Finishing question

Finishing question · 10-11-2009, 10:41 AM

I am in the process of building a vanity for our bathroom out of walnut. There is also a walnut shelf for behind the tub. That has been completed and is ready for finishing. Since I will want them to match, and the vanity is nowhere near done, I need to figure out what will look good. The LOML told me she wants it to look natural and "not shiny". However, it will be in a bathroom, so lots of humidity! While I do not like the idea of putting polyurethane on it, I do not know what else I could do for the humidity protection it will need and since the vanity will get some heavier use, it will need to be durable. Any ideas?

Howard Acheson · 10-11-2009, 12:53 PM

First thing I would apply is a couple of coats of dewaxed shellac. Dewaxed shellac is more water and water vapor resistant than lacquer, waterborne or poly varnish. Then I would apply 2-3 coats of a non-poly varnish. Non-poly varnish is more water resistant than poly varnish. Stay away from any exterior or "spar" varnish. These products are not a water resistant as a standard interior varnish.

DaveO · 10-11-2009, 12:54 PM

Try a satin or semi-gloss non-poly varnish. GF Arm-r-Seal, or Waterlox Orig. S/F. There is also Pratt & Lambert #38 and others that you can get at specialty paint stores. If you can't find them in a reduced gloss, you can rub out the final finish to reduce the sheen.
Another option would be Lacquer, but it is more difficult to work with.

Dave

Howard Acheson · 10-11-2009, 12:56 PM

>>> Try a satin or semi-gloss non-poly varnish. GF Arm-r-Seal,

Arm R Seal is a urethane varnish as is their Seal A Cell. Your other suggestions are spot on but the Waterlox Original Sealer/Finish is not as tough as their Gloss or Satin.

Gregory Paolini · 10-11-2009, 01:06 PM

Catylized laquers, and conversion varnishes are great for high humidity areas, but 9 times out of ten I reach for plain old poly - The plastic or shiney look of poly has more to do with it's application than the actual product.

If you want silky smooth feel combined with protection, mix up the following combo: 3 parts paint thinner, 2 parts Polyurethane (Satin), and 1 part boiled linseed oil.

Flood on a coat, then wipe it off. Let dry a day or so. Then come back and apply a second coat, wet sanding the coat in with either 400 grit paper, or a red scotch brite pad. Wipe off the excess. Allow to dry 1/2 a day. Repeat as many times as desired - 5 or 6 applications should provide a good build to protect, and I promise it will be so silky, you wont be able to keep your hands off of it

Hope this helps

Joe Scharle · 10-11-2009, 01:18 PM

Originally Posted by Howard Acheson

First thing I would apply is a couple of coats of dewaxed shellac. Dewaxed shellac is more water and water vapor resistant than lacquer, waterborne or poly varnish. Then I would apply 2-3 coats of a non-poly varnish. Non-poly varnish is more water resistant than poly varnish. Stay away from any exterior or "spar" varnish. These products are not a water resistant as a standard interior varnish.

Howard, can you recommend a brand of dewaxed shellac?

TominZebulon · 10-11-2009, 01:47 PM

Originally Posted by Gregory Paolini

Catylized laquers, and conversion varnishes are great for high humidity areas, but 9 times out of ten I reach for plain old poly - The plastic or shiney look of poly has more to do with it's application than the actual product.

If you want silky smooth feel combined with protection, mix up the following combo: 3 parts paint thinner, 2 parts Polyurethane (Satin), and 1 part boiled linseed oil.

Flood on a coat, then wipe it off. Let dry a day or so. Then come back and apply a second coat, wet sanding the coat in with either 400 grit paper, or a red scotch brite pad. Wipe off the excess. Allow to dry 1/2 a day. Repeat as many times as desired - 5 or 6 applications should provide a good build to protect, and I promise it will be so silky, you wont be able to keep your hands off of it

Hope this helps

I think I am going to try this technique. I am going to practice first on an offcut from the same board. When you talk about repeating the step, do you brush the subsequent coats on or just pour them on and let them soak in for a few minutes? Also, being a hobbyist, I do not usually have several days in a row to work on this. Is this a technique that if I wait a week between coats, will it still work? Thanks for the input and I will let you know how it turns out!

Gregory Paolini · 10-11-2009, 02:49 PM

Tom,

I just use disposable foam brushes to get a bunch of finish on the workpiece as quickly as possible - whether it's the first coat or the last. And Since you wipe the finish off after you're done sanding it, you don't need to worry about runs, drips, sags, etc....

