Reacquainting myself with French polish

[SColumbusSt]

I used to have the same issues when spiriting off. When I got to that step on my current build I put a new cover on my pad, added literally one drop of alcohol and worked in circles. I used four drops on the top and back, two on each side and one on the neck each session and did three sessions two days apart. Voila, no scratches or streaking and it really did remove the orange peel look.

I think I was using too much alcohol before. Also, in my experience the cover on the pad gets crusty once it has had shellac on it, even a little bit. A fresh cover in the spiriting off step makes a big difference.

[JonWint]

I level the shellac between every 2 or 3 coats during finishing. I “wet” sand with 400 grit wet/dry and end with 800 grit. Put a couple drops of oil on the paper to start. Thereafter, oil from the pad will be enough.

I don’t pore fill prior to French-polishing. I apply shellac coats until the pores are filled to my desired level. I often stop when the pores are only filled to about 95% to simulate a vintage look.

I do very little (if any) “spiriting off” with alcohol at the end because the surface is already level. I usually don’t do a final polish but leave it with worn 800 grit once-over to give a satin look like 100-year old shellac.

Photo shows an "off-the-pad" finish; no polishing. Second photo shows high tech sanding block and paper.

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[Neil K Walk]

I’ve been using 800 and 3000 grit with slightly soapy water and following the grain and going more by “feel” rather than sight. I’m encouraged by the smoothness but the goal is to get less of a “halo” around the reflections. The pictures are showing some good mirror- like reflections when not viewed directly but there are still flaws in the surface that are dulling the highlights.

That being said I appreciate the insight of using less alcohol. I’ll definitely try using a fresh phad and 1-2 drops of alcohol.

[Neil K Walk]

Spiriting is proving to be a difficult concept and I'm finding that no matter how hard I try I'm not going to get things 1000% smooth. I've sanded with 800, 2000 and 3000 grit with both mineral spirits and soapy water and I'm still seeing lots of swirls and microscratches.

So I've opted to do one final session with no oil and let the finish cure. There was very little oil buildup on the surface. I did my last session on Thanksgiving and the surface is dry to the touch and doesn't smear as if it were freshly applied with some oil still in the mix. Here's what it looks like 4 days later:



What to do next? More sanding with the fine grit? Another spiriting session or should I just try to see if buffing would clear up scratches and the spectral highlight. If I am to buff, what compound should I use?

[redir]

As I am sure you know by now it's also a lot more difficult to FP the top with the bridge glued on. Classical guitars are a bit easier becasue the wings of the bridge are thin and you can go right over them.

Anyway if this is your first time French Polishing you are doing a fine job of it.

I don't polish out shellac anymore because I seem to always burn through the finish. So all my FP finishes are done 'off the rag.' The only time I sand is if I screw up or fins a cat hair or something like that in it. Then I will use oil to 'wet' sand.

If you do use a polish then something like Meguiar's Auto polishes in very fine cut works well.

Another really excellent tutorial online is one done by Pablo Requena.

[JonWint]

Your surface isn't flat. 3000-grit won't level it. Look at the photo in my previous post. I achieve a flat surface by block sanding every couple of coats of shellac with 400-grit. Are you using a hard backer for the paper?

Just use a drop of lube oil on the sand paper instead of soap and water. Oil can be cleaned off at the end with naphtha.

You might be using too much shellac. When I add shellac coats, it is "dry to the touch" 10 seconds after application.

[Neil K Walk]

Yes, I’m seeing an “orange peel” effect that indicates that the surface isn’t flat which confuses me since I started the process by sanding it smooth with 320 grit then after a couple sessions wet sanded it with 3000 grit and mineral spirits. At that point it felt smooth as glass to the touch but now it’s not. If I were to go back and do that again even with 800 grit I’m afraid I’ll just burn through the finish though.

[Neil K Walk]

Originally Posted by redir

As I am sure you know by now it's also a lot more difficult to FP the top with the bridge glued on. Classical guitars are a bit easier becasue the wings of the bridge are thin and you can go right over them.

Anyway if this is your first time French Polishing you are doing a fine job of it.

I don't polish out shellac anymore because I seem to always burn through the finish. So all my FP finishes are done 'off the rag.' The only time I sand is if I screw up or fins a cat hair or something like that in it. Then I will use oil to 'wet' sand.

If you do use a polish then something like Meguiar's Auto polishes in very fine cut works well.

Another really excellent tutorial online is one done by Pablo Requena.

I'm seeing burn through as well. I've got the surface as smooth as glass but spiriting is making streaks in the shellac. I'm trying to use just one drop of alcohol but I'm using a used pad from one of the first building sessions that I keep moist in a mason jar. I may have to reintroduce a drop of shellac into the pad.

BTW, I also used a dry 4" buffing wheel on my hand drill about 2 days after the last session and it did wonders for the smoothness.

OTOH that area around the bridge is NEVER going to be smooth.

In any event, I think I should probably start working on finishing my second build now, starting with the back.