Question
I have to use waterbased clear on a job. What is the hardest overall finish? I've tried Campbell, Mohawk, Camger, Valspar and many others - not too impressed.
Forum Responses
(Finishing Forum)
From contributor S:
We just got through using Mohawk's waterbase CV. We were pretty impressed with the product. Hardness seems good also.
1. They raise the grain more than solvents, which will require a little more elbow grease when sanding.
2. You have to spray slightly thinner coats to avoid runs, sags, blushing, etc.
3. Because of #2, I usually spray one more coat to get the build I'm after.
4. If you are dealing with cold or humid weather you just have to be patient or buy some really nice heaters because your in-between coat dry times will increase by a lot.
These are just things you have to accept when using water bornes. As far as what product to use, only you can determine this by what you will be finishing. In my experience with trying water bornes like Chemcraft, MLC, Valspar, Trinity, Target's baseline EM 6000 outperformed all of these in ease of use and durability/hardness. And if you choose to go with any of their other products, durability will only get better. Also their finishing zone website makes ordering a breeze.
I would think that putting on many coats of a gloss EM9300 would give a polyester looking finish. This is what the high build is used for. If you buffed it out it would look that much more awesome.
Several offer post-cat versions, but we think it's important to evaluate the catalyst technology. Several offer good stain/dye lines while others are not that good at all. Some offer sealers which sand incredibly well while others offer sealers which are redundant except that they are a little clearer than the topcoat in case you're worried about haze. Two that I know of offer high viscosity products for vertical spraying. The range of technical support varies immensely.
We spray only waterbornes every day and our conclusion is that the most difficult part of picking a manufacturer has been identifying our needs. If you're in a niche and only spray signs, you could use any of them. If you want a complete system that emulates the ease, durability, and variety of tools in a solvent system, then field narrows considerably. In general, we now think that waterbornes are a great substitution for their solvent-borne cousins but require more research on many fronts.
There are many issues to consider: price, distribution, tech support, post-cat, sealers, clarity, wet-mil build, dry-mil build, wet-on-wet, primer/undercoater grain raise, viscosities, AAA microbubbles, IR-cure, retarders, dyes, stains, colorant vehicles, high-gloss, dull, feel/wax.
As far as hardness goes, the Renner, AguaBarnice, and ILVA post-cats actually felt like a post-cat such as Krystal. I live in NY and it's actually very easy to get all of these products. MLC can be delivered with my plywood or there are two local distributors within 20 minutes driving distance. I've tried Target's 9300 as well as Valspar's Zenith without catalyst and they do get very hard. Both can be catalyzed and I've heard that the 9300 gain in chemical resistance but that the Zenith only dries faster. These are also easy for me to get. The three post cats I mentioned were much harder than the other two single components.
As far as coloring goes, ILVA colors are great and Fuhr has a wide range of stains and dyes. MLC has the Azetone system, but I wasn't impressed with the samples and it's just not available where I am. Because we are constantly making custom colors I decided to go with ICA's CNA stain kit which lists at around $1,500 but which comes with a library of recipes. Moreover, their colors are super (like ILVA) and they have vehicles to allow you to wipe which are actually slow enough to be useful. We did a very dark stain that Sherwin Williams made up for us and it was extremely difficult to wipe on large surfaces even after I poured in the maximum amount of propylene glycol I could (it was on rift white oak and we needed to wipe and couldn't spray dye or tone and get exactly the same look). If you need to wipe, the vehicles are a big deal. So are the colors.
We're impressed by the MLC, Renner, ICA, and Fuhr clear dulls - they all appear to be around 5 degrees. I didn't like the feel of the Fuhr. The ICA has Naturewood which claims that it can go to 2 degrees but we couldn't tell the difference between that and the other manufacturers' 5 degree. Strangely, we got a cloudier result by spraying MLC satin and dull than dull plus dull.
In my opinion the MLC Agualente primer has no competition. It blocks well, raises the grain on MDF least (by far), dries fast (they all do), and sands really well. It also goes under their AquaBarnice post cat so it makes for a simple overall opaque system.
The Renner clear sealer is very cloudy - I'm assuming this is because it has a ton of sanding agents in it - but if you can get away with it, you will not believe how well it sands. I would almost say order a sample just to try it even if you'll never use it. I've never seen anything like it. Perhaps all of the manufacturers could achieve the same thing by pouring in whatever makes it easy to sand, and it's something to ask. I'm not kidding when I say that it scuffs to the best powder I've ever seen with minimal effort. By contrast, SW Kem-Aqua Plus sealer is practically a gloss and quite hard to sand but it has excellent clarity. I've found Fuhr primers to have a strong odor (almost sulfur) when drying and sanding.
