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Rustoleum Varathane in a HVLP Sprayer?

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Forum topic by gauntlet21 posted 08-10-2018 04:13 AM 398 views 1 time favorited 13 replies Add to Favorites Watch
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gauntlet21

12 posts in 294 days


08-10-2018 04:13 AM

Topic tags/keywords: finish polyurethane critter sprayer hvlp top coat clear coat matte varathane

I’m brand new to spraying finishes and I’m very pleased with the performance of my Critter sprayer (purchased from Amazon) and the General Finishes High-Performance Water Based Matte Top Coat. The General Finishes top coat is a bit expensive and I’ve seen good reviews on the Varathane Water Based Polyurethane. The instructions say to use a brush or roller but I was wondering if anyone has tried spraying it and whether the results are positive? For comparison, 1 quart of the G.F. is $25-$30 while 2 quarts of the Varathane is $32 from Home Depot.

Thanks,

Dan

Also, if there are other recommendations for water-based polyurethanes that you’ve had good results with via spraying, please share. Thank you!


13 replies so far

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Rich

3342 posts in 673 days


#1 posted 08-10-2018 04:38 AM

There’s no reason it should spray any differently in your Critter. I will say that if you’re limiting yourself to waterborne poly finishes, you’re doing your projects an injustice. It just will never provide the depth that other finishes can. Also, my experience with them is that they are not all created equal. Irrespective of spray quality, some are more prone to clouding the surface. The GF HP is an outstanding product. I bought some Behlen on sale once, and it performed dismally. The surface had a strange bluish glow that I ultimately had to sand off and replace with GF. If you try the Varathane, and you should, be sure to test it before you use it on a finished piece.

A quick Critter tip — if you haven’t done so already, install a pressure regulator at the gun. The Critter is super sensitive to air flow, and trying to regulate it at the tank is hit or miss. A photo of mine is below. it requires a special connector to go from the 1/4 NPT down to the 1/8 that the Critter uses. LJ woodbutcherbynight has a cool setup, where his regulator is at the end of the hose, so he can control the pressure for any tool he connects to it. Very smart and versatile.

-- Half of what we read or hear about finishing is right. We just don’t know which half! — Bob Flexner

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OSU55

1787 posts in 2073 days


#2 posted 08-10-2018 12:36 PM

WB finishes can have a slight color to them after curing out. Amount of color dependent on film thickness. Most look a little blue, some pinkish, some very clear. I have some clear plastic 2 oz condiment containers that i put a little of the finish in and let cure out so I can see its color and clarity. A little Transtint dye can move the color any direction except to more water white. The Varathane should work just fine, but always test a new finish schedule on scrap. My choice for wb poly is Target Coatings EM9000. As for cost of finishing materials – certainly depends on the item (shop furniture vs dining table for example), how much time, effort, and $ do you already have in the project? Is it worth $15 to take the chance? Properly tested, it isnt a chance and can be a good cost reduction, but testing is needed.

WB finishes are lifeless compared to oil based – its called chatoyance. With a dead flat finish as you have used its irrelevant, but as gloss increases it is more important. Shellac under the finish will create chatoyance.

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Andybb

1144 posts in 687 days


#3 posted 08-10-2018 05:07 PM

Varathane is an awesome product. To use in an HVLP you need to thin it some. When I’m lazy I use tap water. No more than 10%. “They” say to use distilled water but I never have. Otherwise they make a product that I have at home whose name I cannot remember.

Brushed or sprayed, don’t mess with it once it is applied. It always looks strange but within a half hour it flattens out and looks good. Varathane is great stuff and very durable. It’s used for everything from stairs to guitars. You can apply shellac or transtint wb dyes first to help give it that oil based look. When using it I usually just brush or roll as I don’t see much difference between that or spraying after it has dried and save myself the trouble of cleaning the gun. I usually just use a foam brush.

-- Andy - Seattle USA

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Andybb

1144 posts in 687 days


#4 posted 08-10-2018 06:25 PM

P.S. The transtint honey amber is my go-to fake oil look. Try a few tests on scrap with shellac or the dye. Everybody has their own method but I like to apply the dye, wipe it good and let it dry for an hour then a coat of shellac and let it dry, then the Varathane top coat. Your mileage may vary.

-- Andy - Seattle USA

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OSU55

1787 posts in 2073 days


#5 posted 08-10-2018 06:42 PM



P.S. The transtint honey amber is my go-to fake oil look. Try a few tests on scrap with shellac or the dye. Everybody has their own method but I like to apply the dye, wipe it good and let it dry for an hour then a coat of shellac and let it dry, then the Varathane top coat. Your mileage may vary.

- Andybb

Is there a particular reason you dont just add the transtint to the shellac and/or the wb finish?

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Andybb

1144 posts in 687 days


#6 posted 08-10-2018 09:03 PM


Is there a particular reason you dont just add the transtint to the shellac and/or the wb finish?

- OSU55

No reason. Never tried it that way. In my mind the shellac is a sealer also and I would rather not mess with that since shellac is oil based so mixing it with a water based product just didn’t seem prudent to me. I could be wrong but it’s just what my little brain told me made since oil and water don’t mix. My thinking is that once the dye dries the shellac will seal it and give that semi oil based look. Again, I could be wrong and I don’t pretend to be an expert. Charles Neil would be the one to ask. I don’t add the dye to the Varathane because I can control the look of the dye by either sanding it or adding another coat. The Varathane is clear so what you see is what you get. My thinking there is that putting the shellac on top of the dye gives the dyed wood the look I’m after. Don’t know if it would look the same if the dye was on top of the shellac.

