Replies

1. 
   Rich14 | Apr 26, 2008 07:29pm | #1

   Your description of your method of applying the shellac gives absolutely no information.

   If you give some information about what you're actually doing, we may be able to help. What dilution shellac mixture are you using? How are you adding it to the "rubber?" How are you applying the rubber to the wood?

   It sounds as though you have little or no shellac getting laid down and only a film of olive oil (olive oil!!?) looking glossy until it dries, leaving dull spots.

   Rich

1. 
   BG | Apr 26, 2008 09:16pm | #2

   Rich,"It sounds as though you have little or no shellac getting laid down and only a film of olive oil (olive oil!!?) looking glossy until it dries, leaving dull spots."That's what I think is happening too.
   I first tried this process/protocol on a piece of scrap mahogany and it came out beautiful. This 3' round table top I'm having trouble with I tung oiled back around 76 and it took forever to dry. I washed it well with mineral spirits before the shellac spit coats were applied (wipe on 1.5lb cut). As I padded the shellac the pad was picking up something from the top, perhaps the tung was still not dry. Eventually it looked okay so I went onto the boding up step.For the boding up sessions I used a four inch square tee shirt with a walnut size piece of wool. Ten drops of 2 lb shellac, 4 drops of alcohol, 1 drop of olive oil..work it on a 8-10" square area. As I swirled to the right I'd see the cloud and when I reversed direction the cloud disappeared. I'd finish up with pull over strokes. Everything looked good and the finish looked deeper and deeper with each application. After six sessions, flattened with 400 grit using a cork bottomed block. Applied another layer and then flattened with 800 grit using a cork bottomed block. I applied one last session and let dry for a couple of days. When I look at the top its got nice shiny spots and areas that appear to by totally void of shellac. All areas are dry and don't respond to finger prints per se., in other words, the shiny sections are not from the olive oil but appear to be the shellac. I can't figure out how the totally void areas could have occured...and what do i do...thanks

1. 
   Rich14 | Apr 26, 2008 10:30pm | #3

   BG,You have so many things going wrong, it's hard to tell if there is a single problem or multiple problems.1. Wood must be meticulously prepared for french polishing. There's no telling what the condition of that old tung oil finish is in. I would prepare the wood by sanding with 150, then 220 grit to get the wood clear of the old finish. Then I would brush or spray a base coat of 2# cut shellac, one or two applications before proceeding with the french polish. Level sand the base coat with 320 to remove all nibs, dust, etc. It wont be possible to perfectly level sand this thin base without sanding all the way through, so don't try.2. Oil is used simply as a lubricant for french polishing. I have never heard of using olive oil, although I suppose it could work if all other factors are ok. Linseed oil or mineral oil is the usual. I prefer mineral oil, if any at all. It's barely, if ever needed.3. You are not using enough shellac. Your pad is much too starved. Your dilution is ok, although I use a little stronger - about a 2# cut. Apply it to the inner padding of the "rubber," never to the outer covering. That's so the outer covering can act as a strainer for any shellac particles that may be present in the solution or that may form. Any particles (or even tiny wrinkles in the pad) will mar the surface of the finish. The inner pad should be fairly wet, though not dripping wet.Now, here's a "secret" about french polishing. It's certainly a beautiful finish and those who learn to do it can justifiably be proud of their skill. But it came into use long before the modern abrasive industry, especially the technologies surrounding modern automotive finishes. Using techniques from that technology can give a finsih as beautiful or better (!) than the surface that only meticulous rubbing of a constantly re-dissolved shellac surface with a cloth could accomplish without them.Carefully apply coats of 2# cut shellac, by brush or spray, level sanding every several coats with 320, until you can achieve a perfectly uniform surface. Each sanding will get better and better until all the hills and valleys of the shellac surface coalesce into one uniform ground-glass appearance. Then use 400 grit, 600 grit, then 4-0 steel wool, then automotive polishing compound.All this sanding is much easier, more controllable and actually faster than french polishing. The final step is "swirl remover." I like Meguiar's Scratch X. It's the "magic ingredient" to the process.The Meguiar's contains a clay called Kaon (the stomach-soothing ingredient in Kao pectate!) which is even "softer" than cloth, yet has a "cutting" action on the shellac.The shellac will look like glass. Compared to the effort and the final result, it's almost like "cheating." But it's not. It's simply using improved technology to a better end.But if your aim is to get familiar with french polishing - go ahead and continue with what you're doing.Here's a great resource site and a good description of the traditional way to get the results you want. Scroll down the page to the PDF, "Guide to french polishing with shellac,"http://www.finishsupply.com/articles.html Rich

1. 
   Hastings | Apr 27, 2008 04:32pm | #4

   Another great post!Your advice to the various posters on Knots has proved invaluable to me over the last year. Thanks to you, I can confidently rub out a finish going up through the grits to the swirl remover. I think this is the first time that you suggested Meguires?Thought you would like to know that your contribution is greatly appreciated.Regards,Hastings

