Tips: All about Aluminium
Joan Gordon shares some of the techniques she has learned to colour and texture aluminium.
Joan is an Australian freelance writer, author and designer. She is passionate about passing on traditional and new craft skills. Joan offers jewellery and sewing workshops from her studio in the Model House, Llantrisant, Wales.
Health warning! Do not eat or drink when you are colouring or dyeing as some of the colourants contain toxins and dangerous chemicals. Only use plastic tongs when dyeing aluminium sheet. Do not place your hands in the dye solution
In my latest venture to discover innovative ways of working with metal l booked a one-day aluminium class with Mandy Nash who is a professional jeweller, teacher and felt artist. Aluminium is a fascinating metal that was extensively used in the aerospace engineering industry during the 1950s and 60s and also for home wares, such as pots, pans and canisters. Aluminium is remarkable for its low density and ability to resist corrosion. The chief ore of aluminium is bauxite, which was of interest to me as my son works at a bauxite mine in Australia, but bauxite is also found in China, Brazil, Guinea and Jamaica. In our workshop we used 0.7mm thick pre-anodized aluminium sheet. The oxide film that coats and protects the metal is porous. This means that it is important not to touch the metal with anything other than paper towel and plastic tongs during the colouring process as body oil, heat, even direct sunlight will close the pores of the oxide film making it impossible to colour the metal.
PERMANENT FELT-TIP PENS
There are many methods used for adding colour and print to the surface of aluminium. Permanent felt-tip pens are ideal for drawing, doodling and for making patterns on the metal. Before drawing onto the surface, first draw your pattern on a blank sheet of paper. It is important to remember that once you put the pen onto the metal it cannot be erased. Happy accidents will happen, no doubt, so don’t be disappointed if you think you have spoiled a piece. The sheet you are using may be cut up into a variety of shapes so various aspects of the coloured surface will look completely different once sealed and made into jewellery. It’s also important to note that both sides of the metal may be decorated with pens and then the metal can be placed into a dye bath to further colour any blank areas on the sheet.
As an experiment I used the permanent felt-tip pens with my brass stencils to see what sort of effect I could create. The tip of the pen was quite thick, which made it difficult to produce a neat image. I think that if I’d used a fine-tip pen it would have resulted in a more defined pattern. The ink was left to dry completely before I turned the metal over to decorate the other side. Once that was dry, it was placed in a bath of turquoise dye and left for three hours. When the metal had achieved the depth of colour required it was washed in clean water, wiped dry with a soft cloth and then placed in a pot of boiling water for 20 minutes to seal the pores of the oxide film coating. A couple of faults showed up in my stencilled piece once it was boiled in the hot water. The brass stencil had scratched the surface of the aluminium, so plastic stencils would be more suitable when stencilling. Also my fingers must have touched the left hand corners of the plate as the turquoise dye didn’t take properly.
TEXTURE MATS AND STAMPS
Texture mats and stamps are a very easy way to add instant designs and patterns to aluminium sheet. The sheet may be dyed a certain colour first and then printed or you can print first and then place it in a dye solution after the print is completely dry. Here I have used a permanent felt-tip pen to colour a texture mat. The mat was then pressed onto the metal very firmly to create the impression. Both sides of the aluminium were printed and then it was placed into a dye bath where it was soaked for about two hours. The longer the metal remains in the bath the stronger the resulting colour. Some dyes such as black and red need to left overnight for the aluminium to take on the colour. The dyes are specifically made for aluminium, approximately 5g of each colour were used in individual baths of warm (not hot), water. They have a shelf life of a few years and you know when they have become exhausted when the colour of the powder begins to fade.
The piece here is an example of a triple-dipped experiment using a wax crayon, three dye baths and torn bits of craft tape. The aluminium was drawn onto with a wax crayon which stopped the coloured dye from permeating the oxide film. Next the metal sheet was placed in a bath of bronze dye for a few hours. It was then removed, washed and wiped dry. More crayon was applied and the metal was then placed in a second dye. It was also cleaned and dried before strips of craft tape were torn and placed randomly over the stripes and the piece was then placed in a turquoise dye bath. The turquoise dye bled under some of the tape and being the stronger colour it covered some of the earlier dye, where it made contact with the metal. After it was washed and dried it was sealed in a pot of boiling water where the wax melted and the aluminium surface was sealed. The original lines show up the two different coloured dyes that were created using the wax crayon. The texture on the metal was made with the blue netting which is explained in ‘texturing’.
In texturing aluminium care must be taken not to damage or weaken the metal. A rolling mill is one of the most successful ways to impress a pattern onto the already coloured and heat-sealed plate. In this exercise the metal was wrapped in a fine layer of netting and fed into a metal rolling mill. The press was set to allow both the metal and fabric to pass through the roller so that as the handle was turned, the netting was pressed into the aluminium under considerable pressure which resulted in a faint attractive pattern. Many different materials may be used to texture metal. The rolling mill featured here is a professional piece of equipment that may be too expensive for an amateur jewellery maker to afford let alone get sufficient use from. However, small rolling devices are available from reputable tool suppliers so if you decide to explore aluminium as a jewellery making medium you may wish to have a look at what companies such as Palmer Metals have to offer.
- Date 16th May 2016
- Tags Tips & Techniques
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