Help: can I varnish over glaze? or, what is happening to my doors?

[Patrick McCarthy]

Dear Finishing Experts (Howie, Steve and Scott) as well as all others,

I am installing three new exterior doors that are veneered with clear vertical grain douglas fir. Three doors gives me six faces.

Following Steve Schoene's advice to "test your finish on scrap or be prepared to scrap your finish", I used what will be the interior face of my shop door to test the finish. I first sprayed (rattle can) Valspar's sanding sealer and then applied an oil-based glaze, first applying a heavy coat and then brushing it off until I had the desired color/grain pattern. I let it dry overnight. My first varnish coat was Epifanes in what I believe to have been a 50/50 mix . . . although I now wonder about that, as discussed below. When applying that first coat of varnish over the glaze on my test face, I noted the stiff bristles (Omega - ox) was "lifting" some of the glaze, but did not necessarily seem to be smearing it. It gave me a wood grain effect. It ended up going from a darker red mahogany appearance to a lighter, perhaps walnut color appearance to which my wife immediately said "ooh, I love that." So, it appeared I had my marching orders.

Assuming that the sanding sealer was merely a barrier coat to keep the glaze from penetrating/staining the wood, I figured I would do the next three faces (it is easier working on the faces when they are horizontal, and I only have 6 saw horses so I was doing three faces at a time). I figured that on these faces rather than using the sanding sealer I would use a barrier coat of 50% varnish and 50% thinner. I wiped that on and after letting it dry overnight I again brushed on/brushed off the glaze. IT IS AFTER THIS POINT THAT MY PROBLEMS BEGAN.

This time when I applied the first coat of varnish (50/50 is recommended on the Epifanes can) it immediately started lifting the glaze in somewhat of a blotchy fashion. This was a different result than previously, where the glaze had some "workability" and I noted that the brush bristles were lifting some of the glaze. Rather, this time it was almost like there was no underlying adhesion between the glaze and the initial barrier coat. This first finish coat was a disaster and I reluctantly took a t-shirt and started wiping everything off. Perplexed as to whether the problem was lack of adhesion between the barrier coat and the glaze, I started to wonder if perhaps the 10% of thinner I added to the glaze somehow affected its overall performance. However, I thought that since the thinner had evaporated in the drying process, that was probably not the culprit.

Next, I wondered if my 50/50 varnish mix was "too hot" so I poured more varnish into the mix - I didn't measure but I am guessing I ended up with a 75% varnish 25% thinner mix. Using that I went to the second door and in two spots had similar failures but over 90% of the door had satisfactory results. Since one of the two failure spots was where I started using the brush, I assumed the residual "mix" on the brush where I started was more of the old mixture than the new. At this point I don't know if I figured it out or I just stumbled upon some good luck. Therefore, before I start re-glazing the faces and mixing more Epifanes, I could use some education, guidance and direction. Feel free to throw in some ridicule, as I got used to that attending parochial school . . . although it was in the last century. In a nutshell:

1. Is glazing and applying varnish via brush incompatible? i.e. when glazing must the top coat be sprayed?

2. Assuming the glaze is dissolving because the varnish and thinner mixes too hot, then; Since Epifanes recommends the first coat be 50/50, am I going to hurt the integrity of the final finish (four top coats are recommended) by starting with a 70/30 or 75/25 mix? Or is the 50/50 first coat on the can recommendation just to treat the raw wood which has already been done by either the sanding sealer or 50/50 coat applied BEFORE the glaze?

3. Am I missing the real point and screwing up because of something else???

This is my first attempt working with glaze . . . . . . in case i didn't mention that earlier.

Thank you in advance, Patrick

PS: also, how do i keep the varnish from getting tiny little bubbles in it? I got less when i kept the brush vertical and didn't back -n-forth motion it.

[Todd Burch]

Hi Pat.

I try not to experiment combining different manufacture's products. I stick with a "system".

For instance, ML Campbell has toners, stains, glazes, sealers and topcoats. If I use only ML Campbell's products, per their data sheets, if I have an issue, I call ML Campbell. Once I start mixing different products from different vendors, there is no one to call but myself.

Case in point - ML Campbell's glaze specifically calls for a vinyl sealer to be applied over it prior to any topcoats.

What does your glaze say?

Todd

[Patrick McCarthy]

Todd, thank you.

My glaze is a custom brew that i got from an owner/builder in town building a custom home. I saw the mahogany cabinetry he did in the kitchen and was impressed with the finish. He then started showing me the rest of the woodwork - ceiling beams, etc, all from doug fir and he explained the sanding sealer process, glaze brushed on and off, and then - - - big difference -- he sprayed lacquer. The color match was great so I bought a quart out of his last gallon. The house was recently on the market for $2.3 million so I suppose i can track him down thru the realtor. IIRC, he said the glaze was done by a colorist but I have no idea who . . . . .

Sounds silly now that i explain it, but his woodwork finish was NICE, very nice. . . . . . and one of my door faces came out great, but i didn't write down the precise mix and steps . . . apparently because i forgot my memory isn't what it used to be, and thought i could easily repeat the process, especially since the first one went so well. It was only when i started having problems that i lamented not writing notes on each stage and measuring the mix accurately, and drying times, etc.

My educational journey continues . . . . .

[Scott Holmes]

Epifanes is an excellent EXTERIOR varnish. EXTERIOR varnishes are much softer and less waterproof (read this as don't seal as well) as interior varnish or sanding sealer. Stick with the process you tested. Epifanes is a much slower drying and curing finish than a fast drying interior sanding sealer... see the problem?

I would only recommend the Epifanes on the EXTERIOR of these doors; if both sides are inside than I would recommend and interior varnish.

Always practice on scrap and WRITE down exactly what you did. I can't tell you how many times I've said "no problem I'll remember" then had to start over matching (this time writing it down) a color/finish for some project.

[Patrick McCarthy]

Scott, so on a door to the exterior (such as my front doors or back door), rather than using a single product on the entire door, i would use P&L 38 on the interior faces and then exterior on the exterior face . . . . and i assume exterior on all the 2 sides and top/bottom???

What about the integrity of the final finish if i do not use the 50/50 mix on the first top coat over the glaze, and instead go to a 75 or 80% strenght mix?

Thank you, patrick

[Scott Holmes]

If these are exterior doors then the Epifanes is fine on both sides. Epifanes is much darker than P&L #38. If you want to use a wash coat of Epifanes before you glaze you will need to give it more time to dry before you glaze. 50/50 or 70/30 should make too much difference. Just make sure it has plenty of time (maybe a few days or a week depending on humidity etc.) to dry before you glaze.

Test it out on a sample board or do a small section of the door if you don't have scrap from the doors.