Water based Poly over Linseed Oil

[Greg Hampton]

The piece I'm working on is a free standing cabinet that will be in a bathroom and used for storage. Part of the cabinet is dyed and then has three coats of General Finishes (GF) Polyacrylic semi-gloss (water based).

The remaining pieces of the cabinet are a maple top, maple base and maple drawer fronts.

I sanded all the maple to 180 then applied boiled linseed oil. It really made the grain "pop" and looks great right now.

My shop is in the basement with limited ventilation and I really like the water based finishes.

My plan was to now apply three coats of the same GF finish to the maple that I've oiled in hopes it would add some depth, shine and protection.

However, someone in a store recently suggested I leave as is with the oil only because water based finishes should not be used for bathroom pieces due to the fact alchohol will break it down.

Beyond spilling something, I guess a main concern is my wife's hair spray.

So.. a few questions:

Should I sand the maple to 220 or is 180 fine ?
Should I leave as is with just oil ?
Am I okay with going with the GF water based finish and if so will that add to the "look", depth, protection ?
Will it be eaten away in the bathroom?
How long should I let the oil dry ? (others told me a week).

I'm ready to finish this thing so I'm really looking forward to hearing the thoughts from you guru's. I've

Thanks in advance !

[Prashun Patel]

Linseed oil won't offer any kind of protection; it'll only retard water absorption a little but it'll also inhibit water evaporation, which means it can promote mold and mildew.

If it were me (I'm not an expert), I'd shellac and then varnish/poly. If you use a dewaxed shellac, you can use a water based varnish on top. I believe there are waterbased varnishes that are appropriate for a bathroom if yr skittish about using an oil-based varnish.

The reason I'd shellac even if yr using an oil topcoat is because it seals in the stain, helps to fill pores, and has caused the varnish to build quicker for me. They also say that shellac is an excellent vapor barrier under varnish.

[terry hansen]

I use BLO to pop cherry and let it dry until I can't smell it anymore, usually a couple days. I've never used water based poly (or other water based finishes) but I seal the oil w/shellac prior to a waterlox finish (also adds a bit of color depth with garnet shellac). I'd probably put water based poly sequence on a scrap, let dry a couple days and spray hairspray around it to see if it goes tacky or dissolves. You can always tell SWMBO not to use hairspray and then run.

[Greg Hampton]

Hey Terry,

Thanks for the scoop. As simple as a suggestion as it is, the test you suggested has to be the ticket.

btw: You cracked me up with the "don't use it and then run". And although I'm somewhat shamed to have to access, what does SWMBO stand for ?

[Peter Quinn]

Not sure about General finishes specifically, but I don't think alcohol affects any water based poly finish. Perhaps a water based shellac, but not the poly. I'd do a test piece before application to your actual work piece, but current water based clear coats are pretty tough stuff.

There is a lot of bad advice given regarding finishing, perhaps more than any other area in wood working.

If general finishes prove to be a problem, check out Target Coatings water based lacquer, poly and varnish. Definitely can be applied over BLO, definitely wont be affected by alcohol.

Please refer to above warning regarding bad advice if mine proves to be so.

[Jim Becker]

I prefer a barrier coat of dewaxed shellac over BLO before finishing with a water borne finish. This speeds up the process because you must have an absolutely full cure of the BLO before you put a water borne on top or you may have adhesion problems. The dewaxed shellac fixes that issue. Although it's a greatly accelerated technique, I've done BLO in the morning (very light application), shellac an hour or so later and sprayed several coats of water borne that after noon and then on to installation. This was for built-in face frames for the wet bar in our new addition.

And with ANY finish containing polyurethane resins, you have to take great care relative to adhesion. Poly hates to stick to itself even...and I never use it on furniture.

BTW, there is really no risk of problems using "today's" excellent water borne finishes relative to routine cleaning unless you or whomever cleans prefers to use harsh chemical cleaners that frankly are not necessary. We use Method cleaning products and the Target Coatings finish all over our kitchen since 2003 looks nearly new. I can't say the same for the {expletive deleted} polyurethane product I used on the kitchen table...

[Scott Holmes]

And windex and many oter household cleaners.

As for putting it over the BLO... a barrier coat of super blond dewaxed shellac will give you a surface you can coat with the water-borne finish. The water-borne finish will be MUCH more durable than plain BLO.

[Greg Hampton]

Good stuff.

Thanks !