I’ve used your shellac as my finish of choice for a number of years. Once numerous coats have been brushed on, I sand with 320 and then #0000 steel wool, then wax. Several years ago I built a piece of furniture that consisted of a botton hutch with a bookcase mounted on top. Gave it away as a wedding gift. One of the shelves and on the edges of the top of the hutch (which were rounded over) became marked. They look like dull spots comapared to the rest of the finish. They wouldn’t sand out but can be repaired with another coat of shellac and sand etc. I’m trying to figure out what caused it to occur. The shelf had numerous areas where this occured but not the whole piece. The hutch top seems to be mostly on the round overs with 1 other spot.
Would anyone in the research dept. etc. be able to give some ideas what caused this. Looked thru many woodworking forums but could find nothing. Thought maybe they cleaned it with something that reacts with shellac, but the whole piece would be the same. Maybe water on the shelf, but that doesn’t answer the round overs on the top. Would appreciate any help you can provide.
Replies
Sounds to me like the "dull" spots hadn't been sanded well enough before the shellac was applied, causing the shellac to soak in more in those areas than in other areas.
Two other typical sources of this would be either water marks - where the water opened up the wood grain, resulting in more finish soaking in there than elsewhere - or some type of endgrain type swirl in the wood where the shellac soaked in more than it would have otherwise.
Whatever the cause, from your description I'd say that the shellac soaked in more in those areas and thus didn't build up as it did in other areas. Which is why another coat of shellac fixed the problem. The first coat sealed the wood, allowing the second coat to build a film on the surface.
If I understand correctly, when you gave the piece away several years ago, the finish was fine? And recently, you have seen the piece and and the spots are present? If this is the case, maybe the piece has been splattered with alcohol, ammonia, or several other liquids?
Malcolm
http://www.shellacshack.com
The piece sat in our home for at least 2 years before we gave it away. It was perfect at that time. We gave it away in August/05. It was only in the last year that this began to happen. The piece received at least 6 coats of 2 IB. cut of shellac before it was finish sanded etc. Will an ammonia based cleaning product cause this. Almost positive it wasn't alcohol, unless there is an alcohol based cleaning product out there. Thanks for your input. What should people clean or dust with?
Alchohol would just disolve the finish and cause it to harden in a odd way. Any mineral spirits/ kerosene based (endust, pledge) polish wont hurt it. Most likely is water or heat with amonia as a posibility.
Pardon my spelling,
Mike
Make sure that your next project is beyond your skill and requires tools you don't have. You won't regret it.
It should be an easy repair. First make a french polish pad and use straight alchohol on the affected area. Use a very quick, sweeping/wiping motion. You want the alchohol to soften the Shellac but not stick to the pad. If this dosent work use the same alchohol soaked pad to remove the damaged shellac and refinish with another pad using traditional padding technique. There are spot removing chemicals out there for shellac, and I have heard that they work. But I don't know there names, maybe someone else knows
Edited 5/22/2007 11:28 am ET by mudman
Ammonia is a solvent for shellac and can surely damage it.
I've always felt that a cloth just dampened with water is good for cleaning and dusting.
I would go along with the previous two posts.
Malcolm
http://www.shellacshack.com
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