Luthier Tips du Jour - Buffing High Gloss Finishes - O'Brien Guitars

Uploaded by OBrienGuitars on 24.04.2009

Most people agree that a high gloss finish on a guitar can be very appealing.
However, this can take a lot of work and can be a very frustrating process.
Not only do you need special equipment and skills to apply the finish
you also need the skills and equipment to level and buff the finish to achieve the high gloss.
A buffing machine and a set of buffing wheels is the method I use
and in this video I will walk you through the steps I take
to get that showroom shine when buffing to a high gloss.
There are many commercial buffing machines available on the market today.
The one I am going to use here is one that I had made when living in Brazil.
This machine started out as a thickness sander.
After building a few guitars I quickly realized I needed a way to buff the finishes to a high gloss.
So, I added an attachment with a buffing wheel.
I use one belt and pulley to drive the drum for thickness sanding.
I can then remove this belt and put on another belt that will drive the buffing wheel.
Notice how the belt that drives the buffing wheel is a few sizes too large thus making it loose.
I will demonstrate why in a minute.
Before going to the buffing wheel you must first level the finish.
This is done using sandpaper after allowing for appropriate cure time for the finish after it has been applied.
There are two different grades of sandpaper on the market; Commercial and Industrial.
The commercial grade is commonly available at hardware stores and home project centers.
The industrial grade is usually available only through industrial supply stores.
It’s made from higher quality materials and I therefore recommend using it.
Also, there are two systems for grading sandpaper, the American and the European or “P” grade.
In grits below about 320 both grading systems are almost identical.
However when going to higher grits there is a huge difference.
For example, the European “ P” grade paper in 1200 grit is equivalent to about 600 grit in the American system.
If you use the two types of papers on the same project you could end up putting scratches
back into your finish instead of removing them.
I highly recommend doing some research on sandpaper types and grades to learn more.
For this lacquer finish I will begin leveling with a high quality 600 grit wet/dry sandpaper.
I have a small dish of water to which I add one drop of liquid soap.
This helps break the molecular structure of the water and allows the sandpaper to work better.
Try sanding without adding a drop of detergent to the water and you will see what I mean.
I use a quarter sheet of the paper and fold it into thirds.
I then place it in the water for a few minutes.
I will use a thick sponge as a backing pad for the sandpaper while sanding.
Now comes the fun part! Place the paper around the sponge and begin sanding the finish.
I use circular motions.
Keep the surface wet as you work by periodically dipping the paper back into the dish of water.
After a few minutes of sanding wipe the water off the surface you are leveling.
As the surface dries you will see that the shine has gone away.
If it hasn’t, keep sanding until there are no more shiny spots on the surface.
You want a nice satin finish that is completely level.
The trick though is to not sand through the finish and into the wood if using lacquer
or not sand through the top layer of finish and into the next layer
if using a product that builds in several layers like urethane.
Now you will begin to see how your spray technique can help or hurt you when leveling the finish by sanding.
If you did a good job applying the finish it is much easier to level it later.
Sand the entire guitar with 600 grit sandpaper.
Don’t use much moisture around the tuner holes in the peghead
as it can it can swell the wood and cause problems with the finish.
Sometimes I even dry sand this area.
Once the finish is completely level repeat the entire process with 1000 grit paper.
Some people even sand all the way up to 2000 grit or higher but for my purposes I stop at 1000 grit.
It is now time to use the buffing wheel to get the finish to a high gloss.
I use a dedicated wheel for each grit of polishing compound.
Also make sure to use proper safety equipment.
Since I sanded to 1000 grit, I start by using a polishing compound a bit courser than this.
Here I am using 800 grit.
I just do a quick buffing with this grit to help me see any course sanding marks that
may not have been removed from the finish. Apply a small amount to the buffing wheel.
While buffing make sure that you don’t get the wheel above the centerline of your work piece.
You run the risk of it grabbing the work piece and throwing it to the floor.
This is never good.
My buffing wheel is running at about 1700 RPMs.
This is a little faster than most.
It can tend to build up more heat and heat is the enemy while buffing.
You will notice that I lightly buff the finish and keep the guitar moving.
Around the fretboard you will notice that the wheel slows down.
This is due to the oversized belt driving the wheel.
It works like a clutch and allows me to get in tight places without running the risk of
burning through the finish or grabbing the work piece.
I prefer the belt drive buffers over the direct drive buffers for this reason.
Watch how easy it is for me to get in around the heel block area and slow the buffing wheel down.
Be careful while buffing the sides.
Don’t let the wheel get above the centerline or you risk having some expensive firewood.
Once I have buffed the entire guitar lightly with 800 grit compound,
I change the wheel and buff the guitar again with a fine 1000 grit compound.
I then change the wheel again and buff with the extra fine compound.
Watch carefully as the finish becomes a super high gloss.
Now that I have the guitar super shiny there is one more step I like to do.
That is to polish the guitar by hand with a swirl remover.
This helps remove any residue left from the polishing compound.
I use a soft flannel cloth and a small amount of the swirl remover.
I also try and go only with the grain.
This technique also works well for polishing the peghead or other areas where heat build up could ruin a finish.
There are a lot of things that have to go right in order to get the end result of a shiny high gloss finish.
With some research and a bit of practice you can achieve very satisfactory results adding value and beauty to your guitar.