# Conversion Varnish, few questions.



## Jeff000 (Oct 18, 2016)

I'm making a nice coffee table and just not happy with the min wax spray can varnish holding up. My search has led me to conversion varnish, but a few questions have come up. 

I am looking for a satin finish that looks natural on the wood, is this possible with conversion varnish? 
Now there are lots of brands and they seem the same but not the same. Is there a beginner friendly one?
And my biggest question, how is over spray with it? If I sacrifice pot time will I have less over spray issues? 

I guess the biggest question is, well is conversion varnish really the best finish for something like a table to take the abuse of everything that is a table?


Thanks in advance.


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## Steve Neul (Sep 2, 2011)

If you have any experience spraying lacquer, conversion varnish will spray about the same. As far as overspray, with conversion varnish since it dries faster won't be near as bad as conventional varnish. In warm weather it would dry before it hits the floor. Under normal conditions conversion varnish can be a excellent finish for furniture. The down side is the finish is a two part finish kind of like working with epoxy glue, you have to use what you mix or throw it away. Another bad is if your family is especially hard on furniture. If you think the furniture will need to be refinished every few years you might have difficulty stripping the finish off. Some conversion varnish is immune to paint stripper. If you think you will need to refinish from time to time then a catalyzed lacquer may be a better choice. It's nearly as hard as conversion varnish but easier to strip off if necessary.


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## Rick Mosher (Feb 26, 2009)

Conversion Varnish is an excellent finish but like any finish it has strengths and weaknesses. I wouldn't use CV unless you have a functional spray booth and respirator, it has a very strong odor and is very difficult to spray without removing the fumes from the area. It has a 4-5 mil dry film thickness maximum that can cause catastrophic failure of the finish if exceeded. It is also very sensitive to temperature and if sprayed or allowed to cure in an environment that gets below 65 degrees Fahrenheit for a 48 hour period it is subject to cold checking. It is also important to measure the catalyst proportions very carefully as well or you can have bad problems in the future. That may all sound scary but it is an excellent finish and is used by most professional cabinet shops due to it's hardness, durability and low cost compared to other 2 part finishes.


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## Jeff000 (Oct 18, 2016)

Steve Neul said:


> If you have any experience spraying lacquer, conversion varnish will spray about the same. As far as overspray, with conversion varnish since it dries faster won't be near as bad as conventional varnish. In warm weather it would dry before it hits the floor. Under normal conditions conversion varnish can be a excellent finish for furniture. The down side is the finish is a two part finish kind of like working with epoxy glue, you have to use what you mix or throw it away. Another bad is if your family is especially hard on furniture. If you think the furniture will need to be refinished every few years you might have difficulty stripping the finish off. Some conversion varnish is immune to paint stripper. If you think you will need to refinish from time to time then a catalyzed lacquer may be a better choice. It's nearly as hard as conversion varnish but easier to strip off if necessary.


I don't mind tossing a little bit, it's not that expensive, and really only a tiny fraction of the cost of the wood I am using. It is a thick slab, so taking off 1/16th or so and restaining wouldn't be an issue. 
It's not so much that they are really hard on it, it's just a living house with kids, and it's not always treated as nice as it should be. CV seems to be about the only finish that won't let rings appear if you don't use a coaster with a can of beer or whatever. 




Rick Mosher said:


> Conversion Varnish is an excellent finish but like any finish it has strengths and weaknesses. I wouldn't use CV unless you have a functional spray booth and respirator, it has a very strong odor and is very difficult to spray without removing the fumes from the area. It has a 4-5 mil dry film thickness maximum that can cause catastrophic failure of the finish if exceeded. It is also very sensitive to temperature and if sprayed or allowed to cure in an environment that gets below 65 degrees Fahrenheit for a 48 hour period it is subject to cold checking. It is also important to measure the catalyst proportions very carefully as well or you can have bad problems in the future. That may all sound scary but it is an excellent finish and is used by most professional cabinet shops due to it's hardness, durability and low cost compared to other 2 part finishes.


I do not have a spray booth, I just poly off a part of my garage, I do have a respirator that I use and have many different specific filters for. 
The garage is heated and I can keep it at whatever temp is best. I do not have an exhaust fan, although adding one wouldn't be an issue, normally I just crack the door a couple inches. 
Measuring portions shouldn't be an issue either. 

