Behlans nitro over shellac sealed top???

[Jackspt28]

Hello Guys, I am about ready to finish using Behlans Nitro and vinly sealer. I had originally sprayed the spruce top with a coat of Rattle can Bullseye shellac. Do I need to remove all of the shellac and the seal with the behlans vinyl sealer, or do I use the vinyl sealer over the shellac followed by the nitro. I will be pore filling the back/sides with Zpoxy, should I use the vinyl sealer before pore filling with the Zpoxy or after??? I really like the way the top looks with the shellac as it adds a little tint to the very light colored top, but I have read about crazing problems when using Behlans Nitro over shellac. Any suggestions welcome , Thanks Jack.

[B. Howard]

Jack, I would advise you sand back the shellac, or strip it off with DA. The rattlecan stuff has a spotty track record at best, I would not trust it myself. I assume you are going to be using spray cans for the finish rather than a gun. You can get that nice amber tone back by using a coat or 3 of Behlins Starcast amber guitar toner B104-1202. If you are pore filling with epoxy, that should be done on bare wood. Follow that with the vinyl sealer. If you use the toner it is applied directly over the vinyl sealer and then followed by top coats of the clear lacquer.

[Jackspt28]

Thanks Brian, I will strip the shellac off and than seal the top with the Behlens vinyl sealer. I am using spray equipment to spray it with. (I have painting equipment and lots of experience with automotive /motorcycle finishes). So you are saying fill the back and sides with zpoxy resin and then spray with the vinyl sealer (2 coats??) and then spray the laquer right ? Thanks, Jack.

[B. Howard]

Yes, Epoxy first followed by sealer and then lacquer. One coat of sealer should be good over the epoxy, spruce may want two. You can still get that amber look as well, just add some transparent dye to your first coats of lacquer. Think of it like a "candy" without a basecoat.

[Jackspt28]

Got it, Thank You for the help. This is my first one.hopefully it will come out looking and sounding decent. Jack.

[pete nardo]

why would you apply sealer over epoxy? Doesn't the epoxy also seal the wood?

[B. Howard]

why would you apply sealer over epoxy? Doesn't the epoxy also seal the wood?

First that depends on how you use the epoxy, do you use it just as a pore fill and sand most of it back off or do you leave a coat of it on the entire surface? If you leave a coat it will "seal" the wood but that does not mean you do not necessarily need the vinyl sealer. There could be bond issues down the road, nothing worse than finishing a guitar just to have it craze or de-laminate in a year or so. Most modern coatings are highly engineered systems. If the nitro lacquer system you are using requires a vinyl sealer then it is an acrylic modified nitro of some type and contains some plasticizers at the least and most likely some type of acrylics as well. The vinyl sealer forms a bridge or a foundation so to speak that the lacquer will adhere to chemically rather than mechanically. The sealers job is to form the mechanical bond to the object.

[pete nardo]

Ah, i see. Thanks for that explanation.
Regards.