# Sanding Sealer and Poly Application ...



## cfs (Jan 19, 2009)

5 questions for the experts:

What do I sand the sanding sealer (applied over 2 coats of finish) with?

Do I sand and apply a 2nd coat of sanding sealer or is 1 coat enough?

What do I cut the poly with and what ratio? (I was thinking about 2 thin coats of semi-gloss and then a final thin coat of gloss)

What do I sand with in between coats of poly?

I have heard that sanding with steel wool is bad - correct???

Thanks a bunch!


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## cabinetman (Jul 5, 2007)

cfs said:


> 5 questions for the experts:
> 
> What do I sand the sanding sealer (applied over 2 coats of finish) with?
> 
> ...



You've got questions...I've got questions.
_Do I sand and apply a 2nd coat of sanding sealer or is 1 coat enough?_
*What is the wood you are using?* 


_Do I sand and apply a 2nd coat of sanding sealer or is 1 coat enough?_
*What did the finish look like after the first application?*


_What do I cut the poly with and what ratio? (I was thinking about 2 thin coats of semi-gloss and then a final thin coat of gloss)_
*What "poly" are you using? Water based, or oil based?*


_What do I sand with in between coats of poly?_
*That would depend on your finish. Usually no coarser than 220x for the first application, and 320x thereafter.*


_I have heard that sanding with steel wool is bad - correct???_
*Steel wool can leave remnants of metallic particles that can rust. Abrading works as well with sandpaper of the proper grit. Some finishes can be sanded with garnet or aluminum oxide sandpaper, while others benefit from wet sanding with silicon carbide sandpaper (wet-or-dry), used wet with water.*


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## cfs (Jan 19, 2009)

Thanks Cabinetman - answers below:



cabinetman said:


> You've got questions...I've got questions.
> _Do I sand and apply a 2nd coat of sanding sealer or is 1 coat enough?_
> *What is the wood you are using?*
> Alder
> ...


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## cabinetman (Jul 5, 2007)

What you have there is an oil base polyurethane. You can thin it with mineral spirits. For wipe on, the first coat you could thin it up to 50% for better penetration. Subsequent coats can be 1/3 to 1/4. 

You could sand the in between coats with 280x to 320x aluminum oxide sandpaper, or the light grey silicon carbide sandpaper intended for dry use, called "open coat" or "free cut". In between sanding is just to remove the dust nibs. It's actually a light sanding, not intended to remove the finish to the wood. The first coat may be very thin, but should still be lightly sanded with the grain. Allowing imperfections to "read" from coat to coat, will be visible until removed. If the application is cured, sanding shouldn't gum up the paper.


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## cfs (Jan 19, 2009)

/\ /\ You make it sound so easy - maybe you could swing by and take care of it. Thanks again for the great advice CabinetMan!

I know this is very "rookie" - but to thin 50% would be 1 part poly to 1 part mineral spirits - correct?


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## cabinetman (Jul 5, 2007)

cfs said:


> /\ /\ You make it sound so easy - maybe you could swing by and take care of it. Thanks again for the great advice CabinetMan!
> 
> I know this is very "rookie" - but to thin 50% would be 1 part poly to 1 part mineral spirits - correct?



Yep...that's close enough. For wiping, use a lint free "T" shirt type rag. Don't shake the mix, but stir slowly. No bubbles!!


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## mmtools (Aug 21, 2008)

cfs said:


> 5 questions for the experts:
> 
> What do I sand the sanding sealer (applied over 2 coats of finish) with?
> 
> ...


Briefly..
1.VERY lightly with 180grit. Just enough to remove the "gloss" sheen, but do NOT sand tothe bare wood! That removes any effect the sealer has.

2. One coat

3.OK depending on the look you want...

4. since poly dries so slow, you will have"dust" settle on surface. Use a white 3M scrubbing pad (Very Fine)

5. If you are using water based anything (stain, sealer, finish) DO NOT use steel wool!!!! Rust spots WILL appear:yes:!!! Oil based products are compatible w/steel wool. I use the line of 3M pads .

I realize there are many opinions here, so if you have any, plz add...:blink:


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## cfs (Jan 19, 2009)

mmtools said:


> Briefly..
> 1.VERY lightly with 180grit. Just enough to remove the "gloss" sheen, but do NOT sand tothe bare wood! That removes any effect the sealer has.
> 
> 2. One coat
> ...


Wow - thanks a bunch. Will any of those 3M pads work? The link takes me to a group of 4 I believe.


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## mmtools (Aug 21, 2008)

The key is the eQuivalent grit... White (about 220/240 grit) being finest. grey, more coarse(about 180Grit), maroon 120/150, green 80/100 coarsest.


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