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Mirror Frame with 'Plants Box' in the Stile of Neo Baroque, 19th Century

Introduction

Dimensions:

Mirror frame - 300 cm in height, 145 cm in width, 9cm on the thickest part.
'Plants box' - 38 cm in height, 95 cm in width, 38 in length.
Final facing:
Parcel water silvered, parcel water gilded, parcel imitation of gilding
Type of treatment:
Restoration
Storage and display:
Private collection, for everyday use


Condition

The Mirror frame arrived in studio separated from crown elements. The body of mirror frame and 'plants box' were cowed with thick layer of probably bronze powder emulsion, which oxidized. Crown elements were covered with layer of dark yellow material, probably shellac, blended with dust so the surface head rough look. All surfaces were embedded with surface dirt.
In constructional sense, Body of mirror frame was solid, as well as the 'plants box' although, on the down panel of the body of mirror frame, the long crack was visible. The crack was the after effect of change of properties of thin (13 mm) wooden board due to aging and influence of environment. The crown elements were broken along the joints. Cause was yielding of organic adhesive, probably fish aye glue, under the influence of environment. Traces of this adhesive were visible on the joining parts. Some parts of crown ornaments missed. Elements for mounting of the crown missed too.
Along the frame area which mounting the very mirror, parts of ornament missed. Also, many small cracks were visible.
Small parts of ornaments missed on the 'plants box' too (fig.1., fig.2., fig.3. & fig.4.).

Technical Analysis

Prior to restoration work the following analysis were performed:

Analysis of Materials and Techniques Involved

The body of mirror frame, crown, and the 'plants box' was made of Pinewood (Pinus nigra). Ornaments wear made by woodcarving except the floral ornaments on the forehead and on a sides of 'plants box', along the frame area which mounting the very mirror, under the candela holders plate attached on the mirror frame and above the down panel of mirror frame. Those ornaments were made of traditional stucco. Some surfaces were covered with traditional gesso approximately 2mm thick, (calcium carbonate powder and organic adhesive probable fish-eye glue), then with very thin layer of dark ocher bole. Those surfaces were gilded and silvered by water gilding technique. Other were decorated with imitation of gilding probable using schlag metal foil and some oil size technique.

Identification of Cowers on the All Parts of the Object

As it was presumed, the layer of cower on the body of mirror frame and the 'plants box' was the bronze powder mixed with inorganic adhesive.

fig.3. click to zoom
fig.1. click on to zoom fig.2. click on to zoom
fig.4. click on to zoom
Choice of Treatment

Treatment on this object was performed in two phases:

Phase I: Choice of Cleaning Treatment

Selection of Solvents for Cower on the All Parts of Object

Test for dissolution of cower was performed by two solvents on the samples taken from the body of mirror frame and 'plants box'. Solvent Nr.1 was prefabricated methanol free, acid paint remover (1). Solvent Nr.2 was the admixture of methylen chloride, methanol, cellulose powder and paraffin oil. Evaporation time, do to presence of cellulose and paraffin was appreciably reduced, concentrating the reaction on cower. Solvent Nr.1 endangered the original surface made of traditional gesso with organic adhesive. The test with solvent Nr.2, after 20 minutes of exposure, resulted in complete dissolution of cower substance. Dissolved substance was rinsed with nitro thinner (2). After the process gesso and final facing on it stayed undamaged. Same procedure was tested for removing cower on the crown. Test resulted with same effect.

Cleaning Process

Adopted solvent Nr.2 was gradually applied on all surfaces. After 20 minutes dissolved cower substance was rinsed with nitro thinner (2). On some areas process was repeated due to very thick layer of cower.
Organic adhesive left on the faces of broken joints was melted with beam of water steam and removed mechanically. During cleaning process front legs of 'plant box' delaminated, revealing the long nails.
The original gesso surface open up in numerous small cracks, especially visible on the silvered areas. Parts of gesso delaminated from wooden surface.
Cracks in Traditional Stucco areas, opened up after rinsing, were filed with plaster. Also parts of stucco ornaments were made of plaster probably before they were covered with bronze powder emulsion in try of restoration time age. Plaster was removed mechanically during the cleaning treatment. During the treatment imitation of gilding was removed (fig.5.).
Object was left for few ours to dray and then test with drop of water was performed to determine ability of porous. Result of test was good so it was decided not to repeat cleaning process.

fig.5. click on to zoom

Phase II: Choice of Restoration Treatments

Selection of the Materials and Procedures for Crack Recovering

For recovery of cracks in wooden body test was made with admixture of powdered gypsum (CaSo4), kaolin and PVAC resin. Prior to application of admixture crack was moistened with 15% ethyl alcohol to assure good contact of admixture and wood. Solidification time was about 15 minutes. Sample was left to dray for 12 hours. Test resulted with solid, consolidation backfill. For recovery of larger and deeper cracks in Traditional Stucco, which were presenting risk for the firmness of structure, same procedure were tested, resulting with same solid, consolidation backfill. Filer for Smaller cracks, which were not presenting a risk for the firmness of structure and would not be later cowered with gesso, was founded within prefabricated CLOU filling waxes (3).

