Water Base Polyurethane over BLO mix?

[Mac McAtee]

Can I put the standard BLO mix on wood to pop the grain and then cover it with Water Base Polyurethane varnish?

Or, BLO - Shellac-WB Poly? That sounds like a lot of trouble to me.

[Bob Lasley]

Mac,

I've never tried water base over BLO, but I have used it over some oil based stains. I should think that if you let the BLO cure good it would probably work. As usual, try it on scrap first. The shellac as a barrier coat will work for sure.

Bob

[John Preston]

with mixed results.

I did my kitchen cabinets with this, without using shellac as a barrier coat. I used a blo/oil based poly mix, let it cure, then came back and sprayed some waterbased poly over it. Not without its problems.

A major drawback of waterbased poly is that every coat turns things a little more cloudy, and a little more blue, or white. If you're using the BLO to get that nice rich tone, the WB poly is going to obliterate that, in my experience.

I've had this problem with my cherry kitchen cabinet doors, using a hybrid WB poly, that has worked the best, I've had this happen with my oak desk top, and that color is completely different than the desk I used OB poly on. The strange part is that the places I put epoxy in the knots are beautiful, then where there is no epoxy it is toneless and blah. I've also used this on other things, and had similar results. Recently, I sprayed a bunch of WB poly on some kitchen cabinets stained with a walnut stain (oak) and each coat of poly made the doors lighten up and the bluish tint didn't exacly blend in. Some I had to restain and respray to get them to color match.

My kitchen cabinets of cherry came out the best, with the least whitening problems. I used Oxford Hybrid poly, bought it from Homestead Finishing.

WB poly is great for maple. Don't do anything but spray it on. Clear and white.

I like spraying it, it dries fairly quickly, sands good, etc, but it just screws up the color of everything you put it on unless it happens to be white to begin with.

one fix I've heard, but not used is to tint the finish with a little brown, or something to get rid of the white.

my .02, and worth every penny of what you paid for it (nothing).

[Jim Becker]

A sealer coat of shellac between the oil and the water-based top coat is a good idea unless you allow the BLO to cure for a month or so untill there is NO smell. You want good adhesion of your top coat. You need to use de-waxed shellac for this purpose as you do with regular poly. (De-waxed shellac is not necessary with non-poly varnishes, however) If you don't want any color change, use blond or super blond shellac. For species, such as cherry and pine, garnet shellac is a nice choice for the sealer coat.

[Eric Apple - Central IN]

Can I put the standard BLO mix on wood to pop the grain and then cover it with Water Base Polyurethane varnish?

Or, BLO - Shellac-WB Poly? That sounds like a lot of trouble to me.


yes you can.. I do blo- shellac - wb all of the time. Skipping the BLO and just doing shellac will also pop the grain nicely. WB with no shellac/oil can look washed out. Looking cloudy, white, or blue, this totally depends upon the product that you are using and does not apply to every WB product. I would agree that some of the low end and early stuff does this. Even the low end stuff does not exhibit this with 2-3 mil finish. It only shows if you build for a rubout or just a filled pore finish. Oxford HB mentioned above is a nice product. It is hard to apply by brush.

I guess trouble is relative. I can finish several large pieces say about small dresser size by wiping on blo on day 1, let dry for 2 days. That takes about 1 hour to wipe. Then flood/brush shellac that takes about an hour, dry overnight. Then shoot three coats (higher solids contents let you use fewer coats) of WB taking about 20 minutes each spread 2 hours a part. A total of around 4 hours maybe as long as 6 setting up / tearing down.

[Brad Schafer]

what exactly is BLO? i've never heard of it.


b (not an expert, particularly on finishing)

[Jim Becker]

what exactly is BLO? i've never heard of it.

So called "boiled linseed oil"...it's not really boiled, but it is formulated with dryers, etc. It's my favorite finish base.