How To Coat Pigmented H20 Over Solvent CV

09/28/2014


From original questioner:

I have a client who wants their Walnut Panels (on Z clips) painted. Current condition of Walnut is extreme color fade due to UV exposure and numerous paintings in 20 X 15 foot room with 9 foot ceiling.

I know the panels are coated with a clear solvent CV. I spray with a Kremlin 10-14 for on-site work.

This is what I had in mind. First coat Zinsser 'Bin-Shellac' white. Sand, correct for defects and then another coat of White Bin-Shellac. Pigmented top coat from Ilva 2K poly. I know Zinsser makes an H20 'Advance' shellac, but have no experience with the product. Need to go low odor on the job....high rise condo.
Can vent to a shared outdoor terrace.

Any other suggestions for handling this project would be helpful.

From contributor Ri


Ilva 2K poly is definitely not low odor or job site friendly (isocyanate exposure) However if you are going that route skip the shellac and just use TF25 which is Ilva's isolante.

Clean all surfaces, scuff sand 320 for adhesion, spray one coat of TF25 wait 2 hours and then you can spray your pigmented 2K right over the TF25 without sanding. This should assure good adhesion. After drying you can scuff and apply another coat if you don't get acceptable coverage of the color you are using.

From contributor ni


FYI...Bin's "WB synthetic shellac" is not a great choice as a barrier coat if you plan to top coat with WB lacquers/CV or other spray only WB finishes as it is fairly slow to cure causing crazing...my distributor gave me a couple of gallons to try out on a rush job where the home owner insisted on only WB materials ( WB lacquer refinish of 1970's era birch/alder kitchen stained dark walnut with nitro top coat).
The stuff comes fairly thick in the can so I thinned with close to a pint of water, sprayed two thin-ish costs with a hour dry time between coats (temps were in the low 90's and 20% RH), I came back the next day, sanded with 320, sprayed a top coat of targets 6500 and within an hour had umpteen million spider cracks over every part of the job...yes I should have tested for compatibility first but like I said it was a rush job...so once again proving "the surest way to slow down a rush job is to rush it". axiom
Fixing the job took some dry time, sanding and two thin coats DA thinned pigmented shellac.


From contributor Ro


Rick,

Ilva now makes a Waterborne 2K poly...number is PW710

I have used the clear on a previous job and liked it....the pigmented I hope with a hardener added will be just a user friendly to apply on site.