# How much can I thin a water based poly?



## ric53 (Mar 29, 2014)

Can anybody tell me how much to thin a water based poly to make it a wiping poly?


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## CharlesA (Jun 24, 2013)

Ric,

My experience is limited to General Finishes High Performance. They say you can thin with 10-20% with water or their extender. I don't think they recommend more than that. I do wiping varnish a lot, but I've found that spraying gives superior results with water-based. Just my two cents.


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## wapakfred (Jul 29, 2011)

Of the 2-3 brands I've used, it was no more than 20% on any of them. Whatever you're using should say someone on the label or maybe the manufacturer's tech data sheet. It's fairly important to stay to their guidelines (IMHO) sine waterbornes can have their chemistry screwed up with too much water. Even so, it's probably not going to make a good wiping finish; just doesn't seem to work too well with the waterborne formulas.


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## ric53 (Mar 29, 2014)

Thanks Charles & Fred. I think I'll go in a different direction. Probably shellac.


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## CharlesA (Jun 24, 2013)

The recommended way to "wipe it on" is to use a paint pad applicator with a footsie (women's hose) over it.


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## bonesbr549 (Jan 1, 2010)

Call your mfg and talk to them. I use general finishes and have called and asked questions and applications on a combination of finishing products and they are good and know what they talk about and will flat out tell you since they know their products.


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## AlaskaGuy (Jan 29, 2012)

The different brands that I have used had that information on the can. Your doesn't?

Not that I'm a fan of min-wax products but they do sell a waterborne wipe on poly. There are youtube videos showing how to apply it.


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## bonesbr549 (Jan 1, 2010)

> The different brands that I have used had that information on the can. Your doesn t?
> 
> Not that I m a fan of min-wax products but they do sell a waterborne wipe on poly. There are youtube videos showing how to apply it.
> 
> - AlaskaGuy


There's whats on the can and then there is "this is the equip i'm using and the method of application and the medium to be applied to"

What's on the can is the lowest common denominator for most cases and as reviewed by lawyers. Kinda like that expiration date on eggs.


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## ric53 (Mar 29, 2014)

Some of you are indicating that I don't read the directions. They all say not to thin but it has been my experience that you can thin even though it says not to. Of course I know enough to read directions and to call manufactures of the products but I mistakenly thought that there may be someone here with some usable answers. This isn't my first rodeo, in fact I been WW for approx. 30yr's, but I haven't had much experience with water based products so pardon my STUPIDITY. I won't ask a dumb question like this again.


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## gfadvm (Jan 13, 2011)

ric53, Poly and Spar Urethanes (oil based) also state on the label: "do not thin". I have thinned both with mineral spirits to make a wiping finish with excellent results. I didn't think your question was dumb at all and I have often wondered about wiping on water based finishes.


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## HerbC (Jul 28, 2010)

Ric,

Not sure what set you off like that. I don't read anyone's comments as being critical of you. The fact that nobody had a better answer than "read the instructions and call the manufacturers" just means that that is pretty reasonable advice.

I hope you don't take what's been said here as criticism.

Good Luck with your project.

Herb


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## ric53 (Mar 29, 2014)

Herb, AlaskaGuy's comment struck a nerve.


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## wapakfred (Jul 29, 2011)

> ric53, Poly and Spar Urethanes (oil based) also state on the label: "do not thin". I have thinned both with mineral spirits to make a wiping finish with excellent results. I didn t think your question was dumb at all and I have often wondered about wiping on water based finishes.
> 
> - gfadvm


It's a little different with oil based finishes. They are labeled "do not thin" due the manufacturer's trying to cover their ass legally relative to VOC content and environmental laws. With waterborne finishes, it's more about the way they work.


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## OggieOglethorpe (Aug 15, 2012)

*It's a little different with oil based finishes. They are labeled "do not thin" due the manufacturer's trying to cover their ass legally relative to VOC content and environmental laws. With waterborne finishes, it's more about the way they work.*

Correct about VOC laws and many thinning warnings, but there's more to it for certain solvent based products. All crosslinking finishes, oil based or waterborne, will suffer from over-thinning at some point. Different finishes have different tolerances, as listed on the label.

