Raise grain/pumice

Construction and repair of Classical Guitar and related instruments
vesa
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Location: Sulva, Finland

Raise grain/pumice

Post by vesa » Sun Dec 16, 2018 10:25 am

When finishing RW.
1. Do you raise grain-sand-raise-grain-sand...etc. and then give the smooth surface
spit coats of shellac before pumicing (is this to overkill?)?
2. Or do you make the surface reasonable smooth by scraping and sanding
and then spit coats and pumicing ?
3. Plan C (something else)?

Vesa
Vesa Kuokkanen

Antonio Marin nr. 813 1995 (Bouchet)
Vesa Kuokkanen 2016

vesa
Posts: 833
Joined: Tue Mar 01, 2016 12:52 pm
Location: Sulva, Finland

Re: Raise grain/pumice

Post by vesa » Fri Jan 04, 2019 10:39 am

Nobody grainfilling IRW with pumice anymore? :)
OK the point with my question was:
Would it be easier/faster to pumice when the surface is not totally smooth (as it is after raise grain-sand sequence) because you would (at least theoretically) have a bit more meat (RW dust) to work with?
OR would you get too much slurry that can be difficult to get rid of?

Vesa
Vesa Kuokkanen

Antonio Marin nr. 813 1995 (Bouchet)
Vesa Kuokkanen 2016

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Michael.N.
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Re: Raise grain/pumice

Post by Michael.N. » Fri Jan 04, 2019 12:22 pm

Don't see the point of 1.
2 is the normal method.
Historicalguitars.

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Alexandru Marian
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Re: Raise grain/pumice

Post by Alexandru Marian » Fri Jan 04, 2019 12:53 pm

I sand to 240 or 320 depending on how the rw responds to it, raise the grain with water, sand again. Do a very very light coat of shellac then start the pumice rubbing with alcohol only. For me, the more shellac, the worse it goes. A bit helps glue the slurry but too much and it turns very messy. In theory a lot of sealing helps keep the purflings clean but the rubbing with alcohol wipes any seal instantly so you just end up with a lot of shellac in the mix to create a sticking goo. The goo can be dealt with in a couple ways: a very wet (alcohol) cloth can easily break and spread it, and the sooner you do it the better. The next day it will be harder to break, so whatever leftovers i have for the next day, I first reduce by more sanding (very carefully as to not expose new pores) then use the wet cloth and a bit of fresh pumice.

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geoff-bristol
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Location: Bristol - UK

Re: Raise grain/pumice

Post by geoff-bristol » Sat Jan 05, 2019 11:40 pm

You can apply several coats shellac and let dry. Then rub with pumice and white spirit ( household paint thinners ) It stays wet longer than spirit - and the dried shellac still seem to buff into the bare wood. The thinner evaporates off completely - so its not big deal if it goes wrong. Makes a very smooth surface. You can add some dark pigment to the pumice as well - I use cassel earth ( but raw/burnt umber would do ) Once smooth seal up with a brushed shellac coat to set it all before any more sanding.

Not a fan of water on bare wood - if it can be avoided !

James Frieson
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Re: Raise grain/pumice

Post by James Frieson » Tue Jan 08, 2019 2:34 am

Shellac and pumice make an excellent non-slip surface

Stephen Faulk
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Re: Raise grain/pumice

Post by Stephen Faulk » Tue Jan 08, 2019 5:35 am

James Frieson wrote:
Tue Jan 08, 2019 2:34 am
Shellac and pumice make an excellent non-slip surface
Should we put it on skateboard decks and stairs ? LoL
Patience at the bending iron pays in rounded dividends!

Tobias Braun
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Re: Raise grain/pumice

Post by Tobias Braun » Tue Jan 08, 2019 7:21 am

Good morning!

Just to add one more funny comment that I "invented" in a conversation with an English friend/colleague a couple of years ago: "I have a poor feeling about your pore filling." :-)

Have a nice day!

Tobias

Stephen Faulk
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Joined: Tue Jul 03, 2012 3:27 am

Re: Raise grain/pumice

Post by Stephen Faulk » Tue Jan 08, 2019 9:17 am

Tobias Braun wrote:
Tue Jan 08, 2019 7:21 am
Good morning!

Just to add one more funny comment that I "invented" in a conversation with an English friend/colleague a couple of years ago: "I have a poor feeling about your pore filling." :-)

Have a nice day!

Tobias
In some cases the filling is fine, but some are born with poor pores. They can't help it, and it's not a big matter. Now a bartender who pours a poor pour, that's no laughing matter. I want a good pour, preferably scotch.
Patience at the bending iron pays in rounded dividends!

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