When you say 4-5 mil dry film thickness, that is per coat right? scuff sand between coats, and spray just enough to give it a wet look. 
It sounds like the time between coats can be as quick as a couple hours. And pot life can be several days even.


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## Rick Mosher (Feb 26, 2009)

> When you say 4-5 mil dry film thickness, that is per coat right? scuff sand between coats, and spray just enough to give it a wet look.
> It sounds like the time between coats can be as quick as a couple hours. And pot life can be several days even.


You will need to read the product information sheet for the product you decide to use but the 4-5 mils dry film thickness is TOTAL coating. (With ML Campbell products if you use their Level Sealer then the DFT applies only to the topcoats.
Here is a link on how to determine your DFT. 
As far as the pot life it also depends on the brand. Some will have a pot life of a week or longer and some 8-12 hours, usually the longer the pot life the less the durability but I am sure that there can be exceptions. If you're not doing the work professionally then you will learn by screwing up and then have to redo it as you learn from your mistakes. Also I would recommend a full face respirator if you don't have a real booth. There are some water based conversion varnishes out there but I am really not familiar with them so someone else will have to chime in on those. :smile3:


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## firehawkmph (Apr 26, 2008)

Just finished spraying a set of kitchen cabinets I built for my son's house with conversion varnish from Sherwin Williams. Most of what Rick and Steve said apply. I set up a temporary spray booth outside my shop, bought a new respirator with the proper filters. The CV I used was white, low sheen, like a satin. It had to be reduced by 50% with their reducer, then their catalyst added at a rate of 6.2% of what you had just reduced. I used two different HVLP guns on two different occasions. The first gun was a high quality Devilbiss that started to drip on the second coat. Wasn't sure what was causing that so I switched to another HVLP gun from Husky. The husky took twice as much air to develop a good pattern but still worked well. It was around 80 degrees when I sprayed. It dried to the touch in a matter of a few minutes. Sanded very lightly after the first coat only, just to get the nibs off. The particular stuff I used was available in one gallon containers. I was contemplating a clear final coat, but that was only available in five gallons and up, so I didn't. Gun cleaned up with lacquer thinner easy enough. I cleaned them immediately. If you let this sit over night, you could throw the gun away.
For what you are doing, you might want to consider a water based poly, and I would highly recommend anything from General Finishes. Very easy to work with, doesn't necessarily have to be sprayed, and very durable.
Mike Hawkins


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## Jeff000 (Oct 18, 2016)

Rick Mosher said:


> You will need to read the product information sheet for the product you decide to use but the 4-5 mils dry film thickness is TOTAL coating. (With ML Campbell products if you use their Level Sealer then the DFT applies only to the topcoats.
> Here is a link on how to determine your DFT.
> As far as the pot life it also depends on the brand. Some will have a pot life of a week or longer and some 8-12 hours, usually the longer the pot life the less the durability but I am sure that there can be exceptions. If you're not doing the work professionally then you will learn by screwing up and then have to redo it as you learn from your mistakes. Also I would recommend a full face respirator if you don't have a real booth. There are some water based conversion varnishes out there but I am really not familiar with them so someone else will have to chime in on those. :smile3:


5 mils is really thin, do I use another product to build up the surface? I'm not looking for a really deep looking finish that is thick, but just to smooth out the slight imperfections. 
Looking into the water based a bit, hard to find information that makes sense to me, lol. 




firehawkmph said:


> Just finished spraying a set of kitchen cabinets I built for my son's house with conversion varnish from Sherwin Williams. Most of what Rick and Steve said apply. I set up a temporary spray booth outside my shop, bought a new respirator with the proper filters. The CV I used was white, low sheen, like a satin. It had to be reduced by 50% with their reducer, then their catalyst added at a rate of 6.2% of what you had just reduced. I used two different HVLP guns on two different occasions. The first gun was a high quality Devilbiss that started to drip on the second coat. Wasn't sure what was causing that so I switched to another HVLP gun from Husky. The husky took twice as much air to develop a good pattern but still worked well. It was around 80 degrees when I sprayed. It dried to the touch in a matter of a few minutes. Sanded very lightly after the first coat only, just to get the nibs off. The particular stuff I used was available in one gallon containers. I was contemplating a clear final coat, but that was only available in five gallons and up, so I didn't. Gun cleaned up with lacquer thinner easy enough. I cleaned them immediately. If you let this sit over night, you could throw the gun away.
> For what you are doing, you might want to consider a water based poly, and I would highly recommend anything from General Finishes. Very easy to work with, doesn't necessarily have to be sprayed, and very durable.
> Mike Hawkins