Selection of the Materials and Procedures for Consolidation and Recovering of Original Gesso

Due to good experience with admixture tested on cracks, it was tested for filling of areas where the parts of original gesso delaminated. Area was prepared with 15% ethyl alcohol as the crack in previous test. Admixture was pushed into and flattened with moistened spatula. The Result was satisfactory.
In order to consolidate the numerous small cracks in original gesso, make better contact within original gesso and new fill and make solid ground for new gesso the 'contact ground' was tested. Request was to obtain surface solid enough to resist pressure during the polishing of gold and silver and porous to except new gesso. The ground was composed of calcium carbonate, in form of fine powder (Bologna chock), zinc oxide powder and PVAC resin. By the and of mixing 90% Izo propil alcohol was added to improve leaving of captured air. To make it applicable with brush admixture was diluted with distilled water. Surface was coated 3 times with time delay of 15 minutes to provide solidification time for each layer. Sample was left to dray for 12 hours. The result was solid but porous surface, enough resistible on pressure preventing the original gesso from delaminating.

Restoration Process

Nails from the `plants box` legs were removed. Joints were supported by dowels and affixed with aliphatic resin glue (4). Dowels and aliphatic resin glue were used too to support the down panel of the body of mirror frame. Six 8x100 mm dowels were placed, with distance of 10 cm, through the down rail of the frame of the down panel in a board of the down panel. Missing parts of woodcarver ornaments were made of similar wood - Pinewood (Pinus nigra) (fig.6.).
Silicon moulds were made for missing ornaments in areas of traditional stucco. Some ornaments with unique shape were made by sculpturing. In both cases prefabricated material - Model plaster (5) with addition of PVAC resin was used. Ornaments were left to dray for 12 ours (fig.7.).
Tested admixture was applied on cracks and flattened by moistened spatula. Priors to application cracks were moistened with 15% solution of Etil alcohol. Smaller cracks were field with CLOU wax (3) (fig.7.).
Delaminated peaces of gesso were removed mechanically. Previously tested Procedure was applied now. After 12 ours of drying areas of intervention were shaped by the help of turbine.

fig.6. click on to zoom fig.7. click on to zoom
Prior to application of the 'contact ground' whole surface of object was cleaned whit 96% etil alcohol. The 'contact ground' was applied in three layers as it was tested and then it was left to dray for 2 hours (fig.8.). New traditional gesso consists of technical whiting (CaCo3), zinc whiting (Zn2O) and rabbit skin glue was applied shortly afterwards in four layers. Every layer was left to solidificate for 15 minutes. The ground and the new gesso was applied only on surfaces planed for water gilding and silvering and on surfaces where the procedure with filing admixture was applied.
After 12 ours surfaces of object was shaped with sandpaper. In order to prepare flat and smooth surface important for quality of water gilding sanded surface was colored with ocher bole and sanded again with 4 grades of sandpaper. During the sending surface was rinsed with mineral spirit. Next 12 ours object was left to dray (fig.9.).
Bole (6) mixed with 5% rabbit skin glue was partially applied in 6 layers and then partial gilding and silvering was performed by water gilding technique. After 12 our gilded and silvered surfaces were burnished.
On the surfaces planed for imitation of gilding, prefabricated nitro ground (7) were applied in 3 layers. After 30 minutes of drying one coat of synthetic oil size (8) colored with dark red neutral pigment (9) was applied. Imitation was finished with Dutch metal leafs.
Toning was carried out with 'bitumen from Judea' (10) mixed with Turpentine and Damar lacquer.
Due to fact that this object will be exposed to the circumstances of everyday use, final protection was carried out with Zapon lacquer (11) thinned with acetone (propanone).
To prevent from possible damages and decorate the inside area of the 'plants box' was treated with waterproof prefabricated gold effect spray paint (12).
Same material was used on the down panel of the mirror frame. Treated areas were finished with `bitumen from Judea` mixed with turpentine and Damar lacquer. (fig.10., fig.11., fig.12.)
fig.8. click on to zoom fig.9. click on to zoom
Mounting

New elements for mounting of the crown were made of Pinewood (Pinus nigra) and placed on the mirror frame. They were supported with 10x5mm dowels and adhered with aliphatic resin glue (4). To provide possibility of easy dismounting crown was mounted by 4x5mm screws. Also, peace's of leader was placed in order to provide better connection and higher friction between elements (fig.13.).
Original 10 mm thick mirror glass was placed and held by dowels.

fig.10. click on to zoom
fig.11. click on to zoom
fig.13. click on to zoom
fig.12. click on to zoom
List Of Used Prefabricated Materials

1. Acid paint remover: Karuwa - Brutal Abbeizer , Feidal GmbH, Germany
2. Nitro thinner: HB Body , Grece
3. CLOU filing wax: Clou wax, Germany
4. Aliphatic resin glue: Titebond wood glue , Franklin International , USA
5. Model plaster: Krone Hiliges Gipswerk, Germany
6. Bole: Red, Lefranc & Bourgeois France
7. Nitro ground: Duga, Yugoslavia
8. Synthetic oil size: Goldanlegeol - Mixtion, Lukas, Germany
9. Dark red neutral pigment: Lefranc & Bourgeois France
10. Bitumen from judeja: Liberon , France
11. Zapon lacquer: Liberon , France
12. Waterproof gold effect spray paint: Hadrien spray paint, Costo Paints LTD., Grece

Applied Gold, Silver and Metal Leafs

Gold leafs: Orange Doppel Gold, 22 Karat, Noris, Germany
Silver leafs: Blattssilber Normal, Noris, Germany
Dutch metal: Noris, Germany