UV Gloss Lacquer – procedure

Like conventional finishes UV cured lacquer can be tricky to use but if done succesfully it has many  advantages.

Top tip:

The problem most likely to occur is that the lacquer fails to dry hard enough. If this happens it feels waxy and is easy to scrape off with a fingernail. To prevent this from happening any dark wood, stains, dyes, pigments that you may be using must be ‘sealed in’ using the Insulator product. An alternative 2-pack ‘dark colour’ method is described below but it takes a little longer.

 

Follow Steps 1-9 for a perfect UV Cure finish!

Step 1. Base Colour – Optional

Colour is optional- if in doubt don’t,  as it adds a further level of difficulty. We use colortone dyes but there may be others that work. These pigments can be added to insulator, gel filler, and top coat for sunburst effects but darker colours must be sealed in with ‘Insulator’ before any UV cure product is applied.

1. Apply dye to bare wood with a rag or spray it on

Note: An alternative method is to mix the pigment with 2-pack lacquer just for a colour coat (see below). This locks in the dark colours, preventing them from affecting the UV lacquer top coat, but it needs to be left over night as it takes a few hours to cure. Also you are re-introducing solvents into the proceedings…

Step 2. Insulator – Optional

This is used to seal in dark colours which can prevent the lacquer from drying. Dark refers to the colour of the wood or any colors that you intend to apply. Dark means anything darker than amber…if in doubt do it anyway.

Apply the insulator on the bare or stained wood using a rag, or spray it on.

If no stain is used:

1. Use a rag to rub insulator into the surface of the wood using small circular motions, working it well in over the whole surface.
2. Allow to air dry for 10-15 minutes

If the wood is stained:

Using a rag might disturb the color, especially if a sunburst has been applied. In this case the insulator is sprayed on. After air drying check very carefully for dry spots where the insulator has sunk- in especially into the end grain. Apply further coats until there are no dry spots.

1. Spray a coat of insulator
2. Allow to air dry for 10-15 mins
3. check for dry spots and re-coat as necessary

Step 3. UV wipe on gel filler- Optional

The gel filler is used to fill the pores on open grained wood…if in doubt do it.

1. Use a clean rag to wipe the gel filler into the surface of the wood using small circular motions, working it well in. Try to leave a reasonably smooth surface with no large peaks or troughs caused by rag marks.

Step 4. UV Gloss top coat

A coat of UV gloss lacquer is applied straight over the gel filler while it is still wet. There is no need to rush as the gel will not dry until it is exposed to the powerful UV light.

UV to coat can be applied with conventional spray equipment but HVLP is recommended.

1. Spray a coat of UV gloss
2. Zap it with the light

Step 5. Scuff sand

Scuff sanding is basically scratching up the surface, providing a ‘key’, so that the next coat fully adheres and preventing any de-lamination. You do not want to rub right through the gloss especially if there is a stain or dye underneath, so proceed with care – you only need to take the shine off.

1. Sand the entire surface very lightly with 320g sandpaper
2. Switch to green abrasive pad (approx 320g) to remove any shine that is left

Step 5A. Alternative Dark Color Method – Optional (see above)

1. Spray the color using dye diluted in 2-pack lacquer (or solid color)
2. Leave over night to fully cure

Step 6. Apply a build coat of UV gloss

1. Spray a coat of UV gloss
2. Zap it with the light

Step 7. Sand the surface flat

After two coats the surface should be ready for ‘flatting’.

Flatting is the process of sanding the entire surface perfectly smooth, ready for applying the last UV gloss top coat.

Depending on how good a job you have done or the quality of the surface you are spraying, sometimes 3 or more coats may be necessary – you will have to use your judgement. If you think you might rub through during this stage then go back to ‘scuff sanding’ and apply another coat…if in doubt, do it.

1. Sand the entire surface with 320g to remove any runs or sags until it is completely flat

Step 8. Apply final coat of UV gloss

1. Spray a coat of UV gloss
2. Zap it with the light

The guitar is now ready for polishing!

Step 9. Polishing UV Cure Gloss Lacquer

Polishing UV Lacquer follows the same process as conventional lacquers:

1. Sand the surface flat with 800g sandpaper
2. Repeat with finer grades 1200-2000g making sure to remove the scratches from the previous grit every time.
3. Buff to a high gloss. The final polish is achieved with a buffing wheel, but it can also be rubbed by hand.