When crosslinking finishes cure, a chemical reaction takes place where the molecules literally link together. This is why you can't rub the appropriate thinner on a dry polyurethane or other crosslinked finish, regardless of formulation, and have it change back to a liquid state. To put it simply, if you add too much thinner to a crosslinking finish, the molecules can't "reach" each other to properly cure. Oil based products can be more forgiving than waterbourne, but they still have a limit.

Waterbourne products, including paints, aren't really water "based", they only include a small percentage of water, and the wet product cleans up with water. The real base is usually glycol, a component of anti-freeze, not water. Adding too much water wrecks the formula, which is how it works as you wash the equipment with water.

Examples of non-crosslinking, evaporative finishes include shellac and nitrocellulose lacquer. These don't cure, they dry, as the solvent evaporates. Wetting the dry film with more of the proper solvent will reconstitute them back to a liquid. You can thin them to literally nothing, almost all thinner, and not mess with the formulation or final dry film quality, only the final film thickness will change. The property that allows them to melt, allows each new coat to melt or "burn" into the last. Some crosslinking finishes (polys, WB, latex paints) may not burn in, which can create visible "witness lines" when rubbed out or sanded.


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## Wildwood (Jul 22, 2012)

Water is a carrier for water based/borne products and not really a thinner. Have seen all kinds of water to poly percentages but guess never want to exceed 5%. Too much water and will have a mess!

A simple trick of warming water based products will thin the product to some degree depending upon where you live. Water base products seem easier to apply in warm weather verus cold! Another trick is run the poly through a paint strainer.

Many manufacturers have additives & retarders for spraying but they might not be compatible with other products. Waster based and waterborne products while similar not exactly the same!

Glycol ether is a solvent for retarding water based products and might work for waterborne products not sure. Ask for instructions on mixing water with glcol ether or may end up with a product that never dries.

Ric53, helpful if be specific and tell people product want to use and method of application.


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## AlaskaGuy (Jan 29, 2012)

> Herb, AlaskaGuy s comment struck a nerve.
> 
> - ric53


I simply was curious if your product didn't have that information on the can. If you want to read more into it than that then nothing I can do.

As you can see by what others have posted thinning waterborne and oil products is quite different.


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## ric53 (Mar 29, 2014)

Thanks for all the info. I have used oil based products in the past and have had no trouble with thinning any of them, however, like I stated above I have limited experience with water based products and wanted to use it on a table top to preserve the natural color. My intent was to 1 coat it with a very thin coat of water based poly followed with numerous coats of oil base. Since that strategy obviously won't work I am going to use a thinned shellac followed by poly. Thanks again for the info. Sorry I blew up AlaskanGuy.


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## DrDirt (Feb 26, 2008)

Ric curious how far you want to thin it and why.

Guess I never found GF water base poly to be overly thick that I needed/wanted to go further than 20%.

Is it for better atomization? or to change drying or get to a thinner coat?

What are you trying to do?
I have only used WB poly on two projects the first was done with rattle can poly.

The other I sprayed (Harbor Freight HVLP gun 66222 the one with the regulator included) with no thinning at all, for maple dining chairs - that were "pickled" white - and so wanted durability with kids, and no yellowing. But I shot it straight - - or maybe ~5% thinned with water because I 'rinsed the applesauce cup I was using as a dipper from the can.


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## wapakfred (Jul 29, 2011)

> Ric curious how far you want to thin it and why.
> 
> - DrDirt





> Can anybody tell me how much to thin a water based poly *to make it a wiping poly*?
> 
> - ric53


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## Daruc (Apr 20, 2015)

"Some of you are indicating that I don't read the directions. They all say not to thin but it has been my experience that you can thin even though it says not to. Of course I know enough to read directions and to call manufactures of the products but I mistakenly thought that there may be someone here with some usable answers. This isn't my first rodeo, in fact I been WW for approx. 30yr's, but I haven't had much experience with water based products so pardon my STUPIDITY. I won't ask a dumb question like this again."

