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High humidity.

4K views 23 replies 4 participants last post by  Steve Neul 
#1 ·
Am using retarded thinner k27 in with the nexus precat lacquer by Gemini. What ration should I cut with. Humidity is 92% doors coming out cloudy. Been just guessing but I think I'm using too much of the k27 doors are way soft

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#2 ·
At 92% forget it, retarder won't save you. Retarder thinner is only good from about 68% to 75% humidity. You'll either have to wait until dry weather or get a dehumidifier. One note though, don't run the dehumidifier while you are working lacquer, the fumes will cause an explosion. Just get the humidity down and work without ventilation until the humidity goes up to where you have to stop.
 
#8 ·
I have never used retarder thinner I have always added retarder to my lacquer as recommended. Even at that, 85% Humidity is my very max I would do. When you approach 85%, make a few sample sprays and check out the results. if the piece blushes, you will have to strip and re-do There is no cure for blush. It's all in the prevention.
BTW, what are you making and what type of finish are you using?
 
#9 ·
I have never used retarder thinner I have always added retarder to my lacquer as recommended. Even at that, 85% Humidity is my very max I would do. When you approach 85%, make a few sample sprays and check out the results. if the piece blushes, you will have to strip and re-do There is no cure for blush. It's all in the prevention.

BTW, what are you making and what type of finish are you using?
Face frame and doors and some trim. Finish is all Gemini. Sealer and lacquer satin

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#10 ·
Great, I only used lacquer. But unfortunately you will have to wait for humidity to go down. my last shop was just south of Houston, Tx and humidity was always a problem. Not so much in winter because I could always heat the shop to drop the humidity.
Gemini is a good product but it has its limitation like other lacquers. If you already sprayed and have blush, your only solution is to strip it. If pre-cat lacquer finish is fairly fresh, like a day old or so, it should strip relatively easily with lacquer thinner. If you used nitrocellulous lacquer it will very easily strip off with lacquer thinner.
 
#11 ·
Great, I only used lacquer. But unfortunately you will have to wait for humidity to go down. my last shop was just south of Houston, Tx and humidity was always a problem. Not so much in winter because I could always heat the shop to drop the humidity.

Gemini is a good product but it has its limitation like other lacquers. If you already sprayed and have blush, your only solution is to strip it. If pre-cat lacquer finish is fairly fresh, like a day old or so, it should strip relatively easily with lacquer thinner. If you used nitrocellulous lacquer it will very easily strip off with lacquer thinner.
I did add 2 oz. Of the retarded thinner to the lacquer and a dabble of thinner to that to help eat into old spray yesterday. Turned out good surprisingly. Not best pic and that's dust. We dont have a designated spray area.


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#12 ·
A side note on satin finish

When I first started woodworking for a living, I took several finishing classes. One from Star Chemical Company and the other from Mohawk - the manufacturers of the chemicals. and here is what I learned..............
If you want a satin finish, make your first 2 coats using a high gloss finish and use the satin finish as your final coat.
That way, when you look at the finished piece you will be looking at the top coat that contains the stearates or whetever they use now-a-days to knock of the gloss and then you will be looking at a clear shot to the grain. If you build all of your coats with satin you will get more of a lifeless dead look. The stearates are there to difuse the light.

I always bought just High Gloss and then bought a jar of 'flattener'. The instructions on the flattener will tell you how much to mix to a gallon of lacquer to get the desired effect - anywhere from a semi-gloss on down to a dead flat finish. All this is only on the top coat.

Also note that a dead flat finish looks and feels like an oil finish while giving you the protection of a pre-cat lacquer.
 
#15 ·
I was hoping you would be using an HVLP rig. Its a little different than conventional sprayers in that it may take some getting used to.
It should take no more than a few hours practice before you figure out what best in the way of thinning.
I had an Earlex HVLP sprayer. It was around $350, not the best around but more than good enough for the job. I'm glad I bought the optional tip to allow for a thicker spray so I didnt have to thin too much.
The finish was excellent and the efficiency was excellent. Not only do you have much much less waste as far as $$ are concerned but you can work in relatively small areas without fogging up the place. Dont know how much lacquer spraying you have under your belt, but for the benefit of others on here, lacquer over-spray turns to dust before it hits the floor. You can simply just blow the dust off your shoes.

BTW, what part of the country are you located in? Just wondering if high humidity is just a way of life like it is on the Texas, Louisiana and Mississippi coast.
 
#16 ·
I was hoping you would be using an HVLP rig. Its a little different than conventional sprayers in that it may take some getting used to.

