applying hard shellac with a rubber??

[contrebasse]

I've been trying to french-polish hard shellac like I do with standard shellac, with a cotton rubber and a tiny dab of linseed oil.

But it just doesn't seem to want to co-operate. I can wipe it on nicely with the pad, and it goes on much more evenly than with a brush, but once dry, I can't seem to get any sort of gloss happening.

Is this the nature of the beast, or has someone had success working with it in the traditional way?

[MacS]

Although, I never used this product, I did read that it contained Shellac and Poly.

Shellac, is an evaportive coating, while Poly is a reactive coating, what this simply means, is that Shellac can be dissolved with the proper solvent, while Poly once cured will never resolvate.

That "maybe" the reason why its not polishing up?

What you might need to do after your last coating is dry, is to do some sanding with fine sandpapers, and then some rubbing and polishing with either pumice and rottenstone, or some fine polishing compounds.

This might be the "trade off" for a more durable and chemical resistant coating.

I hope this helps.

MacS

[bitingmidge]

Because I'm too lazy to log on to the U-Beaut website to find out, what do the instructions say?

P

<EDIT- couldn't help m'self

APPLICATION:
Hard Shellac is applied in the same manner as any normal shellac.
-snip-
ALL application gear must be washed IMMEDIATELY after use.
If rubber, brush or spray equipment is left to dry it will go rock hard and become unusable.

>
Why the linseed oil? That doesn't seem to ring true to me when used with a meth-based coating??

[MacS]

I misspoke, it did not say, it contained Poly, it said, it has the durabilty of POLY.

It mentions "crosslinking" which is a term associated with catalizing, which is adding another chemical that will make the molecules overlap each other, and making for a closer bond between the molecules.

This would basically mean that once the Shellac is cured, it maybe a "reactive coating" that will no longer resolvate, making it more difficult to polish up.

Thinning, the hard shellac will make it easier to pad out, as stated in the instructions.

MacS

[MacS]

A little Boiled Linseed Oil is commonly used in French Polishing, it gives the damp pad what we call "slip or slide" which will make it easier to polish up the Shellac.

That's where the term "slip sliding along" came from. <g>

MacS

[contrebasse]

Mister midge ... although i too am a lazy cad sometimes, I did on this occasion read the instructions, check the website, search the forums AND have a good old think before posting here!

So I was wondering if anyone here had had some experience with using hard shellac as a french polish. It doesn't appear to crosslink immediately, and is dissolvable in meths even a few days afterwards, but it doesn't seem to work quite the same way as neat shellac.

The dab of linseed oil is commonly used when french-polishing as a lubricant to stop the pad "grabbing" the surface when padding out.

[bitingmidge]

Mister midge ... although i too am a lazy cad sometimes, I did on this occasion read the instructions, check the website, search the forums AND have a good old think before posting here!

My apologies, I did actually have an obvious tongue in cheek edit in the post, but it disappeared!

My guess, (and I will pull out the book tomorrow if Neil doesn't find this thread in the meantime), and it's a GUESS, is that the Hard Shellac doesn't re-desolve in layman speak, so you are applying a succession of coats over hard coats, rather than into the previous coat. That would mean that the linseed would be contaminating the previous surface?

I know nothing about French Polishing, but I've seen a lot of coating failures!

Let's see what tomorrow brings! (A blog post about not reading instructions I reckon! )

cheers,

P

[MacS]

This is from the instructions.

This cross linking takes about 20 days to completely cure, less in hot weather.

This would mean you have time to pad it out, I would be careful of the pads you use they would stiffen up, unless you wash them out.

Does the BLO help ? if not, there are other chemicals that may.

Have you tried brushing or spraying it? This chemical may work best on a lathe or by spraying. Its possible because of its hardness, it may need to be sanded and then polished up with compounds.

[kiwigeo]

Matthew,

Some questions/comments:

1. PaulB uses hard shellac on his guitars but he sprays it. PM paul for details.

2. For french polishing my preference as far as oil goes is cold pressed olive oil that is free of additives. Make sure it's fresh. I normally get a new bottle of the stuff every 3 months and consign the old bottle to kitchen duty.

3. Are you using the Hard Shellac neat or are you cutting it back? I think straight out of the bottle the stuff is a 4lb cut. I normally use about a 1.5 to 2lb cut for body sessions on my guitars and I cut it back even further for glaze sessions.