We've found that in general all the clears are easy but have different characteristics. Some bridge pores better than others but if you want an open pore look (we just had to do this with rift oak) then many require adding water. ICA apparently has different products for closed vs. open but I haven't tried this yet. In general ICA has the most complete line and we're just becoming familiar with more and more of what they have to offer. In the clears there is definitely a difference in the slickness of the feel but that's pretty subjective so I won't comment beyond that we thought there's a noticeable difference.
A big obstacle for us is colors. We were used to the ease of an oil based system and some of the waterborne stains, while very vibrant in their colors, are almost impossible to push around on a large scale or on something like an ornate mantle. You end up doing something like glazing instead of wiping on, letting it sit and wiping it off. Fuhr and ICA have great colors and offer retarders. We had distribution issues with Fuhr and we also prefer the ICA or ILVA colors. Target's stains are easy to manipulate but we couldn't get the dark colors, I believe because they are all dye based. The dark browns and black from ICA and ILVA are perfect. We also like Fuhr's Jet Black pigment. In the end we chose ICA to get the recipes and force ourselves to learn more about how to work up complex colors from simple ones. That plus the range of vehicles and the fineness of the color.
I want to bring up one more issue. We've found the most difficult thing is opaques on MDF because of the grain raise. You might think that doing it with stains on clears is tough, but it's actually not once you get the hang of it. You can seal the color layer, sand it, and not cut through before you topcoat. Seems like it might be tricky until you try it a couple of times and then it's nothing at all. Perhaps you just end up paying more attention to what you're doing. In our experience it's not the stains that raise the grain, but the seal coat over them and so that's the part of the system to play with.
Anyway, opaque on MDF. We're using only NAUF board like Medex. We found a green tinted board (I think Norbord) which was moisture-resistant. It was made in NY and far and away the best for not raising the grain. However, the mill is closing and besides, it's not NAUF. If that isn't a concern of yours then I'd buy all the units you can lay your hands on before they shut their doors. We bought it through Atlantic Plywood.
To fight the grain raise on MDF we've tried just about everything. In the end we found that sanding to 320 does help somewhat but if you want to stick to an all waterborne system, then you're just stuck with more work. We used to shoot Clawlock and Resistant and I really wish we could get that kind of performance from our waterbornes, but as of yet we do not.
If you're willing to shoot shellac (dewaxed like Zinsser Sealcoat or your own blend) then you can beat the grain raise, but you're not introducing formaldehyde into the system. Once the denatured is gone you're done (as far as I understand). I'll say again that Agualente is a great primer and the Agualente and AguaBarnice make great topcoats. One thing we've found is that you need to use open coat silicon-carbide paper, not aluminum oxide, and that random orbit sanding hides the scratch pattern better than long strokes by hand.
Another non-formaldehyde option is the ICA Isolante product. It's a clear, iso-cat product for sealing MDF. We loved the result. It was like spraying Krystal Sealer. No grain raise, dried fast and hard, sanded like a dream. We hate the fact that it is catalyzed at a 1:1 ratio, i.e. 50% Isolante and 50% catalyst. We're going to used it on our current job along with the ICA post-cat opaque for all the work in the bathrooms. I feel this is a bit of a compromise but I want to make sure that we're putting out the most durable product that we can in those environments. I think you could go with shellac, Agualente, and Aguabarnice too, but I'm not sure about that system and nobody at MLC wants to comment.
So, I'd say the distribution issues are a really big factor because it's nice to be able to go and get some more product on a Saturday morning. Right now we're concentrating on ICA because they're available, I've had great tech support from them, they offer in my opinion the best color system, and have the widest range of iso-cat products available. Apparently, they also offer a higher gloss than is available from anybody else. We're bidding on a gloss polish job and if we get it I'll know more on that score.
I hope my post hasn't seemed biased as it certainly was not meant to be. I've had many great conversations with the tech support at most of the manufacturers, and while I want to support them all, I feel most loyal to other woodworkers and finishers, so I've given my anecdotal experience here.
1) Target Coatings claims that you can spray a coating, let it dry and (within an appropriate window, e.g. 24 hours) spray another without sanding. This is not wet on wet but wet on dry without sanding. We've not only tested this but used it on a couple of jobs where we wanted to get a lot of build then cut back before final topcoat. No problems then (5 years ago) and no problems now. If I recall, our coating schedule was around 3 wet mils.
