Gold and Metal Leaf Part 2 - Application Methods

A selection of gold leaf catalogues and Sizes....and my FAVOURITE skewings brush

We apply gold leaf, silver leaf and a range of other metal leaves in a wide variety of styles, shades, carats and weight.

We are often asked about the application methods and why we use one over another so I have outlined below the different types of application, what they are generally used for and why. This follows on from Gold and Metal Leaf Part 1 where I explain the different types of metal leaf. I'm thinking this may need a part 3 to show you some of the amazing and outrageous extra bits and bobs there are available. Meantime let me explain why size REALLY does matters
Size
Size is the material used to stick the leaf to the surface.

 

a selection of Oil Sizes

Oil Gilding
Oil gilding is the most common form of architectural gilding, highly durable and providing the substrate is prepared correctly and the size and gold applied correctly, a surface that is gilded with a high carat gold will have an incredible life span where the substrate is more likely to break down before the gold will.
The process involves using an oil (solvent borne) size. The material is similar to a yacht varnish in appearance. It comes in different drying times (3-4 hour, 8 hour, 12hr and 24hr). Which one the gilder will use depends on the size of the project and the brilliance of gold required but also on site conditions. The slower the set of the size, the brighter the gold will be but if site conditions are dusty then the slower drying sizes may pick up dust and dirt.
The gold is applied when it just becomes tacky enough….an experienced gilder knows when this is and how to manage the size types to maximise the gilding time in the day. The time each size is going to come tack is indicated by the “hours” but it is variable depending on atmospheric conditions - humidity and cold can slow the setting time, in hot dry conditions the size may come to tack early

Benefits of Oil Size – 

• Oil size has self-levelling qualities and sets to a smooth, glossy surface.
• Oil size cures to a hard durable bond for the gold. 
• Oil size will adhere and give good intercoat adhesion to most substrates well. We advise a substrate of high quality water based eggshell for all interior work. Alkyd eggshell or gloss for exterior projects 
• Oil size is not affected after curing by damp

Disadvantages of Oil Size –

• Slow drying so it tends to attract dust however goodhousekeeping and timing can minimising this
• Limited working time which means that it may not be ideal for very, very large areas and also means careful management of time
• Affected by weather conditions during application however a skilled gilder can manage these.

2 different acrylic size products

Acrylic Size using the Oil Gilding Technique

Acrylic size is a contemporary material usually associated more with “hobby” crafts however it does have its use in interior architectural gilding.

It is similar in appearance to a thin PVA glue and it dries within about 15 minutes to a permanently sticky finish. There is no complete drying of the material that can be bought in the UK, although Marlow Demars has kindly pointed out in the comments below - there are some US products that dry hard.

Benefits of Acrylic Size –

• The main advantage to the material is you can size a very large area such as a ceiling and spread the work over a period of days rather than having to complete within very tight drying times. We recommend it for areas that will not be subject to traffic like ceiling areas. 
• It is better for Copper Metal Leaf as it is a more inert less complex product and less likely to encourage oxidising 
• It is water based which may suit some site conditions where solvents are strictly controlled 
• If the leaf needs to be varnished then you don’t have to wait for curing.

Disadvantages of Acrylic Size –

• The material holds brush/application marks and doesn’t level off 
• The material never dries, it stays soft and sticky under the gold so if it gets scratched what will be revealed is a dust attracting sticky layer. It is also much more easily damaged because of this 
• The material will deteriorate quickly if moisture gets into the area, because this material scratches through easily then this happens more readily in high traffic areas than if oil size is used 
•  Acrylic sizes reduces the sheen 
• Poor adhesion and a tendency to ciss over oil based paints

The Absolute Maestro of Water Gilding and Verre Eglomise Gareth Evans of Watergilders.com

Water Gilding
Water gilding produces the highest shine but because of the very complex and slow preparation of the surface required, the cost is generally prohibitive for most architectural purposes. It is a technique generally used for high quality furniture and frames and for Verre Eglomise (gilding on glass). The Size used is Gelatin

Instacol
Instacol is a German Sizing system that offers the gilder a method of achieving a very well bonded high sheen look similar to that achieve with a slow set oil size and can even give the brilliance of Water Gilding. It is entirely water based and is a two stage system which controls when the size will become ready to gild reducing the chance of dust pick up.
There are many advantages to this system but it is a more expensive system than traditional oil size and because it is a two-stage system then sizing is double the labour.
We are happy to discuss Instacol with you and offer you costings if this system would suit your project best.

Varnishing Leaf
High carat leaf and those metals that are not prone to tarnishing do not require varnishing and in fact the varnish can reduce the sheen and appearance of the material. All architectural gilding done with low carat metals need to be sealed. There are instances where due to high traffic that all metal leaf needs varnishing to increase protection. These may be instances when we would consider recommending metal leaf as opposed to Gold Leaf.
We now produce a metal leaf sealer called Whitson's Universal Lacquer for this specific purpose and this can be found at www.caitwhitson.com

Please feel free to ask questions, post comments etc and if you'd like to talk to us about a gilding project give Cait or Gibson a call on 01738 587600

Gold and Metal Leaf Part 1 - What's What and How do I Specify?