As far as time frame, you can spend all year doing this if you want - You'll never have adhesion problems between coats, because as you wetsand (by hand only) the surface, you're creating small scratches which gives the new coat somthing to grab on to. The wet sanding also removes any dust which may have landed in the previous coat.

Now your first coat will take a day or so to dry. But after that first coat, I can usually get 2 to 3 coats on in a day, depending on the weather/temp. So if all you have are weekends to work on this, you can wrap it up pretty quickly.

Howard Acheson · 10-12-2009, 02:49 PM

>> can you recommend a brand of dewaxed shellac?

There is only one pre-mixed. It is Zinnser Seal Coat or Zinnser Spray Can shellac.

http://www.zinsser.com/product_detail.asp?ProductID=72

Tarhead · 10-12-2009, 04:10 PM

Tom if you want to try mixing your own from dry flakes and/or trying different shades check out: http://www.shellacfinishes.biz/

North Carolina Woodworker DQ members get a 10% discount. PM me if you need the code.

TominZebulon · 10-16-2009, 12:25 AM

Ok, so I used Gregory's technique on a scrap piece I had sanded to 220 grit. It is silky smooth with no sheen whatsoever and I absolutely love it. But more importantly, the LOML really likes it also. Now my only question is about the humidity resistance. WHile it will have 5-6 coats of poly, they are thinned coats. Will this be enough to keep the water vapor exchange in a comfortable range? Again, this is in a bathroom and I have a very strong ventilation fan, but the LOML likes to take long, hot showers. Just want to make sure this will work in this environment. Thanks Gregory for the tip and I will definitely be using this technique on many projects to come.

fergy · 10-16-2009, 06:36 AM

I personally think I would rather chew broken glass than ever use Arm-R-Seal again in it's normal application manner. Yet again I started a project with it that I'm living to regret and hate the finish. I did find that thinning it about 20% with mineral spirits helps alot with streaking and flow-out. I have yet to try to spray it, but the open tack time is a killer for me. The stock thickness also makes it build too fast, resulting in ripples and runs which can't be sanded out well between layers without leaving marks because you're sanding through a layer and subsequent layers don't "melt" the previous layers.

I love spraying lacquer. There are several catalyzed versions of them out there now that are going to give poly a run for it's money in regards to durability on a project like this. You can get nice automotive paint guns to work with it for for a relatively inexpensive price. The other advantage is how fast it dries, meaning no dust in the finish, and several coats of application in a day. I've found that winter time here is dry enough to allow outdoor spraying. If you've got a compessor, this is how I'd go. I'm so sick of trying to wipe out a finish and deciding that I'm unhappy with it in the end. The other advantage with spraying is that you can tint and tone as you need to shift color.

Sandy Rose · 10-16-2009, 11:17 AM

Hey Tom...I went through the same thing about a year ago. I built a vanity out of hard maple and finished it with a General Finishes dark brown dye and top coated it with Rockhard Table Top Varnish that I got from Woodcraft. It was a pain to work with - it's really thick, but Rockhard makes a reducer for it and that made it easier to work with. I don't know if you are using a dark finish or not, but the varnish is a dark amber, so I don't know how it would look on a light finish. Our countertop is solid maple also and after 4 coats of the varnish, there has been no movement/warping in over a year. Since the varnish only comes in a glossy finish, to tone it down, I put 1 coat of Minwax Polycrylic semi-gloss figuring I may have to worry about it absorbing moisture - which it will if water sits on it for a long time, it will turn a little white, but completely goes away after it dries.

Gregory Paolini · 10-17-2009, 08:26 AM

Tom,

I've used this finish on several bathroom projects, including one of my own. I never have a problem with it. Even though it is thin, we purposly put on twice as many coats to make up for it.

I know what you mean about humidity build up too - there are days our jacuzzi runs for over an hour.

I knew you'd like it!

scsmith42 · 10-17-2009, 08:41 AM

Great question and even greater answers! This one is getting printed out for my files.

Gregory - a couple of questions for you.... do you try to finish the entire workpiece, so that no humidity can enter from underneath, behind, etc the boards, or just the visible surface areas?

Also, what is your preferred brand of poly? Do you use a non-yellowing one?

Thx.

Scott