Friday, April 15, 2011

Fixing a Dented Poly coated guitar

Today I repair my Taylor 514ce

So I smacked my Taylor guitar and dented it nicely. Damn!

The dent is about 0.5mm deep!

It is important to use resources at hand. There are many repair people out there but the gold standard is set by Frank Ford at FRETS.COM. I gleaned this repair information from Frank's website and I strongly urge you to go directly to the source as I'm only a disciple.

I know that Taylor uses a Polyurethane UV cured finish so lacquer is not compatible for this dent fill. At this point in time only Cyanoacrylate will work for my given problem.

Unfortunately, in my haste I failed to take a photo of the damage at it's worst.

The damage was about 0.5 mm deep on the edge of the lower front corner of the guitar.

The damage is still visible even though the dent is partially filled - It will get better!

First, I cleaned up the damaged area with a razor scalpel to remove the shredded micro burrs created by the initial impact damage. Be certain to remove any flakes or slag left over from the damaged region. It is better to chip and cut away the damaged area (even if it seems like you are exacerbating the problem). I then used Naphtha to remove any residues of wax, skin oils and anything that would impair the adhesion of my fill solution. For the fill I used CA glue or better know as Super Glue but more appropriately know as Cyanoacrylate. THIS IS IMPORTANT: I used two viscosities of glue, a thick solution which I purchased from Stewart MacDonald, a second mixture was the normal viscosity and I applied the thin coat once a day for about 3 days (IMPORTANT) allowing 24 hours to cure BEFORE reapplying and cleaning the guitar affected surface with naphtha before each application of CA .

(SUPER GLUE - CYANOACRYLATE - will glue your skin together. Use with caution!)

It is important to approach this problem patiently. I found that quickly filling the gap often generates air pockets in the hardened glue.

I filled the gap on a daily basis for a few days until I achieved a smooth lake of plastic filling the dent. While the CA glue was fluid I could manipulate it on the surface using a clipping partial of a business card (white heavy bond paper will suffice). I used the card for minor manipulation and only would move the CA fluid then toss the card into the trash (immediately for safety precaution).

I have found another method (after posting this article) that works better for dispensing the CA - I utilize a low pressure air brush. Using an air brush to apply the CA allows for better fusion between the old poly and the new poly. This distribution method decreases the chance for air pockets and reduces the discolored ring that I had on my example featured in the photo's. This method requires an air brush and a lot of additional parts. The craftsmanship is far superior using this tool as the CA applicator but it is also far more expensive! If you are doing this for a business then without question you should apply CA on dents and crack with an air brush.

Next, I took a Single edge razor blade and wrapped scotch tape around the edges (warning - make sure you cover the blade and check the tape often or you will scratch the surface of the instrument), thus leaving the middle uncovered. The reason for the taped edges is so that the middle of the blade would work as a plane which would shave down the excess plastic fill stock. The tape also prevents damaging the area which I do not wish to plane down.

This photo is from

Once I plane the area near level to the surrounding area, I'll apply wet sand paper using turpentine as a lubricant while gentle sanding the area. I use usually sand paper that is very fine often above 1000 grit to start, then move to finer grit then finally buff the affected area.
Once I have sanded the guitar to my satisfaction I then apply the guitar to a buffing wheel to bring back the shiny finish.

Now the gap is filled, my fingers don't find it anymore and my brain knows the guitar is happier.

This is the finished product. Had I to do it over again I would have chipped out the dent so that there wasn't any shattered remnants of the original finish. I think the repair would have turned out better looking with less white flake on the perimeter of the repaired dent. This white ring is under the new surface and only visible under black light or direct flash light (evidence is in this photo). I will show other pictures where the repair is almost invisible. A lacquer finish would require the same amount of work but would require lacquer fill instead of Cyanoacrylate. I used Cyanoacrylate (super-glue) on my poly finish guitars. In contrast, Lacquer repairs are less evident upon completion but there is a trade off with finishes as the poly finish is far more durable and less prone to checking.

The following photo's are the finished product.

You really need to look hard to see the old damage. Being my own worst critic - I'd like a do over but for now you can learn from my experimentation. However, looks far better than it did and I don't snag my finger on the dent or nervously pick at it instead of the strings while noodling between songs!

Special Thanks to Frank Fork whose FRETS.COM gave me the inspiration and information needed to complete this project. Also Thanks to Alex Glasser who helped me with this project. Check out Alex's Iron Horse Instruments here!

Gratuitous glamor shot!


John Zane said...

Yum !!!!

Anonymous said...

Where's the guitar? I don't see one in that last pic.

Scott said...

The guitar is in the last picture. Look closely and you will find it!

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