Switching to Water-Based Finishes
A finisher who feels healthier after switching to water-based finishes kicks off a long, useful discussion on water-based finishing techniques. December 31, 2005
My one man cabinet shop does about 1-1/2 homes a month, or 10-15 gallons of finishing coats. When I first started out I shot lacquer, then I switched over to CV. About six months ago I switched to waterbased finishes, using Sealcote by Zinsser for a sealer. For two jobs with the same finish, I had to switch back to solvent based products - vinyl sealer and pre cat. I've never been so sick in my life! Even though I'm using brand new respirator cartridges each day and have an adequate booth, my body just isn't used to those chemicals anymore. I'll admit when I first switched over to waterbased I had to go through the learning curve, and I'm still not quite up to the high quality we had before, but we are close. My customers never notice the difference, but I do and maybe a few of you top notch finishers would. I am very glad I switched and I'll never go back. I use to be the biggest CV fan, but now I can't believe how much better I feel. This was very noticeable even before switching back for these last two jobs.
On a side note, the reason we had to switch back was for a couple of jobs that were pigmented - antique white with milk chocolate color glaze. We are still using an oil based glaze because I haven't found a good water based glaze. We sandwich this glaze between two coats of Sealcote on stain grade work or with pigmented colors that may have a little yellow in them. But for that antique white we can't use the Sealcote. Do you know of a good waterbased glaze or a non-solvent water white sealer?
From contributor A:
Do you mind sharing which waterbased products you prefer? I used to spray waterbased and switched to a precat lacquer. I have had great results with the lacquer, but am concerned with health issues as well as the hazard of having combustible products in use all the time. The waterbased products seem to mar easier, although I have not ventured out much beyond Sherwin William products. Do you have any recommendations?
Can you provide more information on your process - finish schedule, number of coats, sanding, coating manufacturer, spray gun and settings, etc.? Anybody else going through the learning curve will really appreciate it.
From the original questioner:
I use three airless sprayers. One set up is for topcoat (WB poly), one set up is for sealer (Sealcote), and one set up is for pigmented, or any odd thing that we may use. As I stated earlier I have been using Sealcote by Zinsser for our sanding sealer. It might be different with an HVLP but the only trick Iíve found is to make sure and lay it on in thin coats. This is not always easy with an airless- I have a heavy hand when finishing. It's a great product and costs around $22 per gallon. Sometimes I'll use two coats of Sealcoat on oak or hickory jobs or clear coat jobs to give the live look to the wood. For the topcoat we've been using a local brand waterbased poly. It costs around $35 a gallon. It does mar easily for about 3 weeks, however after that I have found it to be very durable. It looks horrible when you first spray it. Youíll see bubbles everywhere, but they soon leave and leave a very nice satin finish. It is not quite as smooth as lacquer, but my customers have been more than happy.
The only down side is that I used to finish, mount the doors, and then wrap in plastic and load in the delivery truck. I've found that now they need to cure 3-4 days before I can wrap them. I do admit that isn't always the most convenient. However, since I have a small shop, not just strictly finishing, I have adjusted my schedule so the doors sit in the finishing racks for the time needed while I cut and assemble the boxes.
For pigmented jobs, I use the best latex I can find over a Zinsser's shellac based pigmented primer. Thin the latex about 20-25%, add half a quart of Floetrol per gallon and lay it over the Zinsser product. It looks as good as any lacquer or CV I have ever used. Put a clear topcoat over it and you got a first rate, durable finish.
A normal finish schedule on a stain grade job would be:
Stain (Benite beforehand if needed)
Sealcote, sand lightly with 320
Glaze if needed
Sealcoate, sand with used fine sanding sponge
One fairly heavy coat of WB poly
If desired, add another coat (usually not needed)
From contributor C:
Latex paint top coated with waterbased clearcoat does make an amazing cost effective finish. Fuhr 255 urethane or Chemcraft acrylic are all I use. I use the Chemcraft if I want a crystal clear top coat without any warming of the undertones. Fuhr's 255 warms up the undertones a bit. Be careful with natural oak. The high tannin content of oak darkens urethanes like Fuhr 255.
From contributor D:
When you topcoat the latex with waterbased urethane, do you sand the latex first? I've used SW Woodclassics waterbased urethane many times with great results on stained wood. It flows out to a great finish.
From contributor E:
There are many alternatives to using a latex/clear coat method. If you are already looking Fuhr, why not use their acrylic paint? It uses their 375 resin system. My favorite is Muralo's Ultra acrylic topcoat. It's a lesser known brand than Ben Moore or Sherwin Williams. I believe it's the best waterbased off-the-shelf paint available today.