It should take no more than a few hours practice before you figure out what best in the way of thinning.

I had an Earlex HVLP sprayer. It was around $350, not the best around but more than good enough for the job. I'm glad I bought the optional tip to allow for a thicker spray so I didnt have to thin too much.

The finish was excellent and the efficiency was excellent. Not only do you have much much less waste as far as $$ are concerned but you can work in relatively small areas without fogging up the place. Dont know how much lacquer spraying you have under your belt, but for the benefit of others on here, lacquer over-spray turns to dust before it hits the floor. You can simply just blow the dust off your shoes.



BTW, what part of the country are you located in? Just wondering if high humidity is just a way of life like it is on the Texas, Louisiana and Mississippi coast.
This gun and touch up was 120 I think. I am using the 1.8 tip. Someone bent the 1.3 and I'm in Cherokee county ga

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#17 ·
The flattening agent is a fine gypsum material similar to baby powder. If a person had to they could put baby powder in lacquer to flatten the sheen. I'm sure there is other ingredients in the flattening agent and in the baby powder which wouldn't make it an ideal substitute but it will work.

I started off my business with binks and sharp sprayers and I kept having employees breaking them. The solution for me was to just buy cheap guns and throw them away when there was a problem. Then along came harbor freight so I tried their guns and was stunned how close they came to performing like the expensive guns so that is all I use. Now I have had some issues with metallic automotive base coats with the hf guns but wood finishes work just fine.

One other note on using retarder thinners. They slow the drying time down and they also slow the curing time down as well. If you use a lot of retarder thinner in a finish handle that item more gently for a couple of months to give it time to harden. Otherwise you will find the finish scratches a lot easier.
 
#19 ·
............
One other note on using retarder thinners. They slow the drying time down and they also slow the curing time down as well. If you use a lot of retarder thinner in a finish handle that item more gently for a couple of months to give it time to harden. Otherwise you will find the finish scratches a lot easier.
Exactly. Just plain retarder added to the lacquer in the proper amount only delays the set-up/drying process by very little maybe a few minutes longer, at least from my experience.
Usually when I first open the can of lacquer, i automatically add the retarder and fish-eye remover. That way, when I'm ready to spray, I just add thinner.
 
#18 ·
Thanks everyone. I started learning maybe 10 years ago and haven't done tons of spraying. The ones I learned from never had any formal training. I did take a short class through highland woodworking. Forget guy who taught it he insisted on staining after sealing. Never tried it but want to. I do take you guys advice and when I do things for myself on side I apply them.

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#20 ·
........... I did take a short class through highland woodworking. .......guy who taught it insisted on staining after sealing. ............
That's odd. I would think that the stain wouldnt stick to the sealer. In affect, a sealer is a finish coat of sorts. Is it possible that he meant using a paste wood grain filler after the sealer?

If you apply a sealer coat, then lightly sand, the stain will only be absorbed on the surface. In the pores, it would be sitting on the sealer because it wasn't sanded off. Maybe he assumed that the residual stain in the pores would be completely absorbed by the first coat of lacquer. That would result in poor adhesion and the pores likely would be lighter in color that the surface. Normally, this is not the desired affect. In most cases, your eye/brain likes the the darker pores better.
Maybe the Highland guy never took a finishing products manufacturing course.
 
#23 ·
I know what you are saying but I never had a problem with it. Most of my shops were fairly large and high. Much more volume than the normal refinishing shops. Also, being a neat freak, I swept at least twice a day and blew down every evening so I never really had much of an accumulation of overspray.

I never really got into the chemistry of it all but I have heard this rumor for years about fish eye eliminator and silicone, but it never made sense to me.
If silicone causes fish eye, and fisheye eliminator contains silicone then how could any lacquer dust containing fish eye eliminator be bad? There are all forms of silicone and chemistry was not my favorite subject in school

Anyway, it was something i just always did was to add fish-eye eliminator and retarder to every can of lacquer I opened. I never knew whether the lacquer was going to be used up on new or refinished furniture.
 
#24 ·
Most people that do finishing look at silicone as the devil and to put it on a piece of furniture that is clean they won't do it. By adding silicone to all of the finish you use certainly won't cause you any problems but the next person that refinishes the piece may have H with it. Silicone doesn't just stay on the finish it penetrates through the finish an gets into the wood. I've had furniture in my shop that had such a high concentration of silicone in it that it was almost un-refinishable. I would have to put 6 or 8 coats of sealer on it very dry with less an less silicone in it before it could be finished.
 
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