09-11-2013 03:21 AM
Just recently completed building a new cabinet built from red oak plywood and red oak hardwood. Was planning to finish with Waterlox. It will be stained with an oil based stain by daughter-in-law request. Have read numerous postings about Waterlox and have read their procedure recomendations several times. I am a beginner and do better at wiping than brushing. I have Waterlox original sealer and have used it before, but only on bare wood and I really like the color it brings out. I am open to using another finish if it is better suited for my problem. The cabinet will be inside and not used in a kitchen or harsh environment. Most likely in a living room or den.
I am somewhat concerned about applying over the stain. In some test the stain is easily wiped off by the mineral spirits in the waterlox, even after waiting several days. I have read in some post about using Shellac as a sealer over the stain and then Waterlox. Is this a good method and/or is there a better procedure out there I have not seen. The Waterlox procedure is to apply over the stain. I am using General Finishes Oil Stain and their recomendations are to wait 72 hours and about directly.
Looking for some advice before I make a mess of a project I have a lot of time in.
Thanks for any advice.
09-11-2013 04:50 AM - edited 09-11-2013 04:55 AM
… by welcoming you to the WOOD Magazine Forums, particularly to the Finishing & Refinishing Forum. I hope you will visit often. You will find a number of accomplished woodworkers and finishers here who stand ready to assist you with your finishing and refinishing questions.
The finish schedule you have presented will work just fine; but, let me comment on what you intend to do by dissecting your planned approach. You wrote:
“I am somewhat concerned about applying (Waterlox Sealer/Finish) over the stain. In some test the stain is easily wiped off by the mineral spirits in the Waterlox, even after waiting several days.”
It is helpful to understand that oil-based stain is simply insoluble pigment suspended in a weak varnish binder. The purpose of the binder is to hold the insoluble pigment in place after the thinner has evaporated and the stain has “dried”. Without the binder the dry pigment could be brushed, blown or vacuumed from the surface. Two important points need to come from this understanding:
1. Marketing hype notwithstanding, pigment stains do not “penetrate”! Pigment is an insoluble solid that builds (paint like) on the surface and/or accumulates in structure such as pores and tare-out.
2. The varnish binder used to hold the insoluble pigment in place is nothing more than highly thinned oil-based varnish (usually Polyoneverythane). If all of the excess pigment is not removed (wiped of) in the process of application the weak binder film will be insufficient to hold it all in place. Therefore, it is not uncommon to get some degree of lift-off when the topcoat is wiped on. More to the point, even wiping on of a water-borne finish will result in some pigment lift-off. If you are getting a lot of pigment lift-off it is a strong indication that you are not properly applying the stain; you are leaving too much on the surface.
“I have read in some post about using Shellac as a sealer over the stain and then Waterlox. Is this a good method and/or is there a better procedure out there I have not seen.”
Shellac as a “sealer” in your application will be an excellent idea; but, not just to further bind the pigment to the surface. But, let me back-up just a bit in offering this explanation. Red oak presents unique problems when applying any oil-based finish, including oil-based stain. The cell structure of red oak can be compared to a bundle of soda straws running the length of, and coming to the surface along the length of your lumber. The oil-based finish will be drawn into these “straws” where, isolated from air (oxygen) the thinner will not evaporate and the varnish will not cure. As the finish on the surface “dries” the still liquid oil-based finish in the pores will “bleed” back to the surface and, unless removed, will produce a somewhat rough finish. To eliminate the problem when you apply your stain be sure to remove all of the excess stain and then return to your project every few minutes to lightly wipe the surface again to remove the droplets the bleed out on the surface.
When the stain is cured you can then apply a single coat of shellac to “seal” the surface. Since alcohol is the solvent used to dissolve shellac it will dry very quickly as the alcohol evaporates and there will be virtually no bleed out. Further, the dry shellac will seal the pores of the oak and will not only prevent the wiping on of your oil-based varnish from lifting excess pigment; but, it will prevent the varnish from running into the pores and thus bleeding back to the surface.
Finally, while not an issue in your application, shellac will significantly improve the moisture resistance of your finish (resistance to the passage of water vapor).
“The Waterlox procedure is to apply over the stain. I am using General Finishes Oil Stain and their recommendations are to wait 72 hours and about directly.”
There is nothing wrong with the Waterlox recommendation. I will suggest that 72-hours of cure time is unnecessarily long; the stain (if properly applied, meaning the excess wiped off) will cure sufficiently for either the shellac or the varnish in 8 to 12-hours. It won’t hurt to wait 72-hours but it isn’t necessary…
09-11-2013 10:06 AM
Thanks for the quick reply.
This sounds good. I do have one question concerning shellac. I have read that de-waxed is better, but regular shellac with wax is ok unless it is polyurathane. Is this correct. I do not have an immediate source for de-waxed but I'm sure I can find it somewhere near by. And, is there a particular brand or version that is better.
I have some Zinser clear already.
09-11-2013 12:10 PM
Most people like Zinser brand, no wax.
Wax and Poly don't like each other.
09-11-2013 01:03 PM
… if you intend to topcoat with either Polyoneverythane or a water-borne acrylic. However, if you have a big box or well stocked paint/hardware store in your area they probably stock Zinsser SealCoat®. SealCoat® is a two-pound cut of de-waxed shellac. For reasons that I will never understand Zinsser has chosen to market the stuff as “Sanding Sealer” but in the final analysis, it is simply blonde de-waxed shellac and will work just fine in your application full strength from the can…