4. How many body sessions have you done so far?

5. Are you stiffing off after each body session and/or are you spiriting off or cutting back with 1200 grit W and D after every 5-6 body sessions?

Cheers Martin

[ubeaut]

You probably need to cut the shellac with more metho. It is a pretty strong brew and needs to be cut at least 50/50 to bring it in line with most regular shellac consistencies, you then need to cut it more again for application with the rubber and even more as the work progressed to the point where it is like 1 part cut shellac (05/50) to 20 or more parts alcohol.

As for the oil. I prefer to use mineral (paraffin oil) which doesn't dry or skin like the linseed can. You can walk away from it for a week and the oil is still there ready to begin again, where linseed will have skinned and wouldn't be able to work. You will also need a bit more than a tiny dab of oil. On a piece the size of your bass I would dip my finger into the paraffin and then flick what was on the finger all over the work and finally wipe what's left onto the face of the rubber. This should give you enough slip to keep on going with the rubber for an hour or so with maybe a couple of small top ups as you proceed and if needed.

Don't work with the rubber too wet this will cause a real problem so will working with it too dry in the initial stages. There should be just enough polish in the rubber that when banded down hard onto a piece of paper there should be a light damp patch visible.

Start with a light hand and as the polishing progresses get heavier with the pressure to bring out more polish from the internal reservoir of the rubber. Keep changing your patterns and about every 8-10 rubbings, straighten out, using long straight strokes going with the grain.

There is no polyurethane in the shellac, as Mac pointed out after it has about the same durability as poly. It is, a cross linked product, but that doesn't start to take place until after the surface is well dry and takes around 20 days I refuse to say what we use process, other than it's based on melamine.

Hope this is of some help.

Cheers - Neil

Strewth - This was in reply tocontrebasse post # 6 I'm gunna have to learn to type faster.

[bitingmidge]

Thanks Neil,

I'm still going to dig out the book tomorrow though!

(and I've made my own example about replies that are WRONG too!)

P

[Skew ChiDAMN!!]

So, I beat Midge too it. Reading the book, that is.

Didn't see any mention of "hard" shellac, is it also known as something else?

I may've just missed it, though... I didn't really read the book as such, just sorta squinted real hard while I thumbed the pages...

[ubeaut]

Hi Guys - there is no info in the book on Hard Shellac. It is a lot newer then the last revirion of the book. Might have to do an addendum or something.

It reads much the same as regular shellac . You should also be able to come back to a polished surface after it has cross linked and apply more hard shellec if you want to. Don't know why you'd want to but should be quite doable as shellac has the ability to hang o to almost anything and being as how they are both the same there should be no problem with crazing, etc However this is all just supposition on my part. I don't know of any one who has tried it and I have never done it as a trial. I do however have a piece of mdf thet weuse as a dipping stick to measure the shellac in our drums. It has been dipped many many times and often many months between dippings and the hard shellac on the stick is like rock and shows no signs of any deterioration due to delaminating or crazing or anything else.

However another one I had did protest violently to being dipped into a drum of extremely hot molten wax around 135 ºC (275 ºF) it bubbled but didn't delaminate or anything else.

Even rubbers are ok for a week or so if moistened with a little meths and kept in an airtight ziplock. I always wash out my mops (brushes) in clean metho keep them suspended in or over metho in a tall glass jar with a hole in the lid to secure the brudh handle and stop it from toughing the bottom of the jar. I haven't had a problem with them. Yet.

Hope thisis of some more help.

Cheers - Neil

[Iain]

I had a quarter of a bottle left over and past it's use by date, diluted it 4:1 (I think, close anyway) and tipped it over the hallway floor to see how hard it was.
That was about a year ago and it's still there.

[contrebasse]

Well ... because I was in a hurry, I just ended up wiping on a good body of the stuff, sanding off the ridges with 280 grit between coats, and touching up some small chips with a matchstick.



I put it out in the sun on the weekend and it got nice and hot, and now the finish seems plenty hard.

After the gig tomorrow night, I will probably take the strings off again and try a french polish with a much-diluted cut. But to all intents and purposes, its done now. Its an old bass, plenty of dings, so antiquing is built-in.

Thanks all for your help and suggestions. I think I like this stuff.

In fact, hard shellac smells almost identical to the "camus" cognac I bought duty free. But I won't be wasting the shellac by drinking it.