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Posts tagged “polyurethane

The Headstock and Neck

You may remember that I did not want to build the neck for this guitar considering the precision work that is involved and so I bought a cheap guitar to use for parts. Having previously striped the headstock of the black top coat I was now left with the bare wood. Unlike the body the neck will be finished with a satin lacqeur, this time polyurethane because it was readily available from bunning in the small quantity that is required. Satin lacqeur is like clear lacqeur except that it has chemicals in it that make it less glossy and smoother to the touch after light sanding, being satin the sanding doesn’t show up much either which negates the need for buffing. Satin is my prefered finish for a neck because it creates a less sticky, smooth finish which is much nicer to play on.

Having sanded the headstock with 240 and then 360 grit paper I sprayed on the satin lacqeur to a wet consistency, unlike the nitrocellulose the polyurethane takes a bit longer to dry and also dries harder. I had to wait about 5 hours before applying a second coat. After applying the second coat I let the finish dry over night before sanding with 360 grit paper to smooth over the finish in preparation of recieving the water transfer decal. I located water transfer decal paper online. The water transfer is a lot cheaper than the vinyl transfer paper and is more easily concealed by the subsequent top coats, and besides, if water transfer is good enough for leo fender, it’s certainly good enough for me!

The 2nd layer of satin freshly applied to a wet consistency.

I tried various different font and sizings before I eventually decided on this;

Headstock design using the font “Cybertooth”

Broken Wizard is an online alias I have been using for over 10 years, my music prodcution and other creative enterprises also bear the Broken Wizard moniker so I decided to give my guitars the same name. The cybertooth font stood out to me, it’s not like a lot of other guitar fonts which have resembled the Fender logo or more 20s and 30s style fonts like Gibson and Gretsch. It’s a bold, solid modern looking font which should be visable form a decent distance, even if not legible. Sticking with the Broken Wizard theme I decided to name all my custom guitars after types of wizard. In this case I went for soothsayer, a soothsayer is a fortune teller and magician from the roman era, the name seemed to fit the curvey edgey design of my guitar. To contrast the manufacture font and create a sort of mystical feel I used the Algerian font for the guitar name.

I used my printer to print the decal, cut it out and then soaked it in water for thirty seconds or so. The transparent top part of the paper slides off easily and located fairly easlily when applied to the sanded surface. I used a small soft brush to smooth out the decal and then used dry kitchen towel to remove the excess water. The manufacturer reccomends that you let the decal dry for three hour so I will leave it over night, this way it will be as dry as possible before I spray another two coats of satin lacqeur over the top of it to seal it in.

The headstock decal after being applied to the headstock.

Once the 2nd layer of lacqeur has dried for 5 hours or so I will sand it lightly with 360 grit, and then wet sand it with a higher grit paper, maybe 400 or 800 to properly smooth out the finish, this step will be especially important on the neck for the other project guitar I am finishing because this will be the playing surface on the back of the neck so I need it to be smooth for a good playing experience.


Applying Colour

This week I applied the colour to my guitar build, I also started the finishing process on a kit that I purchsed from 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 two layers of stain the top colour is complete.

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.

My girlfriend Nat helped me apply the masking.

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.

The primer coat before sanding.

The primer coat after sanding.

Freshly sprayed black lacqeur.

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.

The guitar has a real shine already with the build coats.

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!


Laminating The Wood

The wood is all finally cut down to size which means it is time to laminate the wood. This is arguably one of the most important tasks in creating the guitar because the stuctural integrity of my body blank is the single most important thing in making sure the guitar will not fall appart at some point. I chose the best glue I could find, a polyurethane based glue which will not only be strong, but being ployurethane based shouldn’t interfere with any subsequent finishing materials that I use.

In order to make life easier on ourselves me and dad glued all pieces together at the same time. Firstly we glued the two halves of pine together, next the glue was applied to the top of the pine, glue was applied to one half of the ash and then the two halves were placed on top of the pine. During the whole process the two joins were placed as far apart as possible which you can observe in subsequent pictures.

Applying glue to the one half of the wood

Glue applied to the top of the pine ready for the ash to be placed on top.

The wood was all joined flat together onto plained surfaces, this is very important because an uneven surface would have resulted in dead spots where the two surfaces being glued were not in contact with each other, which structurally would not have been as strong.

I clamped in two planes horizontal and vertical which means you need a lot of clamps, you need large clamps for the horizontal plane that can span the width of the wood (I used 45cm clamps).  I had originally intended to use 3 clamps for this part but one broke becasue it was cheap… so a lesson for you there, invest in good equipment, you’ll save in the long run with how much longer it will last. Smaller clamps were used to apply preasure to the vertical plane, I used 6 clamps for this part.

The wood with all the clamps

It’s easier to see the horizontal clamps in this picture.

Something to note when glueing is that there will be nothing you can do about quite a lot of glue coming over the sides and making a large mess. If this happens you know that you have applied enough glue because the glue has covered all the surfaces and has run out of space and therefore escapes throught the cracks.

Here you can see the mess that is made by glueing and how the two horizontal joins in the ash and the pine do not line up on top of each other.

I’m leaving the glue to dry for a week, this amount of time isn’t really necessary but basically Sundays are the only days I have to work on this. Next week I will be sanding off all the excess glue and cutting out the shape of the body, and depending on how much time I have I may even rout the neck joint so I can plan where to place the routing holes for the pickups and the bridge, but more on the importance of these things when I get to that part of the build.