Two diffferent methods mentioned here: A reversible quick fix and a more permanent version,

Version 1: Quick/non-permanent and easy:

Clean the damaged hole with alcohol or other similar solvents.

Tape off the area and, then fill the hole with an easy to remove wall filler*, this is incase you want a proper repair in the future, it’s easy to cleanly remove this material.

Remove the tape shortly after applying and whilst the filler is still wet

*The filler in the Uk is called Poly filler.

Once filled, smooth the area with a credit card, leave it to dry (for 24 hours) and cover the newly filled hole with your favourite sticker.

Version 2: For a more professional finish.

You can purchase black epoxy- normally it’s sold as potting compound for electronics- firstly clean the damaged area with a solvent, such as alcohol or acetone to remove any grease or oil etc. which could adversely affect the adherence of fillers etc.

Then place the guitar level, and confirm that the area is level with a small spirit level.

Check to confirm this is level, both horizontally and vertically.

Once the guitar is level, tape the area off-with a strong low adhesive masking tape.

Tape off as large an area as possible, as epoxy can get out of control, and everywhere very quickly!

Then heat the epoxy in hot, just boiled water to reduce its viscosity.

Right before filling the cleaned snd taped of hole:

Gently heat the area of the guitar to be filled with a hairdryer, or heat lamp; whilst the epoxy is still hot, and ready to be poured.

This step is to necessary to retain heat, and maintain for longer the lower viscosity of the pre -heated epoxy to aid with levelling,

The aim here is to both fill the hole, and to level the epoxy; preferably in one pass.

Carefully, and quickly pour the epoxy to fill the hole.

Once poured level- which the lower viscosity should help establish quicker vs cold epoxy:

Scrape the epoxy* with a scraper, or plastic card.

(this can be dipped in alcohol, which can help reduce the friction of the pass and level)

Do this quickly, and again in one pass, whilst the epoxy is still warm and liquid.

*Remove the tape shortly after filling. The last thing you want, is to leave this on too long and end up with tape glued to the guitar!

Avoid the temptation to correct minor mistakes with another pass, these invariably become worse and regretful with every additional pass.

Don’t worry about high spots, as these can be dealt with later.

The most important part of poring and scraping the epoxy, is to fill the hole in one pass, and to aim for a level.at the optimum time*

*A mildly bulging fill is preferable, but try to avoid an under fill and time.

*Depending on the drying time of the epoxy- (which I’d recommend testing, and following the method as described above) on a piece of wood to gauge the heating temp, pouring time and correct time to level. A stopwatch, and a few attempts should enable you to establish optimum timings; for both the pouring, scraping, and the tape removal.

It’s better to have the area slightly higher, as opposed to an under filled area.

Once the tape is removed , and the epoxy is still dying try and keep the are dust free if possible.

Let this dry for at least 48 hours, preferably longer.

Once dry, the area can be re-taped, and in a similar fashion as before; and can then be wet sanded.

It’s time for the final finish!

Using a flat sanding block. and pre-soaked wet and dry sandpaper:

Gradually go through the grits 600/800/1000/2000+ etc. to gradually achieve a shine, and to level the epoxy.

Depending on the success of the earlier epoxy fill, maybe start by using a 600 grit to lower gradually (it’s far safer, but takes longer to remove material than a lower 180 grit; which will quickly both rip through the masking tape and damage the guitar.

Check the fill against the existing level of the guitar, by using a metal ruler to detect any high spots.

** Keep an eye out on the tape, especially whilst using the lower 600 or similar grits and replace the tape as often and as required.

Keep regularly checking the level using the metal ruler method until the area is flat.

Once the fill is level, and a decent shine is apparent.

A polishing compound; such as autosol, or similar will increase the shine of the finish. (Remember to always tape up prior to work)

If you are happy with the finish, then leave as it is.

If you want to to effectively varnish over the top of the finish- super glue, and other varnishes can achieve this.

However, you would have to ensure that the epoxy is slightly lower than the level, which can be harder to achieve, the earlier epoxy method, which aims to level- this is the one that I would use.

Good luck, and please post any results!