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KemVar Plus CV not hardening8/16
So this is my first job shooting SW KemVar Plus CV.
I shoot ML Campbell Clawlock II and Stealth, but this was a job for another guy and he supplied the finish for this job.
Primed with KemVar Surfacer- Good stuff, no issues. Impressed with the build. Okay Cool.
So I wasn't expecting to have any sort of issue with the color coats... except wtf. I have a finish that refuses to harden off like I am used to with stealth.
First thought... was it the right catalyst and what was the mix.
Codes match to the SDS- I have the right catalyst.
SDS states 6.2% per Part.
I mixed 8oz of catalyst on 128oz of finish (1 gal) and reduced using the R7K 310 reducer to 50% to get it to flow through my airless.
All matches to the SDS and what the "techs" at SW said when I called about this issue.
I do not have a make up air booth. It is an enclosed/filtered spray room and I am at the mercy or wrath of the humidity and temperature outside.
Yesterday Humidity was in the mid 80s, temps in the high 80s.
I shot some sample drop cuts that were primed 2 coats. So there is only a base color coat on the piece.
at 24 hours If I run a thumb nail lightly over it, I can put scratches in it as if this stuff was some benjamin moore advanced.
Wondering if anyone has any similar experiences with this product. Is it typical for this finish to take multiple days to dry between coats? Or just has a slower dry time overall?
Its finally at the point where I can handle it without feeling too much of that soft finish feel where if you push too hard it will print. So I'm sure I can scuff this and drop a final coat on it. But I'm just surprised it doesn't have the rock hard feel I am used to.
by 8 hours with Stealth, I should be able to handle the parts with no scratching or leaving prints, scuff, and spray the final coat.
Honestly, I've pushed it harder than that and light scuffed at 4 hours for the final coat. 12 hours later we were stacking and loading without issues.
Different product, I know. Just wanted to see what the guys using this for years thought might be going on. Is this finish that sensitive about the humidity? Is something off with the Catalyzing and reducing process?
What product number for the coating and the catalyst and I will look into it for you...... I shoot hundreds of gallons a month of Kemvar.. Any cure problem we have had has been 100% user error.... Give me the numbers and I'll give my thoughts
I also use the SW kemvar plus.. your catalyst ratio for the color coat is correct. If its a custom blend, the blend code should start with H66. Your reduction is correct as well. (I Think)
Some people mistake 50% reduction. They mix half reducer with half product (so half gallon catalyzed product, and half gallon reducer) when its supposed to be a full gallon of catalyzed product and UP TO a half gallon of reducer.
If your catalyzing it correctly, and reducing it correctly, something else is wrong. In my area i have a local tech that would be here in 20 mins to investigate the batch and have it replaced immediately. Not to say that i have had that issue -- as shane said, every problem we've encountered ends up 100% user. Been spraying this stuff for years and we use it alot so dont lose faith in the product just yet. its good stuff.
Just another thought about this, the 310 solvent is great at giving u that silky smooth feel, but it does slow down the dry time significantly in my experience. We only use that reducer for higher sheen projects -- and most of our work is in the dull rubbed range. We just use good lacquer thinner to reduce our kemvar plus. Works great.
Product is H66 W 53
It is a custom color batch using the correct pigment codes. Can't find the lid at the moment that had that printed out on the label. Came from a SW industrial finish supplier.
Catalyst is V66 V 21
Reducer is R7K 310
I mixed the gallons really well and boxed them all together to even the color out like usual... mixed the catalyst first, slowly into moving material (I didn't just dump it all on top and stir)... It sat for roughly 10 minutes while I was explaining some build procedures to a worker... I came back and reduced it to 50%... strained it and loaded it.
I did recently do a super thorough clean out of my system before doing this job using lacquer thinner... what I'm used to and I've never had problems.
From speaking to the guys at SW they were saying there is no thinner formulated to work with this product other than the R7K 310 and that adding anything else could slow down the dry or cause failure.
