Hi all,
Well, I’ve done it now. Attempting to get increased build-up of lacquer after an initial rub-out (high gloss is what I’m after) which showed some deeper brush marks than I first thought, I applied some Deft Brushing Lacquer last night here in Augusta, Georgia. It wasn’t overly hot or humid, but I guess I’m just getting used to it after a few months since I moved here. I put on two coats with about 45 minutes to an hour of dry time between coats. I pulled the project (a small box) inside after about another 45 minutes of drying outside and noticed that some areas of the finish appeared clouded and dulled white. It wasn’t the normal shine that I see with the Deft Gloss.
Am I buggered? I’m thinking that water vapor is the culprit (and I’m REALLY kicking myself because Jeff Jewitt told me he’d be wary of applying it in hot/humid weeather although he mentioned longer dry times, not clouded finish, either way, I should have been more patient!). I looked at it again this morning and clouded areas are still there. I’m hoping that time might solve the problem, or even another coat (since they melt together), or maybe a wipe with some lacuer thinner. Any solutions? Thanks all for the input!
Erich
Replies
DAMN! I'd go inside in the Air-Conditionin.. And have a few drinks!
sorry, no easy fix. you'll have to remove the finish to remove the cloudy appearance.
if it remains humid in your area, i'd suggest spraying standard lacquer, not brushing.
Erich,
Sounds like you were finishing outside, in the evening? Dropping temps, approaching dewpoint was likely the culprit, putting moisture onto the surface of your fresh finish.
Have you tried to steel wool the blushing out? If it's purely on the surface you might get lucky.
A local outlet for Gemini Coatings, also known as Wood Finisher's Supply, sells an aerosol product called "Blush Eliminator". Sounds like that's what you need. Your local coating supplier will likely have something similar.
If you can't find a proprietary product, you might try wetting the affected areas with Butyl Cellosolve (Retarder thinner). That might let the trapped moisture out. Worst case, you'll have to strip.
Regards,
Ray
Ray,
Thanks everybody for the responses so far. Ray, I think you are spot on. I think that as the temps were starting to drop and we approached the dewpoint the vapor was introduced. Here's a solution that I didn't think of until just now when you mentioned the steel wool. I'll be rubbing out this project anyway. It had about 9 coats on it which I rubbed down, so call it maybe 5 coats, then I added two, then two more and the vapor was trapped with the last coat. If I rub again, maybe back to the thickness of 5 coats would the water blush go away? Or does in penetrate in deeper than the coat it contaminated (especially as lacquer melt previous layers)? Any thoughts? This is a much more attractive option for me as it's work I was going to do anyway. Any thoughts everyone? Thanks again for the help!
Erich
Or does in penetrate in deeper than the coat it contaminated (especially as lacquer melt previous layers)?
No, I think your initial thought is the correct one. Lacquer blush tends to be on or very close to the surface of the layer in which it occurred. Which is why spray on solutions work well. If it was deeper or even bit into layers underneath it then spraying on a retarder would be a considerably dicier solution as it would risk the entire finish sagging down.I'm sure that rubbing down a layer or two would remove all traces of the blush.
Edited 8/10/2005 6:03 pm ET by Kevin
Erich,
I'd try rubbing out, what have you got to lose? If that doesn't do the trick, then get some blush eliminator, or the solvents suggested above.
Good luck,
Ray
Yes, it sounds like trapped moisture. Or, more precisely, components of the lacquer were pulled out of solution by the presence of moisture... according to technical explanations I've read. What happened was that your lacquer flashed off (skinned over) before all of the moisture could get out, causing it to "blush" because it upsets the chemistry of the lacquer. I would disagree with Jeff slightly in that the humidity is the chief culprit rather than the high temperature. The heat really just aggrevates the humidity issue by causing the lacquer to flash off faster. But, the humidity is the culprit, not the heat. Spraying in really cold temperatures is also known to cause blushing because of the much lower dew point.
It is easily fixed. But, I have never tried it using any other medium than spraying. And I don't know how readily available the proper solvents would be for you.
