jr said:

Good stuff. That "curing in the cold" thing is the biggest drawback I see with them, although a lot of folks really grump about the grain raising (not me, no big deal).

"bury the grain."    Let the first coat raise the grain.  It's up and stiff, knock it off with P400 sandpaper and maroon Scotch-Brite pads.  No need to "pre-raise."  

I guess I should add another warning.  Oil, varnish, and mineral spirits are widely compatiable.   Mix in whatever proportions you want.  Dump in a thinner to reduce viscosity of varnish, add enough and you have a wiping varnish.  Mix oil and varnish to make an oil-varnish blend, add thinner to make a wiping consistency.   Buy some Danish Oil and add some varnish to make it a more film-forming finish.

 

Not so fast with water-borne finishes.

 

W/b finishes are delicate balances of up to a dozen components.  You can't always just add some water, glycol ether, resins, colorants, surfactants, or de-foamers and expect them to work as designed.  Some mfrs offer a thinner, some do not.  Some you can dump in selected stains and make a toner, some not.  Remember the rule -- if you have not done it before, test of scrap before you put it on the top of that table you've spent 100 hours making.

On 7/17/2018 at 8:11 AM, kmealy said:

Runs are usually due to too thick application.

 

https://www.popularwoodworking.com/techniques/finishing/how-to-avoid-runs-sags

Thanks for the link!