Water-based poly?

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I just used a water-based polyurethane for the first time. (I'm no woodworking expert. The last time I refinished anything was my grandma's old oak table, 20 years ago. Now it's time to refinish it and I'm using water-based this time.)
I noticed the grain popped up after the first coat of poly. I assumed that was because the water soaked into the wood. I sanded lightly with 220 grit and applied 2nd & 3rd coats.
It looks pretty good now. Not as smooth as the old poly, but that might have been because the old stuff has 20 years of wear. I think I might sand it again and put a few more coats on -- any harm in that?
It seems to me the water poly isn't filling in the open oak grain as well as the old poly did. This is a kitchen/dining table that gets plenty of use every day, including lots of spills from my 7-yr-old. I want to make sure the wood is appropriately protected from spills and is easy to clean up. Should I keep putting on 4th, 5th, ? coats until it looks like the grain is filled in better?
Thanks, Gary remove xxx's to email
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Snip

Typically when using water based products on bare wood you should lightly wet the wood surface, let thoroughly dry, lightly sand to get rid of the fuzzy grain that popped up and then apply the water based product.

No harm.
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Hm. There was no mention on the can. They just said sand with 220 after the first coat. Hopefully that does the job as well.
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If you put the first coat on too thick that might have popped the grain. What brand are you using? Sand to 22/330 between coats.
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Gary Fritz wrote:

Good.
Nope!
You can. Usually pore/defect filling is best done before the finish is applied, but the only real drawback for you is more work and extra coats.
Keep in mind that water based poly is nothing at all like oil based. They have the same name bit that is about it. Water based poly is much like latex paint, it is not a very good water barrier at all. The finish is emusified, which basically means the dried finish is much like scales on a fish, lots of small "plates" each overlapping each other. Oil based poly is actually cross linked and much more water tight.
I really like water based poly however since it is very easy to apply (I like to spray), clean up, and adds no tint to the project.
-Bruce

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Gary, as much as I like applying WB poly, it wouldn't be my finish of choice for a well used dining room tabletop. You can increase the durability (water resistance, abrasion resistance) of Enduro polys by adding Crosslinker. It is expensive, at $30 for a small bottle, but it goes a long way.
Another option would be to use a more durable finish such as C-V.
David
Gary Fritz wrote:

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Gary, No matter what the 'purists' say . . . I like water-based poly for finishing a 'working' surface, like your kitchen table. It's both hard and relatively impervious to liquids & damage.
Agreed, for a faster 'dead flat' & smooth surface, you should have filled the pores first. However, that type of surface is not a necessity but more of a cosmetic choice. To fill the existing grain with the poly, think about 6 coats . . . as a start. {Bare in mind that I consider 6 coats of varnish, etc. as normal !!}. Sand with progressively finer grits between coats. Use 220 for the first AND second, then 320, 400, and 600.
Note, that after the 2nd or 3rd coat the surface is sealed. Even if you see the little 'dimples' of the pores, they have sufficient finish in them to repel spills. Therefore, if you can live with the 'look', and still have it after 6 coats . . . don't worry about it.
Regards & Good Luck, Ron Magen Backyard Boatshop

SNIP I sanded lightly with 220 grit and applied 2nd & 3rd coats.

more coats on -- >

This is a kitchen/dining table that gets plenty of use every day, including lots of spills from my 7-yr-old. I

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Well that's good to hear. From what some of the other posters were saying, I was starting to think it was going to dissolve the first time my son spilled his juice on it. :-)

I have no problem with doing more coats. It only takes about 20-30 minutes to slap on a coat. I did 3 coats yesterday and I can easily do another 3 today if I want to. Except 220 is the finest grit I have, so I'll have to go out to the store to get 320/400/600.
Thanks! Gary
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Hm. Does it harden as it cures? I just looked at the table and I can fairly easily scratch/dent the finish with a fingernail. That would NEVER stand up to my kids.
I just put the 3 coats on yesterday, so maybe it just needs more time.
Gotta say though, the surface is nice and satiny. Just a few dust pips here and there. Not sure why it would be necessary to use the uber- fine sandpapers unless you wanted a glassy finish.
Gary
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It will harden over time, Gary, but I'll bet you the contents of my shop that even 3 months from now, you will be able to scratch it with your fingernail (dragged vertically in line with the edge of the fingernail). Moisture left on the surface for most of the day will mar the finish. Short term spills shouldn't bother it, however.
David
Gary Fritz wrote:

