3 April 2015 at 12:58 pm #126226
Hi, ive been using liberon sanding sealer on a few of my projects, all different types of wood, oak, cherry, pine and each has 3coats. I have wire wooled first coats and applied wax with wire wool on the final coat and they all looked great. But…any contact with the surface causes the shellac to scratch and leaves a white scratch mark, very brittle. Surely this cant be normal, it looks terrible. Do I have a bad batch maybe?3 April 2015 at 4:44 pm #126232raze599Participant
I’ve noticed the same thing. It’s probably just how it is.
By the way use sandpaper after the first coat. Worn out 240 or 320, somewhere around there.3 April 2015 at 4:49 pm #126233Matt McGraneParticipant
Hey Jimbo. I cannot see why you are getting this brittleness. Do you mean that just touching the surface with anything leaves an ugly scratch? Seems like the wax on top should help protect the shellac. Could it be the wax that is scratched?
There are a couple of things to know about shellac. First, it has a shelf life. I’ve read that after it is mixed (if it is made from dry shellac flakes), it should be used within a few months. I’ve only ever bought pre-made shellac. And I’ve used it for a couple of years without issues. Although, I did have some once that seemed a little gummy (not brittle) and I thought that could be from getting old.
Many shellac products come somewhat concentrated. The product I get in the US is Zinsser’s Sealcoat. It is a 2 pound cut, meaning it was mixed in a ratio of two pounds of dry shellac flakes to one gallon alcohol. I thin it to approximately a 1 pound cut (1 for 1 Sealcoat and alcohol) before using it and I typically apply three coats. I know some people use heavier cut shellac for sealing wood or knots. I don’t know if using the heavier cuts make it more brittle.
Not sure if this helps. Maybe others will add some thoughts.
Matt, Northern California - Started a blog in 2016: http://tinyshopww.blogspot.com/3 April 2015 at 5:06 pm #126237
Yea I mean I made a cook book stand which rests on the kitchen top and at most gets slid into its home when not in use and the shellac on the bottom is all breaking up. If I drag my finger nail down it with very little pressure it will scratch. Yea I cant remember if I used sandpaper or not on the first coat. I will not be using it on my toolchest im making thats for sure! I like how easy shellac is though so I dont want to discount it. For a toolchest with lots of use would anyone suggest a hard-wearing finish?3 April 2015 at 5:09 pm #126238
Here is an example