Thread: Dreaded "Fish-eye" in brushed polyurethane finish.

Two possible causes come to my mind. Yes the cold but may be water vapour in the air, then the other is.....the dreaded Mr Sheen, Silicone on the surface. Warmer dryer air will fix it if that is the cause but for the Mr Sheen....big wash down with solvent

Thanks chambezio,

Can't be Mr Sheen as the tables were stripped/sanded/stained.

Now that I think about it, it wasn't freezing when I coated them, but look at the humidity reading on the attached BOM chart for that time of day on 07/06/16. Wet air alright.

BOM June 7.jpg

Ah!! one has to look at "de facts" like Hercule Poirot. Another manifestation of moisture when spraying lacquer id "blooming", moisture gets trapped in the coat and looks like a white haze on the surface.

Bloody Melbourne climate!!

Originally Posted by wynyard

Thanks chambezio,

Can't be Mr Sheen as the tables were stripped/sanded/stained.

Don't discount silicon contamination (from Mr Sheen or similar products). Stripping and sanding won't always get all the silicon out, especially if the owners have religiously cleaned and polished those table tops with Mr Sheen for years and years. One coat of Clear De-waxed Shellac (clear so you don't change the timber colour, and de-waxed so that the top coats of poly will stick securely) will seal in any silicon and any other contamination, and pretty much any finish will go over the Shellac without problems.

RoyG

Don't know if it'll help with your specific problem, but foam rollers are great for getting an even finish with poly - probably faster than brushing as well.

If you want to have a crack at sanding, we have a calibrating wide-belt sander at work accurate to 0.1mm. I've run veneer board through it many times (some jobs worth several thousand dollars) and have 100% confidence in it

Can't speak for poly, but this time last year I was spraying shellac on a job and got blooms. On one particular day they were so bad the surface looked nearly white. It just so happened the blooms disappeared after a few hours (perhaps the next day) as the moisture escaped. As for fish eye .. ???

Thanks guys.

It's funny Roy, I didn't get on the pc until late in the day, but a couple of hours after you posted about dewaxed shellac, I was discussing the problem with my old man, who suggested just that. He's been at this caper twice as long as the 20 years I have. Unfortunately, by then I'd got a second coat on a few tops before they started to "orange peel" rather than fish-eye, trying to take the first coat with it. They will sand flat fortunately. The rest have now been nicely sealed with shellac, and are ready for a light sand, then on goes the final coat of poly. Thanks for your advice.

I did get a bit of bloom in the 2 coats of brushed shellac yesterday, Glenn.Visca, but like your experience, they vanished within a couple of hours luckily.

Thanks for the tip elanjacobs - I'll give the rollers a go on the next job - don't want to temp fate with this one. I'll be in touch re your WBS re a different project.

Cheers.

It sounded to me like condensation. Insulation or sarking under your gal tin roof could prevent a repeat.

My work area has more gaps than a barcode! Something to work on ASAP.

Hi coming from an spray painting background if it is silicone contamination, wiping down surfaces with say prepsol etc just moves silicone (hopefully onto the cloth ) we use a product called "silicone drops" in the 2 pak paint if there is a problem in the first coat. What does everyone wipe there dashboard down with ......Amour All !!!! Pure silicone. Cheers.