Glazing Techniques
Advice on achieving good adhesion and appearance with a glazed finish. January 2, 2012
Question
I am in the process of glazing a set of cabinets. I painted the cabinets with SW white lacquer. When I try to glaze over the white lacquer, it seems to bite in too much. It is hard to wipe out. Seems like it dries instantly. Do I need to thin my glaze, or can I spray a 50/50 lacquer and thinner mix on first so it won't bite in as bad? It is very humid where I am working.
Forum Responses
(Finishing Forum)
From contributor M:
Please give us your finishing schedule (before you started to glaze). I will only glaze on a glass surface. That means that I have sprayed on a coat of color, sanded with 280 grit and scotch brite. If you are glazing on a clear finish, then mix your finish 50/50 with thinner and retarder and lay on the smoothest coat you can. If paint, thin and retard, then spray. Sometimes I will need to lightly rub down the door backs with a brown paper bag (it is about 2000 grit when broken down). Your problem is the porosity of the paint. If you sand and glaze, then you will get color in the scratch lines.
From contributor S:
Wait a day after spraying your lacquer before applying glazing. Otherwise the glazing will bite into your lacquer.
From the original questioner:
I am not sure which is the best way. I am going to SW in the morning to talk with them. I am planning on going right over the paint right now. I don't see how it could get much smoother. I went by a friend's shop Thursday to see how they do it. They use ML Campbell vinyl primer, two coats, and their glaze glides on effortlessly. Looks great. They thin their glaze down 3 to 1, and that might help me some. They rub glaze over the entire door and it gives the white door just a slight brownish tint. Next time I will go this way, but I have started with lacquer.
From contributor R:
What are they thinning the glaze with? Usually a glaze is just some color and a solvent like paint thinner. It's applied over an unsanded coating and manipulated with a brush or rag.
If you're looking to add an accent color to some carvings or to the nooks and crannies of a door/drawer, I typically use naphtha instead of paint thinner as the vehicle. Also in this case, I would add more color to the thinners than I would if I was simply mixing up a glaze.
If you're using a glaze that's mixed with a hot thinner like lacquer thinner or acetone, it's going to dry too fast for you to be able to manipulate it with the rag or brush. Can you post the details of the finishing schedule you're using? That's key.
From contributor B:
In the past when I used solvent based finishes/glazes we would add some BLO to slow down our glazes (paint thinner based) and to get less bite. You only need to add just a pinch. Do some samples.
From the original questioner:
I am starting with a raw door and frame and applying two coats of SW white lacquer primer flow with 2 coats of white finish lacquer. I then apply glaze and 1 or 2 coats of clear. I believe I didn't have a smooth enough finish to start with. I did some samples and think this is going to work for me and I am going to thin my glaze with paint thinner. Thanks.
From contributor R:
I think the point contributor M was making is that if you apply your glaze over a sanded white color, the glaze will end up in the sanding scratches and might not look very uniform.
Since you're still in the sample stage, try this. Sand the white with some 280, apply a coat of clear over it, do your glazing, and then proceed with your finish coats. If you use a tack rag to remove any sanding residue prior to coating over the white, your clear coat (sealer/semi) will come out quite smooth and your glaze color will come out even. Try not to rush through any of the steps and you should achieve the results you're after.
From contributor S:
You mentioned glazing over an unsanded surface. I've always been told to sand between coats. I use CV, so how does that work when the CV needs a mechanical bond?
From contributor R:
I've been following this finish schedule for years on both CV coatings and various lacquer coatings, pre-cat, post-cat and no-cat. Feel free to apply a thin coat of sealer over the glaze and you will get a nice bite, sandwiching the glaze between whatever you applied the glaze over. Most adhesion issues can be traced back to temperature, lack of dry time for stain, too much/not enough catalyst, moisture in lines, etc.
From contributor S:
Not questioning your expertise, I just want to make certain I understand what you're saying. I'm going to list a finishing schedule and please tell me if it's correct.
stain
catalyzed vinyl sealer
sand
conversion varnish
glaze without sanding the CV
second coat of CV
no sanding between the 2 coats of CV
From contributor R:
In lieu of glazing over the CV, have you tried glazing over a coat of vinyl sealer? You're an experienced finisher yourself, so you know the importance of making up samples and experimenting with different ways to accomplish the end goal.
I'm probably going to get flamed for saying this, but I think there's lots of misinformation floating around about a reactive coating versus one that's not. Same holds true for whether a vinyl needs to be catalyzed or not. I'm from the school that, as long as my samples pass an abuse test and I'm not called out a year or so down the road to fix something that was wrongly done, it was the correct finish and the correct finishing schedule to use for that particular project.
Being able to adapt a finishing schedule to meet the demands of a particular project comes from experimentation and by researching and developing and trial and error. For example, who would have thought that a manufacturer would develop a coating that has both primer and topcoating mixed into a single material? Products are starting to hit the market now that are formulated as an all-in-one finish. Is it right, is it wrong, or is it what is going to work?
From contributor L:
An oil base glaze will go on smoother and dry slower than a water base glaze. Some of the glazes seem to dry so fast they are too difficult to use unless you are quick and know exactly what you are trying to accomplish.
