Anyone padded shellac?

[geekette]

I have a 75 year old sewing machine cabinet (like this one) that has a badly scratched fold out top, like someone scraped a lamp base across the top of it for a couple decades (which is probably what happened).  It's shellac.  I've read that you can use denatured alcohol to soften, and a pad (wool in muslin) to spread around the remaining shellac to smooth it out.  That doesn't seem to work for me - mostly I seem to be wiping it off. 

I'm undecided if I want to attempt to remove the shellac (from all surfaces of the fold out top) and apply poly, or get some shellac flakes and try again.  Can I just wipe all the shellac off with denatured alcohol, sand, and poly?

The body of the cabinet is fine and I'll just clean that.

[Uturn]

Shellac is awesome stuff!  I would not replace it with poly. Poly has a different look and feel, and you could be killing the value of an antique. Clean it with denatured alcohol diluted in water, sand any rough spots, reapply new shellac over the old. One of the great things about shellac is it is reactivated by alcohol and does not need to be removed to reapply.  The new coat will mix with the old.  The only problem I can see happening is if either the old or new shellac is tinted and the other is not. You will get some color variation. 

[geekette]

So do you pad it or brush it? 

[Uturn]

I usually use foam brushes, but cotton rags work also.  Old t-shirts work great.

[BDWW]

You'll probably want to pad*. To brush shellac well you need a high quality natural bristle brush ($25+). With cheaper brushes you'll almost certainly get runs because the brush doesn't flow well. Shellac has very low viscosity.

*Rather than the instructions that say to load up a pad, and squirt shellac into it, I just use a square of lint-free cloth. Fold it a couple of times. Dip one folded edge into a cup/jar of shellac, and drag it across the surface in one smooth motion edge to edge. Don't press down, just drag across. Dip into your jar again, and drag across the next run. The key is to keep a wet edge, and let the shellac flow naturally out of the cloth. 

Don't worry about any missed spots in each coat, just keep progressing and you'll get them on the next pass. If you try to rework shellac, it will just gum up. Wait about an hour, and repeat the process. It takes a bit of practice, but as has been mentioned shellac is very forgiving, and you can always rub it down with alcohol and start over.

[geekette]

Flakes or pre-mixed?  The flakes are expensive, but I read...somewhere...not to use the pre-mix on old furniture.  There seems to be a lot of conflicting info. I just want to get it done and be able to use the machine.

[BDWW]

Either should work fine, just make sure you get a newer can if you go premix. Premix has a limited shelf life, I wouldn't use something more than a year old. Flakes are great for long term storage. You only have to mix what you need and can control the cut easily.

[Uturn]

I find the store bought to be a bit thick.  Another great thing about shellac is it is easily thinned by adding some denatured alcohol.  I mix my own, but I also do enough finishing that it makes sense to have flakes on hand.