shellac

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biffo
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shellac

Post by biffo »

Please tell me how most people use it,do you make a stock solution ,or wait for an age for it to dissolve? If a stock solution is made what is the ratio of meths to shellac powder .Any advice will be gratefully received. B
sambo
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Re: shellac

Post by sambo »

This is a good question mate. One I have looked at - guessing you're having a bash with that Paris Green as I did ;-) I'm sure others have their own experiences but I'll post the link that I used for much of my experiments at the end.

I've found this has to do with where my shellac came from, how old it is and how damp it and my alcohol are. Basically the older it is ( and I have some from Cooperman which I think is ancient ) the slower it will dissolve. Fresher Shellac dissolves quicker, quicker with a low heat and agitation using a magnetic stirrer - then once it has globulated ( technical term ) - I leave it overnight. Nowadays I make it up in advance dissolving under agitation using alcohol I have dried with Potassium Carbonate.

This will help you :

https://www.toolsforworkingwood.com/store/blog/235
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biffo
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Re: shellac

Post by biffo »

Thanks Sam that's what I wanted to know,and yes the Paris green stars are drying right now,I see you've been down this road ,did you stay with this comp Sam?. Thanks B
sambo
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Re: shellac

Post by sambo »

No worries, That was the last comp I tried ( supposedly the best blue ) but I have left things there for now. I've been heavily side tracked with perfecting my Bombettes / making some well timed and neat cakes.
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Pyro-Gear
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Re: shellac

Post by Pyro-Gear »

Well you certainly have enough tubes Sam. ;)
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richardh08
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Re: shellac

Post by richardh08 »

sambo wrote:I've been heavily side tracked with perfecting my Bombettes / making some well timed and neat cakes.
How well I know that feeling - there's always something else to be done...
Even when I'm wrong, I'm convincing.
Paul Moulder
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Re: shellac

Post by Paul Moulder »

Just curious but why do you want to dissolve the Shellac ? I pressume from the previous comments you are making Blue stars. Shellac makes a poor binder. Add 5% dextrin to the comp instead.
Of all the Blues I have made in the past few months these 2 stand out as the best I have seen.

Hardt's Blue 1
Potassium Chlorate 62
Paris Green 21
Stearin 8
Hexachlorobenzene 4

My own formulation.
Potassium Chlorate 63
Copper Oxychloride 8
Paris Green 7
Shellac (200 mesh seedlac) 12
CPVC 4
Airfloat Charcoal 1
Dextrin 5

Total
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biffo
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Re: shellac

Post by biffo »

Hi Paul thanks for the info,There were no instructions on how to use shellac in the comps listing so I assumed that was how it was done.I note that you had a group buy for shellac not so long ago what's your main use for it Paul ,? Regards B
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Re: shellac

Post by Paul Moulder »

B, It's only real use is in Chlorate based star compositions and some Chlorate parade torches.colour pots where it burns faster and with a cleaner flame than Red Gum. Red Gum burns better in Perchlorate mixes. If you see Shellac listed in a composition it is, never to my knowledge, used a the binder only as fuel.
Yes I bought amost 150kg of 'Seedlac' the raw material from which Shellac is made. I do still have around 20 kg spare if anyone needs any.
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biffo
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Re: shellac

Post by biffo »

Yes Paul the comp I used also contained dextrin as binder but the shellac wasn't very finely milled,have you noticed a better colour with a chlorine donor in use with Paris green,it's a bit new to me,a bit exotic.Thanks B
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Boophoenix
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Re: shellac

Post by Boophoenix »

Biffo, I'm think calomel was an excelent donor for Paris green. However it's fairly hard to come by. I'm still new enough I save my exotics till my skills improve. It would be a shame to waste them on a newbie error. I might add if you're not familiar with it that the amount of chlorine is very low, but it is suppose to be one of the best performing donors for blue I believe where all the rest you'd look for high chlorine content. I've collected enough to find out one day when I'm comfortable enough to give them a try.
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Re: shellac

Post by Paul Moulder »

Yes I found Blues to have a clearer more saturated colour with a Chlorine donor. CPVC is my donor of choice as it helps give a faster burn time.
sambo
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Re: shellac

Post by sambo »

Ixan for me ;-D, but I'm gonna run out soon, luckily I have a stash of your CPVC Paul. my shellac is pretty clumped and unusable as it is so i don't have much choice but to dissolve it, I think B. is having the same problems. PM sent to you then Paul I'm in the market for some Seed Lac.
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biffo
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Re: shellac

Post by biffo »

Hi Boo isn't that another pretty toxic chemical ? I wouldn't like to leave any unignighted stars made with these things lying about on the ground ,so it's perhaps a good thing to get a bit more experience first, Wadaya think. Regards B
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Lloyd
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Re: shellac

Post by Lloyd »

Calomel is toxic, but it's also nearly insoluble in water. Only 0.2mg per 100ml of water.

It's most toxic if ingested, but doesn't significantly contaminate the soil. Besides, if the stars light, it's decomposed!

Lloyd
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Boophoenix
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Re: shellac

Post by Boophoenix »

Yes Biffo, I had a stage of not having supplies every time I started on a project and went into an aqusition mode for about a year. I do enjoy the Blues so I acquired some of these unobtaniums for future use. I've read about them in use and don't know that I'd ever see them in unless I do it myself. However I won't use them in stars for shells untill I'm satisfied that I can as Lloyd put it burn them up. I'm fairly safe and reserved in my practices especially when it comes to unknowns. I've actually only got a couple of plans for any shells this year. If those even transpire. Most of the year will spent in charcoal and fuel mines ( which I'm fair at after a few hundred now on my own and with a friend ).
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richardh08
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Re: shellac

Post by richardh08 »

Lloyd wrote:Besides, if the stars light, it's decomposed!Lloyd
That is undoubtedly true, but the mercury doesn't go away. It will be released, most likely as the metal, in vapour form, which is much more toxic, even though it will be well dispersed.

