Technical Thursdays - Metal Effect Finishes archive

Thursday 9 April 2015

Mark Baker and Nick Agar look at how you can use reactive metallic finishes on turned work

Gallery

It was a chance question I posed to Nick some years back when discussing a new piece of work he had created. I asked how he achieved a certain rusty iron effect that set me on track to achieve one of my long-standing aims to create some 'ancient' pieces, which I had been longing to bring to reality but had not found the right products to get the results I needed. Nick's response was quite an eye opener for me when he smiled and said: "It comes in a bottle." Quizzically, I probed further and he told me it was one of a selection of reactive metal paints that oxidise over time when exposed to the elements. Alternatively, this process can be speeded up by using pre-prepared activators or ageing solutions.

I must add that he did ask me to keep this secret to myself as there was a lot more experimenting to be done in terms of how they could be used and what could be done with them. So, we both set off exploring these further. This article is in response to requests from us both as to what we use and how we do it, so here is a collaborative article where we show some of the effects we create using these coatings and a quick guide to using them and avoiding some of the pitfalls.

What are reactive/oxidising metal finishes and related products>

Quite simply, they are water-based paint products that have a metal content in them that, when set, forms a hard layer on the substrate they are applied to. They can be applied with an airbrush, brush, sponge applicator, and no doubt there are a few other routes too.

There are two companies who supply them, both of which have extensive web presences and video clips to show how to use their products: Modern Masters and Sculpt Nouveau. Depending which make you go for, there are various metal finishes you can opt for and use patinas to apply to them should you choose to. That said, you can use the metal coating on its own and then apply another product on top to create a given effect. The metal coatings looked at in this article are iron, copper and bronze.

The patinas are thin liquids you can spray, sponge, drizzle, etc. onto the coated surface. You need to read the well-written instructions to know whether you apply these to wet freshly-applied coatings or once the coating has dried. They come various colours for copper and bronze, but here, we looked at shades of green and blue.

Depending on what you coat, you might need a primer. A special one from both companies is available, which coats the surface and prevents any contaminants leeching from the surface and affecting the metallic finish. Also available are specialist clear surface coatings with different lustres, which protect the piece it is applied to and stops the oxidisation process from happening, or you apply the ageing solution followed by the top coat at a point of choosing to stop any further reaction at that point. It is worth noting that the coatings are not food-safe, so they should only be used on items that are designed to be sculptural and looked at. Also, it is best not to place jewellery and other metallic items on a patinated surface that has not been sealed with the surface top coat, as you may end up with a reaction occurring. I err on the side of caution and only use the effects on sculptural items.

Warning: take note of all the safety precautions when using these products and wear the recommended PPE at all times. That means gloves and eye protection at all times and also lung protection when spraying the patinating fluid and sanding the metal coating and aged surface. Some of the chemicals are hazardous/harmful.

Creating a patinated metal finish

STEP 1

Surface preparation is key to getting a good finish. Wood is different to metal plaster and other substrates and you have a choice to apply your metal coating directly onto a sanded - to a fine grit grade - bare-wood surface. Alternatively, you can apply gesso, texturing pastes and then prime it. You can use the specialist primer, or, we have found good quality primers from hardware stores work well when coating wood. If you use water-based products, then you may end up raising the grain, or highlighting areas you have not sanded well previously

STEP 2

If you find that you have ended up with any surface anomalies, you need to remove them at this stage. A quick sand will solve most of them, then...

STEP 3

... apply a quick recoat of primer, or a coat of metal finish if you applied this onto bare wood

STEP 4

Assuming you have used a primer, you can now coat the surface with the metal finish of your choice. In this case, it is copper - the two in the background have been coated with a bronze finish. If you are applying the metal coating to a textured finish, make sure you get in all the nooks and crannies without over-filling it, thus causing runs of the coating to form

STEP 5

Once the first coat is dry, denib it with a fine abrasive and wipe the surface clean, then, give it another coat of metal coating. It is all too easy to inadvertently pick up dust and debris on the brush, so keep clean paper kitchen towel handy and wipe the brush on it every so often

STEP 6

If you are using the copper and bronze coatings and you want to use a patina coating, don't allow the second coat to dry. Instead while wet, spray your chosen patinating spray. If using iron coating, one make instructs you to let it dry before using the patinating fluid and the other suggests using on a wet coat

STEP 7

If you are working on the inside of your work, you may find that a pool of the patinating fluid can settle at the lowest point, which can look unsightly, although gives the effect of an aged bronze or copper vessel. To reduce the puddle size, touch the top of the fluid with paper towel to suck up some excess

STEP 8

Here you can see the freshly coated copper coating, which has been sprayed with a green patinating fluid

STEP 9

Here you can see the freshly coated bronze coating, which has been sprayed with blue patinating fluid

STEP 10

Here you can see the inside of the finished items. The piece on the upper left-hand side shows what happens when a pool of patinating fluid dries in the bottom. This piece and the lower one also show clear brush marks. The top right-hand piece shows no brush marks and most of the surface has been aged. By altering where and how much patinating fluid is applied, you can have a lesser effect and here, have clean metal showing through. If you need to start again, sand the surface - wearing PPE - and either re-coat with metal coating followed by the patinating fluid, or sand, re-prime and then go through the coating and patinating process again. If you do not re-prime, the previous coating of patinating fluid can affect the fresh coat of metal coating that is placed on top of it. This is not necessarily a bad thing as this creates another look entirely

STEP 11

If you choose to seal the surface, you lose some of the effects seen in the previous photos. On rusty iron you lose the look of the powdery red residue and on the bronze and copper. The choice to seal or not is yours, but if you handle the rusty surface, then the rust transfers if it is not sealed and the copper and bronze surfaces will leave a powdery residue on your hands and clothes. The top portion of this bowl is sealed and the lower section is not

STEP 12

The three finished vessels showing copper and green patinating, bronze with blue patinating and iron and rust patinating fluid. This will hopefully give you an idea of what can be done with a few simple to follow steps


Woodworkers Institute

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Mark Baker , Technical Thursdays , Nick Agar