Sam777 Posted January 27, 2018 Author Report Share Posted January 27, 2018 Here another question Will oil based Polyurethane go well over Shellac? Thank you Sam Quote Link to comment Share on other sites More sharing options...
tomsteve Posted January 28, 2018 Report Share Posted January 28, 2018 sam heres a good video, and site with lots of awesome info https://www.thewoodwhisperer.com/videos/shellac-under-polyurethane/ Karl S 1 Quote Link to comment Share on other sites More sharing options...
JTTHECLOCKMAN Posted January 28, 2018 Report Share Posted January 28, 2018 Just a point about using waxed shellac under poly and the test that guy did. It is not the lifting that becomes a problem it is the cracking that can happen on certain woods. I highly suggest to use Zinzzer dewax shellac if using shellac under poly or any finish. tomsteve and WayneMahler 2 Quote Link to comment Share on other sites More sharing options...
ScollSaw Slasher Posted January 28, 2018 Report Share Posted January 28, 2018 (edited) Glue ups are possible with 1/4" hardwoods. The trick is doing it on a perfectly flat non stick table, square edges of the stock what ever it is, light clamping pressure, weighing it down from the top to prevent bowing from the clamps and allowing sufficient time for the glue to set up. Have done larger panels this way. Think about guitar tops which are even thinner than 1/4". Edited January 28, 2018 by ScollSaw Slasher Quote Link to comment Share on other sites More sharing options...
Bill WIlson Posted January 28, 2018 Report Share Posted January 28, 2018 16 hours ago, Sam777 said: Here another question Will oil based Polyurethane go well over Shellac? Thank you Sam Oil based polyurethane does not have very good adhesion, even to itself. That is why the manufacturer recommends that you scuff sand the surface before applying additional coats, if the previous coat has been allowed to dry over a certain amount of time. Scuff sanding provides tooth for the next coat to grab on to. Shellac has been called the universal sealer/barrier coat, because it sticks to just about anything and just about anything sticks to it. The one exception to this statement is waxed shellac and oil based polyurethane. With shellac, the conventional wisdom is to use de-waxed shellac, as John mentioned. Zinnser sells a couple different products in their line of pre-mixed shellac. In its natural state, shellac contains wax. The one you want for use under oil based polyurethane is Seal Coat. It is de-waxed and provides an excellent base for just about any top coat. WayneMahler and JTTHECLOCKMAN 2 Quote Link to comment Share on other sites More sharing options...
Sam777 Posted January 29, 2018 Author Report Share Posted January 29, 2018 Bill, Thank you for (as usual) your detailed explanation and advice It is always appreciated Sam Quote Link to comment Share on other sites More sharing options...
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