Yet more finishing questions.

[TominZebulon]

I am finally at the point where I will be putting the back on the vanity I have been working on for a long time now. The interior and back is the cheap Chinese plywood from the local BORG. I have a couple questions about finishing the interior of the case.

1. Do I need to finish the inside? The vanity will be in my bathroom, so high humidity at times. My guess is yes, but I am not sure.

2. What do I finish it with? I saw a thread about finishing the inside of a dresser with shellac, but will this be good enough?

3. How thick of a buildup (or how many coats) will be required of whatever finish I end up needing to use.

The exterior and top will be finished with a mixture Greg Paolini gave me the recipe for several months ago: 3 parts mineral spirits, 2 parts poly and 1 part BLO.

Thanks in advance for any and all answers!

 

[Bas]

I am finally at the point where I will be putting the back on the vanity I have been working on for a long time now. The interior and back is the cheap Chinese plywood from the local BORG. I have a couple questions about finishing the interior of the case.

1. Do I need to finish the inside? The vanity will be in my bathroom, so high humidity at times. My guess is yes, but I am not sure.

2. What do I finish it with? I saw a thread about finishing the inside of a dresser with shellac, but will this be good enough?

3. How thick of a buildup (or how many coats) will be required of whatever finish I end up needing to use.

The exterior and top will be finished with a mixture Greg Paolini gave me the recipe for several months ago: 3 parts mineral spirits, 2 parts poly and 1 part BLO.

Thanks in advance for any and all answers!

I would definitely finish it. In addition to looking better, the finish will help prevent some moisture absorption, and also ensure moisture is absorbed/ lost more equally. Shellac is a good finish for interiors, as is polycrylic (water-based poly). I'm not a fan of oil-based finishes for interiors because it takes a long time for the smell to disappear. I'd do 2 coats of polycrylic. The number of of shellac coats depends on how much you thin it, but I'd say 3.

 

[TominZebulon]

I would definitely finish it. In addition to looking better, the finish will help prevent some moisture absorption, and also ensure moisture is absorbed/ lost more equally. Shellac is a good finish for interiors, as is polycrylic (water-based poly). I'm not a fan of oil-based finishes for interiors because it takes a long time for the smell to disappear. I'd do 2 coats of polycrylic. The number of of shellac coats depends on how much you thin it, but I'd say 3.

Thanks Bas. I did not think about polycrylic. For the shellac, what # cut are you talking for 3 coats? I think the premixed comes in a 3# cut if I am thinking right?

 

[Bas]

Thanks Bas. I did not think about polycrylic. For the shellac, what # cut are you talking for 3 coats? I think the premixed comes in a 3# cut if I am thinking right?

Yes, I believe out of the can it's a 3lb cut. For spraying and brushing, I usually mix it 1:1 with alcohol (making a 1.5lb cut). I believe padding is usually done at a 2lb cut, but I'm sure everyone has their secret recipe. With a 2lb coat, I'd do three coats. With 1.5, probably four.

The good thing about shellac is that it doesn't matter a whole lot. Just find the largest cut that you find easy to work with and gives good results. For the interior of a vanity, getting a perfectly smooth even coat isn't critical, so this is a great project to practice handling various ratios.

 

[FredP]

I always do at least a seal coat inside.[or 2] it makes cleaning easier and keeps the moisture at bay. I use whatever I am using on the outside.:gar-Bi I usually use oil based products.:icon_thum

 

[TominZebulon]

That makes sense. I appreciate the advice. Now to clean up the shop so I can get to it.

 

[Bill Clemmons]

Like Fred, I usually use the same thing on the inside as I'm using on the outside, which is more often than not an oil/varnish blend. It's just easier than mixing up something different. Having said that, however, I'm starting to lean more and more toward shellac for my interiors, primarily because of some good points Bas has raised in a previous thread, and in this one. The long drying time hasn't been an issue w/ the oil/varnish because I use a fast drying poly (interchangeable w/ varnish), but the lingering odor of oil can be.

As for diluting shellac, the link below tells you exactly how much to mix depending on the desired cut you want. Click on the # symbol at the bottom, then "dilute", then fill in the numbers you want. When using shellac I generally start w/ a 1# cut for the first coat, then a 1.5 # cut for the second, and a 2 # cut for all subsequent coats. Rarely do I try to apply anything heavier than a 2 # cut.

The Woodshop Widget

HTH

Bill

 

[Jeff]

+1 to the lingering odor of an oil based product as an interior finish that BAS noted.

Zinnser "Seal Coat" is a 2# cut of 100% dewaxed blond shellac. It's available at Lowe's and has a warranted 2-3 year shelf life.

http://www.rustoleum.com/CBGProduct.asp?pid=246