Varnished items from older collections.

Norman McCormick · 24th March 2016, 02:11 PM

Hi,
I think some of us if not most of us have come across items from older collections that have had the metal parts of an object varnished in order to protect the piece from rust. I would value the opinions of the members with regard to removal or not of this type of old protective varnish. If removal was proposed then how would you proceed and with what method? I look forward to your opinions and suggestions.
Regards,
Norman.

Roland_M · 24th March 2016, 04:11 PM

Hi Norman,

yes, i have some blades which were covered with shellac. Shellac becomes discolored and ugly after some decades.

I use Nitro thinner or Aceton to remove the shellac. After that treatment the blade must be oiled thoroughly.

If i have wood with shellac I use very fine sandpaper (from 1000 or 2000 to 7000 grain) and a metallpolish called "Gundelputz" for the finish (thank you very very much for that tip Alan Maisey!).

Roland

Sajen · 24th March 2016, 04:27 PM

Shellac can be removed by benzine, chemical clean.

Jens Nordlunde · 24th March 2016, 07:23 PM

Yes you are right, that acetone is quite good.
When it comes to blades it is relatively easy, but when it comes to chiselled hilts, it is not always that easy to remove the lack in all corners - so be very careful when you do it - to get out in all the corners.

kronckew · 24th March 2016, 07:38 PM

and now the mandatory OSHA warning:

remember to use volatile solvents outdoors or in very good ventilated rooms. most are poisonous and some are carcinogenic. i don't want to lose any of us. solvent resistant gloves and goggles/face mask are a good idea. nice strong outdoor lighting from that big white ball in the sky will also assist in improving your removals from corners and areas that may hide in artificial lighting.

acetone has a much lower toxicity that benzine which can cause permanent damage if inhaled, ingested or absorbed thru skin contact. both are highly flammable, so no smoking, or sources of ignition nearby. benzine is the major constituent of gasoline/petrol.

sadly, we rarely see that thing in the sky that gives off all the light here in the UK. i think it's astronomical name is Sol, or something similar. (it is raining here as usual) i have a dim memory of something we called the sun, way back when i was a younger in alabama, usa. might be the same thing.

fernando · 24th March 2016, 07:56 PM

Quote:

Originally Posted by kronckew

... i have a dim memory of something we called the sun, way back when i was a younger in alabama ...

Wait a minute; have you forgotten the Douro and the Portuguese Sol ?

Norman McCormick · 25th March 2016, 07:13 PM

Hi,
Many thanks to all those who took the time to answer. I take it from your replies that nobody would advocate leaving the varnish as is and that removal is the best option.
Regards,
Norman.

RDGAC · 26th March 2016, 01:43 PM

Norman,

Personally and professionally, I'd say that if you're careful then removing the varnish is generally preferable. Primarily this is for four reasons:

1) The lacquer's composition is unknown, and undesirable impurities may have been added to it during mixture (i.e. the purity of the original solvent is unknown, in addition to potentially damaging impurities entering the compound from the crushing and liquefying stages).

2) The lacquer's integrity is unknown; an uneven coat may have worn away in certain spots while remaining thick in others, or may never have been properly applied at all. Liquid coatings such as shellac (and also nitrocellulose lacquers such as Frigilene) are always problematic in this regard since they tend to run, and I tend to think that a coating that gives a false sense of security is as bad as no coating at all.

3) The lacquer is likely not to be up to scratch vis-a-vis long-term conservation properties. Shellac undergoes hydrolysis into acids (aliphatic and alicyclic acids, no less - from what little chem I understand, the more unstable sorts of organic compounds), which are in turn likely to cause damage to the object if they aren't neutralised. Frigilene and other nitrocellulose lacquers, in accelerated aging tests, have tended to peel off, discolour, and become difficult to remove. I myself have observed the characteristic yellowing of frigilene lacquer on a sword in the RDG collection, the lacquer having been in place approximately 20 years by that time. There's a rather good publication from the Getty Conservation Institute for anyone interested.

4) Frankly, that's a bloody ugly finish!

Let us know how you get on; there are a few objects in our collections that have been lacquered in their long (and long-suffering) lives, and I'd be interested to see the results of your work when planning any on these objects.

- Meredydd

Battara · 26th March 2016, 04:04 PM

Be very careful with the niello - a type of oxidation easy to take off and not to place back on. In fact, I'm not sure if anyone does niello anymore since the chemical fumes are very toxic.

Shakethetrees · 26th March 2016, 08:10 PM

Quote:

Originally Posted by Battara

Be very careful with the niello - a type of oxidation easy to take off and not to place back on. In fact, I'm not sure if anyone does niello anymore since the chemical fumes are very toxic.

Niello is a horrible mix of lead, and a little copper. When it's thoroughly mixed and still completely molten, a handful of powdered sulfur is mixed in, stirred, and poured into long thin (1/4") strips and allowed to cool.

Once a decorative design is chiseled into a piece of metal, the metal is heated and the niello strip is "mushed" into the design leaving excess. Or, it can be ground into a fine powder and applied like vitreous enamel and then fired. Allow to cool, and file the excess away, using a coarse single cut file. It's like filing graphite, soft, with a tendency to chip if you rush it. Polish any file marks polish with emery.

I did some of this while a student forty years ago, under a laboratory vent hood, and, believe me, it's a smoky, sulphurous, stinking mess. Glad I did it once or twice, but I don't think I ever want to do it again.

There are many formulae recorded, each with slightly different compositions and working attributes coming from early sources from around the world, but, I post this here for reference and not as a recipe, so unless you have laboratory ventilation, don't do it.

If repairs are absolutely necessary I would look into using an epoxy based mixture instead.