We apply gold leaf, silver leaf and a range of other metal leaves in a wide variety of styles, shades, carats and weight.
Often there is confusion between the different types of materials and the benefits and risks associated with each. Particularly for those specifying the material I felt it was important that they have a better grasp of the material and some time back put together a description for Interior Designers, Architects and Specifiers we work with. I had the need to go and drag it out again for a customer and realised it was possibly a blog post....or even two. So here is part one and I have added to this by doing a second part which is all about the best application methods and that I'll post in the next few days. This is a HUGE subject and I could have written a lot more but I've tried to keep it a manageable amount of information

Gilded dome using 24ct in the Middle East - this was a huge project that the Carte Blanche team played a
small part in.

Gold and Silver Leaf

•    Genuine gold leaf is 85mm X 85mm There are 25 leaves in a book and this will cover 0.18 square metres with no waste. We allow about 7 books per sq metre depending on the type of surface we are applying it to
•    Genuine silver is 95mm X 95mm
There are 25 leaves in a book and this will cover 0.22 sq metres with no waste. We allow about 6 books per sq metre depending on the type of surface we are applying it to
Gold leaf comes in various colours and carats. As a rule of thumb the higher the carat the less likely it is to tarnish. The different carats also are to do with colour. All gold is cut with another metal – despite what you will read on the internet, even 24ct has the tiniest amount of another metal (usually silver) in it to make it malleable enough to use. Correctly applied, high carat gold will normally last longer than the substrate that it is applied to.
To produce a wide variety of colours, copper and silver is mixed with gold. When copper is added, the leaf becomes warmer and richer in tone. When silver is added, the leaf becomes paler in tone. The addition of these other metals lowers the carat value of gold leaf. Gold leaf is manufactured in a range from 9ct "White" to 24ct. Gold is completely resistant to corrosion. The addition of silver and copper lowers the resistance of gold leaf to oxidisation. However, the copper or silver in 23.75ct or 23ct leaf is so low that it will maintain its integrity outdoors for 30 years or more. Carats less than 23 are recommended for indoor use only and many colours and carats are available. We carry colour charts to help you determine the right tone for your project.

A winged lion holding a Bible is known as a Lion of St Mark - these two once graced the Savoy before it's refit.
They were bought at auction in very poor repair. We gilded them in Palladium Leaf.

Silver leaf is very prone to tarnishing and so we seldom recommend using it in architectural gilding – our recommendation is to use Palladium, Caplain, Platinum or Aluminium

There are 3 types of leaf in the "gold leaf" category that aren’t gold and none of them tarnish readily – Palladium, Caplain and Platinum. However it must be noted that be care should be taken using palladium (and therefore also Caplain) in a chlorine rich environment (a swimming pool or fountain. etc.) as the chlorine will cause the palladium to turn. once again I'd like to thank Michael Kramer for this information which he gave in the comments below.
Palladium is a base metal that is similar to Platinum but a slightly warmer look than Platinum. It is good substitute for silver but offering a slightly different tone, like a silver with a slight gun metal undertone. Caplain leaf is a combination of palladium and gold so just a slightly warmer cool tone. Platinum…well that’s platinum, with a suitably platinum price tag to go with it!!!

Copper Leaf Wall - this installation is being finished off by Gibson removing the last of the "skewings"

Metal Leaf
Also known as Schlag, Brass Leaf and Composite Leaf
Metal Leaf comes in 3 colours – Gold, Copper and Aluminium
•    Metal leaf comes in sheets 14cm x 14cm. There are 25 leaves in a book and this will cover 0.49 square metres with no waste. We allow about 2.5 books per sq metre depending on the type of surface we are applying it to
Both Copper and Gold Metal Leaf tend to tarnish Copper being the most risky. Reducing the risk of this tarnishing relies on a number of factors – most are to do with product knowledge and strict good practice but there are no guarantees with it. The reduced cost comes with a risk, like so many things in life. 

Patinated Aluminium Leaf

Aluminium leaf on the other hand seldom tarnishes - as pointed out by Michael Kramer in the comments below - it can tarnish if it is in a salt air environment (along the sea shore, a port city, etc.) and there is high humidity. This makes it an excellent alternative to Silver Leaf, although the larger size of the squares does give the knowledgeable person the hint that it isn’t silver if you are installing a gridded wall or ceiling

Reducing Risk of Tarnishing
Here are the things we do to reduce the risk when using metals that tarnish 
1.    Great care is taken in the preparation of the surface to ensure it is sealed as many oxidants can come from the back of the leaf - thanks to Marlow Demars for reminding me in the comments below of the importance of this. If we are not doing the preparation we supply a comprehensive specification for the decoration of the substrate prior to the leaf being applied.
2.    We insist on a strict site conditions – there are a number of atmospheric site conditions that can affect the metal. These are mainly chemical; glues, solvents, acids and alkalis used in the area can affect the metal.
3.    The substrate must be scrupulously clean as must the tools used.
4.    Great care is used not to touch the leaf and leave acid from the skin on the surface.
5.    Knowing the correct combination of products to use for each leaf to minimise contamination is vital.
6.    Sealing the leaf with the correct material

I hope this is a useful post - do ask questions if I've missed anything I'd be delighted to help.
If you'd be interested in finding out more about the costs of having gilding carried out in your home or business premises, please don't hesitate to give us a call 
01738 587600 and speak to Cait or Gibson