Recommend sanding sealer before finish?

[leehljp]

I cannot find sanding sealers here like in the US.
1. So what is a good "sealer coat" that will act as a sanding sealer?
2. Do I really need sanding sealer, or will a plain coat of some kind do just as well?
The top and finish coats will be oil based poly. (This is Japan, so lots of choices or brands are not available as is the case for the US. )

The grain has some rather good size open pores that I would like to seal before finishing. The finish will be a stain in polyurethane oil base - stain due to color variations of the wood.

Finishes readily available here;
• Polyurethane, oil and water based
• Poly stains
• Water poly stains
• lacquer,
• shellac
• oils such as TO, BLO and others, which I do not wish to use.

Will this work: I have read that one coat of shellac is a good sealer coat, but will it cause problems with stain or oil poly over it? I am planning on several coats of poly after the stain. (It will be medium dark red mahogany color.)

I will be experimenting with the color itself, but known problems ahead of time from all of you will be appreciated. I would prefer to spend a week "finishing" rather than a week experimenting before finishing.


The wood: I am making 2 book cases and close to being ready for finish. I have been working on it 'off and on' for almost 4 years, and I have to complete it before returning home in December.

The wood is the Philippine mahogany, which is in reality luan. Normally this is cheap wood. I got the wood from whole wall bookshelves from a student center that was being torn down 5 years ago. The boards were 1 1/16 thick, 9 to 11 inches wide, 8 to 12 ft long and about 50 years old. While luan, it was some "very good" luan from long ago. The only problem is that I did not get enough of the same color - some pinkish and some yellowish, which is common with that wood. The wood is clear and nice looking.

[phi1l]

you will have to experiment with your wood, but a shellac "spit coat" is what is usually use to get a more even stain application. That is a 1/2# cut of shellac, a very dilute mixture.

[cabinetman]

The top and finish coats will be oil based poly.

The grain has some rather good size open pores that I would like to seal before finishing. The finish will be a stain in polyurethane oil base - stain due to color variations of the wood.

I like to keep the finishing chemicals in the same base group. If you have some unwanted variations in color, those can be "toned" or "shaded" in with an oil base stain, which can be thinned with MS or Naptha to achieve some uniformity.

If you want to seal the grain, use a "grain filler" AKA "paste wood filler". That will close all the pores and give a slick feel to the finish. If that isn't available there, or you can't order it, you can dilute oil base polyurethane 50% with either MS or Naptha (for a faster dry) as a sealer. I wouldn't use shellac.

Sealing before staining could affect the colorization, and how well the wood takes the stain.
.

[leehljp]

Thanks fellows. You both told me what I needed to know but didn't want to do - it really needs a seal coat but that will also affect the staining.

I did something like this a long time ago - I applied more stain in light areas VERY carefully and precisely, and then let it dry for a few weeks to cure before putting several layers of clear on top.

I just did not want to go this route but it looks like I will have to custom stain it. Cab, I agree with you, I want to stay within the same base group.


ONE more question: A long time ago, (40+ years) I mixed some talcum powder with some clear finish to create a sanding sealer of sorts. IIRC, it did Good, but I don't remember if it colored the finish any or much. Has anyone tried this?

[Uncle Cracker]

Sealing and staining are opposed... To stain, you need penetration, and sealing inhibits that very thing. If you want to color the wood, then you most often need to let the top coats (whatever you put over the stain) do the sealing.

[cabinetman]

Thanks fellows. You both told me what I needed to know but didn't want to do - it really needs a seal coat but that will also affect the staining.

If you do your staining before the sealing, the color won't be affected. As for the talc, the times I tried it there was a bit of cloudiness. I like using predictable materials and steps. You can achieve good results with a straight forward finish schedule.

Using a grain filler/paste wood filler can be a PITA and time consuming. A thinned version of oil base polyurethane (or even an oil base interior varnish works good) will seal and be fairly easy to sand. It will be a good hard base for your final finish.
.

[LJR]

Homestead Finishing: ever since I followed Jeff's suggestions I've had much better luck with finishing. I'm nowhere near as good as he is, but it sure helped me. http://www.homesteadfinishingproducts.com/