Refinishing a bodytop - method

[donnyb]

Originally Posted by charles Tauber

I hazard a guess that the top was not stained, nor was the finish. I suspect the wood and finish have yellowed over time.

That adds up Charles. Now the pickguard wood area makes sense.

[donnyb]

Originally Posted by mirwa

Looks like a laminate to me from the photos, whilst yes a couple of spots almost look like vertical grain, I put that down to more the finish is split and giving the illusion of grain.

Scrape the finish away dont sand it

I'll scrape away a small area of the sound hole edge and take another photo.

[donnyb]

Scraped an area under the fretboard extension. Not conclusive.
I'll treat it as ply and go very careful.

[donnyb]

Originally Posted by JonWint

What's wrong with the original finish?

How will you deal with the stain? May end up blotchy.

Don't remove any wood. Wipe it off with lacquer thinner.

Steam out dings. Scrape flat. 320 or 400 grit for a few passes.

[IMG][/IMG]

Hi Jon,
It seems (thanks Charles) that the teak colour of the body top is aged yellowed clearcoat over bare spruce. So I probably dont have stain to deal with.
I tried rubbing acrylic thinners on the area that was under the pickguard, which definitely has a clear coat over it , as there is a small chip out of clear lacquer on its non- yellowed surface.

However there was no effect with the thinner. Do you know if poly clear was used around 1970 by Japanese builders, in this case, Suzuki ? Or is it just the age of the clear acrylic or nitro clearcoat thats at play here?

[donnyb]

This is the guitar before I got started on the neck reset.

https://i.imgur.com/cePBR8f.jpg

[donnyb]

Originally Posted by charles Tauber

I hazard a guess that the top was not stained, nor was the finish. I suspect the wood and finish have yellowed over time.

Hi again Charles,
Im pretty certain the top is ply, but there's more top spruce "meat" then anticipated. Maybe there was more spruce around in 1970 !

Also, Im fairly certain the top has just yellowed as you thought, but still unable to be sure if its poly or acrylic lacquer. I think though, that its hardened, aged acrylic lacquer.

Anyway, in the photo ( I hope appears here), this is where I'm at. Scraping done initially, starting under the pickguard to get an indea of the clearcoat depth. You can see where the bare spruce has been revealed there, which is unstained.
Now sanding all the top (after the scraping of a lot of clearcoat)with 320 grit, and in spots starting to just touch the spruce.

Assuming I get the whole top back to bare spruce, my question is : when do think I should I glue the bridge on ?

1.After I stain and clearcoat with the bridge area masked off, or

2. glue the bridge on before staining and clearcoating the bodytop, with the bridge itself masked off ?Cut the lacquer around the bridge with a scalpel later ?

[Victory Pete]

I have been gluing the bridge down before finishing for my last few guitars. I have a consistent and successful method of masking and leveling around the bridge.

[donnyb]

Originally Posted by Victory Pete

I have been gluing the bridge down before finishing for my last few guitars. I have a consistent and successful method of masking and leveling around the bridge.

I like it Pete. Simple, clever.

[donnyb]

And Pete, could you expand on your refinishing methods generally ?

[Victory Pete]

Originally Posted by donnyb

And Pete, could you expand on your refinishing methods generally ?

I mask the bridge intentionally leaving a gap to scrape later. Careful experimenting can be beneficial.
My method took 20 years to evolve. I don't do wet sanding or use a buffing wheel. It takes me probably 4 hours to get a gloss level surface. I make sure my wood surfaces are as level as possible, which is difficult sometimes because you don't always know where the hills and valleys are until you get the surface to shine. I don't do any initial pore filling. Once I start getting some Nitro or Shellac spayed on I sand with 120 3M Stikit Gold on a somewhat hard block and look for the shiny low spots. I then use an Airbrush to fill the valleys. I put on more finish and then repeat the process. Once I am satisfied with the build and level of the finish I start sanding with 220 on a firm foam block, then repeat with all grits up until 800. 1800 MicroMesh on a foam block and then I used liquid medium buffing compound on a cloth rag and start buffing, you can get quite a shine up until this point. I don't usually use fine compound as I like a mirror finish but I like it to have a warm glow to it. To end up with perfectly consistent reflected contours in the guitar really makes it look great. Here is my most recent spray job, it is Nitro. https://www.acousticguitarforum.com/...d.php?t=607083

[mirwa]

Originally Posted by donnyb

Assuming I get the whole top back to bare spruce, my question is : when do think I should I glue the bridge on ?

