malcolmbebb Posted December 24, 2011 Share Posted December 24, 2011 The ends of my (aforementioned) mahogany Lachenals have what seems to be the usual selection of scratches, scrapes and dull spots. I was wondering what the original finish is (pre 1900), whether it's lacquer or varnish, and how best to remove it. Following that, what would be the best replacement finish - I would prefer not to mask the wood detail too much. Any special preparation or just sand smooth? And finally, there are a few hairline cracks - how best to deal with those? Thanks for any ideas, Malcolm Quote Link to comment Share on other sites More sharing options...
SteveS Posted December 25, 2011 Share Posted December 25, 2011 (edited) Malcolm The finish is almost certainly shellac An easy test is to wet a small inconspicuous area with alcohol (methylated spirits (meths) / denatured alcohol) and if it goes sticky then chances are its French polished with shellac. The shellac used was probably blond or lemon shellac. Other colours are available, including button shellac, which is a brown colour. This is my method to remove old shellac: using a brush paint meths onto the item to soften the shellac, then place it into an airtight container (I use a plastic box) with a small amount of meths in the bottom. Leave overnight. In the morning the shellac having been exposed to alcohol all night should be nice and soft. Open the lid to the box and using 00 wirewool, scrub the old shellac off. This process should take it back to the original wood. The woodwork will then need to be prepared for finishing. I usually repair the woodwork before I strip the shellac back - allows some degree of blending new wood with old finish and patina. How fine are the cracks you mentioned? Hope this helps. Steve Edited December 25, 2011 by SteveS Quote Link to comment Share on other sites More sharing options...
malcolmbebb Posted December 25, 2011 Author Share Posted December 25, 2011 . How fine are the cracks you mentioned? Steve Thanks for the info. On the 20 button box there is a crack near a corner, it's about 1/2 inch in and 1 1/4 long. On inspection it goes right through. It's on the air button edge. First attached photo. It also shows the scratching etc round a screw, which would be nice to clean up. . The 30b has two smaller cracks. The second photo, sorry the focus isn't brilliant, is right through. The third I'm not sure if it's a crack or a scratch. Both have a fair number of scratches. Is this one of those jobs where psyching yourself up to do it is more work than actually doing it - or the reverse? (This isn't for resale - at least, not yet - it's for me!) Cheers Malcolm Quote Link to comment Share on other sites More sharing options...
Frank Edgley Posted December 26, 2011 Share Posted December 26, 2011 There is a product that I have seen and used which swells the wood around a crack and glues it together. Can't remember the name offhand, but it is used to repair wooden chairs.....maybe something like "Chair Lock?" You might try that for the cracks as it will not only glue the wood but also make the cracks thinner, if they are not already too wide. I would suggest reinforcing the cracked area behind the grills. Lee Valley in Canada and hobby places online sell 0.8 mm Baltic birch plywood that can be cut using scissors. You can use thick Crazy Glue to attach the piece. This glue is easy to work with as it does not set up instantly, giving you a chance to remove your fingers before you become trapped. After the glue has dried sufficiently (a few minutes) you can trim it and/or thin it further by hand using 320 grit sandpaper or a Dremel tool with a half inch sanding drum. Quote Link to comment Share on other sites More sharing options...
Alex West Posted December 26, 2011 Share Posted December 26, 2011 Frank I think the product you mean is Chair Doctor, made by Veritas. As far as I remember, it's an aliphatic resin glue (like Titebond original) but it's a low viscosity glue so it gets into even quite small cracks. The syringe type applicators they supply it with are useful for getting the glue in minute quantities just where you need it. I've used it successfully for stabilising ebonised fretwork which tends to de-laminate over time. Your cracks don't seem so big Malcolm so I'd be tempted just to reinforce them as Frank suggests and use either Chair Doctor or even ordinary Titebond without trying to fill them with a wood shim. If you wanted to make them disappear, you can mix glue with wood dust (taken from a hidden part elsewhere on the fretwork) and fill the surface of the cracks, then sand them back with very fine paper or wire wool. I'd suggest that your cracks don't need this kind of treatment Alex West Quote Link to comment Share on other sites More sharing options...
malcolmbebb Posted March 28, 2012 Author Share Posted March 28, 2012 Just to revive this a little - I've been reading up on French polishing. Done properly it can be time consuming, and I wonder whether the finish on the basic concertinas would have used traditional polishing methods? Would they have brushed the shellac, or would they have done it the hard way? Cheers Malcolm Quote Link to comment Share on other sites More sharing options...
Geoff Wooff Posted March 28, 2012 Share Posted March 28, 2012 (edited) Just to revive this a little - I've been reading up on French polishing. Done properly it can be time consuming, and I wonder whether the finish on the basic concertinas would have used traditional polishing methods? Would they have brushed the shellac, or would they have done it the hard way? Cheers Malcolm It certainly is time consuming.. I am on the 32nd coat of French polish on two pieces of Elm at present. That is one application each day and a rub down after the tenth and twentieth coats and when I am happy with the depth of coverage I will finally finnish with a liquid metal polish, usually Brasso. I can imagine that lachenals perhaps either did this work in large batches, so one person's job was to add a coat of FP each day to each end of dozens of concertinas or they used a brushing varnish for the cheaper models. Back in those days everyone at the Factory had their specialist 'Trade' and the wood finnisher was no exception. Good luck with the restoration, Geoff. Edited March 28, 2012 by Geoff Wooff Quote Link to comment Share on other sites More sharing options...
apprenticeOF Posted March 28, 2012 Share Posted March 28, 2012 Speaking of Lee Valley... after trying to teach myself french polishing in the traditional manner (shellac flakes etc.) with only fair results, I purchased some of their prepared french polish. It is advertised as being compatible with all old finishes. Much better results using this product given that I started with zero experience in french polishing. At least I can eliminate errors in making up the polish - plus it has a long shelf life. A bit pricey, but for me, worthwhile. In your picture, the finish doesn't look too bad. I found this product to be especially good for "sprucing up" the finish, rather than refinishing. Doug Quote Link to comment Share on other sites More sharing options...
malcolmbebb Posted March 28, 2012 Author Share Posted March 28, 2012 Thanks - one box is getting new ends from Bill Crossland, so I will be starting from scratch there. As for the others (above), I am as yet undecided. Probably depends how the first one goes, but I plan to do something with them. When time permits... Malcolm Quote Link to comment Share on other sites More sharing options...
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