Furniture, Wood and Cabinetry Finishing - Shellac and French Polish
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gonzoguitars
03-06-02, 12:37 AM
I probably should have surfed this site more but I saw there is no listing for my question. My name is Tim Gonzalez and I am a Luthier (guitar building and repair) and I have a 3/4 bass that I repaired when the neck was broken. The way to touch this type of finish is often french polish but I don't have much experience with frenching. I am working with Behlen's Super Blonde shellac flakes and the Behlen's Behkol which is Isobutanol and Ethanol. The directons are not writen writen well but I understand it to be a one to one ratio. I have mixed it over a one to one and is still "clumpy". (I love getting to use that word)
Does anyone out there know about shellac and french polish? What consistancy do I want. If I stick a dipstick (I love that word too) how many seconds should it run before it starts dripping? Brush vs. Sray, What is the best oil to use on the rag and what is the best rag to use?
If you can answer any of these questions please let me know or post were I could go on the web to find these kind of answers. Thank you,
Tim Gonzalez
Does anyone out there know about shellac and french polish? What consistancy do I want. If I stick a dipstick (I love that word too) how many seconds should it run before it starts dripping? Brush vs. Sray, What is the best oil to use on the rag and what is the best rag to use?
If you can answer any of these questions please let me know or post were I could go on the web to find these kind of answers. Thank you,
Tim Gonzalez
George
03-06-02, 05:00 PM
Tim:
Let's take the questions as they appear:
1- The consistency I use is 2:1 - alcohol to flake. Normally, I'd make up only a pint at a time unless I had a lot of work to do.
2- Dipstick measures are not consistent unless everyone is using the same size stick and putting it into the finish to the same depth...A Viscosity guage used by spray painters would be much more useful.
3- Shellac can be brushed or sprayed - don't know what you're looking for here...
4- I use mineral oil (from the drug store) for the oil - pure cotton (also from the drug store) for the interior of the pad, and linen (150 threads per inch or finer) from a good fabric store.
Don't let the cost of the linen throw you - it'll probably be $12-$15 a yard - but a yard from a 5' bolt is a LOT of linen. I keep what I'm not using stored in a zip Loc freezer bag - dust free and handy when I need it.
Let's take the questions as they appear:
1- The consistency I use is 2:1 - alcohol to flake. Normally, I'd make up only a pint at a time unless I had a lot of work to do.
2- Dipstick measures are not consistent unless everyone is using the same size stick and putting it into the finish to the same depth...A Viscosity guage used by spray painters would be much more useful.
3- Shellac can be brushed or sprayed - don't know what you're looking for here...
4- I use mineral oil (from the drug store) for the oil - pure cotton (also from the drug store) for the interior of the pad, and linen (150 threads per inch or finer) from a good fabric store.
Don't let the cost of the linen throw you - it'll probably be $12-$15 a yard - but a yard from a 5' bolt is a LOT of linen. I keep what I'm not using stored in a zip Loc freezer bag - dust free and handy when I need it.
gonzoguitars
03-06-02, 05:28 PM
George,
Thank you so much. What I have is at the neck joint of this bass a lot of the old wood got torn out and so I had to replace a lot of wood that is in the white. All around the new wood is the old varnish. I'm pretty sure that the best way for me to put it on this job is to brush and rub but I'm very curious about spraying it on other projects. Can you say a little about spraying it? I know that it needs to be spayed with very light coats, but how many do you recomend if you are finishing a new piece (I know repair is always dependent on the old finish). If you want to say anthing about measuring the viscosity I'm interested as well. Oh yah, I also wanted to know how long will it store.
Again, thank you so much for taking the time to respond to me.
Tim Gonzalez
Thank you so much. What I have is at the neck joint of this bass a lot of the old wood got torn out and so I had to replace a lot of wood that is in the white. All around the new wood is the old varnish. I'm pretty sure that the best way for me to put it on this job is to brush and rub but I'm very curious about spraying it on other projects. Can you say a little about spraying it? I know that it needs to be spayed with very light coats, but how many do you recomend if you are finishing a new piece (I know repair is always dependent on the old finish). If you want to say anthing about measuring the viscosity I'm interested as well. Oh yah, I also wanted to know how long will it store.
Again, thank you so much for taking the time to respond to me.
Tim Gonzalez
George
03-07-02, 03:20 PM
Tim:
Spraying is one of the best ways to obtain a smooth finish with a minimum of debris. This is especially true using lacquer or shellac because it dries so quickly.
The apparatus used can range from a professional rig (such as by Binks or Devbliss) all the way down to an airbrush - such as Pasche.
What you spray (and how much) will determine to a large extent which apparatus is correct for your long term needs. You may opt for a 'pro' ugn, or a smaller 'homeowner' type may be more what you need (and can afford).
The number of coats of finish is dependent on the material being used, as well as the look you're trying to achieve.It can vary from 3 to 30 (believe it or not!).
When you talk about storing shellac, I never keep it longer than 2 months after mixing. I keep mine in an airtight container and use one of the new gas aerosols to remove the oxygen from the can before sealing.
Shellac (or more properly the alcochol) is an anhydrous material - it will absorb water. If enough water is absorbed by the shellac mixture, it will not dry properly and will leave you with a gummy mess.
Spraying is one of the best ways to obtain a smooth finish with a minimum of debris. This is especially true using lacquer or shellac because it dries so quickly.
The apparatus used can range from a professional rig (such as by Binks or Devbliss) all the way down to an airbrush - such as Pasche.
What you spray (and how much) will determine to a large extent which apparatus is correct for your long term needs. You may opt for a 'pro' ugn, or a smaller 'homeowner' type may be more what you need (and can afford).
The number of coats of finish is dependent on the material being used, as well as the look you're trying to achieve.It can vary from 3 to 30 (believe it or not!).
When you talk about storing shellac, I never keep it longer than 2 months after mixing. I keep mine in an airtight container and use one of the new gas aerosols to remove the oxygen from the can before sealing.
Shellac (or more properly the alcochol) is an anhydrous material - it will absorb water. If enough water is absorbed by the shellac mixture, it will not dry properly and will leave you with a gummy mess.