From contributor C:
I scuff sand between all coats. I spot many defects when scuff sanding and I can relax when a client runs his fingers over my woodwork.
From contributor F:
I use waterbased products for several reasons - health, fear of explosions, and environmental issues. I'm not a great finisher, but I do get good results with Enduro's primer and polyurethane finish. They have a hardener you can add (cross-linker) but it's not really necessary on cabinets. The finish seems quite tough. I did a hardwood floor with it using the cross linker and it's holding up really well. I use Sherwin Williams Pro Classic for painted items. The results are okay but it could be smoother. Where can I get Floetrol? I assume it helps flow-out. I like the idea of putting a clear urethane coat over the paint, but are there any adhesion problems? What's the cleanup solvent for the Zinsser primer - alcohol or lacquer thinner?
From contributor G:
I have had good results with Enduro's tinted waterbased lacquer. You can get any color you want and they mix it to manufacturer's specifications. They make a conditioner which is supposed to help with flow out but I have never used it.
I'm curious about what types of guns you use. If air powered, do you use an oil-less compressor or just filter the air? What about the Kremlin Ė that gun takes some air as well, correct?
From contributor B:
To contributor G: We've had great success with all waterbornes running through our Kremlin 10-14 MVX. The various manufacturers will help you with settings. We had a problem with air bubbles in the finish not popping, then we got an 09-094 and an 06-094 tip. We just shot an entire kitchen vertically with waterborne using a small 25 gal compressor. An expensive coalescer in front of any gun is worth its weight in gold.
Waterbornes can cause clogging at the tip. It is worthwhile keeping a cup of water and a toothbrush nearby, especially if you're spraying cabinet interiors. Also, switching between waterborne and solvent born means you must flush the lines very well with water first, and then acetone. Most waterbornes tend to gum up as soon as they come in contact with the solvents, leaving a mess in the system.
From contributor H:
I used waterbased for a few years almost exclusively but actually had more health problems with the waterbased finishes than the CV. I finish a lot of oak and found after some experimenting that I can do a better finish with CV in 2 coats than I could in 3 with waterbased and I no longer have to be concerned with tip clogging or damage to the finish from moving the items too soon after spraying. Also, I have found that the waterbased, while it looks good at first, tends to degrade in appearance faster. Look at those same projects 5 years down the road versus CV and see how they compare. I am very environmentally conscious and as soon as the waterbased products can give me the same results, I will switch. But basically to get the same results with waterbased as with CV, it is necessary to add ingredients that are potentially harmful. It is really just trading one evil for another.
Also, because you can use water to reduce and clean up, there will be a lot of product going down the drains and into the sanitary system. That doesn't happen when using solvent products and that can potentially impact the environment also.
From the original questioner:
To contributor F: Floetrol can be found just about any paint or hardware store. For Zinsser shellac based, either clear or pigmented, I use denatured alcohol for cleanup. The directions say you can use a water ammonia mix, but I've found it doesn't work as well as denatured alcohol. I've never had any adhesion problems putting the water poly over the latex. I do always lightly sand with used 320 before putting on the clear coat.
To contributor B: When switching from water to solvent, clean well with water, then run denatured alcohol, and then your solvent.
To contributor H: Because I use 3 airless sprayers and 90% of our products are shot with Sealcote and waterbased poly, they have designated guns. Those guns rarely get cleaned out. I don't have any waste going down the drain. I cleaned them out today finally after a month and I could have waited at least another month or two. When youíre not switching products back and forth, your filters and such just don't get clogged. I've never had the tip clogging problem with my airless- what type of spraying system are you using? We use the most inexpensive Graco airless sprayers - right around $300 Ė and they work well for us. One reason I got away from CV is mil limit.
Most of our work is glazed and especially on paint grade glazed jobs I know I've passed mil limits. For example, one primer coat of pigmented CV or vinyl, one coat pigmented CV, and at this point, depending if you believe on sandwiching your glaze between clear vinyl, you spray vinyl, then glaze, and maybe spray vinyl again - if not, do a top coat of CV. No matter how clean your finish room is, dust will land in the glaze while itís drying, so you need to sand that coat and then put on a final topcoat. Depending on your views on vinyl, you are now either at 4 or 5 coats. Even if you are light at hand while spraying, that will put you over the mil limit.
From contributor i:
Try Golden Paints Acrylic Glazing Liquid. Use their Fluid Colors to make any color glaze you like. Sandwich this glaze between your topcoats of waterbased.