-Ric, Mazomanie

Wasn't a dumb question, you were just given an inconsiderate answer.


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## DrDirt (Feb 26, 2008)

Fair enough fred -

but what is the problem right now…. certainly it is brushable and you can thin it 20%.... Apparently that is still too thick to wipe?

I would wonder is it Too Thick - - or does it dry too fast. So maybe just thinning with some retarder will give it the flow out and slow the drying enough to work versus just lowering the viscocity with water.

There is this from Oxford/Target coating - -

http://targetcoatings.com/products/additives/series-sa5-universal-retarder/
SA5 Universal Retarder is specifically engineered to reduce the viscosity and slow down the dry-time of our waterborne coatings during high temperature applications. SA5 is best used when EMTECH Series WB finishes are being applied with turbine HVLP spray equipment or when the substrate surface being finished is above room temperature. Start with a measured amount of 5% by liquid volume when used for spray applications. Use an addition of 10-20%, SA5 to improve the brushing and *wiping* actions of all our systems.


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## jonoseph (Dec 13, 2015)

Even though water based floor varnish is thin (after stirring it as per instructions ) it still shows brush marks .The advice on the tin says to use a wide brush if possible .That seems to make it worse .So now I am using a narrower brush and spreading it so thin there will be no visible brush marks . My wooden block floor was made in squares with 3 blocks per square .Each square alternates the grain direction by 90 degrees .If I brush each square along the grain you never see the brush strokes .But brushing across the grain , you still get the brush strokes showing .So using a smaller brush and really spreading it thin seems to be the slow laborious way to make it work . Manufacturers can do what is possible for us but nature has it`s own complicated ways and it`s hard to fight nature sometimes . Main reason to use water based is to prevent it going darker over time . I have to do what the wood tells me and now I have to do what the varnish tells me .


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## OSU55 (Dec 14, 2012)

> Thanks for all the info. I have used oil based products in the past and have had no trouble with thinning any of them, however, like I stated above I have limited experience with water based products and wanted to use it on a table top to preserve the natural color. My intent was to 1 coat it with a very thin coat of water based poly followed with numerous coats of oil base. Since that strategy obviously won t work I am going to use a thinned shellac followed by poly. Thanks again for the info. Sorry I blew up AlaskanGuy.
> 
> - ric53


This clarifies things a bit - you dont want to thin the wb to make a wipe-on finish, rather you want to use it to limit or stop penetration of solvent poly.

If you want to fully seal the surface, shellac would be my choice, but a wb product could work. If you want to just limit, ie blotch control, then a thinned wb product, or glue sizing, works very well. You can read more here, but I have thinned wb finish up to 1-1/2 parts water to 1 part finish for blotch control.

There is a huge difference between thinning a wb finish and building a film with it by wiping it on (dont, spray or foam brush and rub it out) vs using it to block absorption, which it does very well and I have done with great success. The blog gives more details. It helps if someone fully explains their intent vs kind of open ended questions that leave folks guessing. BTW I thought max thinning for wb used as a finish was 10% - maybe that's for Target Coatinds products. Also, I have thinned solvent poly by 3:1 or more and never had an issue with crosslinking occurring, and its almost the viscosity of the thinner at that point, so I cant see thinning it too much.


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## sunnybob (Oct 12, 2021)

> Some of you are indicating that I don t read the directions. They all say not to thin but it has been my experience that you can thin even though it says not to. Of course I know enough to read directions and to call manufactures of the products but I mistakenly thought that there may be someone here with some usable answers. This isn t my first rodeo, in fact I been WW for approx. 30yr s, but I haven t had much experience with water based products so pardon my STUPIDITY. I won t ask a dumb question like this again.
> 
> - ric53


You got the simple answers (read the instructions) because you asked a simple question. If you had given more info in your first question about your experience and why you were asking the question, you would have avoided the answers that "struck a nerve"


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