2) I mentioned above the problem of grain raise, which for us is typically a problem with MDF and opaque systems. However, we once had a job where the coating had split and cracked and at the bottom of the cracks, the raw birch veneer was exposed. Moreover, it looked as though much of the finish had either disappeared from constant cleaning or was never adequately there in the first place. Our contract was to refinish the kitchen and so many of the fronts we were able to take back to the shop. However, there were many fixed panels, sidewalls, etc. that we had to spray on site. Because the existing coatings had failed so badly in many areas when we shot it with waterbornes we were getting grain raise. However, we couldn't sand it because of the photo discoloration of the veneer which was a substantial yellowing. In short, we had to shoot a lot of veneered wood on site with waterbornes and couldn't find a way to deal with the grain raise.
We wanted to shoot super blonde dewaxed shellac but it was still giving us a slight color shift. So, we shot a seal coat of MLC solvent borne vinyl sealer where we needed to. After 24 hours dry time we proceeded with Target topcoats and got the result everybody wanted.
This anecdote is only to point out that the interaction between oil borne undercoats and waterborne topcoats should be qualified on a case to case basis. In this case we were able to get good tech support about our proposed solution from Target but only the standard "Haven't tested that" from MLC.
3) Fuhr colors + MLC clears worked as toners. Of course you're probably better off F+F then F+MLC but if you're in a pinch they seem to work in at least one direction. We never tried Azetone (MLC) colors + Fuhr.
4) I was told by Adam Fuhr that some dewaxed shellacs, in some parts of the country, are definitely incompatible with their topcoats.
5) Most importantly, although a lot of my observations came through personal experience in the booth and from talking to manufacturers and other professional finishers, we've recently pushed forward into a lot of testing and many of the results I tried to post here were derived from the hard work of our lead finisher.
Before we switched to waterbornes we were using a lot of MLC oil based. We would often shoot Microton dye as a washcoat cut with a bit of vinyl sealer, then spray a Woodsong wiping stain which we wiped off, then tone as required.
One of the challenges in switching to waterbornes has been finding a line of wiping stains that mimic the oil based MLC which, apart from whatever one says about the grind of their pigments, are very user friendly. Wipe-on-wipe-off stains have been a real problem when formulated with the waterborne bases that we've tried. Recently, we tried to wipe a dark stain over a somewhat ornate mantel. There were a lot of moldings and flat surfaces to stain and it took both myself and my lead finisher to do a good job at it because the waterborne stain we used (which had already been slowed with propylene-glycol) was too fast.
We've recently tried the ICA CNAs with their retarder and found that one can achieve open times that surpass oil based stains. We were able to quickly make a very dark wiping stain with their CNA stains plus retarder that left the same color when wiped at 30 secs, 2 mins, 5 mins, and 10 mins. So, if anyone else has had the same worries we've had about waterborne wiping stains, I would suggest they look at the ICA line.
I'll qualify this post in two ways:
1) I only post the anecdotal results of what we've found to work for us. We're not in the business of selling coatings but we are interested in promoting the use of waterborne coatings and have taken on the expenses involved in testing different products. The observations we post are directed toward streamlining the decision making process for others.
2) The problem (solved by ICA) of wiping stains may be able to be solved by (any number of) other manufacturers. However, we haven't found this in our testing. I won't go over those systems that we have tested again, but the open time has consistently been a problem. In the one case where the stains wiped like oil, we couldn't find a way to get them really dark.
A last comment: In the past few years I've followed the move toward waterbornes, used them, learned a lot from manufacturers and posted my findings. One of the challenges that those who are working with waterbornes face is a comprehensive source of information. Finishes aren't finishes; they're finish systems. Those who implement this new technology need manufacturer support which extends beyond unsubstantiated claims to metrics of comparison that a growing number of professional finishing departments can assess.
It may be the case that several formulators for manufacturers other than ICA could read my post, understand my claims and the needs upon which they are based and retort "we can do that too!" Nothing would please me more, as I would love to have a range of finishing lines that took care of all or our needs.
But either these formulators exist and can say this, or they cannot. If they can, then I wonder why they haven't already developed the right products. Perhaps it's because they don't understand the market, but I doubt it since anybody who has tried to wipe a 4' x 8' panel with a typical waterborne stain has understood the challenge and griped about it.
That said, I guess I'm trying to explicitly identify a part of the process of a waterborne finishing system that's tricky (dark wiping stains) in order to motivate all formulators to step up to the plate. Yes, it's actually important to some of us and we rely on and purchase from the manufacturers who take these requests seriously and provide solutions.
