# smooth finish on rough wood?



## desertsp (Apr 5, 2016)

Finishing rough cut oak with the saw marks intact. Not rough enough to snag terry cloth, but there is noticeable texture remaining. Sanded to 120. 

Would I be better of putting down multiple coats of shellac to fill in some of the roughess, then top with poly, or the other way around? Or do I just live with the texture?

It's a dining table and I just want it to be more easily cleanable, not mirror smooth or anything like that. The table is stained with oil-based stain so I'm already using shellac as a barrier under the water-based poly....just wondering if I should lay down a couple extra layers or not.


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## Steve Neul (Sep 2, 2011)

First of all you need to be careful what you use around shellac. It isn't compatible with everything. Shellac has a natural wax in it that will prevent the proper adhesion of waterborne finishes as well as polyurethane. They make a de-waxed shellac that would work in that application. 

If it were me I would use a sanding sealer which is compatible with what ever finish you are going to use and sand between coats and keep applying sealer until the wood is close to the smooth you require. Then topcoat it with the final finish.


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## desertsp (Apr 5, 2016)

Thanks Steve. I am using SealCoat which I believe is dewaxed.

So I can just go and add multiple coats and not worry (too much) about having the shellac be quite thick (say 1mm) in places?


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## Steve Neul (Sep 2, 2011)

desertsp said:


> Thanks Steve. I am using SealCoat which I believe is dewaxed.
> 
> So I can just go and add multiple coats and not worry (too much) about having the shellac be quite thick (say 1mm) in places?


While shellac dries to touch very quickly if you are going to build that much thickness you need to allow more drying time with each consecutive coat. What ever amount of time you normally use for drying time double that with each coat. Like if you normally let a coat dry an hour use two hours with the second coat, four hours with the third coat and so on. The finish may dry to touch and you can handle it and sand it but it's not fully dry. If you keep adding coats it will refresh the previous coats and eventually with a thick coat when it fully dries can crack. If you have ever seen tempered glass which is also laminated break the finish ends up looking like that.


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## TomCT2 (May 16, 2014)

you are I hope aware that shellac and water/steam pots/pans/dishes/chafers/ etc are not a good mix?

past that, yes you can do a "thick" coat - via various approaches depending on your tolerance for "gosh what a mess I made"

I use a rubber 'squeegee' so I brush it on thick, squeegee off the high spots. the low spots will fill in much much faster than a brush on - wipe off routine. but - and this is really important - you must allow time for the thicker coats to dry to a crisp. failure to do so makes for really ugly finishes that there is really no 'fix / rescue' for.

the squeegee technique makes a big mess - the excess gets squeezed out on the floor, dribbles down the sides, you hands get sticky / gooped up to no end . . . but 2-3 coats is typically sufficient to fill in fairly deep 'character markings.' you want to medium-fine lightly sand off the 'itty bitty bumps' between coats.


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## Quickstep (Apr 10, 2012)

I think it's going to take a long time to build any serious thickness with SealCoat. Steve's idea of using the appropriate sanding sealer may build faster. 

Another might be to use TomCT's squeegee method using epoxy, then topcoat it with a good varnish.


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## desertsp (Apr 5, 2016)

Love this place - for every question every answer is an excuse for a new project!

Come to think of it, I don?t think I?ve ever used sanding sealer. Is that the stuff with soap particles to lubricate the sandpaper? How does that impact the clarify of the finish? About as much as regular flatterers would, like for a satin or semi-gloss poly? Sounds like something I need to try. 

Unfortunately, as always I?m down to the wire time wise. I?m actually having a guy pick it up on Saturday to move it to my in-laws where we will spend thanksgiving. I don?t know why I never learn my lesson about promising things by certain dates and then putting off important details like finishing! Waterbased poly to the rescue...and a space heater. I?ve done it before and it am not worried but it means I?m stuck with the products I have at home and don?t have time to buy new stuff or learn to use it. Again, more projects!

Anyways, I just hit it with a spray coat of dewaxed shellac from a can, and WOW the colors sure do pop! Tomorrow morning I?m Probably going to brush on a coat of diluted SealCoat, then two or three layers of waterbased poly for protection (throughout the day with sufficient time between). It sounds risky to build up thickness in such a short timeframe so hopefully those few layers are enough to mask the surface roughness.. Suspect they will be but I?ll report back either way. 

Thanks again for the quick feedback so I can continue the project!


