French Polish Question

[Diane Kauffmds]

I've started fp my guitar for the first time. I started on the back and I know that I have several days, with numerous sessions to go before I'm done. I may be putting it on a bit thin, but at least it's even over the entrie back.

Once I'm done, should the shellac be allowed to harden further before doing the opposite side? If so, how long? How long after I've done the whole guitar, before I can attach the bridge, etc. and string her up?

Thanks!

Here is the result of my first session. Truthfully, this was my second session, but I wasn't satisfied with my first attempt, so I stripped the shellac and started again. As I said, it may be a bit thin, but I'd rather do more sessions, than apply too much and really mess it up.

first attempt 1.jpg

first attempt 2.jpg

[johnnparchem]

I have no definitive answers to your question (at least none that I would trust) but I FP the entire guitar at once. I will do the back for a while (two to three charges of shellac), followed by a side, followed by the top, followed by the other side. So I guess I am waiting only as long as it takes to get bored with a side (1/2 to one hour). Once finished polishing I do let every thing sit a week or so before I buff and glue on the bridge.

[Diane Kauffmds]

I have no definitive answers to your question (at least none that I would trust) but I FP the entire guitar at once. I will do the back for a while (two to three charges of shellac), followed by a side, followed by the top, followed by the other side. So I guess I am waiting only as long as it takes to get bored with a side (1/2 to one hour). Once finished polishing I do let every thing sit a week or so before I buff and glue on the bridge.

So, you have no problems with placing the recently fp guitar on a surface? I worry about imprints in the finish. I had problems with my fingerprints imprinting on my OM, even a week after leaving it sit. But, I didn't french polish it.

I really don't want to have to redo the guitar, or repair the finish this time around. I'm a bit gun shy about the finish.

[johnnparchem]

I would wait for Brian to respond as he is a true FP expert. With FP the shellac should be going on thinner than your previous pad and sand method. My FP bench setup is carpet with cotton tea shirt material on top.

[Diane Kauffmds]

I would wait for Brian to respond as he is a true FP expert. With FP the shellac should be going on thinner than your previous pad and sand method. My FP bench setup is carpet with cotton tea shirt material on top.

It's going on much thinner and seems hard and dry when I'm done. Because of physical limitations, I dont have the stamina or strength of a lot of people on the forum, and I don't know how that effects the fp hardness.

Thanks for your help John. I learned a lot.

[B. Howard]

I will do one rim and one side in the same session and then do the other in the next. My system is to do the bass side rim and back together and the treble side rim and top together. Think T's and B's. This ensures that the finish is built evenly on the entire instrument and will have the same color and luster. I will do my sessions about 2-3 hours apart, that is typically enough time for the previous session to harden enough to to allow me to do the other side and allows me to get one session or more on the entire guitar each day.

One of the great things about a FP finish is that when done properly it is pretty much good to go a day after the last session. Alcohol evaporates so much quicker than the solvents in lacquer and by applying the finish in so many fine layers there is no solvent really trapped in the film. So my usual practice is to wait a day or two , do a light cut and buff, and then glue my bridge and set my neck.

In response to your query about pressure during application. That is one thing you really need to make a good durable FP finish. The two most common mistakes are not enough sessions and not enough pressure during application. It is the pressure that makes the finish hard and resistant to sweat and abrasion. That is the difference between a FP and a sprayed or brushed shellac finish. It makes a world of difference in durability and is one of the reasons that FP gets such a bad rep for being fragile. you may need to do shorter sessions and more of them as your stamina allows. I would also recommend pummeling rather than stretching at the end of each session. Here is a link to a presentation I did a while back where I talk about pummeling a FP finish.https://www.youtube.com/watch?v=aJ5Zmm9ZKvc

[Diane Kauffmds]

Thanks Brian. I must be doing it right then. I just got done with session 4 for the back, and the first session on the sides. I thought about doing each rim separately, but wasn't sure if I should, so I did both in one session. I had to hold the guitar firmly in my lap, with the side I'd just done against me. It didn't mar it at all and seems as hard as a rock. I timed myself and it took me 1 1/2 hours to complete and I sweated bullets. If I'd known the exercise I'd get french polishing, I would have done it long ago. Lol

I'll follow your pattern. Thanks again for taking the time to answer my questions.

1 left.JPG

1 right.JPG

1 wedge.JPG

[glasalle1]

I use the following, and really like it:

http://www.stewmac.com/Luthier_Tools/To ... older.html

I use this for both French Polish and Tru Oil (only 2 finishes I have tried so far).

Glenn

[Diane Kauffmds]

I use the following, and really like it:

http://www.stewmac.com/Luthier_Tools/To ... older.html

I use this for both French Polish and Tru Oil (only 2 finishes I have tried so far).

Glenn

Thank you for the information Glenn; I'll check it out.

[Oldsoldier]

On the subject of French Polishing, I've been pleased with the final results I got in French Polishing two ukuleles. However, I was not happy with the result I got from pumicing, so I stopped pumicing and left the grain open. I'm about ready to start finishing a OOO guitar with rosewood back and sides, and I don't want open grain under the French Polish. Any recommendations for a commercial grain filler to use prior to French Polishing?