What you'll need is some Methyl Ethyl Ketone (MEK). Acetone should work in a pinch since it is a Ketone too. And you'll need a lacquer retarder like PM Acetate or Glycol Ether. Mix it 50/50. When I spray this mixture I usually use a mist coat. You don't want to flood the surface to the point that the solvent will run or pool up too much. In your case... padding it on might work.
Essentially what happens is that the MEK redissolves the surface of the lacquer and the retarding solvent keeps it open (wet) long enough for the lacquer to go back into proper solution. MEK (and Acetone) dry much, much too quickly and used alone would more than likely result in even more blushing. So, that's why a "retarder" (a very slow evaporating solvent) is necessary. The presence of the retarding solvent physically prevents the lacquer from drying quickly on the surface.
The brushing lacquers differ from sprayable lacquers primarily in that they are packaged with retarding solvents in them. But, a happy medium is really what their chemists shoot for. And the high humidity in the South is a known issue even with brushing lacquers.
An alternate solution would be to try to find a source for Mohawk brand aerosol touch up cans. What you want is their "No Blush" aerosol. It contains the same basic solvents that I described above and being an aerosol you don't need spray equipment to apply it.
H. Behlen (a sister company to Mohawk) has a comparable aerosol product called "Blush Eraser". This one might be easier to find since Mohawk exists mostly to service commercial clients whereas H. Behlen exists to service the hobbyist.
You also might try to lessen the blush first with a heat lamp. Don't let the project get hot. It's not a cure-all, but it'll be an easier fix when you use the retarder. When I get blushing, a flash coat of retarder several hours later generally takes care of the problem. Good luck.Craig
Go to a regular paint store and get some lacquer retarder and spray it directly on the surface. Don't need a heavy amount.
Next time it's humid, mix in about 20% lacquer retarder.
Lacquer drys so quick that moisture can get caught under the surface film. Having a fan blowing over your work helps too.
PlaneWood by Mike_in_Katy (maker of fine sawdust!)
PlaneWood
I agree with Plane Wood. I always mix about 15 or 20% retarder when I thin My Lacquer and use regular lacquer thinner for the remaining 30%. Havent had a problem since.
Have a nice day Lee
Excellent advice, Mike.
I would just caution readers to be sure to know what type of lacquer retarder they are using and what the recommended usage ratio is, however.
Some retarders like Butyl Cellosolve (aka: Ethylene Glycol Monobutyl Ether, 2-Butoxyethanol, etc.) are extremely slow and aren't recommended at more than 1-2% in lacquer. Similarly, Texanol Ester Alcohol isn't recommended at levels higher than 1-2% for the same reason. But, Glycol Ether PM (my favorite retarder) is a medium speed retarder and is recommended at up to 10% by volume, although I've used it at higher ratios without problems.
Of course those reduction ratios are all predicated on average conditions. So, they aren't written in stone or anything. But, caution is in order when exceeding the recommended ratios.
I guess the relevant point being that adding say... 10% of Butyl Cellosolve will yield pretty dramatically different results than adding 10% of Glycol Ether PM.
There are a slew of other solvents in the Glycol Ether and Glycol Ether Acetate families which can effectively be used as lacquer retarders. There are even some Ketones which can be used to retard the drying time of lacquers and polyurethanes, although they aren't typically used that way in lacquers.
Out of everything I've ever used to retard lacquer, my hands-down favorite is a mixture of MEK and PM Acetate. In fact I don't use lacquer thinners at all and haven't for a very long time. I use this mixture and simply adjust the ratio of MEK to PM Acetate to meet the conditions. It easily outperforms lacquer thinner blends, IMHO.
I use Deft brand lacquer all the time and even here near Houston rarely use thinner or retarder. Even when it's pouring down rain outside. But, there have been a few occasions when the lacquer turned milky after spraying. When that happens, I spray a little pure retarder on the object (mostly plane handles & knobs) and the cloudiness disappears. I then mix in a little retarder for the rest of the day.
Even though it says "brushing lacquer", I don't recall ever brushing it on. I use a mini paint gun and compressor. The air line has a moisture separator on it.