-- Andy - Seattle USA

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Desert_Woodworker

1537 posts in 1298 days


#7 posted 08-10-2018 11:16 PM

Thanks, Rich for the Critter regulator advice. Does this reduce the amount of consumption of finish versus without it?

-- Desert_Woodworker

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OSU55

1787 posts in 2073 days


#8 posted 08-10-2018 11:45 PM

I think you misinterpreted my question. Shellac is alcohol based not oil, and no I did not mean to mix shellec and wb finish. Transtint mixes with alcohol or water and can be used directly in shellac or a wb finish (and solvent lacquer). Since you are using the dye only to provide the yellow color as with ob poly, it can be mixed directly into the shellac or wb finish, shortening your finish schedule and time. If you are applying the shellace to otherwise bare wood, it would be best to put the dye into the wb finish. The shellac will absorb at different rates at different areas and could blotch depending on the wood (no worse than the dye application you have been doing though).

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Rich

3342 posts in 673 days


#9 posted 08-10-2018 11:53 PM


Thanks, Rich for the Critter regulator advice. Does this reduce the amount of consumption of finish versus without it?

- Desert_Woodworker

No, DW, you still need to spray whatever amount it takes to get the finish you want. What it does is allows better control of the pressure and air flow at the gun. You can adjust the pressure at the compressor, but depending on the hose length and diameter, you are going to lose some pressure by the time it reaches the gun. With a local regulator, you can adjust it right there.

The Critter is really touchy when it comes to air flow. Just a couple of psi can mean the difference between a perfect spray and one that is too heavy or light.

-- Half of what we read or hear about finishing is right. We just don’t know which half! — Bob Flexner

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Andybb

1144 posts in 687 days


#10 posted 08-10-2018 11:56 PM

I think you misinterpreted my question. Shellac is alcohol based not oil, and no I did not mean to mix shellec and wb finish.
- OSU55

Good point. As I said, I’m no expert so forget everything I said. :-) . Alcohol based. Probably why it dries so quickly. I’ve just never tried mixing but yes, transtint is water or alcohol based. I usually use DNA not water.

-- Andy - Seattle USA

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Desert_Woodworker

1537 posts in 1298 days


#11 posted 08-11-2018 12:38 AM

Thank you, Rich-
I use my Critter for bulk material- boiled linseed oil for cactus spine projects. After using the Critter I felt that this gun has more potential. Again, thanks

-- Desert_Woodworker

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gauntlet21

12 posts in 294 days


#12 posted 08-12-2018 07:40 PM

That’s awesome advice by all of you. Thank you very much. I’m going to be purchasing another quart of the General Finishes WB High Performance to finish this project but then will try out the Varathane next. I’ll also get some oil based poly’s to see what that is all about. I’ve toyed with a regulator at the end of my pneumatic hose but haven’t entirely conquered the fitting sizes yet. I started with some Flexzilla hose and matching Flexzilla air hose fittings but then ran into a few issues with tools over the past year where I needed an adapter here and there. I eventually purchased about 20 fittings to outfit all of my tools to the same fitting and then again needed to use some spare pieces here and there to get the Critter Sprayer to fit since, as mentioned above, it has a tiny 1/8” fitting that can’t be swapped out at the base of the tool without the exact size threading. To be accurate, the Flexzilla fittings that I purchased are 1/4” but are considered High Flow. Also on a brief tangent, I’m located in SE Wisconsin and a store nearby me (Northern Tool + Equipment) had some kind of button release fitting to go at the end of my air hose. There were a few different colors and of course, each had its own slight variation and specific name. I didn’t decide to purchase one that day because I was entirely confused as to what exactly I had at home in terms of fittings and what piece would be compatible at the hardware store I was in. I later learned that what I was looking at purchasing is called a Safety Coupler, the brand and model of the one that I eventually purchased was the 1/4” Prevost S1 Safety Coupler (and a new coupler was necessary at the time because I upgraded my entire pneumatic hose to a 3/8” hose from a 1/4”) Apparently, the European style is the correct one for the High Flow Flexzilla fittings that I purchased and finally I had everything I needed to continue working pneumatically. If anyone who is still reading this has a recommendation for as minimalistic as possible, end of hose regulator I’d appreciate it. I’d hopefully like to avoid going down the rabbit hole of trying to refit all of the fittings that I have compatible again but if there’s a style or brand that you’re fairly certain would have a regulator for my setup, I’d appreciate it. Although I’ve had my air compressor for about 2 years now, I only know what I’ve encountered from using it so I am by no means an expert. All of my garage hobbies (woodworking, pneumatic compressors, dust collection, etc.) are all functioning strictly because of online forums and YouTube. That said, I greatly appreciate any input as I realize that shared experiences are an incredible resource to pass the baton onto the younger, less experienced guys still trying to hone their craft. I’m only 35 and been at woodworking for a year now so I do appreciate any shared experiences that you’ve learned along the way.

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Rich

3342 posts in 673 days


#13 posted 08-12-2018 07:44 PM

Here’s the 1/4 NPT to 1/8 NPT adapter you need to be able to reduce standard air hose threads to fit the Critter.

https://www.amazon.com/gp/product/B0131CFP44

Or, you can do what woodbutcherbynight did and just put a regulator on the end of your hose with a female coupling on the out feed side and then any of your tools that you plug into it can be regulated. My concern with that is, at least for me, I’d be likely to drop the end of the hose pretty often and it might damage the regulator. Either way works though.

-- Half of what we read or hear about finishing is right. We just don’t know which half! — Bob Flexner

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