Back in the day when synthetic chlorine-rich compounds weren't known, chlorine donors were far less efficient. As well as calomel, I've come across formulations that recommend the use of either lead chloride or ammonium chloride. I can't see the point of using any of them now that more efficient alternatives are available.
Even when I'm wrong, I'm convincing.
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Lloyd
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Re: shellac

Post by Lloyd »

I can't see the point of using any of them now that more efficient alternatives are available.
-------------
Please don't get me wrong, Richard. I agree. It's just that the occasional, selective use of "old fashioned" chemicals should not be discouraged, so long as reasonable care is used... they're a great 'benchmark' against which to compare that which we have, now.

LLoyd
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Boophoenix
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Re: shellac

Post by Boophoenix »

Something Mike Swisher wrote back in Jan of 2013 stuck with me and caused my curiosity. Here's the full paragraph. I don't think he'd mind me sharing the quote.
Dechlorane - at least the original product so called - is C10Cl12. It yields elemental Cl to the flame like HCB and is the closest substitute. The only other chlorine donors I know that do this are the now-disused calomel and lead chloride. Calomel is a very peculiar ingredient in its effect. It slows burning while enlarging the flame envelope. Calomel colors burn with a big, languid, dreamy flame. You can see why Chertier liked it so much.


It seems many of the chlorine donors are going out of style in the US. It just seemed like such a waste to not aquire any for the future. I've acquired samples of all but a couple of the donors for the future when they will be next to impossible to aquire most likely.
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richardh08
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Re: shellac

Post by richardh08 »

Please don't get me wrong either; I wasn't meaning to criticize.

Like - I guess - many other people, I've experimented with many of these substances in the past. I can well understand the fascination of reproducing historical compositions, if only to see how they compare with more recent ones. But I've never felt comfortable with the idea that I'm contributing - even in the tiny quantities that I habitually work with - to the pollution of the environment with compounds of lead, mercury, arsenic, etc.
Even when I'm wrong, I'm convincing.
sambo
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Re: shellac

Post by sambo »

I've just read Kentish's method on the preparation of Lac solution ( shellac ). Can someone explain to me what is going on. It sounds as though there is a chemical change occurring as he talks about "curdling". The description is as follows :

PUt 1/2 ounce of flake shellac into a tin pot and pour upon it a quarter of a pint of denatured alcohol. Let it stand for about a day, stirring it occasionally until dissolved. Then half fill a basin with boiling water; set the tin, containing the lac, in it, and leave it till it boils and curdles...

Clearly I am not doing this "correctly" as I have never executed the "boiling and curdling" part.
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Lloyd
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Re: shellac

Post by Lloyd »

The "curdling" part probably has to do with insoluble fats and water-soluble resins rising to the top, to be skimmed.

Modern painters' shellac is not truly cleaned as thoroughly as old practicioners did. In older times, shellac was prepared in much the same way as "boiled" (not really, but heated) linseed oil varnish. Both were heated while very still until all the insolubles rose to the top, where they were then skimmed-off to provide the finally-pure product.

Modern shellac and (even) natural varnishes are now compounded with "drying agents" that will oxidize and harden those fatty constituents. So, even though NOT pure, they will still dry when applied to a surface.

Lloyd
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sambo
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Re: shellac

Post by sambo »

Is this the "de-waxing" as it is referred to ?

However, this explanation doesn't seem to quite add up. He goes on to say that it should be used as-is (so no skimming ) and that hot alcohol dissolves gum-resins more completely than cold and this renders it more adhesive. If any alcohol is added at any time it needs to be re-dissolved ( boiled again ) or it will not mix properly. The implication here seems to be that the goal here is to achieve complete homogeneity ( so precipitation within suspension [ of something ] as opposed to separation and removal of a layer ) - if this is the case you would expect it to settle-out after a time.

I'm interested as Shellac seems to stand out in it's ability to remove black body radiation from the flame.
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Re: shellac

Post by sambo »

I have some "seed lac" from Paul Moulder and I'll be vacuum distilling and then drying some absolute ethanol and making up some stock solutions and running some tests to see what this is all about.
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Re: shellac

Post by Paul Moulder »

Seed Lac is unbleached Shellac and contains approx 3% wax. As a fuel in firework comps esp Chlorates it does not need refining in any way. Shellac is refined Seedlac and has had the wax taken out and the small amount of organic debris removed. Seedlac would be unsuitable for laquer application on wood etc.

I did some tests with Chlorate comps using both Shellac and Seedlac and could not see any differences between the colour, burn rate or ignitability of them.

The Seedlac I sold to a lot of people on Fireworking is 20 to 40 mesh and needs to be milled to at least 80 mesh to be usable. Milling takes some time and you need to make sure the Seedlac and mill don't get to hot while doing it or it will soften.
Tyvole
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Re: shellac

Post by Tyvole »

Paul Moulder wrote: Milling takes some time and you need to make sure the Seedlac and mill don't get to hot while doing it or it will soften.
Ken's mill will run underwater, I believe.
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