I want to use an amber or even darker shellac to both stain and seal some alder I am planing to use for baseboard and window trim sometime down the road.
Can I seal the waxed shellac with a coat of dewaxed shellac so I can put a final coat of poly on top, or does the shellacking process “melt” with previous coats and cause the waxed shellac to mingle up into the dewaxed shellac and cause problems with the poly?
Thanks,
Chris
Replies
Chris,
I'm not sure if you will totally seal out the wax with one coat. Two coats of a 2# cut would probably work. However if you plan on sanding or abrading the surface prior to varnishing, you may rub through and expose the waxy layer.
You can purchase dark garnet dewaxed shellac from homestead finishing products. This is the darkest shellac sold and has great color.
http://www.homesteadfinishing.com/
I use this shellac all the time and have not had a problem with topcoating it with varnish.
Why risk mixing the two? Use dewaxed everywhere. I presume that you already have some waxed that you don't want to toss...
Seems like I've seen some instructions for removing the wax from shellac. I'd call Jeff at Homestead or go on his forum and ask: http://www.homesteadfinishing.com
lp
Another idea -- trade the poly in for an alkyd or phenolic varnish. Then it won't matter if there's waxed shellac because it will adhere.
Hoohy, I'm getting confused. I thought that as shellac went from clear to dark it was because it got more and more wax (as in bug do-do, or whatever it was the critters excreted).
Tell me there, if more if you guys can.
But thanks all for the help, just want to be able to overcoat a nice golden undercoat with something more durable than shellac. Other varnishes than polyurathane are OK, but these days ACE hadware and True Value don't offer many alternatves.
Tnanks again,
Chris
Thanks for the advise. Now would you please translate your suggestion into words a retired nuclear engineer could understand?
This forum does not allow me to see your message as I reply, so what is an alkyd or that other witches brew of varnish you suggest? I sure would appreciate names brands and why.
Chris
It is the urethane resin in polyurethane varnish that is incompatible with the wax in shellac... Urethane can be finicky about adhesion in general. But there are wonderful varnishes that don't have urethane resins. In fact, some people think varnish without urethane gives a more beautiful finish, albeit without quite as much scratch resistance. A nice alkyd varnish is Pratt & Lambert #38. There's a Benjamin Moore paint store in my neighbhood that carries it, but I'm not certain if all Benjamin Moore stores have it... I've heard that it can be hard to find but I bet a search on the internet will be successful. I believe it's made with soybean oil (instead of linseed oil) and that gives it more clarity in that it will darken the wood less (initially and over time) than other types... An excellent example of a phenolic (another type of resin) varnish is Waterlox. It's my understanding that phenolic varnish dries harder than alkyd and that's something you may want to consider if you intend to rub out and buff the finish to a high sheen. You can use a waxed shellac under either alkyd or phenolic varnish with no adhesion problems. If you use another brand, just be sure there's no urethane in the mix and you'll be fine.
I guess one could say that short molecular threads don't stick to well to long molecular threads?? Or is it the other way around??
PlaneWood by Mike_in_Katy (maker of fine sawdust!)PlaneWood
Thanks, everyone, for the help. I had a sneaking suspicion the poly wasn't going to work. I got off my duff this morning and went to a paint store and got some Pratt & Lambert #38 varnish. We'll see how that works.
Chris
>> Can I seal the waxed shellac with a coat of dewaxed shellac
No, as you state, shellac melts together with previous coats forming a continuous film. The wax in the natural shellac will permeate the dewaxed shellac you attempt to put on the top.
The easy way out is to use a non-poly varnish as your topcoat. You will get a nicer looking finish that way too.
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