Yet Another Fisheye Mystery

      Finishers add more names to the long list of usual suspects in a fisheye case. April 19, 2011

I was wondering if any of you would share all of the different causes you've experienced for fisheyes in the hope that I might find my cause. It crops up every couple of weeks and I can't figure out where it's coming from.

Forum Responses
(Finishing Forum)
From contributor W:
I suspect your crater problem is caused from the environment air. Check the place around your shop, there may be some peoples of factory that do some activities that create some silicon or other contaminant material. The materials is blown by the air and come in your shop. What you can try to do is make your finishing shop is close enough from the outside air.

From contributor M:
I heard of a shop that nearly went bankrupt because they couldn't get fish eyes out of their finish. After six months of new guns, lines, cleaning, and changing products, they traced the problem to the purchasing department who had started ordering powdered gloves because they were cheaper. The powder contained silicone, causing everything they handled to fisheye.

From contributor A:
There are dozens of causes. The latest one I've figured out is the harbor freight blowers that we give to our sanders. Heavy coats of any material will cause fisheye, especially. 2K urethane. If you think you have oil/water in the airlines, keep a supply of the disposable filters that screw to the spray gun

From contributor S:
If it just crops up periodically it is most likely coming in airborne from somewhere else. Silicone based products are the most obvious but not only concern. Airborne particles of many kinds can cause it too. Determine if you have neighbors doing a suspected operation.

Metal working (coolants and particles) or polishing (compounds and particles) nearby can ruin a finishing operation. Sometimes I think there must be close to a gazillion products that contain silicone based formula's. If it ends in "icone", ie dimethicone, it's a likely suspect and it can migrate like crazy. If you get inundated with it, it can be a nightmare to clean out but it can be done. First you have to stop it from entering your building.

From the original questioner:
I don't think it's coming from the outside air. It could be water in the lines, but then I would think it would be more consistent. I don't have an air dryer, but I can go for weeks without a problem and then just like 5 minutes ago, a 2' x 8' panel was littered with about 100 fisheyes. This is new work, not refinishing. This particular project is pigmented conversion varnish.

I have a new theory I'd like to run by you guys after this morning. Is it likely that older material that has been freshly catalyzed could be the culprit? This particular end panel was sprayed with 1 coat of SW Kemvar Primer and no fisheyes. I followed that up with a coat of leftover white from a previous job that I'm using as a build coat - no fisheyes. Finally, I put down the final color coat of white, freshly catalyzed from a bucket that's been around for a few years but never opened, and crazy fisheyes.

From contributor G:
Fisheyes rarely show up in a first coat. I would say either your second to last or last coat has some sort of contamination in the finish. Do a test only using a primer and the final coat to see if it fisheyes. If not, then do a primer coat the second to last coat and then the final coat and see if it fisheyes. This will tell you if there is contamination in one of those buckets.

From contributor A:
If you’re going to look at your material, go and get yourself some glass for windows. Get them cut in sizes like 10x10. Clean them well with acetone and spray out your products. You then can see if it is the product, especially on the first coat. When I was with Akzo, we once had fisheyes caused by mixing three different batches of catalyst together.

From the original questioner:
I'm in the midst of an experiment to see if it might be my thinner. SW recommends Butyl Acetate, which I used for years without fisheye problems. In the last few years, I've switched to just plain lacquer thinner, and even more recently to a less expensive lacquer thinner.

From contributor F:
I can't believe no one has mentioned WD-40. I had a horrible time tracking down the cause of fish eyes on a conference table a few years ago and finally traced it to the cabinetmaker that built the table who had just re built his belt sander and lubed it up with WD-40 before sanding the table top. I won't let the stuff in my shop.

Would you like to add information to this article?
Interested in writing or submitting an article?
Have a question about this article?

Have you reviewed the related Knowledge Base areas below?
  • KnowledgeBase: Knowledge Base

  • KnowledgeBase: Finishing

  • KnowledgeBase: Finishing: General Wood Finishing

    Would you like to add information to this article? ... Click Here

    If you have a question regarding a Knowledge Base article, your best chance at uncovering an answer is to search the entire Knowledge Base for related articles or to post your question at the appropriate WOODWEB Forum. Before posting your message, be sure to
    review our Forum Guidelines.

    Questions entered in the Knowledge Base Article comment form will not generate responses! A list of WOODWEB Forums can be found at WOODWEB's Site Map.

    When you post your question at the Forum, be sure to include references to the Knowledge Base article that inspired your question. The more information you provide with your question, the better your chances are of receiving responses.

    Return to beginning of article.

    Refer a Friend || Read This Important Information || Site Map || Privacy Policy || Site User Agreement

    Letters, questions or comments? E-Mail us and let us know what you think. Be sure to review our Frequently Asked Questions page.

    Contact us to discuss advertising or to report problems with this site.

    To report a problem, send an e-mail to our Webmaster

    Copyright © 1996-2016 - WOODWEB ® Inc.
    All rights reserved. No part of this publication may be reproduced in any manner without permission of the Editor.
    Review WOODWEB's Copyright Policy.

    The editors, writers, and staff at WOODWEB try to promote safe practices. What is safe for one woodworker under certain conditions may not be safe for others in different circumstances. Readers should undertake the use of materials and methods discussed at WOODWEB after considerate evaluation, and at their own risk.

    WOODWEB, Inc.
    335 Bedell Road
    Montrose, PA 18801

    Contact WOODWEB

  • WOODWEB - the leading resource for professional woodworkers

      Home » Knowledge Base » Knowledge Base Article