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## desertsp (Apr 5, 2016)

After gel stain and one coat of shellac. Very happy so far.


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## epicfail48 (Mar 27, 2014)

If I wanted to keep the look of the rough-cut wood on a dining table, I'd go with a heavy coat of pour-on epoxy. You preserve the look, but it wouldn't be nearly as much a bloody nightmare to clean. 

The rough-hewn look is great right up until the first time someone spills something


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## desertsp (Apr 5, 2016)

epicfail48 said:


> If I wanted to keep the look of the rough-cut wood on a dining table, I'd go with a heavy coat of pour-on epoxy. You preserve the look, but it wouldn't be nearly as much a bloody nightmare to clean.
> 
> The rough-hewn look is great right up until the first time someone spills something


Epoxy was actually the original idea but I thought it might be too plastic looking. Didn't want to purchase a kit just to decide I didn't like it and then have it expire before another project comes up. 

[EDIT] It sounds like it's possible to pour epoxy over polyurethane. So that'll be my contingency plan if the shellac and poly leave too rough of a final surface. 

http://www.woodworkingtalk.com/f8/epoxy-over-polyurethane-56103/


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## Steve Neul (Sep 2, 2011)

desertsp said:


> Epoxy was actually the original idea but I thought it might be too plastic looking. Didn't want to purchase a kit just to decide I didn't like it and then have it expire before another project comes up.
> 
> [EDIT] It sounds like it's possible to pour epoxy over polyurethane. So that'll be my contingency plan if the shellac and poly leave too rough of a final surface.
> 
> http://www.woodworkingtalk.com/f8/epoxy-over-polyurethane-56103/


No, don't do that. Poly will dry on the surface and stay wet underneath for months. It's different with epoxy. Once mixed with hardener you could pour it into a jar to the top and put a lid on it and put it in a vacuum chamber completely free of air and it would harden all the way to the bottom in a matter of hours. 

I believe I misunderstood the objective with the finish. I though you were trying to get the surface just smooth enough to be able to keep it clean. If you are trying to completely level the surface then epoxy is the only answer. It may have a plastic look to it but so would polyurethane. You could brush a few hundred coats of poly on letting it dry completely between coats but poly isn't elastic enough to deal with wood movement. The first time the wood expands or contracts poly would crack. It's just too hard for that application.


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## desertsp (Apr 5, 2016)

Steve Neul said:


> No, don't do that. Poly will dry on the surface and stay wet underneath for months. It's different with epoxy. Once mixed with hardener you could pour it into a jar to the top and put a lid on it and put it in a vacuum chamber completely free of air and it would harden all the way to the bottom in a matter of hours.
> 
> I believe I misunderstood the objective with the finish. I though you were trying to get the surface just smooth enough to be able to keep it clean. If you are trying to completely level the surface then epoxy is the only answer. It may have a plastic look to it but so would polyurethane. You could brush a few hundred coats of poly on letting it dry completely between coats but poly isn't elastic enough to deal with wood movement. The first time the wood expands or contracts poly would crack. It's just too hard for that application.


No you were right - I'm just aiming for a surface smooth enough to be able to easily clean. 

Now that I have two coats of shellac and two poly, the roughness from the saw kerfs actually DID fill in, but now it's the porous oak grain (dark areas) which is remaining rough. The poly doesn't seem to level itself over the grain and almost seems to accentuate it. I have not tried spreading it on thicker. 

Any tips on resolving the rough grain texture at this point, in the next two days? I'm doing a light scuff sand between coats, but am afraid to go hard and possibly expose bare wood. Is that what I need to do though? I'm not expecting perfection anymore but hope I can get it a bit smoother by the time it's done. 

I'm using this polyurethane (semi-gloss, the final layer will be satin)


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## desertsp (Apr 5, 2016)

Would something like this be of use?

https://aquacoat.com/collections/wa...filler-wood-putty/products/clear-grain-filler

I can run to Woodcraft this evening (other side of town during rush hour...1:30 round trip) if it's likely to help and not make things worse!


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## mackman (Mar 2, 2016)

desertsp said:


> Would something like this be of use?
> 
> https://aquacoat.com/collections/wa...filler-wood-putty/products/clear-grain-filler
> 
> I can run to Woodcraft this evening (other side of town during rush hour...1:30 round trip) if it's likely to help and not make things worse!


