Shellac Help

[Clancy]

Hi All,

I've been applying Hard Shellac to a couple of OM bodies & have some queries.

I have mixed the stuff in the bottle 50/50 metho.
My method has been to 'swooge' on an initial coat with the grain.
I have then applied further coats with a pad, moving in a circular motion.
The pad is initially charged with the 50/50 shellac mix.
Each additional charge to the pad uses less shellac mix & more metho until the last charge is only metho.
I then move the pad with the grain only.

This has worked well with the back & sides which were pore filled with epxoy, sanded back & an epoxy wash coat.
The bare spruce top doesn't seem to want to go so nicely.
Even though the top gets shiny, & you can even start to see a reflection, as the coats build the grain lines become ridges and the top feels rougher rather than smoother.
Twice now I've cut it back to smooth with 600/800 grit and both times these grain ridges have returned.
Is this right and I should just continue building & cutting back?
Will I ever get a 'flat' finish

I've also noticed a crystalline shellac ridge building on the binding edge where it meets the soundboard (at the bottom of the guitar.
It makes me wonder if my last application (metho only) is pulling the shellac out of the grains and depositing it on the sounboard edge??

Also, I started out using oil (parrafin from a vet supply) regularly but I seem to be able to move the pad around now without the need to add oil. Have I overloaded the pad with oil? If so, then how could I be pulling shellac out of the grains.

Bit confused here, but hey, I'm just learning

[kiwigeo]

Craig,

What's the stuff in the bottle? ie what cut is it? For bodying I use a 1.5 to 2lb cut.

Uneven shellac build up on the edge of the top....I treat this edge as a seperate surface and during a top session will work the pad specifically around the edge before doing the top.

If you're using oil are you allowing it to come to the surface and then removing it using a pad loaded with meths (ie spiriting off)?

How long are you waiting between bodying sessions?

You say the ridges are parallel to the grain on the top? Applying shellac using a pad leaves a very thin finish on the top and often you'll be left with ridges and depressions that match the grain...depending on the wood and how it's been sanded. This is possibly what youre seeing. Incidentally one way of telling a french polished top is actually by looking for this phenomenon.

[Clancy]

Martin, the stuff in the bottle is Ubeaut Hard Shellac.
Neil has stated on the OLF that it's

In real gallons it's a little over a 3lb cut
In US gallons it's around 2.6lb cut.

So cutting this in half would give about a 1 1/2 lb cut.

If you're using oil are you allowing it to come to the surface and then removing it using a pad loaded with meths (ie spiriting off)?

I thought the last charge to my pad of 'metho only' was for spiriting off the oil. Should I be using a different pad that's only ever had metho in it? Should I be waiting 'x' hrs for the oil to surface before doing this?

How long are you waiting between bodying sessions?

I've been doing them once in the morning and again once at night. Too soon?

Applying shellac using a pad leaves a very thin finish on the top and often you'll be left with ridges and depressions that match the grain

This is what I'm seeing.

Incidentally one way of telling a french polished top is actually by looking for this phenomenon.

Well there you go. So a shiny, reflective surface but with, let's call them 'grain accents', is OK.

Thanks mate for all that.
(BTW, the top is some Englemann from Graham Hein.)
I purchased Neil Ellis' polishing book and went over & over the instructions at LMII, but neither gives a good description of what french polished spruce should look like.
I've been expecting to get a similiar result to spraying NitroC......

One other question.
In your experience when do I stop?
I know the shellac finish should be thin, but how thin is too thin.
So far I've only used about 100ml of Ubeaut Hard Shellac from the bottle - that's for 2 OM bodies: top, back & sides.

[kiwigeo]

Hi Craig,

Comments:

1. I thought Hard Shellac was closer to a 4lb cut.

2. For spiriting I use a separate pad which only gets loaded with meths. I also change out the cover on same on a regular basis.

3. I usually wait a minimum of 3-4 hours or preferably overnight before spiriting off. This gives the shellac time to harden a bit and also for the oil to come to the surface. If you spirit off straightaway your going to start pulling off the shellac you've just applied during the preceding body session. Don't confuse spiriting off with stiffing off....stiffing off is done immediately following a body session and is done using the bodying pad but with meths applied. Often I dont bother stiffing off and rely on spiriting off to remove oil and level the finish.

4. When to stop? A good question. I generally do at least 8-10 bodying sessions with 2lb cut and then Id do an equal number of glaze sessions with a 1-1.5lb cut. probably a bit over the top but Im anal about such things.

Cheers Martin

[Clancy]

Excellent. Thanks Martin. What you've said makes sense.
I'll adjust my game plan.

Neil also said

Hard Shellac is mixed at the rate of 25 kg bleached white shellac to 80 litres.