I did build a king size head board once and when spraying the lacquer had it blush on me (very hot and humid day). Spraying the pure retarder on made the blush disappear almost instantly. Used a full size gun for that.
By the way, Asphaltum paint makes a very luxurious reddish black stain for native cherry. I was able to duplicate an Ethan Allen stain using it. wipe on, wipe off!
PlaneWood by Mike_in_Katy (maker of fine sawdust!)PlaneWood
Where do you get your asphaltum?
Sherwin Williams used to sell it. But, I've been told that it's long since obsolete and don't know of any other source here in Oregon.
Your staining with asphaltum idea sounds very intriguing to me. What first led me to look into a local source, though, was a woodworker friend who collects antique hand tools and wanted to get some asphaltum so that he could repaint some wood chisel handles using an authentic material. According to him that was what had originally been used by the manufactorer.
Kevin - That was about 6 years ago when I did the headboard. At that time I had bought a quart from some place up in NY. They were on the Internet at that time. I don't know if they are still around or not. Do a Google on "Pontypool Asphaltum".
Anyway, I did not like their Asphaltum for application to old tools so I started making my own. What I had left was used on the headboard. Basically you just boil Asphaltum powder with Linseed Oil and add in some dryers. It has to boil several hours until it gets to the 'soft ball' stage when dripped onto a piece of cold glass. Do it outside with an electric hotplate cause it stinks to all hell.
PlaneWood by Mike_in_Katy (maker of fine sawdust!)PlaneWood
Hey everybody,
Thanks again for all the help! I still haven't had a few spare moments to work on this so I don't have any results to give you, but I will when I figure it out. Paul over at Homestead suggested that with Deft I should be able to just give it another coat and that would remove the blush. I may try that, or I may just get to the rub out. Either way, as some of you have pointed out - what do I have to lose! Thanks again for helping me learn and become a better finisher all of you!
Erich
Your problem likely starts with evening dewpoint as the temp drops in humid conditions. The solution is lacquer thinner to remove the Deft, lightly sand just to resmooth the piece and recoat. Dewpoint variations are common in humidity and lacquers are the most prone to "blushing" that you are seeing. Lacquer thinner in the Deft absorbs moisture under certain conditions and traps it in the coating. Small amounts of Retarder (butylcellusolve) will mostly eliminate the provblem by slowing down the evaporation rate of the Deft but it is usually better to avoid finishing during cool damp times. You can work in warmer spaces (indoors) or in an air conditioned space or in daylight under a warm sun. aloha, mike
An old timer told me to only spray lacquer when you can see blue sky (which implies good dew point and humidity). That rule works pretty well - I don't brush lacquer, but I assume it is similar.
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Charlie Plesums Austin, Texas
http://www.plesums.com/wood
I have had the same problem with spray lacquer here in North Louisiana. I am trying to finish a project I would like to use lacquer on. We are moving to the Baltimore, MD, area and I will have to wait. I will see if conditions are better there. You might consider moving to Arizona....
I assumed that the problem was that the evaporating solvent lowered the temperature slightly and if the ambient temp. is already close to the dew point and the relative humidity is high, it would cause water vapor to condense in the lacquer and cause the cloudiness. Notice, I wrote that I "assumed." Is it as simple as that? I have tried putting small pieces in a microwave. That didn't work. Sometimes just wiping the surface with a rag damp with lacquer thinner works. Sometimes it doesn't.
Very frustrating. Good luck.
Hi Everybody
I just wanted to post back with the end of the story on this since maybe some other people have been learning from my mistake. I eventually wound up putting another coat of the Deft Brushing Lacquer on the affected area of my project and that took care of the white blushing. Paul over at Homestead Finishing suggested this idea, his reason was that Deft already has some retarder in its formulation. He said if another application didn't fix it he would have tried the spray on retarder that some of you suggested. Well, another lesson learned for me. Isn't woodworking and finishing great for the mind? I guess not if you breath in too many lacquer fumes. Have a good one all and thanks for all your input!
Erich
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