Wet sanding water based finishes

ErnieM

Ernie
Corporate Member
I've been using oil based finishes on my instruments for the past 40 years. It's high time to try out the water based finishes that so many folks are using. I'm wondering what lubricant you all use to wet sand water based finishes. I've always used water with a little detergent mixed in to wet sand oil based finishes, but that doesn't make sense to me when wet sanding water based products. Wouldn't water partially dissolve the finish? Your advice will be most appreciated.
 

Oka

Oka
Corporate Member
Ernie, Once the finish vulcanizes water has no effect. When you experiment, pay close attention to the true time for 100% Dry (set), sanding anytime before that can cause the finish to get a haze on the surface, a real pain. Water based anything is a lot like working with plastic, what the manufacturers recommend and suggest must be adhered to exactly.
What I like about oil finishes or solvent types is you really have more flexibility to how you can modify the mix to fit the ambient humidity and environment, maybe it just me more comfortable with old school finishes.
 

ErnieM

Ernie
Corporate Member
Ernie, Once the finish vulcanizes water has no effect. When you experiment, pay close attention to the true time for 100% Dry (set), sanding anytime before that can cause the finish to get a haze on the surface, a real pain. Water based anything is a lot like working with plastic, what the manufacturers recommend and suggest must be adhered to exactly.
What I like about oil finishes or solvent types is you really have more flexibility to how you can modify the mix to fit the ambient humidity and environment, maybe it just me more comfortable with old school finishes.
Maybe I just like oil based finishes because I'm old, but other than ease of cleanup, I still can't find a good reason to switch. I would have thought that the quick drying water based finishes would speed up the process, but it seems they require relatively long curing time before they can be sanded or polished. The video Pete suggested, while interesting, seemed to verify the need for very long curing time - not to mention the expense of the product he was hawking. I'm sure I'm missing something and perhaps I'm too stubborn and set in my ways to see it.
 
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Oka

Oka
Corporate Member
Agreed, but some old ways still are the best, a little more cumbersome but much more predictable.

Here is a great comparison. Tyvek and its ilk, (spun olefin) is a building wrap, but I have witnessed forensic tests and seen with my oen eyes, that that double layer stucco paper (60 min type D) has a 100 + year lifespan, Tyvek is really only about 30-50..... like I said some old ways are still the best ... ;)


Maybe I just like oil based finishes because I'm old, but other than ease of cleanup, I still can't find a good reason to switch. I would have thought that the quick drying water based finishes would speed up the process, but it seems they require relatively long curing time before they can be sanded or polished. The video Pete suggested, while interesting, seemed to verify the need for very long curing time - not to mention the expense of the product he was hawking. I'm sure I'm missing something and perhaps I'm too stubborn and set in my ways to see it.
 

golfdad

Co-director of Outreach
Dirk
Corporate Member
Most waterbased finish’s can be sanded and recoated in 2 hrs
 

ErnieM

Ernie
Corporate Member
Most waterbased finish’s can be sanded and recoated in 2 hrs
Can they be wet sanded in two hours, and with water as a lubricant? That's where the confusion sets in. Someone says you should wait for a month, and you say two hours is fine. I much prefer your answer.
 

BSevier

Bryan
User
I would say that the majority of woodworkers are not taking the extra time to rub out finishes to get to a high gloss - or even rubbing out at all. For them, waterborne finishes are great. They dry quickly (two hours between coats), allow you to get multiple coats on in one day, and clean up really easily. I've been spraying the General Finishes High Performance for several years on the furniture that I make. I love it. But I also am not looking to rub out the finish when I use it.

However, if I am looking to finish a humidor or something that I will want a high gloss, mirror smooth finish, or to pop grain, I wouldn't reach for the waterborne finish. I would go to Lacquer or oil base.

So I guess it really depends on what you are wanting from the finish. I really like the ease of the waterborne finishes, the fact that it dries very quickly means I don't end up with many 'dust nibs' in the finish, and the fact that I don't need to deal with the odors for several days while I wait for the finish to cure. Once I get my last coat on, I will usually let it dry overnight and then lightly sand with either 320+ grit or a grey scotchbrite pad to get a really smooth feel.
 

ErnieM

Ernie
Corporate Member
I would say that the majority of woodworkers are not taking the extra time to rub out finishes to get to a high gloss - or even rubbing out at all. For them, waterborne finishes are great. They dry quickly (two hours between coats), allow you to get multiple coats on in one day, and clean up really easily. I've been spraying the General Finishes High Performance for several years on the furniture that I make. I love it. But I also am not looking to rub out the finish when I use it.

However, if I am looking to finish a humidor or something that I will want a high gloss, mirror smooth finish, or to pop grain, I wouldn't reach for the waterborne finish. I would go to Lacquer or oil base.

So I guess it really depends on what you are wanting from the finish. I really like the ease of the waterborne finishes, the fact that it dries very quickly means I don't end up with many 'dust nibs' in the finish, and the fact that I don't need to deal with the odors for several days while I wait for the finish to cure. Once I get my last coat on, I will usually let it dry overnight and then lightly sand with either 320+ grit or a grey scotchbrite pad to get a really smooth feel.
That makes sense to me. I should have mentioned that I brush finishes on. In most cases, I have to rub out to some extent to eliminate brush marks. Also keep in mind that I'm using acrylic enamel paint - not a clear finish. I do apply a thin coat of satin poly over the paint to even out the sheen, and I don't rub that out.
 

JohnW

John
Corporate Member
FWIW I use both oil and water base finishes depending on application. Water based allowed much faster buildup, muck less VOC and fume issues, easy cleanup and when desired, crystal clear finush. Most of my projects are rubbed out from 4-O steel wool to pumice to rottenstone. The water base acrylic I use can be sander and re-coated in 3-4 hours when building up the finish. The final coat needs to cure 1-2 days before rubbing out. I ALWAYS use wool lube (Mohawk) to rub out or wet sand water based finishes. Also use it on oil based finishes. I've had good success with water based finishes and no issues using wool lube as a sanding/ rubbing lubricant.
 

ErnieM

Ernie
Corporate Member
FWIW I use both oil and water base finishes depending on application. Water based allowed much faster buildup, muck less VOC and fume issues, easy cleanup and when desired, crystal clear finush. Most of my projects are rubbed out from 4-O steel wool to pumice to rottenstone. The water base acrylic I use can be sander and re-coated in 3-4 hours when building up the finish. The final coat needs to cure 1-2 days before rubbing out. I ALWAYS use wool lube (Mohawk) to rub out or wet sand water based finishes. Also use it on oil based finishes. I've had good success with water based finishes and no issues using wool lube as a sanding/ rubbing lubricant.
Thanks John - that's very helpful.
 

Alan in Little Washington

Alan Schaffter
Corporate Member
There may be some confusion in terminology. Most true "water-based" finishes do not rub out worth a darn. Latex house paint is a "water-based" finish. However, as Bryan says, the new generation "Waterborne" finishes are a totally different animal. They are more akin to lacquer and do indeed "dry" or more precisely "cure" to a hard finish which can be sanded and rubbed. Unfortunately, the web, especially WW forums, don't do a go job explaining the differences and many paint manufactures are not too helpful either. By the way, it is all about VOC's and the EPA.
 

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