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Fish Eyes in Ekopoly Premium

Posted: Saturday, June 15, 2013 3:34 AM Quote
Hi All,

I had an interesting problem when I sprayed my aileron and the 2nd side of a test panel I made. The test panel was by far the worst and I was able to save the Aileron.

The effect on the test piece was definite fish-eyes which I always understood meant surface contamination.  The Aileron had the start of what might have become fish eyes had I kept going.

The test panel may have had some contamination as it was in my fathers shop waiting for me to get back to it & I don't think he would have done anything to cause contamination. I did however Ekoclean, re-scuff, blow/wipe down with tack rags and IPA before doing the second side. The Aileron however was in my shop & I know would not have had any contamination. I did also clean, scuff, prime with Ekofill, sand, blow/wipe down with tack rags and IPA just before starting to spray the Ekopoly.

By the time I finished in the late afternoon the temp & humidity on the shop were down to - 63F & 75% Humidity - During the day when I got the fish eyes it would have been around 68F & 70% humidity.

To spray these I used the same technique as I used for the wing - That is apply a more or less continuous fog coat until color saturation & then wait for it to tack off before doing the final coat. While not perfect I'm happy with the results I got using this method on my wing. (The conditions were better when I did the wing).

This image shows the fish-eyes on the test piece:


This image shows the effect on the aileron:


After noticing this on the aileron I waited longer between fog coat passes and turned the exhaust fan off to try & keep the temps inside up. (The heaters can keep the shop above 68F but not if I immediately try to extract all the warm air with the exhaust fan).  This seemed to help and the aileron turned out ok. Using the same technique to finish the test panel resulted in dimples in the finish that didn't flow out.

Is this surface contamination or a case of marginal conditions?

Thanks,
Don H
VH-CRR
Posted: Sunday, June 16, 2013 7:56 AM Quote
Try using less water and shooting the paint a little thicker. Use the viscosity cup to set the viscosity at 21-22 seconds. Verify the cup measures water at 15 seconds first.  Also make sure to wait 4 hrs to topcoat EkoPrime and 8-12 hours on Ekofill


Jason
Posted: Sunday, June 16, 2013 7:57 PM Quote
Thank you Jason,

I measured viscosity at 19 seconds after mixing the paint, catalyst & distilled water by weight. So I guess possibly a little thin for the conditions then?

Regards,
Don
Posted: Monday, June 17, 2013 12:06 AM Quote
Yes I would try thickening it up and shoot again. If you ever have any issue when painting just wash it off right away. It's much better than sanding



Jason
Posted: Monday, June 17, 2013 1:51 AM Quote
Jason,

What's the best solvent / method to wash the paint off with?

How far back in the prep process do you need to go before respraying with ekopoly again?

Thanks,
Don
Posted: Monday, June 17, 2013 5:51 PM Quote
As soon as you start to see any defect you don't like STOP, and wash it off with water and EkoClean. You may need to use a scotch-brite pad to help.  Once the paint dries you have to sand any defect out and I suggest re-priming the area with EkoPrime to fill any voids.


If you wash the surface off make sure to blow out all the nooks and crannies and leave no moisture behind. Let the surface dry overnight before re-painting.


Jason