Non-yellowing finish - for the Sisters

[steve brownell]

Hi fellow Creekers,

A question for those that likely have more knowledge of finishing than I do -- some nuns I know use a laser engraver to burn images in wood, mostly maple, to sell for charity. OK, the finishing question - they've been using a urethane/varnish mix, but are unhappy with the yellow tint it adds to their work. As a favor to them, I'd like to offer up some alternatives regarding a finish for their woodworking. Ideally, it'd dry relatively clear and not obscure detail from the engraving or darken the wood too much, like a tinted oil. Waterborn poly also was a non-starter for them, as it raised the grain. Their work can be seen at http://www.holynativityconvent.com/Laser.html

[Steve Schoene]

Shellac ought to work well. It is like to be quite satisfactory as the only finish. They could use a super blonde or similar, mixing from flakes, for only a little darkening. If that were the total finish they could also use Zinsser Clear which is even lighter than the super blondes. But it does retain the natural wax which would prevent application of a waterborne finish over the shellac.

If they wanted a little more protective finish they could use a first coat of shellac, and then use the waterborne acyrlic over that with the shellac preventing grain raising from the waterborne. In that case they would need to use a dewaxed shellac. The only liquid dewaxed shellac is called Seal Coat and while light colored is what I call "dirty blonde". The super or ultra blonde flakes are slightly lighter in color.

[Neal Clayton]

the spray bomb zinnser cans are almost impossible to screw up with. even if they overspray and it runs, it's clear, you can easily smooth out any imperfection and just spray another coat after.

that's what i'd tell them to try.

[Jamie Buxton]

Have they tried Deft (brushing) lacquer? It is quite clear.

[Joe Chritz]

What Steve said.

Anything oil base is likely to change the color some. Shellac or waterbase is the way to go.

Sounds like a perfect opportunity for the spray bomb shellac.

Joe

[Prashun Patel]

+1 for Zinnsser spray shellac. However, even the Blonde shellac will add a slight yellow tint. You really gotta go with a Superblonde or 'platina' blend if you want it close to colorless. To get that, you'll probably need to mix yr own from flakes and find a way to spray or brush it.

Deft Finish or any of the spray lacquers from the BORG are also good choices. They are the least yellowing in my experience. To be honest, I find the Deft Finish to spray flatter than the Zinsser spray shellac, which has gotten lumpy on me; perhaps I just had a bad actuator on that one...

[Howard Acheson]

For a waterclear, non-yellowing finish, I would use a waterborne acrylic. Minwax Polycrylic is a good choice. It can be brushed on or you can buy it in an aerosol can which are perfect for small projects.

[Lee Schierer]

Have they tried Deft (brushing) lacquer? It is quite clear.

I second the Deft or Varathane Diamond Floor finish. Even though it is water based there was virtually no raised grain and it imparts no color to the wood. It only comes in gallons, so that might be a drawback if they don't need a lot.

[steve brownell]

All, thank you very much for the recommendations on finishing. I've been away for a bit, but was really pleased that so many folks responded with helpful suggestions during that time. I'll convey the information to the nuns and have them try the top 2 or 3 ideas.