Next step advice on broken neck fix -- satin

[JohnMc]

I'm new to this forum coming from a banjo background but lately started playing guitar and uke. Anyway, I'm trying to repair a cracked neck on an inexpensive Yamaha Jr. The neck cracked right along the scarf joint. Easy to glue and clamp. That part is finished. There were some small chips missing from the break and I used the Dan Earlywine method of CA glue drop filling, razor blade, etc. I've sanded up to 2500 grit and the joint is smooth...but now I'm a bit lost. I've read dozens of threads and watched numerous videos, but most of them seemed geared to glossed finishes. The finish on the neck of this guitar is seems more satiny and is billed as "UTF - Ultra Thin Finish" by Yamaha. I've read about using this polishing compound or that, lacquer vs. poly, no silicone, use wax, don't use wax...Too much conflicting ideas.

Specifically, I'm looking for advice to take this repair from 2500 grit sanding to smooth playable finish. I'm looking for specifics here -- please don't assume that if you say "use a good polishing compound" that I'll have any idea what you mean since there appear to be dozens...and I am a little slow (banjo player remember...just kidding, sort of).

Now, before someone chimes in with "it's just a Yamaha Jr.", or "burn it and get something better" or anything along those please let me explain that I realize what I'm working on. Consequently, I don't want to refinish the whole guitar, or even the whole neck. I just want to clean it up and make it, presentable. Plus, it's good practice for the much more expensive guitar that I'm sure to break in the future. And while it is true that it is an inexpensive guitar, it may be instrumental in starting several young players. My whole family gathers at my parent's house many times a year. My dad plays a Martin every gathering and invariably someone is always picking up the pos First Act that doesn't hold it's tune, is painted so heavily in blue that it has no tone, and has an action around 1" at the 12th fret. There are 18 kids under the age of 8 in this family and this Yamaha guitar is going to replace that blue wonder...along with a few baritone ukes for the younger players. These kids are taught not to abuse the guitar and I'll say the blue wonder is still in exactly the same, um, shape it was when they bought it several years ago.

Thank you in advance for any advice you might have.

[fazool]

There are two kinds of satin finish: the first is a sprayed on satin. This has additives in it to cause the surface to contract as it cures. It increases the surface tension, as well so it doesn't spread out. Leaving a microscopically crackled finish.

The other kind is polishing marks left from rough grit polishing.

When making a gloss finish, you simply keep polishing with smoother and smoother grits (paper or compound), each time removing smaller and smaller defects until it is perfectly smooth. To get a satin finish you simply stop when you get the finish you desire (before going all the way to smooth).

If you use a sprayed satin finish, you do NOT sand/polish it afterwards as that will actually remove the crinkles and make it smoother (and in an uneven way).

I'd suggest getting some autobody sanding pad from the auto parts store. You can get 3M foam backed sanding pads in a 3000 grit and I find that they create an ideal satin finish.

[JohnMc]

Originally Posted by fazool

.

If you use a sprayed satin finish, you do NOT sand/polish it afterwards as that will actually remove the crinkles and make it smoother (and in an uneven way).

I'd suggest getting some autobody sanding pad from the auto parts store. You can get 3M foam backed sanding pads in a 3000 grit and I find that they create an ideal satin finish.

So, are you saying that I just sand up to 3000, leave the area a lighter color and then...? What do I topcoat it with to protect the wood?

[charles Tauber]

Originally Posted by JohnMc

So, are you saying that I just sand up to 3000, leave the area a lighter color and then...? What do I topcoat it with to protect the wood?

You stated you drop-filled with CA glue, levelled and sanded smooth/flush to the surrounding area. You then asked about matching the level of gloss to the surrounding area (satin). You received a viable answer.

Now you are asking about color matching, a different question altogether. The CA glue needs no top coat. If the surrounding wood has been stained, and bare wood has been exposed, the drop-fill needs to match that color. One solution for that is to use colored CA glue. One company Gluboost sells products to drop-fill and color-match a finish. Another solution is to stain the wood using a wood stain of your choice prior to drop filling. Another solution is to use an appropriate combination of felt markers to color the area, then drop-fill. If the line or area is sufficiently small, you might be able to use the markers after drop-filling, levelling and buffing/sanding - it can look adequate, but isn't the best approach.

[JohnMc]

Originally Posted by fazool

Now you are asking about color matching, a different question altogether. The CA glue needs no top coat. If the surrounding wood has been stained, and bare wood has been exposed, the drop-fill needs to match that color. One solution for that is to use colored CA glue. One company Gluboost sells products to drop-fill and color-match a finish. Another solution is to stain the wood using a wood stain of your choice prior to drop filling. Another solution is to use an appropriate combination of felt markers to color the area, then drop-fill. If the line or area is sufficiently small, you might be able to use the markers after drop-filling, levelling and buffing/sanding - it can look adequate, but isn't the best approach.

I apologize for not being clear. It's a case of not knowing what I don't know. So the crack ran pretty much the entire length of the scarf joint. I only drop filled two small chips that were missing once the entire crack was glued up..and I did put some coloring in those two chips. I was asking about the sanding that I used to smooth the entirety of the whole crack, not specifically the two small drop filled areas. I'll try to post a photo later as it won't let me now. Anyway, I've sanded the entire glue seam to make it smooth. I don't think I went to bare wood, but the UTF (ultra thin finish) really is quite thin and the seam is a lighter shade than surrounding wood. Surely I have to seal that with something as the player's left hand will spend a lot of time there. Maybe I'm just not asking it correctly.

[mirwa]

For hand polishing I use 3m machine polish, works a treat.

Steve

[JohnMc]

Originally Posted by mirwa

For hand polishing I use 3m machine polish, works a treat.

Steve

Steve, I know this is a really basic question, but are you saying I polish with the 3m polish now and then I'm done? Don't I need to coat this with a laquer or something to protect it when it's being played? Or will the polish be enough?

[mirwa]

If you have drop filled the spots and flat sanded them, then no need to add lacquer, whilst yes its nice to add some, not required if the wood is coated, just hand polish with the 3m and our done

Steve