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Forum topic by Peter Oxley posted 03-13-2008 06:12 PM 1492 views 0 times favorited 16 replies Add to Favorites Watch
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Peter Oxley

1426 posts in 4023 days

03-13-2008 06:12 PM

Topic tags/keywords: varnish rejection dots question finishing

In addition to staining or dyeing, I often color projects by tinting my varnish with stain. This avoids problems like grain reversal and over-coloring, while giving a subtle glaze effect. I’ve done it dozens of times without any problems.

This week I had problems. I had put down two coats of clear varnish without any issues, and put colored varnish on 80% of the project without any issues. But when I put on the colored varnish on the last four doors, I got dots. When I am pressed for time, sometimes I try to solve problems in ways that I’m sure won’t work: when the coat of colored varnish cured, I put on a second coat, hoping to cover the dots. What I got was a piece that was way too dark and the dots were even more obvious.
Curious Dots

The only thing I can think is that, since these were the last few items, they may have had a little overspray from the previous parts. But if they did have some overspray, it would have only been there for a couple of minutes. I would think it would just mix/blend when I put down the coat of varnish.

I’m sure it wasn’t silicone – I don’t use it in the shop specifically because I want to avoid this sort of thing. And I’m pretty sure it wasn’t dust nibs in a previous coat because I scuffed before spraying (the dust you see in the photo is there because the photo was taken in the sanding area, not in the spray booth).

Eventually, I removed all the varnish with a scraper and sandpaper and started again.

So the question is … have you ever had this happen to you, and do you know what causes it?

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16 replies so far

View Bob #2's profile

Bob #2

3810 posts in 4170 days

#1 posted 03-13-2008 06:26 PM

That’s sure a typical fisheye.

You will have to trace your steps backward to trap where they got into your system.
e.g. new rags, hand lotions, cast iron sprays etc.
Was that wood premilled before you got it?


-- A mind, like a home, is furnished by its owner

View GaryK's profile


10262 posts in 4137 days

#2 posted 03-13-2008 07:23 PM

Don’t know what to say. I have never seen that before.

If that’s fisheye then I’m glad I have never come across it before.

-- Gary - Never pass up the opportunity to make a mistake look like you planned it that way - Tyler, TX

View Peter Oxley's profile

Peter Oxley

1426 posts in 4023 days

#3 posted 03-13-2008 07:48 PM

Bob – thanks for the input.

- The lumber was 15/16” H&M knotty alder that I milled down to 3/4”
- I use wax for my metal surfaces because I worry about silicone
- Marianne says I need to use hand lotion … but I don’t
- My tack cloth was not very new – it had been used on a couple of projects before this
- Other than tack cloths I stick with those blue paper shop towels

However …
I’ve had a miserable cold and I put some lotion on my nose one day, and I guess there could have been some on my hands. I don’t know if it was the day that this happened. It seems odd that it wouldn’t be on the previous parts, since these four doors were handled last. I’d think it would be on everything or randomly distributed across the project.
And …
After sanding all the varnish off I used a different tack cloth – one that doesn’t feel waxy – and I didn’t have any problems the second time through. Again, I would think that if it were the first tack cloth, there would be problems across the whole project … and probably on previous projects.

So while lotion and tack cloth seem somewhat unlikely, they are probably the best guesses.

Since I’ve managed to avoid this problem in the past, I’ve never had to deal with a solution. Is there a solution that is less drastic than sanding back to bare wood and starting over?

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View dennis mitchell's profile

dennis mitchell

3994 posts in 4463 days

#4 posted 03-13-2008 07:56 PM

maybe water drops from somewhere?

View Bob #2's profile

Bob #2

3810 posts in 4170 days

#5 posted 03-13-2008 07:56 PM

Peter, I’m glad you were able to trace back to hopefully prevent a mishap again.
I have heard of a cleaner that body shops use to make sure silicone is cleared from paint jobs prior to spraying but I don’t know what it is.
Maybe one of our jocks can fill in here for us.


-- A mind, like a home, is furnished by its owner

View Peter Oxley's profile

Peter Oxley

1426 posts in 4023 days

#6 posted 03-13-2008 08:07 PM

Dennis – I considered water drops, but ruled them out. I have vertical drying racks, and drips from above would have landed on the doors and parts above these. And even though I had a bad cold, I was wearing a spray mask in the booth, so I’m sure I didn’t sneeze on them!

