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THE GUITAR PLAYERS COMMUNITY

Spray Painting DIY Effects Pedal

Many people like to build their own guitars and effects pedals. Getting a high quality finish is important if you want to replicate the look of a factory made guitar or effects pedal. This article will look at a method of getting a nice finish on a DIY homemade effects pedal.

Background

This guide assumes that you have planned out the electronics for the effects pedal first. You will need to drill the holes for the input/output jacks, power, and control dials first.

Tools & Materials

• Assorted grades of Wet & Dry sandpaper (ie 400,600,800,1200,1500)
• Methylated spirits
• Clean cloth / kitchen paper
• Can of spray primer (white / grey)
• Can of spray colour
• Can of lacquer spray (gloss / satin / matt)
• Metal or plastic effects pedal enclosure
• Big cardboard box or spray hood
• Thick wire to hold the enclosure for spraying & baking
• Old oven or camping oven
• T-Cut car paint restorer

Method

This process is best done outdoors on a warm dry day when it isn’t too windy. If you have access to a ventilated room specifically for spray painting - even better.

Preparation

The first stage is to prepare the metal or plastic enclosure for the paining. This envolves removing any dirt, rust, metal odidation, existing paint and lacquer or anything else that is covering the enclosure. I started with a Bimbox 5003-13 which is an aluminium enclosure similar to the Hammond and Eddystone die cast boxes. It was finished with a textured paint and gloss laquer which I sanded away with a small piece of 240grit wet and dry paper.

With a standard unfinished (no paint/lacquer) enclosure, you will need to take a finer grade piece of wet and dry paper and sand off the metal oxide. Around a 400grit is fine. This forms around the metal as it reacts in the air. By doing this, you create a better surface for the paint to stick to. When you can see a brighter metallic finish to the box, you can stop sanding.

Take a clean cloth or some kitchen paper and dampen it with some methylated spirits. Wipe the enclosure to remove all grease and powdered metal and paint from sanding. Try to hold the box from the inside by spreading your fingers out. You can also use some more cloth or kitchen paper to hold it. This removes the grease and other dirt that will prevent the paint from adhering properly.

Priming

Once the methylated sprit has evaporated, you can begin to spray paint the primer. This paint binds to the bare metal acting as a foundatin and creates a better surface for the top colour spray paint to stick to. If you have access to a fume hood / spray hood then these steps will be much easier. I didn’t, so I chose a cardboard box and some wire to spray the pedal in. The wire was used to suspent the metal enclosure in the middle of the box so that it could be sprayed and rotated without touching it. The box also helped shield the paint spray from the wind, allowing me to get an even coating.

Generally speaking, it is better to spray several light coats of paint rather than thicker coats. This again helps to give a better finish, reduces the chance of paint from running, and speeds up drying times. I sprayed 2 thin coats of primer and sanded lightly after the second coat.

The primer should be allowed to dry completely (read the can) before you spray any top colour coat. If in doubt, leave it for 24 hours in a warm dry place. You can also bake it at this point. See the Baking section for details. Use a fine grade sandpaper (600 grit) and very lightly sand the finish to remove any raised spots of paint. Don’t sand the corners or edges as you will quickly go back to the bare metal. If this happens, you will need to lightly sand over the whole enclosure and appy another coat of primer and let it thoroughly dry.

Colour Coat

With the enclosure primed, you are now ready to apply the colour coats. You should again try and spray several very light coats of paint and slowly build up the colour. Don’t be tempted to apply the top coat in one go because it will run, take ages to dry and leave a weaker finish. I spray around 5 fine coats and allowed it to try for several hours between each coat.

If you do get a run of paint, as you can see I did in these next 2 photos, simple let it dry, and then sand down that coat until the run isn’t visible. You will then need to spray this coat again.

After each colour coat, use a fine (600 grit / 800 grit) sandpaper to even out the paint and prepare it for the next coat. Don’t sand the coat if you want to bake the pedal. Some people have done this after each coat of paint, but I decided to bake once after 3 coats and then once at the end after the final coat.

The above photos were after 3 coats and one session in the oven.

Baking

This step is clearly only for metal enclosures! By heating up the metal enclosure, the paint applied to the surface will start to try and turn into a liquid. As it begins to form a liquid, the subtle imperfections will smooth out and set smooth after the metal is allowed to cool. As well as this, it also helps to bond the paint to the surface of the metal, and hence forming a more resistant finish to knocks and scratches.

I applied around 150°C for about 20 minutes after the first 3 coats of paint. After the final coat of paint, I again baked the pedal for the same amount of time to give me a good finish. You will need to use either an old oven strictly not for food use, or a small camping oven - again this should be a didicated bit of equipment and not for cooking food. The paint will emit small quantities of vapour that you really don’t want to consume. You can find these small ovens at camping stores for around £20.

I found the best method was to use some thick wire to build a rectangular box shape that sits inside of the big half of the enclosure. I build a second box that I could rest the bottom plate for the enclosure on. This held the surfaces off the oven so that nothing touches the paint.

After baking, open the door and allow the metal to cool completely. Don’t let anything touch the paint surface as it will still be tacky to the touch and it will mark (imprint) very easily - meaning you have to sand and paint all over again! A couple of hours should be enough but you can leave it for longer just to be safe.

This now leaves you with a good smooth finish that you could almost say is complete, but I went on to give it just a little more finishing.

Final Finishing

The last stage is to give the top coat a perfect finish. Start with a 1200grit wet and dry paper. Soak the pedal in water so that it leaves droplets on the surface. Sand in light circular motions all over the enclosure to level out any uneven areas in the finish. Repeat the process with the 1500 grit paper. You will notice that the water collects the paint and starts to form a paste. You can wash this away and replace with just water. This acts as a guide to how much paint is being removed. Remember, you are smoothing the surface, and not just trying to remove the paint. Keep drying the pedal and check the finish. It should feel smooth and glass like.

For the ultimate finish, take a clean cloth and put a pea sized drop of T-Cut on it. Work it all over the surface of the enclosure in small circles. You will notice that the cloth starts to pickup traces of the paint. This is fine. T-Cut actually eats away a very fine layer of paint to give a seriously smooth finish. Turn the cloth over to a clean patch and buff off the T-Cut. Rince the enclosure in water to ensure all of the T-Cut has been removed. Any left on the surface will continue to eat into the paint and ruin the finish. Dry thoroughly and then buff to a shine with another clean soft cloth.

You should have an incredible glassy finish now. If you baked the pedal, it should be reasonably tough, but for extra protection you can apply a spray lacquer on top to seal and protect the paint. 3 or 4 thin coats should be enough - apply them in the same way as the top colour. It will take 2 or 3 times longer to dry between coats, and it’s important to do this before sanding as you will simply clog up the paper if not. If the lacquer is a glossy finish, you can repeat the 1200grit / 1500grit and T-Cut to give the same high quality finish. Don’t do this if the finish is satin or matt.

After the box is populated with the rest of the electronics, it should look something like this:

Summary

Spray painting an effects pedal and achieving a good finish is fairly simple, provided you take the time and care to do each step properly. You can also apply water slide decals to finish your effects pedal after you have baked the paint, and before you apply the coat of lacquer. I have had a look into powder coating which is supposed to give a much better (and tougher) finish. I will post another article if I can get access to the tools.

Let me know in the comments if you have tried this yourself, or if you have any questions or tips.