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Sayerlack crazing over sealcoat10/18
i am spraying sayerlack hydroplus (clear) over sealcoat, and it's crazing like mad. i've never seen a waterbased topcoat do this, and i've sprayed a lot of it over sealcoat. has anyone experienced this, or alternatively, can somebody suggest a sealcoat-like sealer that i can use under the sayerlack that isn't a solvent vinyl sealer? i'm really trying to avoid vinyl, and had hoped that sealcoat would act as an alternative barrier. thanks for any assistance.
Hi David, just a quick question before any conclusions can be offered up. When you did your sample board with all the different steps that are involved with your project, did your sample board " craze like mad "?
When you did your controlled sample board, did you do the same steps on it that you did on the item that's " crazing like mad" ?
of the three sample boards i made, one showed slight crazing, but none on the other two. the techniques and equipment are the same. i wouldn't have proceeded had my sample boards crazed.
you're clearly implying that i didn't do appropriate homework or setup prior to finishing... so why not just say that instead of digging via your question on the sample boards?
this is the first time i've seen a reaction of any waterborne finish over sealcoat, and i'm curious if this is a reaction that others have seen. i think that's an appropriate question, and i appreciate any constructive feedback.
Greetings David, In my 35 years of finishing I have seen many issues with water based coatings. Sorry if you got the wrong impressions via my questions. In all fairness to you, your response that one sample slightly crazed should have been a red flag.
How is the weather where your spraying, was the seal coat completely dry when you applied the next coating ? Did you use a tak rag to remove sanding dust ?
100's more questions can be asked but start with answering those first.
Whoops; one more thing. Can you post up some photos ?
no tack rag, i use a microfiber and significant volumes of compressed air. the finish was most definitely dry - hours under forced drying. the humidity was somewhat high over the past few weeks, for sure, but i skipped the most miserable days (i'm in Michigan). an expert from the manufacturer suggested that my coat was too thick, so on subsequent panels i tried thinner coats which definitely seemed to help. i'm really most curious about this particular reaction with sealcoat - is it the sealcoat itself? have they changed the formulation? should i mix my own dewaxed instead of using canned sealcoat, or is shellac under waterborne in general a no-no (even though i've done it successfully for years)? i'll grab a few pics tomorrow - thanks for your help.
Not trying to sound like an a$$ but did you make a sample without seal coat? Or try sayerlacks recommended sealer?
Sealcoat is a fantastic product.
I haven't had one issue since they started making it. We've used it under, between and over many, many kinds of finishes.
We typically use it as a sealer on nice woods when trying to "pop the grain" Then multiple wb topcoats. I'd guess we've put 10 different wb clears on top of it.
We often use it as a dye base with transtints instead of a stain. When we have to do a oil based stain we will use the Sealcoat as a barrier between the oil and water.
No problems here. Seal coat was a gift from the finishing gods. I don't believe you can easily dewax shellac.
I would do a bunch of test boards. Brush it out of the can with a chip brush. That way you can rule out the spraying variables. Brush some sealcoat in the morning. Brush the topcoat after lunch.
Is it possible that he's using a stearated sandpaper that's causing the crazing between the seal coat and the topcoat?
I've only sprayed around 20 gallons of waterbased stuff and none of it was Sayerlack, but both ML Campbell and Sherwin Williams cautioned me to try to avoid stearated sandpaper with waterborne stuff because of the chance for poor adhesion and crazing.
thanks for the responses - i appreciate the dialog and commentary.
first of all, yes, i have sprayed sayerlack without the sealcoat (not at all an unreasonable question), and it sprays like a dream. sayerlack is self-sealing, the first coat does an excellent job doing that, and then subsequent coat(s) build. flawless results.
i even tried spraying sayerlack over raw maple, but with sealcoat. THAT crazed, which shocked me. my original concern was that it was my substrate, the veneer glue i used... some other variable, but even just sayerlack over sealcoat on clean maple, crazed. crazy (ha!).
on the sandpaper - thought of that, too. but i'm not new to this rodeo, been at this a long time, and definitely haven't changed papers or added other variables.
i wonder... could the shellac alcohol be off gassing for longer than i figured it would, crazing the coat above it? perhaps that's why a much thinner coat doesn't seem to craze?
thanks again. it's good to hear that others have had such good luck with sealcoat, and agree it's a wonder product...
by the way, the last kitchen i did i didn't use sayerlack, but kem-aqua plus (i recently switched to sayerlack). that kitchen was cherry, stained with a Zar stain, sealcoat barrier, then kem-aqua. i've done this a bunch of times, with terrific results. i expected the same results with the sayerlack, and this is the first time i've seen crazing of any kind over sealcoat. the sayerlack folks seem stumped.
I had an issue with crazing once when spraying a waterborne polyurethane topcoat over some tinted BIN shellac primer.
I resolved the issue by allowing the shellac to dry longer, 24 hours or so and the clear coat didn't craze.
How old is the Shellac that was used? I had an issue when force drying a water based coating; the surface area had dried faster than the area below it. The wet topcoat I applied over the seal coat had a bad reaction.