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Eeesh. In 3 months my kids could make a mess of my beautiful new finish. How long until it's fully hardened? Hopefully it will get a whole lot harder than fingernail-scratching level!!!
I'm starting to wonder if water-based was such a good idea after all...
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|> It will harden over time, Gary, but I'll bet you the contents of |> my shop that even 3 months from now, you will be able to scratch |> it with your fingernail | |Eeesh. In 3 months my kids could make a mess of my beautiful new |finish. How long until it's fully hardened? Hopefully it will get a |whole lot harder than fingernail-scratching level!!! | |I'm starting to wonder if water-based was such a good idea after all...
What (whose) material did you use. As I believe David said, Enduro makes a crosslinking material that is claimed to improve chemical and abrasion resistance by a factor of seven or so when added to their finish.
I have some of this material but have yet use it, so I can't confirm.
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Minwax Polycrylic, clear semi-gloss.
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Minwax's Polycrylic is not polyurethane and is much softer than traditional oil-based polyurethanes. Flecto's water-based Varathane is much harder than Polycrylic. I've used many gallons of Polycrylic on cabinets because I like the way it applies and settles, but I use Varathane on shelves for it's toughness.
They should be compatible. Sand the Polycrylic with 320 grit, then apply a coat or two of Varathane.
-Dave
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Gack. Great.

Hmmm. OK. If I remember right it was a Varathane product that I used on the table 20 years ago.
If sanding with 320 will ensure bonding to the polycrylic, then I think I'll do that. Two coats (on top of 3 coats of the polycrylic?) will be enough? Or should I sand down most of the polycrylic so the varathane doesn't have a soft surface underneath it??
I definitely can't tolerate a soft finish from the polycrylic. This table gets used 2-4 times every day and it needs to stand up to wear.
Thanks, Gary
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No guarantees in life that I know of, Gary - sometimes we just have to take chances. I THINK Varathane should bond well to scuffed-up Polycrylic, but can't remember ever actually doing that.
Certainly, the less Polycrylic under the Varathane, the better, but what you suggest sounds good. If I had it to do, I'd probably sand down the Polycrylic until it's very thin, but not gone (I like the color of the first coat of Polycrylic better than Varathane), then apply 2-3 coats of glossy Varathane (sanding between coats, of course), followed by one coat of semi-gloss (I think that's the surface you wanted). Generally, you want to use gloss for all but the last coat because it's much clearer than semi-gloss or flat, but it depends on whether you think of your table as "fine furniture". The Varathane I use is for floors, specifically: "Varathane Crystal Clear Waterborne Diamond Wood Finish", "Floors".
-Dave
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I guarantee this polycrylic would get trashed within a few months. :-\ I can easily gouge out pieces with my fingernail.

I sanded down the Polycrylic with 220. Much more than just "scuffing it up," but not down to the wood. Unfortunately this means the higher areas of the wood are glassy-smooth now, instead of having the interesting grain pattern I had before. Oh well.
This stuff is nasty to sand, at least with a fine grit. I had to stop every few minutes to scrape goobers of plastic off the sanding disk. The sanding dust feels more like fine plastic balls than like the silky-smooth dust you get from wood. Or even from the old Varathane.
I'm a bit concerned that the color seems a bit irregular now. I'm hoping that evens out when I apply the Varathane. I really don't want to have to start over and sand down to the wood again -- especially if this polycrylic is as nasty to sand with 40-grit as it was with 220 -- but if that's the right thing to do, I'll do it. Better to do it now before I put a couple of coats of Varathane on. I don't want to have to refinish this thing again for 15-20 years so I want to do it right.
Gary
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BTW I thought I didn't get down to the wood. It still feels like plastic in most areas. But e.g. there is a spot where I accidentally gouged the wood with the 40-grit, and I smoothed out a depression around it. Now that area shows a light ring around the depression. Not sure why that would be, if I haven't touched the wood & thus the stain. Maybe it will disappear when I apply the Varathane? Or maybe I got down to the wood in a few spots and removed some of the stain. If so, I probably ought to start over and take it down to the wood again. ***SIGH***
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wrote:

It sands better when it cures longer. The same reason you're trying to take it off is the reason the paper clogs.
Is there any way you can just leave it alone for a couple of weeks? Use another table, until this one cures?
The ingredient most often forgotten in the formula is patience. DAMHIKT.
Patriarch
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Ick. We already have a temporary table but it's definitely a pain. I'm wondering if the 40-grit will take the polycrylic off without so much gunking-up. I might give it a try and see how it works so I can get this project DONE and get this big honkin' table (4 leaves, 10' long) off the floor & out of the way. If I waited a few weeks I'd at least get it off the floor, but I'd like to finish this.
What was that you said about patience?? :-)
When I take it down to the wood again -- this time should I use a filler before the Varathane? Or do you figure there's enough polycrylic in the low spots to take care of it already?
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