I'm almost wondering now if tiny residual amounts of wash thinner is screwing this up?
Do you guys wash your equipment with the same R7K 310? Stuff is expensive to be cleaning equipment with it if that is the case.
I pump all of the wash thinner out before loading the hopper. As the finish picks up into the lines I spray out the thinner in the lines and 5 seconds worth of the actual finish before I cycle the finish back into the hopper to mix it up. That way I'm not introducing thinner to the actual material.
Then I go about spraying.
My sample is at 48 hours now and I'm still able to run my nail across it with nearly no pressure and leave a scratch.
The contractor had brought me a partial gallon of catalyst and supplied me with a new, unopened gallon. I made sure to start with the new catalyst just to be safe.
do this.... do you have any of the uncatalyzed finish left? catalyze that and do a test sprayout...You sure your catalyst is v66v21 and not the v66v26 for the sealer? and is the catalyst clear or pee yellow... if it's starting to turn it oxidizes really bad and yellows out... you math is correct if you indeed mixed it right... do another spray out with another batch with a cup gun and post results.
Just re reading through your guys' responses...
The mix was absolutely 128oz (1gal), catalyzed first, then reduced 50% for flow.
When I first read about 50% I thought, theres no way in hell. But when I was pouring out the finish and seeing the viscosity I understood. The stuff is like taffy.
To kevin... Not that is damn interesting to hear.
This is the low luster 15 sheen.
You know... I asked these guys if it was acceptable to cut the mix with a good quality lacquer thinner.
I asked if they had a good quality thinner specifically SW brand that I might be able to use.
The butyl acetate I figured would prolong the dry time.
I was thinking of cutting the R7K310 to maybe 30% and thinning the other 20% with quality lacquer thinner... Testing of course required
I asked the tech line guys and they told me no no no... can't do it. Nothing other than the R7K 310 is acceptable.
I mean, shit... with the ML campbell Stealth and Resistance I reduce it using half flow enhancer and half care lacquer thinner. Never had a single issue with it in 9 years of spraying it.
Sure do, have 7 gallons left for this job.
Both gallons of cat show V 66 V 21.
Both are clear, but I made sure to open and use the new gallon that hadn't been opened yet.
Will mix some up later today and run another sample.
I sprayed out the original mix and shot some scrap filler material to see how it would harden if left alone.
Curious thing... On maple plywood it seems to be drying better (still not what I expect from a CV) than the sample I shot over some oak. Both primed the same way with 2 coats from the same batch. Both sitting at more than 48 hours to this point.
I once poured off a gallon of black kem-var plus out of a 5 to have a custom tint match made at my local SW paint store. when I got it back I poured off 12.5 ounces catalyzed & thinned it to make samples for a upcoming job. i had already applied 2 coats of black from the can on my sample boards so 1 coat of the custom tint was all I needed to complete the sample boards. As it was the end of the day I just left the boards on the rack in the booth, cleaned the gun and left. When checking the boards in the morning they were as tacky as if I had sprayed them no more than 15 minutes earlier. Since my first 2 coats dried fine I knew the material, catalyst and my ratios were good so I called the paint store and sure enough they mistakenly used the BAC colorants to make my match instead of 844's. Odds are this is not your problem but it's worth checking.
We spray this stuff daily, and we have for the past 5 years. You shouldn't be having this problem.
Now, 80% humidity WILL slow it down some, we see that sort of humidity frequently, but it basically moves it from a 45 minute cure to maybe 2 hours tops, as long as temps are over 70 degrees.
Do be sure that you aren't piling it on too high. I can attest that this stuff does NOT like being piled on thick, or you get the same effect you're talking about-- soft finish, long cure time.
If you guys have been spraying Stealth (like we used to), you may have my old habit-- spray it thick as hell, because that's how Stealth seemed to behave the best.