1.After I stain and clearcoat with the bridge area masked off, or

2. glue the bridge on before staining and clearcoating the bodytop, with the bridge itself masked off ?Cut the lacquer around the bridge with a scalpel later ?

It is a personal choice, Taylor have IMO perfected the process, they mask the top off, an area fractionally under the size of the bridge, they spray finish the top,

The bridge has an edge micro routed around the border on the underside to allow it to sit over the finish edge, it gives a flawless surface.

Be super careful if using a razor blade on the top when marking bridge edges, any cutting by accident into the spruce becomes a zipper line for tear here under tension at a later date

Your biggest decision I think is are you staining the top and clear coating or mixing colour into the first few layers of clear. I advise option 2

Steve

[donnyb]

Originally Posted by Victory Pete

I mask the bridge intentionally leaving a gap to scrape later. Careful experimenting can be beneficial.
My method took 20 years to evolve. I don't do wet sanding or use a buffing wheel. It takes me probably 4 hours to get a gloss level surface. I make sure my wood surfaces are as level as possible, which is difficult sometimes because you don't always know where the hills and valleys are until you get the surface to shine. I don't do any initial pore filling. Once I start getting some Nitro or Shellac spayed on I sand with 120 3M Stikit Gold on a somewhat hard block and look for the shiny low spots. I then use an Airbrush to fill the valleys. I put on more finish and then repeat the process. Once I am satisfied with the build and level of the finish I start sanding with 220 on a firm foam block, then repeat with all grits up until 800. 1800 MicroMesh on a foam block and then I used liquid medium buffing compound on a cloth rag and start buffing, you can get quite a shine up until this point. I don't usually use fine compound as I like a mirror finish but I like it to have a warm glow to it. To end up with perfectly consistent reflected contours in the guitar really makes it look great. Here is my most recent spray job, it is Nitro. https://www.acousticguitarforum.com/...d.php?t=607083

Thanks Pete for the comprehensive reply.
Regarding your recent build and spray job, to quote Dumber (almost) " I am not worthy !". Beautiful work !

[donnyb]

Originally Posted by mirwa

It is a personal choice, Taylor have IMO perfected the process, they mask the top off, an area fractionally under the size of the bridge, they spray finish the top,

The bridge has an edge micro routed around the border on the underside to allow it to sit over the finish edge, it gives a flawless surface.

Be super careful if using a razor blade on the top when marking bridge edges, any cutting by accident into the spruce becomes a zipper line for tear here under tension at a later date

Your biggest decision I think is are you staining the top and clear coating or mixing colour into the first few layers of clear. I advise option 2

Steve

Thanks Steve. I have 2 x Taylor guitars. So that"s how they do it !

Re the stain, I was leaning towards spray shellac with a weak golden teak spirit stain mixed in.
I was thinking Id seal coat the top first with a coat of unstained shellac (?).

[mirwa]

Sounds workable

[richardbruce]

Originally Posted by donnyb

Hi, Thankyou for reading.
I have a 1970s 12 string Suzuki with a stained spruce (golden teak -ish) and clear lacquered bodytop. I have refinished several guitar tops but only with those requiring re-painting with a solid colour , followed by acrylic or pre-cat lacquer. So entering a new territory with this guitar.

There are no deep dings to the surface.

I want to sand back the top to bare spruce wood, re-stain and re-lacquer, but I have been warned that it may a spruce/ply/spruce sandwich top, not solid spruce, and the top layer of spruce may be very thin. I definitely don't want to hit the ply !

I'm therefore intending to carefully sand just until bare wood emerges.

Could I get some afid advice on the grit grades to use and also whether I could use an orbital sander , if gentle.
Thank you.

By way of introduction, I was recently given a cheap (Jasmine by Takamine) acoustic. Apparently someone had attempted to remove the black (lacquer?) finish but didn't know what they were doing and gave up. This is how I got it. After sanding using 160 and 220 grit disks and my drill, I sanded it by hand using 320 grit and a rubber sanding block. There are still some tiny spots of black, but it's super smooth and ready to be finished. So I wouldn't worry about sanding a laminate top unless you're going to use 60 or 80 grit and a belt sander. There's a good video on YouTube showing just how hard it is to sand thru even a thin laminate top to expose the ugly middle layer. My question for the group is this: How can I finish this top without spending a ton of $ or buying a paint booth? I'm thinking just a clear lacquer but do I need to seal it first? I'm looking for a simple natural finish that might bring out what little grain there is.
https://www.facebook.com/richardbruc...AWBXzYt8vX8ndl