Contamination and Fish Eye

Finishers help a colleague track down the source of fisheye, among the many typical (and not-so-typical) suspects. May 17, 2005

I'm a finishing supervisor in the manufacture of wood cabinets. In the last week I have developed fisheye in one paint booth. I have changed the pump, lines, and guns. I know the equipment is clean. I had no problems with this until last week. Also, it doesn't do it on every part. Any ideas?

Forum Responses
(Finishing Forum)
From contributor C:
If you've eliminated sources in the booth and the person spraying, go into the main shop and look to see if some idiot has used Lami-Lube on a shaper or router table.

That turned out to be my source of fisheye several months ago. On a slow finishing day, I was helping out with sanding and noticed that the guy who was making doors had a can of Lami-Lube nearby. Yep, he sprayed the shaper table. Luckily I caught it in time and didn't have a repeat of fisheyes in my finish. Had I not been slow in the booth, though, the entire set of doors (nearly 200) would have been contaminated. It sucks when you have to redo an entire rack of doors that fisheyed.

Any time a new employee starts, even if they aren't in my finishing department, I make sure to tell them what can screw up my finish and that it will be them who fixes it. This guy brainfarted, though.

From contributor D:
I had a similar problem. I don't remember the specific lubricant that was the culprit, but I do remember ransacking the entire cabinet shop to get rid of anything that would create that problem again. I presented the shop owner with a list of chemicals that would cause me problems in the finish shop and swore I would walk if I encountered the problem again.

Thankfully, It didn't happen again and my bluff wasn't called. I also took to adding fisheye flowout (silicone) to all finishes in that shop to add a little bit of security. Sorry for your inconvenience. Start raising hell, who knows - you may just get your boss's attention and get the credit your department deserves.

From Paul Snyder, forum technical advisor:
If the contamination is limited to one booth and you've ruled out the equipment (including the air filtration system), then it's either the personnel (spray operator, stain wipers, or sanding crew) that work that booth or something along the path to the booth. Switch personnel and see if the problem moves. If there's an air vent or heat supply in the path to that one booth, check that as a source. There was a discussion not too long ago where a finisher changed brands of deodorant and caused a contamination problem. May be something as extraordinary as that.

From contributor C:
You need to look for some kind of pattern on the contamination. Not all parts? Which parts, then? A certain spot on the effected part? Random? While I doubt it's random, it could be if something were sprayed or splashed out in the shop. I'm more apt to think you need to take a look at a specific process or individual, though.

The thing that clued me in on the source several months back was that not all doors had it - they only fisheyed on the stiles and rails, never the panels. So it was when the stiles and rails were coming into contact with the contaminant and it would only happen on their faces. That quickly eliminated someone's hands being contaminated, as it would have shown on the backs as well. The only process that matched was when the profile was being shaped on the doors' edges. The reason it was sporadic? As the idiot felt it was more difficult to pass the pieces on the table, he'd apply more of the Lami-lube. The ones cut soonest after he lubed the table were the worst. The ones cut just before he'd spray on some more had no fisheye at all.

Oh yeah, until the source was identified as coming from outside my finishing room, it was assumed to be my fault. When it happens now, I don't go nuts figuring out what I did wrong, I walk out into the main shop and find what they are doing wrong.

From contributor S:
If your sanders or helpers eat on breaks (any oily food product), make sure they wash their hands very good. I make them wear gloves! Also, check all air oil separators. Sometimes they leak too much, causing this problem, especially if they are outdated.

From contributor J:
Paul stole my thunder. That is something I never knew as a source of fisheye. What is different from one booth to the other? Another source, although there would be no pattern to fisheyes on the piece, is the forklifts or heaters for the shop. Are they running rich? As soon as this contamination mixes with all the sawdust in shop, you will be hating life for a good long while.

From contributor W:
While I am truly sorry to hear about fisheye in anyone's shop, I do like to find out new causes for it. I am a wood coatings technician, and I run across it a lot. The problem is that almost everything can cause it. Just last week I went on a call to a shop that was experiencing fisheye, so I cleared my schedule to make time to locate the source. This was one of the most difficult things to do. When I got to the shop, there were 3 different looking forms of fisheye. I was shocked! Long story short, I found some real small micro fisheye, related to improper catalyzing of the MDF primer. The second (in a different booth) was because of moisture in the air line. Simple, right? Wrong! The customer had just had a company come out and re-tube the booth and compressor, etc. They forgot to turn on the refrigeration unit to the air leaving the compressor, so the air was still warm when it hit the trap only 10 or so feet away. The air needs at least 25-35 feet to cool and release the water. And the third was because of tack cloths! These are an enemy, especially to the untrained. The new guys were just rubbing the wax right into the CV.

From contributor R:
In the last month or two we've had this problem and traced it to one worker. It's probably something his wife is using in his laundry since a full body Tyvek suit prevents it. We're now working to trace that substance.

From contributor E:
I've had problems with deodorant causing fisheyes. Certain brands contain silicon oil, which just goes airborne and gets into everything.

From contributor Y:
I remember reading something a long time ago on this forum that may help... The little paper fabric softeners you throw into the clothes dryer often contain some form of silicone. This came up because someone was laundering their rags and ending up with fisheye.

From contributor J:
You'd be surprised at how many things incorporate silicone into their products. The fold-up horses made of plastic that have rubber squares on top to prevent sliding and damage to your work piece are bad news and you'll know soon enough how much fisheye those little things transfer.

From the original questioner:
Thanks. We believe we have found the source of the contamination. The ladies that sort the doors were using hand lotion. I'm currently wiping all the doors down with lacquer thinner and it helps. We just need to wait to see as the old doors work through the system.

From contributor O:
I just had the same problem. It didn't do it all the time. Then when it did, it was a lot. So I bought a Devilbis 3 stage air filtering system with the third stage being desiccant crystals. Solved our problem. I figured the compressor was worn out and starting to use oil. It had to go somewhere. Pulled my hair out for about week. And trust me, I can't stand to lose any more hair.

From contributor C:
I just had a reoccurrence of fisheye, which baffled me for a minute or two. Drawer sides showed fisheye in a pattern along the taped edge and then a finished end without any tape showed fisheye along an edge. Found out that the finished end had been accidentally taped and the tape was removed. Went over to the edge bander and sure enough, there was that damned can of Lami-lube! After doing a full run of laminate banding, the sample cabinet pieces had been quickly run through and got contaminated.