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Hi,

I'm having trouble getting a complete fill on the EIR guitar I'm working on.
I have 3 spit coats of #1 cut shellac for a base. I'm using the hard wool pad material from LMI in an old t-shirt for a muneca. Denatured alcohol and pumice on the pad. NO shellac.

Here are my questions:

1. Is this enough of a base to work with? I think so, because I am getting good fill in some areas.

2. How wet should the pad be with alcohol? It seems to dry out quickly, and I have to recharge it often. Should the surface of the guitar be wet when applying or should I be seeing more of a vapor trail? I've been using the Milburn tutorial for a guide, and I've been using more alcohol than what they say. Maybe my pad just holds more.

3. Is it common to fill the entire guitar and then go back and fill again after the shellac has had time to gas off a bit? Seems that it would stay in the pores better if it had time to cure some.

I have about 6-8 hours into this so far, and only have the back and 1 side done, with not-so-good results. I FP'd my last guitar (mahogany), and I don't remember having such a problem with the filling. That was a couple years ago though.

Thanks again for any advise.

Happy Fall! (or spring for those south of the equator)

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Horton, MI

First, you have too much shellac on already one spit coat of 1# is all is needed to start. I am a bit worried about the fact that because you have 3 sessions (not coats) of 1# shellac on you may have bridged some of your pores and they may shrink back on you later. Also you will have a very thick layer to get through to allow the pumice to cut fibers to fill the pores. This can lead to a lumpy mess.

Second, you did not mention if you are using your inner pad with the residual shellac left over from your spit coats. This is a needed. To add just a touch of shellac as you fill.

Third, Indian rosewood is many times more porous than mahogany. I will take at least two if mot three or four sessions to pumice fill.

If you are not sure you are using enough alcohol and how much pumice then I am not sure you have a good understanding of how the pumice fills so here is a basic explanation/ schedule

The process is to allow "cleared" (transparent) pumice to cut micro fibers off the wood and deposit them into the pores and the “single” spit coat of shellac along with residual shellac from the inner pad will be melted by the alcohol and create a slurry of shellac, microfibers, and a small amount of cleared (transparent) pumice to fill the pores. The pumice is not the main filler solid, it is the abrasive that cuts micro fibers from the wood to be the bulk of the filler.

Note: It is very important that all the pumice on the pad is cleared before the pad ever touches the wood!!!!!!!!!!!!!!!!!

Using a new cover to start and your inner pad with residual shellac add 2 drops of shellac to the new outer cover and smear around with your finger. Add 3 drops of alcohol to the outer pad. Sprinkle some pumice on a sheet of paper and tap the pad into the pumice. Then add only enough alcohol to the pad to clear all the pumice on the pad and apply is figure eighth motion. Add more pumice and Alcohol as the pad needs during the process


I hate t-shirt material because of the interlocking 3d weave especially for pore filling because it is easy to get pumice entrapped in the weave that you can not see and may not clear that can lead to white spots (un-cleared pumice trapped in the film and pores) . I much prefer muslin or linen.

You do not need a hard wood block in fact you are making the process harder.

If you have a copy of the Milburn FP tutorial, follow it and do not improvise. If not it can be found in the resource link at the top of the page.

Oops I miss read hard wool for hard wood never mind that part

Thanks Michael,
I'm trying to follow the tutorial to the letter. And I am clearing the pumice each time I apply it. I didn't use a pad to put the seal coats on, I just used a piece of folded t-shirt material with the shellac. Maybe that's where I went wrong. I tried to do just quick swipes to cover the surface, but maybe that technique layed it down too thick.

Here's an excerpt from Milburn in the sealing section. I read it as saying 3 times near the bottom.

"After completing the sides of the guitar, apply a seal-coat coat to the rosette and the top purflings, re-folding the cloth to a new quarter each time. With a clean cloth, coat the field areas of the top.
An example of a folded pad after it has been used to seal a section of a guitar edge. This coloration will contaminate white purflings and light wood.
You will have to make a new cloth each time you run out of clean quarters. We will repeat this process three times on the entire guitar. For each pass, we will re-fold our pad to a clean side. "

Then a little farther down they says it again.

"After applying three spit coats to the entire guitar, we will take a small artist's brush and again paint all of the purflings to provide additional protection for all of the inlay work since pumicing acts as an abrasive and can burn through the shellac to the purflings."

Don't get me wrong, I'm not dissagreeing with you. I truly appreciate your help.
I'll get some pictures tonight if I get a chance.

Thanks again.

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Horton, MI

Thought about this a little more. I probably do have too much shellac down. That's why it's taking so much alcohol to get it dissoved. Once I get it dissolved I can feel the pumice cutting the wood. And I'm getting alot of color from the wood on my pad. I've been moving the cloth to a clean section when it looks like it's getting heavily loaded. I have not been using any shellac on the pad for filling. They said to lose the shellac.

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Horton, MI

FWIW, Bob Milburn stopped using pumice and switched to epoxy a few years ago.

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Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

I did not remember the Millburn’s using three spit coats but apparently the do.

I use one pit session on the hardwoods and two on the soft wood but of course the softwoods do not get pore filled. I still suspect that the you may have a bit to much on and are not getting the pumice to cut off wood fibers.

I have know other that use only cleared pumice and shellac to fill with but the tradition process is to use the pumice to cut microfibers to be drawn into the slurry that is deposited in the pores.

You may be depleting you load of pumice a bit quick due to having to use too much alcohol to melt into the spit coats.

But in general I suspect another factor is the pores them self. Rosewood pores are typically deep and larger than mahogany. It does take more to fill.

Sorry for the miss read on hardwood vs hard wooll

Hmmmm, I wonder why?

Are you trying to tell me something Howard?

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Horton, MI

You've been a great help Michael. I am getting the wood into the slurry, it's just taking more effort than it probably should. It seems to work best if I start out an area with more alcohol and pumice and then finish up less alcohol and hardly any pumice. Looks like I'll be going over the whole thing at least one more time to get everything filled. I don't think I've bridged the pores at all.

Need to print this out so I don't forget next time.

Thanks again.

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Horton, MI

I switched years ago to epoxy first due to the ease of application and now use med thick CA for both ease and speed. Yes even on FP.