Bob – yeah, I’ve been planning to get away from waxy tack cloths anyway. Now might be the right time to make the break. I guess extra vigilance about clean hands would deal with the possible lotion problem. And now I have a reason when Marianne asks, “why do you let your hands get like this?”

If anyone knows of a cleaner, I’d be interested. Is there any problem with the cleaner damaging the wood?

-- -- --

View Bob #2's profile

Bob #2

3810 posts in 4170 days

#7 posted 03-13-2008 08:22 PM

I think Roman is using some.
Why not give him a PM?

-- A mind, like a home, is furnished by its owner

View Max's profile


56000 posts in 4422 days

#8 posted 03-13-2008 09:08 PM

It is called fish eye killer, it is used in the automotive industry quite a bit, at least it used to be. Here is a blurb from the Deft web site.

(The formation of small depressions in the coating)

a. Cratering (crawling) is the tendency of a film to pull or crawl away from areas of the substrate-check area for contaminations; oil on belts, lubrication compounds, etc. Wipe surface down with solvents then use Vinyl-Tek sealer.
b. Old refinished work could have contaminants-strip thoroughly and wipe surface with Fast Thinner (030 series), test an area. If problem continues use a “fish eye killer”.

-- Max "Desperado", Salt Lake City, UT

View Tim Pursell's profile

Tim Pursell

499 posts in 3931 days

#9 posted 03-13-2008 10:59 PM

It sure looks like fisheye. Something got into your finish or on the surface between coats. I used to paint alot of cars & have seen that effect too often. Fisheye preventer stopped the problems with automotive paint, my only question is: Is it compatable with the finish you are using.


View dennis mitchell's profile

dennis mitchell

3994 posts in 4463 days

#10 posted 03-13-2008 11:24 PM

I use to use one for wood finishes from Mohawk.

View Douglas Bordner's profile

Douglas Bordner

4027 posts in 4212 days

#11 posted 03-14-2008 06:30 AM

I have stopped using tack cloths altogether after going primarily with waterborne lacquer. I get more mileage from those Norton microfiber tack cloths (or better yet the microfiber cloths you can get for cheapness at automotive supply stores). You just have to make sure that you 1) Don’t drop them into any sawdust 2) Launder them without using any fabric softeners.

As to the source of the fisheye, I am as mystified as you are, Peter.

-- "Bordnerizing" perfectly good lumber for over a decade.

View Pretzel's profile


93 posts in 3894 days

#12 posted 03-14-2008 08:11 AM

Could be solvent from cleaning your spray gun, possibly from lubing it. what type of heat do you have? Any number of things can cause fisheye.

-- Pretzel L8agn

View BroDave's profile


107 posts in 3963 days

#13 posted 03-14-2008 01:13 PM

Water from your air compressor maybe?

-- .

View Peter Oxley's profile

Peter Oxley

1426 posts in 4023 days

#14 posted 03-14-2008 03:16 PM

Doug, thanks for the tip on microfiber at automotive supply places. I’ve started using the Norton dry tack cloths, but four bucks apiece for rags? Ouch!

Pretzel, thanks for the input. The solvent would be mineral spirits. Are you thinking overspray from the cleaning process? The fisheye appeared as soon as the varnish went down, so it wouldn’t be cleaning from that coat … and the previous coat was about 12 hours old and had been scuff sanded. The needle gets a touch of grease during assembly, but that’s the same every time. The heat is radiant electric in the spray booth and forced air electric in the rest of the shop. I bet you could get specks of soot from combustion heaters.

Dave, thanks for your input too. That’s a good thought, but I’m using HVLP.

I really appreciate all the suggestions. There sure are a lot of possibilities!

-- -- --

View FrankA's profile


139 posts in 3928 days

#15 posted 03-14-2008 03:20 PM

I was thinking maybe some condensation in the air line too, sounds all the other common causes have been covered. Years ago I worked in a factory that sprayed alot of varnish and have seen outcome like this when our air driers acted up.

-- Frank Auge---Nichols NY----"My opinion is neither copyrighted nor trademarked, but it is price competitive."

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