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I have applied shellac as a sealer on an archtop guitar. I'm going to wait a week for drying to apply lacquer.

Here we have temperatures of about 32º C and a relative humidity of around 40% now.

Do you think that drying time is enough?

You can do as little as 30 min
if you use the flake shellac if you used can shellac your good to go in an hour
a week is too redundant.

Alcohol is the solvent and dries off fast

_________________
John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

I wait overnight.


Steve

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Steve Smith
"Music is what feelings sound like"

Thank you for your replies! I never aplied before lacquer over shellac, hence my doubt because lacquer has a completely different composition.

Most lacquers contain some form of alcohol in addition to the other solvents used, so may dissolve some of the shellac. If shellac is used as a sealer or barrier coat it should be applied thinly and allowed to dry. If lacquer is applied over an existing (heavy) shellac finish it can dissolve the shellac and cause the finish to craze as the lacquer and shellac "dry" at different rates.
Shellac when it gets old will not dry, so if your shellac isn't dry to the touch within an hour when applied thinly, it is probably too old and should not be used.
A thin coat of shellac is often used as a barrier coat to seal oily woods to allow other finishes to be applied over top.

What Clay said, and you are using dewaxed shellac right?

I usually test my shellac before applying it to an instrument by putting a spot of some on a piece of glass and if it is hard to the fingernail in 24 hrs I use it. If not, I use it on other projects like a door or something.

I can't remember if that test was for shellac or hide glue but I use it for both. Anyone else heard of doing that?

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Brian R, Wood Mechanic
N8ZED

A one pound cut of shellac seems to dry almost instantly after it is padded on. It can be followed in a few minutes by another coat. A two pound cut seems to stay soft for hours.

What Bob said, times two.

And then add the acetone to the mix so you can literally watch it dry instantly.


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First off not all alcohol is the same . I never use canned shellac and I will not use denatured as there are chemicals in it we don't need. I only use EverClear and I make a 2 lb cut. This will dry in a short amount of time

So
Seal
Fill
Seal
finish coats.

I also grind my flakes in a coffee mill so they are dust for a better desolve and mix.

You only need a coat after all we are sealing.

_________________
John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

John,
How are you applying the seal coats of shellac? Spray, brush, pad?

I use a paper towel folded and use that as a brush you can use any method , I just find the paper towel cleaner and easy

_________________
John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

Thank you very much. I’m using new shellac from the can.

Thank you very much for your informative reply!!!

Make sure your shellac from a can is DEWAXED shellac!

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Brian R, Wood Mechanic
N8ZED

Thank you. The guitar is already finished and the result is very good. Lacquer on dewaxed shellac.