# Water-based poly. I'm sure I'm doing it wrong.



## Ocelot (Mar 6, 2011)

This has been my first try at water-based finishes and I'm not too happy about it.

I'm finishing a poplar bookcase with 8 shelves about 5' wide.

It was well sanded (to 320) before I started. After the first coat of water-based poly, the surface was *very* rough as a result of raised grain. I sanded (with 220, by hand, on a rubber sanding block) for about 5 hours to put it right - and wondered if there was any poly left on the thing after that. The second coat seems to raise the grain too - just not as much. I figure at this rate, I'll be into the 4th coat before it stops raising the grain.

I'm sure I'm doing it wrong. This is miserable!

Can anyone straighten me out. The product is "Rust-Oleum Ultimate semi-gloss Polyurethane".

-Ocelot


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## wapakfred (Jul 29, 2011)

A lot of folks seal the wood with shellac before using a waterborne finish to prevent that. You could do that, or just go ahead and apply your 3rd coat without worrying about it….then smooth it out. Eventually you get to a point where the whiskers are locked in by the finish and won't raise anymore….I suspect you might be there now. In any case, after the third coat (or however many you come to accept as the right number) sand it smooth, apply your last coat and your done.


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## bigblockyeti (Sep 9, 2013)

Did you by chance try to raise the grain before starting? I usually do that twice even when using oil, cheap insurance.


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## Ocelot (Mar 6, 2011)

Thanks for your replies.

I read something about using shellac on LJ, but did not try it. The reason I'm using water-based finish is that it had been too cold in the shop, so I'm finishing in the house while my wife is newly pregnant and sensitive to odors. I've never used shellac and didn't know how odiferous it is. Does shellac smell?

No, I didn't raise the grain before starting. I've always used traditional finishes and never had an issue - although I'm a very low-volume wood-worker.

-Ocelot


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## pintodeluxe (Sep 12, 2010)

Shellac has a distinctive odor, some people like it and some hate it. Kind of like the smell of Simple Green that way.

With anything water based like dyes or finishes, I like to raise the grain before finishing. Then you can scuff sand with some 320 grit before you apply the finish. This way your stain or topcoat won't be sanded away.


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## Magnum (Feb 5, 2010)

You didn't "Shake" the container before applying it did you? Water Based Poly MUST always be Stirred or else you end up trying to apply a "Vanilla Milkshake" ...LOL.. (Full Of Bubbles.) Usually tells you that on the can. Flecto or Minwax Poly at any rate.

I use Water Based Poly all the time, also on Poplar, never had this happen. Three coats always does it just fine. I've never Pre-Raised the grain.

I use to use WHITE Shellac thinned with Methyl Hydrate to seal any kind of wood. Dries almost instantly.

The water based Poly they have out now, in my opinion dries Way To Fast. You have to put it on reasonably thickly, quickly brush it out and Leave It Alone.


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## PineChopper (May 21, 2012)

I've never had that kind of a problem with the water based poly. Sounds like you might be over sanding in between coats.


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## TheBoxWhisperer (Sep 24, 2012)

keep sanding or dont bother untill your next coat, in my experience the 3rd, thin coat is where it all starts to come together with waterpoly.


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## ClintSearl (Dec 8, 2011)

Forget shellac. WB poly does fine if you just knock down the first coat nibs with 220 drywall sanding screen, followed by a couple more full wet coats.

Note: Never sand past 220 before finishing.


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## a1Jim (Aug 9, 2008)

IMO there's no reason to sand the wood to 320,150-180 is fine .As others have said you can raise the grain first then do a *light* sanding with 220 grit, don't over do it just a quick once over or you will raise the grain over and over again. apply your coat (spray if you can) thinned 10% let dry usually 2 hours then another light sanding 320 grit ,apply second coat(spray if you can) unthinned let dry,if you still have raised grain do another very light sanding with 600 grit or higher grit after that it's up to you and the type of gloss you want whether you do a third coat.


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## Magnum (Feb 5, 2010)

Sorry Double Post.