I stopped pushing the drying times with water based coatings after that.
interesting, on both counts. the age of the shellac is tough to determine - i sprayed 7 gallons, used everything the store had. it's a big store in a populated area, so hopefully they are rotating stock, but i have really no idea. i think the idea of letting things dry longer, and not putting air on the topcoat, both are excellent suggestions. i'll do a sample with those and see how i do. thanks guys.
Iknow target coatings says that there finish will craze if sprayed over sealcoat. They want you to use shellac mixed from flakes. I think they say it has something to do with the preservatives used in sealcoat. That said i have sprayed target coatings over a very light coat of sealcoat a few times with no issues.
that's very interesting. i have some dewaxed amber mixed up, i'll test it over that and report back. i had no idea that jeff says that about his stuff over sealcoat.
Target coating has their own waterborne shellac. They started making it after Sealcoat came on the market. We have used many gallons of Target products over Sealcoat. Call Jeff if you have any questions.
I don’t use WB so forgive my ignorance, but what is the point of sealcoat? I thought the whole point of WB is to move away from stinky stuff that can also explode. Sealcoat does neither. Isn’t there WB sanding sealers?
According to another forum, here is how to decipher Zinssers date code.
Here is what Zinsser sent to me a couple of years ago:
The batch code on the shellac should always be a 6- or 7 digit number, beginning with a letter. For example: S01231D
The first number after the letter will be the last digit in the year of manufacture
In this case a batch code reading S01231D will have been made in the year 2010, in the month of January, on the 23rd day.
So for S0O258D
Batch number 8D
0 for 2010
Shellac flakes are dissolved in alcohol. BIN makes a waterborne synthetic "shellac" primer as well, but doesn't perform the same. Any waterborne primers or sealers I've used raise the grain and especially the fibers on mdf and take more sanding work and coats to get a comparable finish to solvent. Also have to wait longer to dry before they sand well.
I prefer a hybrid system of shellac primer or sealer if I have to use a water based topcoat. I wear a respirator but don't find the alcohol fumes very nauseating at all while parts are drying.
Target Coatings says that WB coatings can craze when applied over high pH basecoats, such as shellac. I haven't used much TC waterborne but I have used lots of General Finishes', and I did have a slight crazing issue with Enduro Clear Poly when I applied it over something that was heavily toned using Sealcoat as the base. At the time I thought the temp. might have been too low, but later I read that comment from TC with respect to pH and thought that could have been the real reason. But it was a one time occurrence with no problems many, many other times over about 10 years.
This is directly off of Targets site
All EMTECH brand water-based finishes can be applied over semi- or fully cured solvent/oil-based stains, sealers and topcoats—pigmented paints included. That’s probably the first question I get when someone is switching to water-based finish—and it’s the easiest to answer!
The use of a dewaxed shellac sealer as a barrier coat is sometimes required. Substrates that are prone to tannin bleed, or surfaces that are highly contaminated with oils or sealants, should be treated with a light application of fresh, one-pound cut dewaxed shellac in the color grade of your choosing. The use of clear shellac should be limited to wood species that will be finished natural/bright, or stained and then clear coated.
I spoke to Jeff years ago about Sealcoat. He was using it in the same manner as we do. I got the idea of using Jeff's transtint dyes mixed into Sealcoat from Jeff. Eventually he formulated the waterborne shellac to replace the Sealcoat.
Often people ask if you are going to switch to waterborne why do you use some solvent products. The answer is 90% of our finishing is done with only waterborne products. It took a very long time for any of the companies to formulate waterborne stains that are on par with the good solvent based one like MLC. We deal with architects and designers who like to spec stains. They can be matched by computer in the solvents. We never found someone who could do it with wb stain.
At the end of the day the toxicity of denatured alcohol is extremely low. The fumes will make you drunk not stupid. We use a bit here and there.
I think I would just go back to your previous WB finish and call it a day. I've heard of the pH issues before. I think you want to spit coat the first coat of WB sealer over the sealcoat before applying a wet coat. I just finished a teak bathroom with 2 coats of sealcoat under GF clear poly. Didn't have any issues.
this is all really informative. i think i know where i failed - first of all, i sprayed the shellac pretty heavy. (clearly) certainly heavier than i should have. second, i probably didn't wait long enough for it to cure before doing a topcoat.
i really do like the sayerlack, and as i said, over raw wood, it sprays like a dream. so, i don't know if i blame the sayerlack on this one, i think i blame myself. next time i will be smarter about the use of (heavy) shellac, knowing that there may be a PH reaction, or just use a different type of sealer to avoid the issue altogether.
in general, the sayerlack sprays like a dream, sands beautifully, and levels out nicely.
i have a sample of Renner and ICA coming to try those, but so far, i would say i like sayerlack more than kem-aqua plus....
thanks again for the help with this one.
Not to make this go on any longer. But I think the ph thing is bs. Once any film finish has cured ph is not relevant.
The problem is you put down a film layer of a shellac sealer. It may or may not have dryed enough(the alcohol has to fully evaporate and the shellac would have to fully harden). You sprayed a fast drying brittle waterborne over a green shellac coating. The shellac eventually cured and caused the wb topcoat to fail.