Here's where Neil commented on his mix. His advice was given 4/3/11 so it's as recent as you can get.
http://www.luthiersforum.com/forum/view ... 01&t=29208
Cheers

[kiwigeo]

Excellent. Thanks Martin. What you've said makes sense.
I'll adjust my game plan.

Neil also said

Hard Shellac is mixed at the rate of 25 kg bleached white shellac to 80 litres.

Here's where Neil commented on his mix. His advice was given 4/3/11 so it's as recent as you can get.
http://www.luthiersforum.com/forum/view ... 01&t=29208
Cheers

25kg shellac to 80 litres of solvent gives around a 3lb cut. I saw it quoted as slightly higher awhile back on the Ubeaut forums...I stand corrected.

Note that I haven't tried French Polishing using hard shellac. I used the old formula but didnt have much success with it....others in here had the same experience spraying the stuff.

[Allen]

Can't help with any of the shellac questions but when I'm done on a top with lacquer I always see the grain lines telegraph through. To me it means I've got a nice thin layer of finish. When I measure the masking tape that I cover the sound hole with against a piece that doesn't have lacquer sprayed on it, the finish ends up being between .0015 and.002" thick. And that hasn't been sanded back or buffed.

[Clancy]

I now remember you saying that once before Allen. Don't breath on it, it'll double the thickness

Martin, I found myself in the perfect position to try out something new.
Alan Hamley had talked about how he's applied the newer Hard Shellac with a brush to get a satin finish so I thought I'd try to get a gloss finish by padding it on.
Will post what I end up with.

[kiwigeo]

Alan Hamley had talked about how he's applied the newer Hard Shellac with a brush to get a satin finish so I thought I'd try to get a gloss finish by padding it on.
Will post what I end up with.

Please do let us know how it goes.

[ozziebluesman]

G'day Craig,

I have had some mixed results with using the hard shellac. My experience is the hard shellac worked great on tassie blackwood but not so good on tassie sassafrass. I put it down to the sassafrass being a softer wood to blackwood but I don't really know why the difference in quality. The sassafrass guitar suffered crazing and I was not happy with the final result. From my research I thought hard shellac straight out of the bottle was a 4lb cut. My process was hard shellac diluted down to a 2lb cut, applied with a brush leaving overnight to dry and light sand the next morning. I did this nine times and the final two coats where a 4lb cut straight out of the bottle. I didn't spirit off between coats just a light 600 grit sand. No oil was used either. The guitars where left to dry and crosslink for four weeks then a final sand with 600 grit paper.

The two blackwood guitars have maintained a nice finish with no crazing.

My last weissenborn copy I used shellac flakes and followed Martin's (kiwigeo) proceedure. This process is time consuming but I love the lustre in the finish I managed to achieve. I will be using this procees from now on.

In a final comment I managed to get a lot more product on and achieve a thicker finish using the hard shellac with the brush. There where some lines, ridges left also but only visible when the instrument was held up to the light at a certain angle. The standard shellac flakes process using a rubber is a much thinner finish but looks awsome IMO.

Cheers

Alan

[Clancy]

Just thought I'd mention that the 'grain accents' are now appearing in the back & sides.
I've tried to take some pics of these to show you but it's hard to catch with a camera.

The finish is so thin & looks so cool, I'm really liking it.

The spruce top

The Tassie Blackwood

The Tassie Myrtle

[Dominic]

So, these are your first flat tops aren't they? Getting closer to string up time. Good luck with it all.
Cheers
Dom

[Clancy]

Well, it's a couple of weeks on and I reckon I'm done.
Despite all that's been going on in my life right now I managed get a coat on most nights, lightly sanding now & then when little ridges appeared or dust & stuff got worked into the finish (damn it's hard to keep the pad face clean sometimes!)
Anyways, these shots are off the pad - I think I've removed all the oil.
(The Guitar Widow has reached a new level of anxiety over my guitar obsession, as she's constantly finding me panting & breathing heavily on the bodies.........)

The Myrtle

The Blackwood

Hopefully the mirror won't crack in the next year or so!

Should have the bridges attached tomorrow. Yay!

[kiwigeo]

Looking mighty fine there Craig....looks like youre getting your head nicely around french polishing.

Cheers Martin

[Dominic]

Hey Craig, did you get the bridges glued on yet? If so you would be close to stringing them up. How did it go?
Dom

[Clancy]

Hi Dom,
Yeah I got the bridges glued on, then noticed a 4 cm long gouge in one of the tops in front of the bridge ?!?!??!
Must have scraped something across it when cleaning of the finish from the bridge area, but you'd think I'd have noticed at the time.
Still scatching my head about it

So I've been trying to repair that and make the nuts & saddles, but time is short and with the Guitar Widow out of action I'm just plain worn out.

Hopefully I'll have them strung up by the weekend but no promises.