Replies

1. 
   SgianDubh | Apr 14, 2005 01:31am | #1

   Fish eye (which often looks like a series of craters as seen in shots of the moon) is the result of contaminants on the surface that cause the the polish to crawl away from the impurity. The classic is silicone (oil) contamination which can get on to the wood in all sorts of ways, e.g., via some after market spray furniture polishes, spray lubricants used in the workshop, etc..

   If the contamination is bad enough you end up with crawling which can look like a series of ridges. It's a bit like putting a bit of soap liquid in the centre of a film of oil floating on water.

   Somehow you must have got some sort of contaminant between the last coat and the coat(s) underneath-- wax, grease, oil, perhaps even the dreaded silicone. It's even possible that the contaminant was on the bare wood prior to application of any of your lacquer and it didn't cause any problems in earlier coats because it can get blended in. This can happen believe it or not.

   Probably only you will be able to identify where the contamination occurred. You'll have to look carefully at all your operations and procedures, even the tools and rags you wiped down with, or perhaps you used some oily wire wool.

   There are several ways you can deal with contamination. One of the following or a combination of a couple work.

   You can wash out the oil/wax/grease/silicone contaminant with white spirits, lacquer thinner, etc..

   You can seal in the contaminant by either, 1, Spray on a couple of thinned coats of shellac or, 2, 'dust' spray four, five or more of very light coats of lacquer. 

   You can add silicone oil (sold as fish eye killer) to your lacquer thus reducing the surface tension of your polish to match that of the contaminated surface.

   I'm not very keen on this last one as it means your finishing equipment is also now contaminated which makes it tricky to clean thoroughly. Slainte.

   RJFurniture

1. 
   warrenspahr | Apr 14, 2005 02:01am | #2

   Can a tack cloth cause this?

1. 
   SgianDubh | Apr 14, 2005 02:59am | #4

   I suppose it's slightly possible Warren. I've never had fish eye problems caused by tack rags when I'm using oil based varnish, the nitro-cellulose or post-cat family of polishes or shellacs. But I don't use tack rags much anyway because if I wipe down between coats I'll often just use a cloth slightly dampened with white spirits or even water.

   If you're using water based lacquer you would be more likely to run into problems. These are very finicky regarding adhesion and you should avoid using stearated abrasive papers and also tack rags which, to be fair, I think all makers of water based polishing products warn against on the container or in their literature. Slainte.RJFurniture

2. 
   Woodhead | Apr 14, 2005 02:13am | #3

   Warren,

   Any chance of posting a picture of this? I do a lot of lacquer spraying and have had what I thought were most of the usual problems. But I've not seen this one.

   Thanks,

   Richard

3. 
   hammer1 | Apr 14, 2005 03:56am | #5

   I've had adhesion problems with tack cloths using waterborne poly and 2K urethane. I don't use them anymore. I haven't had success washing stripped furniture with anything, if there is open grain like oak, silicone contamination and using lacquer. Fish eye reducer worked. If it contaminated my equipment, I didn't notice it with subsequent spraying.

   Beat it to fit / Paint it to match

4. 
   goldhiller | Apr 14, 2005 04:33am | #6

   Warren,

    

       Are you sure this was "fisheye"?  Any chance it was just a bad case of orange peel from shooting outside in the sun and having the lacquer dry too fast? (Was there a little breeze to contribute to the fast drying, maybe?)

   If this sounds plausible, then overspraying with some MEK or lac thinner wouldlikely resolve the problem by remelting the lacquer. ...providing the lacquer in question is nitro.  If it's cat lacquer and you sprayed on last weekend, it may be too late now to remelt it. 

    

    

     

    

   Knowledge is power, but only if applied in a timely fashion.

   
   

   ---

   Edited 4/13/2005 9:49 pm ET by GOLDHILLER

1. 
   warrenspahr | Apr 14, 2005 05:12am | #7

   You have certainly described the weather conditions. There was  a wind blowing and I did have a wet coating of lacquer which could have set up conditions for orange peel. The condition appeared as almost like a small hill of lacquer that  appeared to be wet underneath it. As the afternoon progressed I was able to complete the spraying with a minimum of the defect appearing.

   If it were orange peel what is the preventative?

1. 
   goldhiller | Apr 14, 2005 06:28am | #8

   Lacquer can be tricky, period….but applying it in less than ideal conditions makes it trickier still. This is basically because the solvent has a fast evaporation rate, but there are other factors that can contribute to problems.You need to have your material at "proper" viscosity for conditions, the right tip on your gun (you probably already do), enough retarder for conditions and you need to get enough material on to reach "flow out"……..but not much more. You don't want to puddle the material….especially if it's windy. Rather than go into a long description of all of this, I'm going to assume that your basic spraying techniques are sound.If you shoot lacquer under conditions that contribute to too rapid of a solvent evaporation rate, you're asking for trouble. And lacquer can be very demanding in those regards. If it's too hot, too dry or too humid and/or there's too much air movement…….. problems are looming. Too hot, too dry or too much air movement encourage the evaporation of the solvent from the top faster than the solvent can escape from underneath. This encourages skinning over and subsequent problems like orange peel or solvent pop. The less ideal the circumstances during application or application technique, the worse the orange peel can be. The way to avoid such things is to shoot under "better" conditions if at all possible and/or to add some more lacquer retarder to the mix. (there's a limit to how much you can add) It sounds from your description of a skinned-over hump that was wet underneath that you should have rightly suffered solvent pop in that area later on ….like that night while you slept. If that didn't occur, consider yourself lucky. <G>Take heart knowing that we've all suffered lacquer application problems at one time or another. It's the frustrations, disappointments and teeth grinding that eventually leads us all to learn more about how to handle these materials or to wait until conditions are more favorable. The upside is that nitro lacquer is also somewhat forgiving and if you learn a few tricks of the trade, you can correct blemishes in the finish pretty easily. If you're shooting cat-lacquer, you have less time available to perform corrections, so you kinda want to have your act together before you use these less-forgiving finishes. Knowledge is power, but only if applied in a timely fashion.