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## NormG (Mar 5, 2010)

Sounds like a1Jim has a great idea


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## rg33 (Dec 1, 2012)

I cant recall the last time I used something other than water based poly (as my skills get better I do want to get into the more traditional finishes) but have always had good results. I think you're main issue is that you likely sanded too much after the first coat. Again only from personal experience i've never had to raise the grain beforehand. Here is what I do and works for me:
1. Finish sand with 220. I'ver never needed to use finer
2 Stain with oil based stain and allow for a full dry 24 hrs+(i never thought about this until now but maybe this has helped to condition the wood)
3 As others have said stir DO NOT SHAKE poly.
4 Apply first coat and let dry. At this point finish will look and feel rough.
5 Take 220 sandpaper, and lightly pass over surface. To give you an idea of how much, I spend about 5 minutes on the top surface the size of a desk. All you want is to knock down the peaks really. Poly looks white after you sand but do not fear, you're done when you can pass your hand on the surface and no longer feels rough, even if it doesnt look perfect because the next coat will cover the tiny scratches that are only poly deep. make sure to wipe pretty well
6 Put another coat and let dry. By this point the surface will be well sealed. I rarely sand at this point.
7Finish with third coat.

hope this helps


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## SuperCubber (Feb 23, 2012)

I do almost the exact same process as rg33, except step 5 is slightly different. I use 320 instead of 220, and I do one or two VERY light passes. Like he said, just enough to knock down the nibs. I don't even put any pressure on the block. I let the weight of the block do the work. After that I wipe it down with a damp rag before the next coat.

Also, I usually do a quick sanding with 320 between subsequent coats, but I'm not sure that's completely necessary.

*The process I use applies to both spraying and brushing.


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## Ocelot (Mar 6, 2011)

Wow! Lots of replies.

I'll try to respond.

First, I stirred. No shaking. I'm pretty good at following directions!

2nd. I wanted a natural, very light finish, so there was no stain or other finish prior to the poly. That may be a big difference from what some of you folks (supercubber and rg33) are doing.

I could feel the grain rising while I was brushing it on - could feel the wood become rough under the brush.

Oh, in case it matters, I was/am using a foam brush.

I've never before sanded after applying finish. I could not see any alternative this time since the surface, which had been glassy smooth became quite rough while applying the 1st coat.

So, from what rg33 says, it is normal for the surface to be rough? This is a big surprise to me. I had no idea. Do later coats fill in the roughness and make it smooth again?

-Ocelot


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## SuperCubber (Feb 23, 2012)

Ocelot,

I have never used water-based over a stain. I've used it straight, and over a water-based dye. It is perfectly normal for it to be rough. I would not expect the poly to fill in the roughness. Lightly sand with 320, apply another coat and let us know how it feels.


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## LeeBarker (Aug 6, 2010)

Use a quality brush made for WB finishes.

I like the stuff from Tools for Working Wood.

FWIW, I sand my instruments to 220, spray them with water, 220 again, and start the finish process the next day.

Kindly,

Lee


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## GregD (Oct 24, 2009)

+1 on a quality brush for the finish.

My usual practice on sanding is to wipe down the work with a wet-but-not-dripping rag to get off all the dust. When it is dry I do a quick once-over (maybe 1 to 3 light swipes) with whatever grit I last used. If any coat of finish comes out rough I do another quick once-over just to knock off the high spots. The first coat seems to come out rough more frequently than the other coats, provided you apply the finish in a reasonably clean environment and you wipe the work down carefully with a tack cloth before each coat.


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## Ocelot (Mar 6, 2011)

I want to thank yoiu all again for your helpful suggestions. If I don't reply individually to each, please accept my apology. I'm just posting a quick note at work.

The bookcase is finished and put into service. I'm a little disappointed in the finish, but my daughter (for whom I built it) has no complaints.

After the 2nd coat of poly, I sanded with 320. This took probably 4 hours.

My 2-year-old helped.









There are 24 sections within the bookcase such as my boy is sitting in. It's a bit awkward to sand, so that's why it takes so long.

After that sanding, I vaccumed carefully all the dust and applied the 3rd (and final) coat of water poly. This went on much more smoothly, but I sanded some afterwards (2-3 hours later) with 600. The 600 loads up with poly pretty quickly, so that it's almost like rubbing the surface with a piece of brown paper.

So, I installed it last night.










There's the recipient loading it up.

Before I do another large piece with any finish, I'm going to do some small experiments.

Again, I appreciate all your comments and will re-read and consider my approach carefully next time I try this.

-Ocelot


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## Ocelot (Mar 6, 2011)

@Lee Barker,

I'm sure you make some beautiful things. Right now, unfortunately, brushes such as you use are out of my budget. This year, I'm allowing myself only $50/month for woodworking. Not to worry. I already have a couple thousand board feet of rough lumber in the shop and enough tools and equipment to do interesting things. But for now, I'm making do with what I have or what fits in $50/month. A quart of poly and 2 packs of sandpaper pushed me half-way into March's budget already.