I used that on oak coasters and it DID work. However, it took a LOT of applications. I would just keep the coasters by my desk and reapply whenever it was dry to the touch, and it probably took 5 applications or so before the pores filled. So with a whole table, that would be a LOT of filler. (Then again, maybe others have had easier, more consistent results?)

But at the same time, I wonder whether it's worth the trouble? The pores shouldn't mess with cleaning that much. I'd say ask any other person if they think the pores make it look worse: My guess is they wouldn't even notice until you pointed it out.


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## desertsp (Apr 5, 2016)

mackman said:


> I used that on oak coasters and it DID work. However, it took a LOT of applications. I would just keep the coasters by my desk and reapply whenever it was dry to the touch, and it probably took 5 applications or so before the pores filled. So with a whole table, that would be a LOT of filler. (Then again, maybe others have had easier, more consistent results?)



Do you remember if it was applied over polyurethane though?


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## desertsp (Apr 5, 2016)

mackman said:


> But at the same time, I wonder whether it's worth the trouble? The pores shouldn't mess with cleaning that much. I'd say ask any other person if they think the pores make it look worse: My guess is they wouldn't even notice until you pointed it out.


You're probably right. But it's the principal - *I* will always notice! :laughing:


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## mackman (Mar 2, 2016)

desertsp said:


> Do you remember if it was applied over polyurethane though?


I had to apply it over poly: Applying it before poly messed with the way the poly was absorbed and resulted in an uneven look. But applied after poly, with another coat or two on top, worked just fine.


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## Steve Neul (Sep 2, 2011)

desertsp said:


> No you were right - I'm just aiming for a surface smooth enough to be able to easily clean.
> 
> Now that I have two coats of shellac and two poly, the roughness from the saw kerfs actually DID fill in, but now it's the porous oak grain (dark areas) which is remaining rough. The poly doesn't seem to level itself over the grain and almost seems to accentuate it. I have not tried spreading it on thicker.
> 
> ...


Polyurethane will fill the grain if you sand it well between coats. Ordinarily when it is desired to fill the grain you use a grain filler but in this case where you have the texture of the rough sawn wood you would be filling that instead of the grain. Usually it's only on woods like walnut and mahogany grain is filled. It's pretty much expected and common place to see grain on oak. I have an oak table in my house which the top is smooth. My wife wanted a glass like finish on the top of it so the first time I refinished it I grain filled it and put a high gloss finish on the top of it. Even she admitted the table looked terrible with that finish on it. I have since put it back like it should be.


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## desertsp (Apr 5, 2016)

mackman said:


> I had to apply it over poly: Applying it before poly messed with the way the poly was absorbed and resulted in an uneven look. But applied after poly, with another coat or two on top, worked just fine.


Hmm...I think I'll try this out unless someone else chimes in within the next few hours.


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## desertsp (Apr 5, 2016)

Steve Neul said:


> Polyurethane will fill the grain if you sand it well between coats. Ordinarily when it is desired to fill the grain you use a grain filler but in this case where you have the texture of the rough sawn wood you would be filling that instead of the grain. Usually it's only on woods like walnut and mahogany grain is filled. It's pretty much expected and common place to see grain on oak. I have an oak table in my house which the top is smooth. My wife wanted a glass like finish on the top of it so the first time I refinished it I grain filled it and put a high gloss finish on the top of it. Even she admitted the table looked terrible with that finish on it. I have since put it back like it should be.


Thanks Steve. It's great to be able to get such quick feedback!

That's a good point that oak usually has a grain texture and it might look strange without. I just had my wife go and look at the table and she thinks it's fine as-is...but I'm so tempted to try the AquaCoat clear filler!

Do you think there's any significant benefit (or risk) to the AquaCoat filler versus just more coats of poly sanded back between coats, in terms of achieving a smoother surface within the next two days? (the final coat of poly has to go on by Friday evening)


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## Steve Neul (Sep 2, 2011)

desertsp said:


> Thanks Steve. It's great to be able to get such quick feedback!
> 
> That's a good point that oak usually has a grain texture and it might look strange without. I just had my wife go and look at the table and she thinks it's fine as-is...but I'm so tempted to try the AquaCoat clear filler!
> 
> Do you think there's any significant benefit (or risk) to the AquaCoat filler versus just more coats of poly sanded back between coats, in terms of achieving a smoother surface within the next two days? (the final coat of poly has to go on by Friday evening)


I've never used the AquaCoat so I don't have any experience with it. I have a hunch if you were going to use it that it should have gone on before the poly. I would find out from the manufacturer if it can be used over poly before doing that. You could create a problem that would lead to chemically stripping the finish off. 