We spray a ton of sayerlack hydroplus (in the 200-300 gallon a week range. We use it as a self sealing system and have zero issues.
kevin - are you typically spraying over raw wood? stained? if stained, what is your go-to stain?
We use this both over natural wood or over stain. We primarily use spray on dye stain. (Sherwin Williams S61 dye concentrates)
kevin thanks - very helpful and what you're describing meets my expectations. i think i simply used too much sealcoat. i'm running some tests to prove my theory.
In my experience seal coat sucks as a sealer under high performance WB coatings. There I said it... This has just been my personal experience based on what has happened in my shop, in my tests and in the field. I either self seal or use the recommended sealer by the manufacturer. The sealcoat will always be your weak link in regards to water damage, alcohol resistance and repair-ability. Same thing with the BIN white primer version. Yes you will have to sand a little more, but your system will be more cohesive this way.
Jonathan, how do you avoid the grain raising problem? I've never found a WB sealer or clearcoat with as little grain raising as Sealcoat. On some woods the grain raising is just awful. I have mitigated that somewhat by sanding to 325 grit before finishing, but that starts to bring up concerns of a good bond. What's your process?
There’s no true way around the grain raise. I did mention in my previous response that more sanding is required. The best workaround I have found is to pre-wet the wood and let it dry before your final sanding stage, but this is an added step, and it only gets you 75% of the way there. I prefer to do two coats of primer. Sanding after each coat. This has been the most consistent for me. I would be willing to bet that the sayerlack ether self sealing or has a good sealer
Sorry substitute the word primer for sanding sealer if you are using clear
mlc Aqualente does a decent job of self sealing. Its been our primary clear coat for many years. The grain raise is a non issue. We use it like a solvent coating.
I use the sealcoat when I want to pop the grain. I haven't seen a waterborne other than Targets get that oil/solvent look. I think shellac does it as good or better than any coating. Not necessary on every wood or project.
Shellac used to be used as a glue on wooden boats. BIN is rated as a spot exterior primer. I primed some cedar flower boxes inside and out. They were on my own house for about 5 years full of flowers. dirt and water. My wife was supposed to topcoat, but never got around to it(how surprising). Zero peeling inside or out. BIN is an excellent product. I honestly do not know of another product that would have performed in those extreme conditions. I did it when I had no time and little kids. Interesting accidental experiment.
Al.. Yes we do. We use it on all jobs (except where high gloss or exterior application is required)
Sherwin williams Gen II universal primer is a great surfacer that we use under it.
Adam its true that the BIN by itself has quite a grip, and is moderately durable. Im surprised, though it didn't peel and let go, that you didn't find any cracking due to its lack of elasticity. Also I have found the topcoat is what will depart from it in certain long term use situations. In my testing WB topcoats cling better to themselves or their complimenting primer/sealer.
Johnathan, I just got done caulking a batch of doors/drawer fronts over a primer of gray Bin shellac. After they dry, tomorrow morning I'll sand with 320 the area on the panels where the damp cloth has raised the grain during caulking. I'll then prime again the fronts with Bin sand with 320 again and then put 2 coats of GF undercoat and then 2 topcoats with GF tinted white poly. The mdf panels come out as flat as if I was using solvent and I've had no adhesion issues since going to Bin shellac almost two years ago. It's a little more work up front but I'm not sanding those pesky bits of mdf raised grain until the final coat.
Bart thats 6 coats, and three material changes in your spray rig... and dissimilar solvents. im not saying BIN doesn't do its job, its that ive found that i have to do what you are doing with it in order to have good long term adhesion(two types of primer). if you try to use the GF poly directly over the bin, it has its weaknesses in certain situations. I dont use the GF undercoat at all it doesnt block stain and it doesnt flow as well, or dry as fast as Chemcraft or MLC Agualente primer. I honestly havent found the perfect primer. right now im currently having my best success with Chemcraft Aquaprime, though i have recently had a couple of bad pails. I will be switching again in a couple of weeks to Milesi as my one of my distributors is finally able to bring it in. We'll see how it goes
I was amazed by my flower boxes. The difference between BIN and any other product including things like Clawlock is the sealing effect. The alcohol dilutes the shellac so much that it soaks into the wood. Obviously there is pigment but its different than other paints/primers.
I love the Agualente primer. I found out by losing some money that it is not compatible with some other waterborne paints. This is about 10 years ago. I built and primed a huge set bookcases. The painter tried to field paint them with Muralo Ultra or wb Impervo. Thankfully he started with some of the shelves. The paint orange peeled like crazy. I've used the Agualente primer with oil based Impervo. It works fine.
One of the few things we use BIN for is sealing mdf. Raised panels are a pain. BIN seals raw mdf perfectly. Other than MLC Clawlock I haven't found anything else that works as well.
Yeah 6 coats is a bummer. It's actually more like 5 1/2 but still it is what it is. With 5 coats over the caulking it disappears and they come out fantastic. No more mdf bits telegraphing at all. I had been doing 5 coats for years anyway with straight GF products but the mdf which is not always the best from Decorative Doors would always telegraph to some extent through to the last coat. So here I am doing more work for the same price. Doh