(Updated July 2020)
Sometimes you’re working on a project and you realize you’ve got some oil stain that you want to use or finish up—or simply that you’d applied an oil-based stain, but you’re wanting to use your EMTECH water-based Sealer (for example, USH 3000 UltraSeal-Water Based Shellac Sealer or EM1000 Universal Sanding Sealer) on top of the stain—and you wonder if you can.
It’s a question we get often, actually—especially as more craftsmen are making the move to water-based finish.
And actually, the answer is YES—you can use our EMTECH water-based sealer or top coat over the oil stain.
The beauty of all our water-based sealers and topcoats is that they’ll level and adhere to whatever solvent- or oil-based stain you’ve used. So there’s no need to go oil on oil simply because your stain is oil-based.
If you’re going to apply a water-based sealer on oil stain though, here’s a few tips to ensure a perfect application.
How to Apply Water-Based Sealer on an Oil-Based Stain
Before you begin to apply your water-based sealer or topcoat, first ensure that the stain is thoroughly dry. You should follow the stain manufacturer’s instructions for proper dry time and recoat schedules. You’ll find most oil stains should dry for at least 12 to 18 hours before going over the stain with any EMTECH water-based sealer or topcoat.
Once the oil-based stain has had a chance to thoroughly dry, the next step is to lightly—you don’t want to rub too hard—wipe the dried stain surface with a clean, lint-free cloth that you’ve dampened with a solution of water and denatured alcohol mixed in a 1:1 ratio. This wipe down will remove any oils or mineral spirits that may have come to the surface of the stain during the drying cycle. Removing these surfacing spirits will ensure proper leveling and adhesion of the water-based sealer or topcoat that you’re applying.
After the wipe-down, you can go ahead with the sealer or top coat.
Here Are Some Additional Pro Tips:
Perhaps the best way to know if you’ve done it right is to understand what can happen if you do it wrong. Some of the more common problems are:
Fish Eyes: these are the small “craters” that form if you haven’t removed all of the surface oils. Basically, when the surface tension of your sealer doesn’t match the surface tension of the oil underneath, the sealer can’t “wet out” and you get those pesky dry spots.
Rollup/Sheeting: this is when the film looks good when it’s wet, but when you go to pull off your protective tape, the coating pulls off or “rolls up” with it.
Blue/Purple Hazing: certain well-known stains have an extremely high level of mineral spirits content and it will give a water based sealer a bluish or purplish “haze.”
To fix these (and other) problems, here’s what I recommend:
1. Wipe with the same water and denatured alcohol mix as mentioned above (1:1 ratio)
2. Lightly “scuff sand” to remove the defects. You are not trying to remove the color, just the defects.
3. Re-wipe with the water and denatured alcohol mix (1:1 ratio)
4. Re-apply your water based sealer.
I hope the tips above are helpful and I’d love to hear any of yours.
If you have advice (or questions) about applying a water based sealer over an oil based stain, please share your thoughts or read what other are saying in the comments section below.