Shellac: the magical first coat?

Discussion in 'Luthier's Corner' started by Basschair, Jul 30, 2009.

  1. Basschair

    Basschair .............. Supporting Member

    Feb 5, 2004
    Stockton, Ca
    Maple burl top, curly maple back, African mahogany core. I'm not staining anything for any reason. I'm not looking for a "glass smooth" finish: feeling the wood's surface is fine with me. However, I'd really like to not have the mahogany end grain turn extra super dark by soaking up the varnish I'll be using later in the finishing.

    I know that I can use my finish for a sealer coat, but that could be the problem. I've tried General Seal-a-Cell on test pieces of the wood and have found an article or two which mention that it's relatively easy to build up a film with it, leading me to believe that it'd probably be possible to grain fill, sand down, repeat and then continue on my merry way. Still, I wonder...

    Is a sealer coat of extra blonde shellac for me? I found another article which listed a process for grain filling with shellac. If anyone is interested:

    Again, I don't necessarily want the ultra-smooth finish, just prevention of those super dark spots where the mahogany soaks varnish up. Suggestions? Comments?
  2. 62bass


    Apr 3, 2005
    Shellac is an excellent sealer for what you want. But I suggest you use a de-waxed shellac. You can make your own from dry flakes but why bother when there is now available a premixed 2 lb cut shellac in quart cans. It's called Zinssers Bulls Eye SealCoat. You won't find it everywhere, like Home Depot, but if you go to their website you'll find a list of North American dealers.

    I really recommend the de-waxed. I'm currently working from a fresh can of the Bulls Eye SealCoat.

    I think a few guys here also use it.
  3. Jazzdogg

    Jazzdogg Less barking, more wagging!

    Jul 29, 2006
    San Diego, CA
    +1 You can trust 62Bass - he's been right on the money every time I've read one of his posts. :)

    I probably use 3 or 4 gallons of sealcoat per year - it's really versatile! I find that thinning it to between a 1-pound cut and a 1.5-pound cut makes it easier to achieve a smooth surface texture and also makes it easier to sand if needed; thin with denatured alcohol.
  4. eyeballkid


    Jul 19, 2009
    Shellac is a most excellent band!
  5. Basschair

    Basschair .............. Supporting Member

    Feb 5, 2004
    Stockton, Ca
    Thank you gentlemen: I've used shellac before as a finish on a few turned bowls and french polished bass bows, but not in this manner. Thanks for the tip on the Zinssers Sealcoat: I'm on it as soon as I can find some.
  6. 62bass


    Apr 3, 2005
    You won't regret it. One of its good points is it's harder and more water resistant than the usual waxed shellac. That's good to have in a sealer.
  7. 62bass


    Apr 3, 2005
    Thanks Jazzdog. Here in Canada the thinner sold for shellac is called methyl hydrate. Probably the same thing. it works anyhow. Yeah, 2 lb cut is good for building up thickness faster, but thinned and a couple extra coats would be best for a sealer.

    Shellac is a pretty nice finish on its own and if it was just a bit more chemical and water resistant I'd use it for a top coat. It polishes out to a high gloss easily.