# Water based finish over oil based finish?



## ffjdh (Apr 16, 2010)

Can I put a water based finish over an oil based finish? I am currently working on a box with curly maple and purple heart. The curly maple really pops with Arm-R-Seal oil urethane finish, but i have a water based Arm-R-Seal Exterior 450 finish that has UV inhibitors that I wanted to use on the purple maple to protect its color. Can I do a base coat of oil urethane and a water based finish over it?


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## Dr.Zook (Sep 10, 2004)

ffjdh, welcome to the RouterForums. Glad to have you as part of our community.


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## gav (Oct 12, 2009)

I've always thought the answer to this question is no. Lately though I've been wondering if it could actualy work because they are both urethane and that stuff seems to stick to anything.

I would try it on some scrap if I was you.


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## tdublyou (Jan 8, 2010)

I too have always been under the impression that oil and water don't mix. But then I remembered that when I had my hardwood floors refinished 10 years ago, they used an oil based stain and a water based poly. The finisher did say that the stain had to completely dry, (3 days as I recall), before he could poly or it would turn green.
Gav's advice of testing on scrap is spot on. It would be tragic to find out the hard way that it doesn't work.


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## jmg1017 (Apr 9, 2009)

ffjdh said:


> Can I put a water based finish over an oil based finish? I am currently working on a box with curly maple and purple heart. The curly maple really pops with Arm-R-Seal oil urethane finish, but i have a water based Arm-R-Seal Exterior 450 finish that has UV inhibitors that I wanted to use on the purple maple to protect its color. Can I do a base coat of oil urethane and a water based finish over it?


Good question. No matter what you do any water based finish is going to obscure the grain pattern that you are trying to bring out and preserve. That's just the nature of the beast. It leaves an opaque film. Instead try shellac. It's easy to apply, repairs easily and makes the grain really pop on figured woods. You can finish it with a good quality paste wax rubbed out with 0000 steel wool for a soft sheen.

Here's a box using the same woods as yours finished with boiled linseed oil and shellac...


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## ffjdh (Apr 16, 2010)

jmg1017, which kind of shellac did you use? The colors on your box turned out nicely. Im thinking I might give the boiled linseed oil and shellac a try.


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## jmg1017 (Apr 9, 2009)

ffjdh said:


> jmg1017, which kind of shellac did you use? The colors on your box turned out nicely. Im thinking I might give the boiled linseed oil and shellac a try.


Here's a link to the site I use. 
J.E. Moser's SEEDLAC

The Super Blonde grade is the clearest. Buy the flakes and you can control the "cut" That's the amount of flakes in lbs, to the amount of solvent in gallons. I use a 2lb cut. I usually mix a quart at a time. It sounds complicated but it's not. The instructions for mixing come with the flakes. Keep them cool and dry and they last a long time, then just mix what you need for a project. You can also by it premixed. 
If you Google "Jeff Jewitt" you can find a wealth of information about mixing and applying shellac. Once you try it you won't go back.


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## jerrymayfield (Sep 25, 2004)

As I have often said if shellac were discovered today it would be called a wonder(super) finish. It is also color fast.

Regards
Jerry


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## ffjdh (Apr 16, 2010)

What kind of solvent do you guys recommend to use with the super blonde? I guess the kind they recommend on that site isn't allowed in CA.


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## ffjdh (Apr 16, 2010)

Also how many coats of linseed oil did you use? Ive used linseed oil on ax handles before, but never for any of my woodworking projects


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## jmg1017 (Apr 9, 2009)

ffjdh said:


> What kind of solvent do you guys recommend to use with the super blonde? I guess the kind they recommend on that site isn't allowed in CA.


Try this site. http://antiquerestorers.com/Articles/jeff/shellac.htm

Excellent explanations and options for your solvent.

As for the Linseed oil, I generally use one coat. Apply a generous amount and let it sit for a half hour or so. Then I wipe it down well. After that you need to let it dry properly. I usually give it 3-4 days before I apply the shellac finish.

The number of coats of shellac varies. If I'm making a small box then 2-3 coats is fine. I'll use 4-5 coats on a table top surface or any surface that gets a lot of use.


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