Norman McCormick · 29th March 2016, 11:47 PM

Hi,
Many thanks to all for your continued interest. I have taken on board your advice and suggestions and will proceed accordingly. The items in question are Zulu type spears, 1x Iklwa and another as yet undefined, which would appear to have been collected in the latter part of the 19thC or very early 20thC. I will post said items shortly.
Thanks once again to all who participated in the thread and gave of their experience and knowledge.
Regards,
Norman.

24th March 2016, 02:11 PM	#1
Norman McCormick Member Join Date: Oct 2007 Posts: 1,575	Varnished items from older collections. Hi, I think some of us if not most of us have come across items from older collections that have had the metal parts of an object varnished in order to protect the piece from rust. I would value the opinions of the members with regard to removal or not of this type of old protective varnish. If removal was proposed then how would you proceed and with what method? I look forward to your opinions and suggestions. Regards, Norman.

24th March 2016, 07:38 PM	#5
kronckew Member Join Date: Mar 2006 Location: Room 101, Glos. UK Posts: 4,150	and now the mandatory OSHA warning: remember to use volatile solvents outdoors or in very good ventilated rooms. most are poisonous and some are carcinogenic. i don't want to lose any of us. solvent resistant gloves and goggles/face mask are a good idea. nice strong outdoor lighting from that big white ball in the sky will also assist in improving your removals from corners and areas that may hide in artificial lighting. acetone has a much lower toxicity that benzine which can cause permanent damage if inhaled, ingested or absorbed thru skin contact. both are highly flammable, so no smoking, or sources of ignition nearby. benzine is the major constituent of gasoline/petrol. sadly, we rarely see that thing in the sky that gives off all the light here in the UK. i think it's astronomical name is Sol, or something similar. (it is raining here as usual) i have a dim memory of something we called the sun, way back when i was a younger in alabama, usa. might be the same thing. Last edited by kronckew; 24th March 2016 at 07:54 PM.

24th March 2016, 04:11 PM	#2
Roland_M Member Join Date: Aug 2014 Location: Germany Posts: 523	Hi Norman, yes, i have some blades which were covered with shellac. Shellac becomes discolored and ugly after some decades. I use Nitro thinner or Aceton to remove the shellac. After that treatment the blade must be oiled thoroughly. If i have wood with shellac I use very fine sandpaper (from 1000 or 2000 to 7000 grain) and a metallpolish called "Gundelputz" for the finish (thank you very very much for that tip Alan Maisey!). Roland

24th March 2016, 04:27 PM	#3
Sajen Member Join Date: Aug 2007 Location: Germany, Dortmund Posts: 8,487	Shellac can be removed by benzine, chemical clean.

24th March 2016, 07:23 PM	#4
Jens Nordlunde Member Join Date: Dec 2004 Location: Europe Posts: 2,713	Yes you are right, that acetone is quite good. When it comes to blades it is relatively easy, but when it comes to chiselled hilts, it is not always that easy to remove the lack in all corners - so be very careful when you do it - to get out in all the corners.

25th March 2016, 07:13 PM	#7
Norman McCormick Member Join Date: Oct 2007 Posts: 1,575	Hi, Many thanks to all those who took the time to answer. I take it from your replies that nobody would advocate leaving the varnish as is and that removal is the best option. Regards, Norman.

26th March 2016, 01:43 PM	#8
RDGAC Member Join Date: Mar 2010 Location: York, UK Posts: 167	Norman, Personally and professionally, I'd say that if you're careful then removing the varnish is generally preferable. Primarily this is for four reasons: 1) The lacquer's composition is unknown, and undesirable impurities may have been added to it during mixture (i.e. the purity of the original solvent is unknown, in addition to potentially damaging impurities entering the compound from the crushing and liquefying stages). 2) The lacquer's integrity is unknown; an uneven coat may have worn away in certain spots while remaining thick in others, or may never have been properly applied at all. Liquid coatings such as shellac (and also nitrocellulose lacquers such as Frigilene) are always problematic in this regard since they tend to run, and I tend to think that a coating that gives a false sense of security is as bad as no coating at all. 3) The lacquer is likely not to be up to scratch vis-a-vis long-term conservation properties. Shellac undergoes hydrolysis into acids (aliphatic and alicyclic acids, no less - from what little chem I understand, the more unstable sorts of organic compounds), which are in turn likely to cause damage to the object if they aren't neutralised. Frigilene and other nitrocellulose lacquers, in accelerated aging tests, have tended to peel off, discolour, and become difficult to remove. I myself have observed the characteristic yellowing of frigilene lacquer on a sword in the RDG collection, the lacquer having been in place approximately 20 years by that time. There's a rather good publication from the Getty Conservation Institute for anyone interested. 4) Frankly, that's a bloody ugly finish! Let us know how you get on; there are a few objects in our collections that have been lacquered in their long (and long-suffering) lives, and I'd be interested to see the results of your work when planning any on these objects. - Meredydd

26th March 2016, 04:04 PM	#9
Battara EAAF Staff Join Date: Dec 2004 Location: Louisville, KY Posts: 7,139	Be very careful with the niello - a type of oxidation easy to take off and not to place back on. In fact, I'm not sure if anyone does niello anymore since the chemical fumes are very toxic.

29th March 2016, 11:47 PM	#11
Norman McCormick Member Join Date: Oct 2007 Posts: 1,575	Hi, Many thanks to all for your continued interest. I have taken on board your advice and suggestions and will proceed accordingly. The items in question are Zulu type spears, 1x Iklwa and another as yet undefined, which would appear to have been collected in the latter part of the 19thC or very early 20thC. I will post said items shortly. Thanks once again to all who participated in the thread and gave of their experience and knowledge. Regards, Norman.