NOT the case with KemVar+. It is very well behaved (I always fought Stealth, daily, eventually gave up on it). But spraying the KV+ too heavy will cause really long cures.
There have been numerous reports that "umber colorants" will impede dry and cure of post-catalyzed finishes. Read your PDS's carefully, there's probably a disclaimer, and check your formula. If they used BAC, that'll for sure screw up the dry/cure.
Thanks for all the info and replies.
I switched off this job as there was a delay and picked up work again on a different one.
Anyway, I'm about to get back to this. I'll post up pictures of some new batch base coat samples.
From everything I have seen and triple checked, I have not screwed up on my cat/reduction procedure.
I have been checking on the samples I had sprayed. They have finally hardened up to where I would have expected a CV to be in 8 hours, but I am are talking 4 days!! Which is... completely unacceptable.
I just shot sayerlack for a WB job that reached a safe handling hardness at 3 1/2 hours.
Still scratching my head over this one.
But if that's the way this job is going to go, then so be it. I'm just going to have to get the stuff sprayed with as much time before deliveries as possible. luckily for the schedule delay from the buildings approval committee.
I did check the mixing formula on the can lids the top coat came in. It's showing the 844 colorant.
Honestly I expected the humidity to slow it down somewhat, but I was thinking it would only be for maybe 4 hours tops.
Low humidty today, so I'm curious to see the results.
The finish on this kitchen is paint over scratched white oak (Gag). So I'm spraying it thin to keep the pours visible (they're solid white- no black, but the grain is still visible). So the coats can't be too heavy or they'll fill in too much.
I'll see in the next base coat I'm about to spray if that helps in hardening quicker.
I am used to spraying the Stealth a little heavier for that nice wet look across the entire surface. It definitely seems to perform better when sprayed like that.
I know what you mean on that.
Personally... I think this is probably a better product than the Campbell. But it's always dependable and I just don't have issues with it. I know exactly how hard I can push when things hit the fan to get a job out the door.
But if the KemVar is going to give me issues with production speed, I can't afford to use it. Maybe that's just learning curve and I'll get it dialed through this job. We'll see.
I want to test it and see how cutting the reducer mix with quality thinner changes the finish.
I was always under the impression that butyl acetate slows the dry down where thinner is flashing off fast. So maybe a 1/1 cut with R7K310 and thinner up to 50%.
The SW guys were telling me I'm going to screw it up and all that... Not sure if that's just to keep me buying only their products or if it really will ruin it.
I'll find out through sample testing rather than take their word on it. Unless any of you long time users have played around with it and found the SW guys to be right about that.
I've used standard thinner in Kemvar+ before, the only thing it will hurt is that it probably will cause solvent pop in the summer.
If you are using the KemVar Reducer, and you've doublechecked your catalyst, then you're doing those right.
You probably need to get your SW rep to come look.
I can assure you that KemVar+ is quite capable to NORMALLY cure to a touchable, sandable dry in under an hour, and be ready to stack confidently in 8 hours (but preferably overnight cure) if temps are over 70 degrees.
Something is absolutely not going right. Either you got a bum batch of paint, a bum batch of catalyst, or a bum batch of thinner.
I suck with actually taking photos. Probably more out of laziness about uploading than anything.
Anyway, I think I have this working correctly now.
I made up 2 new batches of paint at this point. Catalyzed correctly and reduced to 50% using straight R7K 310.
I made sure to spray the coats thin as was recommended.
Sure enough, the finished hardened up beautifully how I would have expected.
I left them over night and started scuffing again at about 18 hours of dry. No problems, dusting up nice. Nothing like the first round of parts.
Top coated thin again and they were dry to the touch by the time I completed the rack and checked the first door. (about 30 minutes)
I'm hoping this is all it is. I still have some paint in the hopper so I'm going to shoot a heavier coat like I normally would with ML Stealth and shoot a thinner coat like I did today. I'll put the clock on them and see how they differ.