So CV is also a paint? would explain the nice finish on painted cabinets. Means I could use it for some of the dark gray stuff I want to paint. 

I don't have a spray gun for this yet (Bedliner does bad things to a HVLP gun if you are wondering) but was looking at one of those airless guns. But a decent HVLP like a Neiko is only like 50 bucks. I assume gravity feed is ok? So not sure if 130 bucks is worth it for the airless? 
What size nozzle do you like? 

I am trying to avoid water based poly, it's been ok, but never really what I wanted.


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## Steve Neul (Sep 2, 2011)

You can go thicker than 5 mils with the conversion varnish. The important thing is to allow each coat to dry well before proceeding. Personally I don't think 5 mils is that thin. It's about double the thickness of a lawn and leaf trash bag.


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## Jeff000 (Oct 18, 2016)

Steve Neul said:


> You can go thicker than 5 mils with the conversion varnish. The important thing is to allow each coat to dry well before proceeding. Personally I don't think 5 mils is that thin. It's about double the thickness of a lawn and leaf trash bag.


Turned mils into mm. 5 mils is 0.127mm. So that actually doesn't seem as thin as I thought originally. 

Does the paint spray on the same as the clear? I have a couple little projects that I want to paint, would be good practice if they spray similar.


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## Steve Neul (Sep 2, 2011)

Jeff000 said:


> Turned mils into mm. 5 mils is 0.127mm. So that actually doesn't seem as thin as I thought originally.
> 
> Does the paint spray on the same as the clear? I have a couple little projects that I want to paint, would be good practice if they spray similar.


The paint would be slightly thicker than the clear but would spray the same.


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## woodnthings (Jan 24, 2009)

*mils, the definition*



Jeff000 said:


> Turned mils into mm. 5 mils is *0.127mm*. So that actually doesn't seem as thin as I thought originally. .....


a mil is 0.001"
a mil is 0.0254 mm 

from here:
http://www.dictionary.com/browse/mils

So, 5 mils is 0.005", about the thickness of 28 lb bond copy paper. From here:
http://www.casepaper.com/resources/charts/paper-thickness-caliper/


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## ColorStylist (Jul 19, 2014)

Jeff000 said:


> Turned mils into mm. 5 mils is 0.127mm. So that actually doesn't seem as thin as I thought originally.
> 
> Does the paint spray on the same as the clear? I have a couple little projects that I want to paint, would be good practice if they spray similar.


You do not want to go over 4 dry mils because heavier films may "cause" cracking. Most CV's are high in solids and fill voids very well with just 2 coats. Most CV's can be used as a self seal because of this.

You can use a high solids sealer under a CV to obtain more build, but you must catalyze the sealer as well or that may cause cracking. You can not put a hard finish over a softer finish, so catalyzing the sealer is a must.


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## firehawkmph (Apr 26, 2008)

[QUOTE
So CV is also a paint? would explain the nice finish on painted cabinets. Means I could use it for some of the dark gray stuff I want to paint. 

I don't have a spray gun for this yet (Bedliner does bad things to a HVLP gun if you are wondering) but was looking at one of those airless guns. But a decent HVLP like a Neiko is only like 50 bucks. I assume gravity feed is ok? So not sure if 130 bucks is worth it for the airless? 
What size nozzle do you like? 

I am trying to avoid water based poly, it's been ok, but never really what I wanted.[/QUOTE]
Conversion varnish is not a paint at all. I would recommend an HVLP gun just for the better material transfer efficiency, also most operate on lower air pressure, so not as much overspray. My better gun operates on 23 psi at the gun. It has its own gauge and regulated attached to it.
Mike Hawkins


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