I normally use an oil based grain filler and it is used first before any stain or anything.


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## desertsp (Apr 5, 2016)

Whelp I went ahead and added the grain filler. It?s like nothing I?ve ever used before (which doesn?t say much!). Basically it?s a thick gooey paste the texture of a heavy machine grease, which goes on bluish white and turns clear. Suspiciously like an ultra-thickened polyurethane finish, I wonder if it?s a similar chemistry?

It does shrink somewhat, as evidenced by crackling in the deeper areas filled, like >1/4? diameter nail holes that I hadn?t totally filled to the brim with epoxy in an earlier step. This AquaCoat filler probably shrunk by 10-20% in volume as it hardened in those areas and the crazing resulted. Oh well...I really don?t think anyone will notice! 

The call to the manufacturer didn?t go through (I think it?s my phone, hopefully) but I found a lot of online reviews suggesting it will work over polyurethane. The manufactures instructions don?t warn against that, either. 

Fingers crossed but I think it?ll work out and be ready by Saturday!


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## Steve Neul (Sep 2, 2011)

It doesn't sound good. The product was intended to use on smooth surfaces and just fill grain. I don't know what to think about allowing it to puddle. It may be if you allow it to dry very well and sand the crazing off it might be alright, I just don't know. At this point it really doesn't matter, it will either work or it won't. Might as well go with it and if it lifts strip it off next summer and do it over. 

When I use an oil based grain filler it's thinned to about the consistence of mayonnaise. You brush or spray it on and let it thicken to a paste. Then with a coarse cloth it is rubbed into the grain removing all the excess. Only the grain retains the grain filler. Then it's allowed to dry and lightly sanded and stained before applying the finish.


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## desertsp (Apr 5, 2016)

Steve Neul said:


> It doesn't sound good. The product was intended to use on smooth surfaces and just fill grain. I don't know what to think about allowing it to puddle. It may be if you allow it to dry very well and sand the crazing off it might be alright, I just don't know. At this point it really doesn't matter, it will either work or it won't. Might as well go with it and if it lifts strip it off next summer and do it over.
> 
> When I use an oil based grain filler it's thinned to about the consistence of mayonnaise. You brush or spray it on and let it thicken to a paste. Then with a coarse cloth it is rubbed into the grain removing all the excess. Only the grain retains the grain filler. Then it's allowed to dry and lightly sanded and stained before applying the finish.


I think you're definitely right to be concerned about the crazing. Fortunately it's only in a few small areas (nail holes) and I was able to Dremel it out and replace with black epoxy, which I should've done in the first place. If this weren't a rustic style table it would have been a deal breaker! 

The product did serve its intended purpose of filling the grain, and the table is now smooth enough to wipe clean even for something like peanut butter or soup. I think it would have required at least four more coats of polyurethane to do that. So I'm going to call it a success, but will be observant of future issues. 

Next time I'll follow your protocol of filling grain BEFORE finishing instead of as an afterthought.


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## desertsp (Apr 5, 2016)

Here's what happens with the AquaCoat Clear Wood Grain Filler if you get it into a deeper recession. That's a divot about 5mm wide and 2-3mm deep. This is 8 hours after application and the material feels hard and dry, however it stayed white and cracked. 

Not judging the product...this is user error.


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## mackman (Mar 2, 2016)

Just in case you ever use it again: If you ever do use it before finishing, you need to make sure to sand down to bare wood afterwards. Otherwise, as I said before, it'll interfere with the finish absorbing into the wood and result in an ugly, uneven finish. Definitely not something you could have done on an uneven surface like the one you started with here.


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## Steve Neul (Sep 2, 2011)

If you are going to use the Aquacoat again you better study up on it. Since it is clear I bet it would seal the wood like a glue stain and then you wouldn't be able to stain it. It might be you need to stain the wood first, use the Aquacoat and then the finish.


