This week I applied the colour to my guitar build, I also started the finishing process on a kit that I purchsed from guitarkitsdirect.com as well as continued to work on my Squire strat, the first guitar I ever owned, the finish was in a sorry state so it was a good practice model.
The colour has been the single most stressful part of this whole experience, Mirotone make pigmented lacqeurs, but at $40 for a 4L tin it seemed foolish to buy 4L in several different colours when I only need about 300ml for each guitar. You can also buy acrylic lacqeur in a range of colours from a spray can, but again I already had the nitrocellulose and the spray can finish isn’t quite as good as that of the spray gun. Also for one of the kits I have comming I wanted to make a custom colour, so I set about trying to find pigments to that were compatible with my nitrocellulose finish to mix in to make the colours I wanted. Australia is not a great place to do this at all! In the USA places like Stewart Macdonald have all the colours you could want however the only guitar laqceur specific dyes I could find were analine dyes, these are transparent and wouldn’t have worked.
So eventually I had to threw caution to the wind, I found a hobby site, Dalchem, they had both transparent and opaque pigments for addition to polyurethane resin, given that my guitar finish is basically a thin version of resin, (nitrocellulose in my case not polyureathane) I purchased some opaque white and black as a base and some transparent colours to add to these. Luckily for me they were perfectly compatible! The white especially required quite a lot of pigment to be completely opaque but I wasn’t worried, the pigments were only $15 each so I saved myself a lot of money and also gained the ability to make custom colours, I’ll talk more about applying those later on though.
At the end of last week I had done all the sanding, washcoating, grain filling and barrier coating which meant it was time to apply colour to the guitars. As you may recall I decided to keep the top of my guitar a natural finish so you can see the wood underneath, the back grainfiller did a great job of accentuating the pores but I still wanted to spruce the appearance up a bit. For this I used a transparent stain from feast and watson which was available from bunning, I used elm as the colour as it wasn’t too intense but had a nice golden colour to it. Rather than staining the bare wood (which looked terrible on my test on scrap) I added some of the stain to lacqeur in a fairly thick mix and applied two coats. If you compare last weeks wash coat only with the new colour you can see the diference it has made.
With the most important part of the guitar (visually speaking) taken care of it was time to colour the back, although originally I was going to make the back transparent black I decided it would be easier to make it opaque. When laying down a colour coat I decided it would be best to first lay down a primer. This is a pigmented coat that is sanded to a smooth finish using the 360 grit sanding paper. For lighter colour coats a white primer is common, and for dark backgrouns a grey primer is prefered. Because I was using black, I decided to make the grey quite dark so I added one mL of white and 2mL of black pigment to my lacqeur which was a 2:1 lacqeur:thinner mix. I laid it on wet, this means it’s a bit thicker and shines when still wet, the wash coats being thinner were laid on in a drier more sparse spray pattern to avoid runs. Before spraying the primer I masked off the top of the instrument as well as a little of the sides in order to make a binding like effect using painters tape and plastic liner.
I sprayed the first coat a little too thick in some places which caused runs, build ups of lacqeur, which needed to be sanded out after an appropriated period of drying to let the finish harden, I sanded the whole primer to a really smooth finish using the 360 grit sand paper which meant that a more even smooth colour coat could be applied. You don’t want to have to modify a colour coat because the sanding and imperfections will show through once the top coats are added. Having learnt from the previous experience with coating I made the black lacqeur and sprayed it on being careful not to spray it too thick and managed to avoid runs.
After the colour is applied I left it overnight to dry and harden. I then began the process of applying the top coats, these are thick (2:1) coats of clear lacqeur. You apply 4 -8 coats spread over a few days in order to build up a protective layer of finish that is thick enough to accept the buffing compounds without burning through, I’m currently on the 7th coat, tomorrow I will add one final coat and then let the finish harden for 7 days before beginning the final sanding and buffing process.
In between coats there was a 1 – 2 hour gap, this meant that I also had time to work on the headstock of the guitar, I will talk about that in a different post though. I am really close to the end of the process now with only the buffing, components and the electronics left, as well as the creation of the top and back control plates. It feels good after weeks of work to finally be getting closer to that finish line, I can’t wait to post a video of the guitar in action!