Alder is quite a forgiving wood to work with, when it comes to finishing guitar bodies. It’s similar in many ways to the Obeche timber that framers often favour for modern gilding. Alder is easily carved and shaped, and has a tight, regular, fine-grained structure which acts well as a tonewood – but which, conveniently, doesn’t require grain filling – unlike other possible alternatives, such as Ash or Mahogany.
The body has already been well finished, and so I don’t really need to do any more preliminary refinishing. I need to build a primed, non-porous base for the gilding size to eventually sit on. The finer I can get the finish – the better the gilding will look when finished. So I want to take the approach of building up any primers and basecoats in very fine layers. By following a plan of rubbing each step down with progressively finer grades of grit – I want to gradually build up a polished, sealed and coloured base – on which I can apply my oil size and ultimately, my imitation leaf.
I have a small amount of Fontenay base left from my last gilding experiments. This will give me a rich red earth hue to help contrast with the gold applied over the top and, although the alder doesn’t really need sealing – it’ll help do that at the same time. The Fontenay base is a sprit based primer, with an exceptional pigment load. The pigment is an earth red oxide, and this will help prime and seal the wood. The complementary red colour is intended to bring out the warmth of any overlaid gold colouration.
I apply the base coat thinly and evenly, with a stiff-bristled brush. The spirit base makes the application much more consistent, and the pigment is drawn deep down into the grain of the wood, before the spirits evaporate off. The surface dries quickly – but it’s best to leave things for 24 hours or so – to dry out properly.
Next day – I can begin rubbing back, and polishing the body. I reckon the body is already prepared to 500 grit – so I don’t want to start any coarser than that. I take some 500 grit wet and dry paper, (with a cork backing block on the flat faces), and I begin to knock back the basecoat – using my fingers to assess progress as I go. In some places – especially towards the edges, and on the arm cutaway curves, the grit rubs through to the wood beneath. However – since the basecoat is spirit based, it has already penetrated quite deeply, and so the pores in the wood surface should remain sealed. It’s noticeable that where the wood is exposed – it’s still quite coloured with the red oxide pigment, which is very fine and has obviously been pushed into very fine features in the wood’s structure.
After each pass, I clean down the body with a fine cloth – before gently working over with the next grade of grit. I repeat the process until I take the Fontenay base coat up to 1000 grit. After a thorough clean – I give the body a brush-coat of shellac, and then let it hang overnight, for the shellac to cure. The shellac should fill any remaining fine irregularities in the wood structure. It’ll act as a barrier coat to stop me removing any more wood or base coat, and I’ll also be able to polish it up to a fine sheen.
After the shellac has had a day to cure, the polishing process is repeated – but this time, working with finer and finer grades of grit paper. All the way up to 2000 grit. The shellac is used here as a kind of sanding sealer – penetrating any porous areas of timber remaining. But the shellac will also help provide a polished coat – and I start to use a little naptha to lubricate the grit paper as I go. The wet sanding, combined with passes with finer and finer grit papers, soon begin to provide a highly polished result – with a dull but glassy shine.
To eventually gild the body, I’ll be using an oil size – but to hopefully achieve a little texture and character in the end result, I aim to sort of drape the imitation leaf – rather than try to provide a totally flat and fault-free finish. This hap-hazard application approach can result in a reasonable amount of “faulting” – (where the red basecoat shows through small gaps in the gold leaf). I decide to take the opportunity to experiment with another imitation alternative – Gilt Varnish. This is a thin, solvent based finish, with a heavy load of metallic pigment. If it’s applied to a well-polished surface – I’ve seen results which can look, very much, like the real thing. It’s certainly much more convincing than many of the metallic paints I’ve seen previously. The gilt varnish won’t actually give me the texture I want for this job – but it’ll be a useful experiment in passing, and by using the gold varnish as an undercoat – I won’t have to worry so much about having to spot potential faults, since they will be more closely colour matched. I’m using a gilt varnish by Liberon – in Antique or “Chantilly” gold. A small pot goes a long way
Since the surface is now so smooth – the gilt varnish goes on really easily. It’s important to let the application flow, whilst trying to ensure that there are no runs or sags anywhere. Apply it like a varnish – and not a paint. Quickly brush out what’s on the brush, and then begin the next application a little way away from the previous – using the brush to quickly and gently blend the new application into the previous. You need to work quickly. Just like varnish or oil size – don’t overwork, or try to apply fresh coats over previous, semi-dry applications. It’ll drag and pucker, and will need to be flatted back all over again. If you do need to recoat, or go over missed areas – let it dry first.
Once the body has been fully covered – it’s hung to dry thoroughly, and then the gilt coat is inspected. It’s a little patchy here and there – where I’ve not dared to overwork the application. Now that the coat is dry, however, a second application can be made over the top – providing you work quickly and, again, don’t overwork it. The varnish begins to soften any previous dried coat – so you can’t hang around, and you definitely can’t risk scrubbing or fussing over areas. Once again – spread thinly and quickly. Then let it dry properly – it goes off quick enough.
Before any recoating, however, a light rub over with 2000 grit helps knock back any surface imperfections, and keys the surface slightly. After a few second applications of gilt varnish here and there – there are still a few, tiny, areas where the red shows through, but since I’ll be laying imitation leaf over all of this – there’s no point losing too much sleep over it. I leave the gilt varnished body to dry for 24 hours.
As an experiment – he end result isn’t too bad, (although it doesn’t have the texture I was looking for). However, if I ever want a gold paint job on a project down the line – I’ll definitely consider Gilt varnish as an option. Maybe for an authentic looking, “aged Goldtop” finish.