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## mackman (Mar 2, 2016)

Steve Neul said:


> No, don't do that. Poly will dry on the surface and stay wet underneath for months. It's different with epoxy. Once mixed with hardener you could pour it into a jar to the top and put a lid on it and put it in a vacuum chamber completely free of air and it would harden all the way to the bottom in a matter of hours.
> 
> I believe I misunderstood the objective with the finish. I though you were trying to get the surface just smooth enough to be able to keep it clean. If you are trying to completely level the surface then epoxy is the only answer. It may have a plastic look to it but so would polyurethane. You could brush a few hundred coats of poly on letting it dry completely between coats but poly isn't elastic enough to deal with wood movement. The first time the wood expands or contracts poly would crack. It's just too hard for that application.


Sorry for the thread necro, but I'm working on a very similar project now and the client wants a completely smooth top over rough-cut oak. I suggested epoxy, but since it's a four-foot-wide table, I wondered how well epoxy generally handles that kind of potential movement. Some internet sources suggest that epoxy is terrible with wood movement, and others suggest it's just fine. But here, you seem to say that epoxy is actually _better_ with wood movement than standard polyurethane would be? Could you let me know your thoughts? (it wouldn't be a terribly thick layer: Just thick enough to fill in the saw marks and level the surface).


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## Steve Neul (Sep 2, 2011)

mackman said:


> Sorry for the thread necro, but I'm working on a very similar project now and the client wants a completely smooth top over rough-cut oak. I suggested epoxy, but since it's a four-foot-wide table, I wondered how well epoxy generally handles that kind of potential movement. Some internet sources suggest that epoxy is terrible with wood movement, and others suggest it's just fine. But here, you seem to say that epoxy is actually _better_ with wood movement than standard polyurethane would be? Could you let me know your thoughts? (it wouldn't be a terribly thick layer: Just thick enough to fill in the saw marks and level the surface).


A finish thicker than a lawn and leaf trash bag is considered a thick finish. Any thick finish whether it is epoxy or polyurethane can be trouble with wood movement. What it comes down to mostly is the moisture content of the wood when you do a thick finish and if you also seal the underneath side. If the wood moves very much the finish has the tendency of cracking. The wood needs to be very dry.


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## mackman (Mar 2, 2016)

Steve Neul said:


> A finish thicker than a lawn and leaf trash bag is considered a thick finish. Any thick finish whether it is epoxy or polyurethane can be trouble with wood movement. What it comes down to mostly is the moisture content of the wood when you do a thick finish and if you also seal the underneath side. If the wood moves very much the finish has the tendency of cracking. The wood needs to be very dry.


According to my moisture meter, the MC of the oak is right around 8.5%. It'll be kept indoors in the California central valley, which is typically quite dry. I was intending to finish the underside with poly and the top with a thicker epoxy coat: Would that likely lead to disaster?


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## Steve Neul (Sep 2, 2011)

mackman said:


> According to my moisture meter, the MC of the oak is between 7% and 9%. It'll be kept indoors in the California central valley, which is typically quite dry. I was intending to finish the underside with poly and the top with a thicker epoxy coat: Would that likely lead to disaster?


That sounds alright. Go for it.


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## mackman (Mar 2, 2016)

Steve Neul said:


> That sounds alright. Go for it.


Thanks! So you think an epoxy coat would have at least a shot at not splitting in this circumstance? 

Luckily, it's for a family friend, so I would have the opportunity to repair the finish if necessary. Maybe this will be a good test case.


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## Steve Neul (Sep 2, 2011)

mackman said:


> Thanks! So you think an epoxy coat would have at least a shot at not splitting in this circumstance?
> 
> Luckily, it's for a family friend, so I would have the opportunity to repair the finish if necessary. Maybe this will be a good test case.


With wood there is never guarantees but with the moisture contend as low as it is I don't think you will have any problems.


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## epicfail48 (Mar 27, 2014)

mackman said:


> Thanks! So you think an epoxy coat would have at least a shot at not splitting in this circumstance?
> 
> Luckily, it's for a family friend, so I would have the opportunity to repair the finish if necessary. Maybe this will be a good test case.


Depends on the epoxy methinks. An epoxy meant for finishing wood will actually cure and still have some flex to it, something like Smooth On epoxy. Seriously, i have a sheet of run-off from that stuff that i poured 2 years ago, still flexible and pliable and yes, it was mixed correctly. Just meant to flex with the wood i guess. 

A different sort of epoxy may not hold up as well though. Picture something like a conventional 5 minute epoxy, sets up rock hard. Try to flex it and it shatters. Stick to the dedicated finishing stuff though and id wager youd be fine


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