1. 
   Rich14 | Apr 27, 2008 04:55pm | #6

   Hastings.Thank you. I'm glad I could help.I think I've mentioned Meguiar's before. It was one of those lucky finds several years ago. I knew I wanted a "swirl remover" product to use after automotive polishing compound which left the nitrocellulose lacquer finish of a guitar I was working on just a little less clear than I thought it was going to turn out.There were several swirl removers at the "Advance Auto" store down the street and I bought Meguiar's. It works so well, I've never tried another brand. But I think they all probably work the same way.I've even gone directly from 320 sanding to 4-0 steel wool to the Meguiar's on fully-dried lacquer (at least several days, if not a few weeks to allow absolutely the last molecules of solvent to evaporate) with great results. Now THAT's cheating!Pumice and rottenstone are the "old-time traditional" polishing abrasives. The main advantage of the newer technology is much, much better control of uniformity and consistency (therefore quality) of the abrasive particle size.Rich

2. 
   ashleyjohn | Sep 29, 2015 03:48am | #13

   Thank you all for your advice, I think French polishing is a very difficult skill to learn.

2. 
   hammer1 | Apr 27, 2008 04:54pm | #5

   Is this the method you used?

   http://www.milburnguitars.com/frenchpolish.html

   Beat it to fit / Paint it to match

1. 
   BG | Apr 27, 2008 06:02pm | #7

   Hammer1,
   I've attached the protocol I used. As you can see, I failed to copy the first page. The key concern I have with Rich's comments is I don't want to sand away the patina and thought, wrongly it seems, that washing with mineral spirits would be sufficient.Also note MaGuires is recommended for the final polish...Hammer: I take it back..if its not the same its awful close...

   Edited 4/27/2008 11:07 am ET by BG

   
1. 
   Rich14 | Apr 27, 2008 06:51pm | #8

   BG,Re:"The key concern I have with Rich's comments is I don't want to sand away the patina "What do you mean by "the patina?" The appearance of the surface or some color development that the older oil finish has imparted to the wood?Applying the shellac finish completely overcoats the existing finish's surface, whatever that was, replacing the "patina" with that of a shellac film, or new patina. That's the purpose of the exercise. If it's color development you want to maintain and the old oil is the problem, you really have no choice but to remove it.However, shellac is a VERY tenacious substance, and if you apply it adequately it should just seal over anything you want. Washing the old finish with mineral spirits should really be enough.Reading that "tome" of finishing instructions you posted reminded me of how tedious and dreary descriptions of french polishing tend to be. Actually getting familar with it is nowhere near as tedious as some obsessive finishers would like to make it sound. And to be honest, I think the process took on the mystique of "True Believer" status a long time ago. It works, but is now, not the only way to achieve that quality of finish.French polishers just get to work and get the job done. People who write about it dwell on minute details, in particular the special "amalgamation" that happens between the existing shellac film and the new shellac being applied by the rubber, in very, very thin amounts.That's all well and good, but exactly the same thing happens with any new shellac applied over previous applications of shellac, whether by brush, spray, or by a secretive french polishing method. The alcohol in the shellac being applied dissolves the surface of the existing film, if not the entire thickness of the film, and the end result of any number of shellac applications, is one, continuous thicker film of dried shellac resin with absolutely no demarcation where new "layers" were applied.The advice against mineral oil in favor of olive oil was also interesting in that document and unnecessarily cautious. Mineral oil and linseed have been used for as long as I can remember. Unadulterated mineral oil (no perfumes, etc) is readily available. Works great. Give it a try!Rich

   Edited 4/27/2008 11:54 am ET by Rich14

1. 
   BG | Apr 28, 2008 12:38am | #10

   Rich14,
   First of all, I do appreciate the help. By patina I mean the oxidation and darkening of the mahogany..I prefer not to sand that away.
   For years I've avoided trying a french polish because of all the hoopla and incantations required/implied for success. As you point out, just doing it works too ...and I wanted to try it. So far I'm glad I did try it. It gives you a much better feel for the flexibility of shellac...and now I'm going to learn about its do-over capabilities :)I think I'm going to strip down the top with alcohol, brush on a couple of coats of shellac and start all over with the muncea/rubber...change out the oil.

2. 
   hammer1 | Apr 27, 2008 10:33pm | #9

   I think your problem is with the tung oil. You are trying to french polish something that is already finished. You are just rubbing shellac over a surface that won't accept it well. Typically, you start with raw wood. Washing the surface with mineral spirits won't remove the tung oil.Beat it to fit / Paint it to match

1. 
   BG | Apr 28, 2008 12:58am | #11

   hammer,
   I think your right, the tung oil has been a problem for 30 years and continues to be. I thought the 3 spit coats would seal it up and not interfere with the boding coats but maybe I rubbed to hard or spent too long in one spot and went through to the tung oil. I'm going to give it one more chance and make some adjustments with the technique....little faster, little lighter. I must say however, my demo piece of mahogany came out great following the program.

3. 
   surf n kerf | Mar 25, 2015 11:00am | #12

   Hi there,

   just a thought., but how dry is dry?  (you say you get the dull spots as the finish dries.)  I use mineral oil, and it takes a good few days for all the oil to come up to the surface to be spirited off.  when my entire surface is dull looking, meaning all the oil is up, then I know it is ready to be rubbed with the pure alcohol.  I use a soft cloth, hard rubbin, and get a glossy finish every time. 

   My secret to french polish isnt prep, or the exact right mix, its just patience and elbow grease.

   good luck!