Lacquer & Fisheye

[TV]

I am utilizing lacquer (spraying) as the finish on a chest. One of the panels has these small sunken areas ranging from 1/32 to 1/8 in diameter. I was told this is what is called fisheye. I don't have a pic and am not sure I could get one to come out.

I have really no idea what to do with this. I first thought I would sand it down but was told if it was a contamination problem that might cause more issues. Any direction (besides throwing the panel away) would be appreciated. Thanks


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p.s. This finishing thing can really take some time. I was hoping to spread out how much I learned about finishing over several projects. :-D

Edit: I may have found my answer in a previous thread. Can one use shellac over lacquer to seal and then spray lacquer over that?

 

[NCPete]

I think you can use the shellac method to prevent re-occurrance of what you have... having done body work a long time ago, I would probably go back over the piece with some Prep-Sol (dupont) to remove the offending stuff, followed by shellac.

 

[Tarhead]

Make sure you are using clean, filtered air for your spray gun. Oil contaminated air can cause this...even on top of shellac. If you're using waterborne lacquer some of the stearated sandpapers can cause problems too.

 

[Travis Porter]

I thought fish eyes were caused by contamination with silicon? Any chance you used something to sand, prep, or whatever that had silicon in it?

Shellac is supposed to be the universal sealer. It bonds to almost all finishes.

 

[TV]

An friend told me that silicon would cause the problem and told me to throw all my rags away. There is a possibility that I picked up a rag that had some silicon bike lubricant on it. I thought I was being careful but obviously not. I have thrown out all the rags and will be doing some extra cleaning this evening to make sure this doesn't happen again on this project.

Thanks for the information.

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[jeff...]

silicon contamination is the most common reason for fish-eye defect in a Lacquer finish. Clean everything (gun, air hose and project with DNA first) DNA evaporates quickly and does not leave a residue like a non-denatured alcohol would. Also make sure you got a good air filter and moisture separator on your gun.

Thanks

 

[mshel]

Go to NAPA and get some stuff called "Smoothie". Put 4 - 5 pumps in a quart pot of whatever your are spraying and stir well. This is a fisheye preventer and will work with lacquer or any other stuff. I used to have the same problem until I started using this stuff and since using it, I have had zero fisheye.

Just my .02

Mike

 

[TV]

mshel, so I put it in with my lacquer/thinner mix?

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[Gofor]

Fisheye in lacquer can be due to water or any oily contaminant, not just silicone. Fine oil and/or water in the air from the compressor is a common cause, especially if it is widespread over the entire piece.
If you are going to be spraying a lot, I recommend you get an oil/water separator, and also new air hoses that are only hooked up after the separator. Keep them separate from the ones you use for other air tools because the oil from the compressor will saturate the inside of the hose and come out when you try to paint.
Depending on how bad the fisheyes are, you have a couple choices. One is to sand it back down, and then use the Dupont Prep-sol (Prep-sol is used in the automotive world to remove the silicone car wax. Works well but stinks, too), or wipe good with thinner. You can also strip it down with just lacquer thinner and a rag. As you wipe on the thinner or prep-sol, wipe it off with a clean rag before it dries. This will remove the contaminants rather than spreading them around the surface.
Also check to make sure the parts to be sprayed are not getting contaminated from another source. If you are using any other air tools that blow the oil laden air out the exhaust port, or even a shop vac exhaust with something oily in it, that blows over the piece can cause contamination.
Lacquer is a great coating that dries quickly, but it is the most prone to fisheye from oily contamination. The fisheye eliminator is a proven additive, but if you put too much in, can really screw up your finish, Follow the directions from the manufacturer.

If you have only a couple small spots, try daubing it with you finger wrapped in a clean rag with a little thinner on it. Then smooth out the marks with a little thinner on a natural bristle paint brush. A light scuff sand after it dries and then apply your next coat.

With the weather getting quite chilly, you also want to make sure the shop is heated. Blushing (a milky look to the lacquer) is caused when moisture is trapped in the lacquer coat. The moisture comes from cooling the spray mix below the dew point, caused by the air expanding out of the spray gun and the thinner evaporating when atomized. In essence, you are trapping a cloud in your paint. This is worse as temps drop and humidity increases. The only repair is to sand off (remove) the milky coating. If you are forced to spray in lower temps, you need a slower drying thinner which will not evaporate as quickly when atomized, reducing the chance of dropping the sprayed mixture below the dew point.

Hope some of this helps

Go

 

[mshel]

mshel, so I put it in with my lacquer/thinner mix?

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Yes

Mike

 

[Tarhead]

I can't argue with Mike's use of Smoothie II type product. He will see silicone contamination on most/all of the pieces he refinishes. If this is a one-off situation you may not want to use it as it too contains a type of silicone (Siloxane) and will get in your spray equipment. This is what is in Rain-X. It also has some pretty nasty other stuff my Chemist daughter says to avoid if at all possible...she muttered something about 3 headed frogs and mushroom clouds:tongue6:

I would strip off what you have, wipe it down with DNA (or some other solvent for silicone contamination if ok for wood), sand and spray a light coat of dewaxed shellac to seal it off (with no sanding) and then build lacquer on top of that.

http://www.bondo-online.com/fileshare/product_msds/English/20242.pdf

http://en.wikipedia.org/wiki/Siloxane

 

[TV]

Thanks for the all the information. This is only on one panel but I have numerous spots. Looks like I will be stripping the panel down. I started cleaning up all my tools last night to make sure I am not re-contaminating anything.

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