Shellac - 1 lb cut or 2 lb cut?

[Peter Kendall]

In Robbie's Classical course he seems to use 1 lb cut, but talks about 2 lb too and I can 't determine if 2 lb is used anywhere or just mentioned.  Can anyone clarify?  Maybe I simply missed it somewhere.  

[joe]

Peter, in the general world of french polishing a two pound cut is considered standard. As with all things there are times to vary from what is considered standard. A two pound cut is thicker than a one pound cut and sometimes is too thick for the process in guitar building. A two pound cut has a harder time flashing off as opposed to a 1 pound or 3/4 pound cut. These days i do not normally use a two pound cut. Quite often I use a 3/4 pound cut. It is more controllable for me.  Scooter

On Mar 19, 2021, at 10:36 AM, Peter Kendall <peterk...@gmail.com> wrote:

In Robbie's Classical course he seems to use 1 lb cut, but talks about 2 lb too and I can 't determine if 2 lb is used anywhere or just mentioned.  Can anyone clarify?  Maybe I simply missed it somewhere.  

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[JohnParchem]

With caveat that I mix by eye and feel now, I generally mix a 2 lb cut and work with a 1 lb cut.  I find 2 lb cut gets sticky when I FP. I can French polish with a 1 lb cut all day.  Given that all of the alcohol evaporates, the feel of what works for you is as good of a consideration as any.  

[romsmith]

I've been taught to mix 2lb and then dilute by eye, roughly to ~1.5lb. Everyone has got his own way of doing this I think.

I found that I was developing repetitive strain injury when polishing with 1lb and less.

[joe]

I also start with a two pound cut and adjust by eye and feel.  Scooter

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[jwsh...@q.com]

Roman, do you think you polish faster with a two pound cut which reduces wrist stress? Scooter

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[Peter Kendall]

Seeing this is my first time I have no idea what doing by eye would look like.  Maybe I'm better doing 1 lb this time and then adjust later next time? I don't mind the extra work this time around.   

What about the cut amount protecting the top during the build process?  Would that be 1 lb or does that even matter? 

[romsmith]

Imho (and my french polishing is just about acceptable for a concert guitar), 1lb is harder to mess up. Pure 2lb seems to be very easy to mess up, even with some experience. You want to find the ratio that works for you with your technique and it's most likely somewhere between 1lb and 2lb. Other factors play a role too - how pure is your meths (eg 96% vs 99%), air temperature (6c vs 26c) etc. Simple logic suggests that 1lb cut will require quite a lot more passes than 1.5lb and my wrist joints are completely messed up, so every little helps.

[joe]

Peter, mix a two pound cut according to standard measure of shellac and alcohol and dilute that using more alcohol and math to get to what ever cut you want. Mixing a two pound cut and diluting it 50 percent gives you a one pound cut. As John pointed out he mixes by feel, as do a lot of polishers, myself included. Start standard and dilute to what seems to work best for your style of polishing. Scooter

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[joe]

Roman, for me I always had to back track with a two pound cut which ultimately led to more time polishing with more stress on my wrists, hand and arm. Robbie's advice on french polishing helped me reduce the time spent polishing and yields good results. Thanks Robbie.  Scooter

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[Ryan Evans]

Peter--

When I did my first uke I did a 1lb cut and it worked well - the concept was intimidating but following Robbies instructions I actually found it to be quite forgiving.

The biggest worry I had as I worked was in the first few passes when it didn't really feel like it was building, I wasn't sure if I had enough shellac on the pad, etc. But stick with it and it'll be fine.

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[Stephen Foss]

Roman,

2lb or not 2lb, that is the question. Whether 'tis nobler in the mind to suffer the  slings and arrows of outrageous (mis)fortune...the finishing debate goes on and on.

My limited experience has taught me that with a 1 lb cut, I can put more than twice the number of coats on the surface as with a 2 lb cut over a given amount of time. Mostly because it flashes off so quickly.

If you have weak or damaged wrists but want to use shellac (for the reasons stated here), you might try to use a 2 lb cut and brush it on 3 times a day, then sand it back flat. I've done that using ShellacFinishes Royallac (regular, not post-cat) and it came out just fine. Along this path, I learnt how to brush (use taklon brushes) and sand more carefully as well as NOT to use water as a sanding lubricant on shellac of any kind (about 9 - 12 months later it crazes like crazy; the absorbed water is trying to get out).

I like shellac as a finish. I have a buddy I build for occasionally. We've discussed finishes - he told me that his guitars "live in the real world" and they will get beat up some no matter what the finish. He (and I) believe they sound better and that is more important TO HIM than the appearance. Other customers will no doubt have a different opinion. I still put shellac on the top of steal string guitars; I tell folks that whenever they want, they can bring it back and I'll re-shellac the top. This, of course, is a poor business practice, but I'm not in business...

Steve