Historical Lacquer Formulas

[masonvl]

Hi Lathetrolls,

I'm working on an audio preservation program at the Northeast Document Conservation Center trying to get audio from broken and heavily degraded lacquer discs using an optical imaging platform called IRENE. You can read a bit more about the project on our blog here: http://nedcc.org/audio-preservation/irene-blog/

I'm here though to ask if any of you can point me toward information about the formulas or composition of lacquers from the 1930s-50s. I've got a basic idea of what went into the material (nitrocellulose, castor oil plasticizer, resin, dye), but in order to develop precise conservation treatments that will help us conserve the discs, we'd like to nail down the chemistry a bit more precisely. We're basically trying to get bubbling delaminated media to relax and flatten enough to allow imaging.

If any of you know where I can find historical formulas, or modern analyses of the lacquer material itself, it would be enormously helpful. Also, if you have any questions about my work, feel free.

Thanks!

[Steve E.]

Great stuff you are doing! Some possibly helpful threads:

Cleaning Archival Acetates

lacquer formulas : with some reverse engineering?

HOW TO MAKE YOUR OWN LACQUER BLANK DISCS

Including this from AES:

http://lathetrolls.com/viewtopic.php?t=783#p2931

and this post from mossboss:

Master Lacquers, Formulae etc

[Steve E.]

Check out as well this blog post on the Beck's Beer Bottle project:

http://lathetrolls.com/blog/Experimental/beck%CA%B9s_edison_beer_bottle_cylinder_record_c-9_u-2_b-3.html

[powerstrip]

how is this imaging device going to tell you what is inside the formula?

[masonvl]

Thanks Steve E. for the info!

I found some info in US patent 2,607,699 granted to Audio Devices Inc. (makers of Audiodisc blanks), which
lists the following formula:

33.3% 1/2 sec. nitrocellulose (1/2 sec. is a measure of viscosity)
18.0% wetting alcohol (ethanol or butanol - solvent)
28.2% ethyl acetate (solvent)
10.0% dibutyl phthalate (plasticizer)
10.0% castor oil (plasticizer)
.5% dye

This must have varied between brands and lines, but it gives me somewhere to start. If anyone else has more complete information, please post it or message me!

powerstrip - My imaging won't. We shoot images of the surface of grooved recordings to make digital audio by simulating how a stylus would behave running down the groove. I encourage you to check out our blog if you're interested.

Fourier Transform Infrared Spectroscopy (FTIR) - like flozki used in his 'lacquer formulas' thread can tell us this by shining infrared light onto a sample of the media and measuring which wavelengths are absorbed (which is determined by the molecular makeup of the sample). Unfortunately, I'm not an expert in the technology, and am interested in discs made decades before his sample discs were manufactured. I'm looking into having a similar analysis done of my discs, and I'll report back if I do.

[mossboss]

Well I am not sure what the formlation would do for you In the case of bubling or delamination
I would attempt this:
Get to the metal substrate which most likely be aluminium at say the 2 opposite edges. Attach a variable ac/dc power supply so as to gently heat the aluminium to about 35 to 45 c, whilst the disc is wrapped in a plastic bag which is placed under vacuum. Similar to carbon fiber fabrication methods. The bubles and delaminations will disappear. The material will adhere back to the backing plate due to the applied vacuum heat combination without disturbing the tracks. I would also apply some pure castor oil on the surface of the acetate a week or so beforehand placed in a cardboard box like ex appollo with a nice size potato sliced in half and placed at the corners of the box on that pocket that the box has so as to add some moisture back in to the old lacq coating. It has worked for me in the past. Not sure I want to do it again. Ha

[piaptk]

Have you reached out to Sam Smith (female) or Terry Carlson (male) at Apollo/Transco? They might not give you the current formula, but they would be the most likely to have the old formulas, and could definitely be a great resource for preservation.

[emidisc]

Chris you mention applying castor oil to disc when I have tried this myself I have found it very difficult to remove the excess castor oil even when I have used a small amount? It is terribly sticky thick stuff, perhaps warming it would help.......
Emidisc

[masonvl]

Mossboss - Thanks for the suggestions! Very close to treatments we're already considering! I'll let you know what we come up with.

piaptk - I wrote their business email, but haven't heard back. Maybe I'll write one or both of them individual if I don't hear back soon. Thanks.

[mossboss]

It should be pharmaceutical grade castor oil
One should place the bottle of castor oil in hot water so as to get it to thin out
Let cool down so as to get to say body temp than apply it with a cotton bud or a ball of cotton wool to the old dry lacquer it is sticky stuff aright
Well, after all:
If it takes 20 plus years to dry out, consider that it will it will take quite a long time to soak in, not that long, He He, but it'll be weeks
Wipe the excess off again with a cotton bud or cotton wool
Restoring old lacquers is not a job for any one in a hurry, ask any sound preservation person
Next reply:
Glad to hear you are working close to the suggestion It works on bubbles as well as de-lamination issues so long there is no dirt collected under the area that has lifted off the substrate
In the case of bubbles I have in some cases pierced the bubble with a fine pin in an area which of course has no relevance, hard act to follow, but in some cases it can be helpful as there may be gases trapped under it which will not be able to escape
Be good to keep us informed here
Cheers
Best

Cheers