You see, I had fallen into the habit of buying "one more thing" while producing very little. I'm trying to discipline myself to buy less and produce more.

-Ocelot


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## donbee (Feb 7, 2009)

A foam brush isn't just right for a fine finish. Use a good brush and flow the coat on then stroke through it with just the very tips of the bristles.. I sand between coats, but not very much, just enough to take down the nibs.
After I have a good film, three or four coats, I let it cure for a day or two, then sand very finely, then wet sand to 1000 or so and apply finishing wax and rub well.

You won't want to use anything else!

Don


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## Ocelot (Mar 6, 2011)

Sounds very nice Don! (Wet sand to 1000 or so! LOL) I'm planning a small night-stand for my next project. Something without so much surface area. Maybe I'll try your method, but right now, I can't spend much on brushes - just have to make do with what I have or can obtain inexpensively.


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## jstegall (Oct 9, 2008)

The only issue I had with WB Poly was using poor quality brush (recommended by the know nothing sales rep). I returned it and asked for a top quality brush and that solved the issue. It has always been rough after the 1st coat for me and light sanding solved that problem. It looks terrific now. I also stained it first with a OB Stain

Edit:
Just now read about your wanting to stay on the inexpensive side. The brush I normally use is 20+ years old (loaned to my daughter, since returned). See if you can borrow a good quality brush.


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## Ocelot (Mar 6, 2011)

I have a couple of brushes lying around. (Even new ones, probably.) I'll take a look at them to assess their quality. Thanks for the tip.


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## ChefHDAN (Aug 7, 2010)

The foam brush could be adding to your headache too, by causing bubbles simmilar to shaking the can. I shoot WB poly through a $25 HLVP gun I got at HF, and have been very pleased with the results


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## DavidIN (Dec 15, 2012)

you were sanding too much. i just barely, i mean barely, sand the wood just enough to knock down the nubs. i feel behind it as i sand and as soon as it feels smooth i stop. doesn't take much at all and i don't even use a block.

I don't sand above 180 anymore, and use a 220 or higher to knock down the raised grain.

Water based anything DO NOT use a natural brush as the water will swell it somewhat. use a polyester brush.


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## b2rtch (Jan 20, 2010)

Foam brushes are not good for finishing as they leave thousands of tiny bubbles in the finish.
(Personally I believe that foam brushes are good for nothing)
A good brush would really help.


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## johnstoneb (Jun 14, 2012)

You are sanding way too much. light sanding after the first coat to knock the hairs down. if you don't get them all fine put on a second coat and sand lightly again. I use 220 after first coat and 320 on second. If I am building a finish up after the third or fourth coat I will work up to about a 1000grit wet. With waterborne finishes I will generally stop at 3 coats. And as Bert says foam brushes are good for nothing even a really cheap brush is better than foam.


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## Ocelot (Mar 6, 2011)

DavidIN, b2rtch, Johnstoneb,

Thanks for your comments. I too was certain that I was sanding "too much". However, I was not going to accept a rough surface. I would rather sand all the finish off and start over than accept that. The surface after the 1st coat was rougher than most of the rough-sawn lumber I have in the shop. It felt about like 100 grit sandpaper itself. I don't believe the later coats would somehow have smoothed that out.

While a different brush might improve the final finish, I'm certain that the water was the main issue. I have finshed some years ago a maple table using foam brushes and whatever solvent polyurethane was commonly available 10 years ago. It did not raise the grain, and I ended up with what I found to be a very acceptable surface after 3 coats with only 0000 steel wool between coats. I also built a large (12' wide x 8' high) bookshelf wall unit from oak-veneer ply with solid oak trim and finished it with foam brushes with no problems. With a foam brush, I have found it best to fully load the brush, then brush ever more lightly - so that there is little air in the brush and little pressure to force it out. Still, that is with extremely limited experience. Sure, there are probably better brushes, but I have had acceptable results with foam in the past.

What I suppose is needed is for me to do some side-by-side comparisons of different finishes and different brushes. Experience is the best teacher. Your experience helps, but I need to get me some of my own. For now, I'll use water-based poly only as a last resort. However, I have perhaps a cup of the stuff left in the can, a narrow (1") polyester brush, and plenty of cherry on the rack. (I think I have some other brushes somewhere, but can't find them.) I'd like to do a test on cherry to see if it works differently than it did on the poplar.

Thanks again for taking the time to comment.

-Ocelot


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