Refinishing a damaged Koa / Mahogany Soloist with Tru-Oil (by a beginner)

[Dazkeirle]

I did notice the lighter specks before. I assume it is some type of grain filler in the deeper pores. It might be worth putting a darker grain filler on (across the grain so it gets deep into the pores) sanding back and possibly using some of the Birchwood Casey Walnut stain which if not too heavily used can lift the colour a little. If the pores are closer to the colour of the Koa, it will be less obvious.

Hmm, yeah I saw the specs I just kind of assumed they were natural and would become darker colour as the tru oil soaked in.

Perhaps you're right though, perhaps Warmoth used some very light grain filler to begin with and then a darker after? You can still see some of the darker filler in some of the grain. Bollocks.

That probably makes sense though and why it isn't apparent in the very worked areas, it's simply been sanded away.

You think working the body with some acetone might remove it?

 

[stratamania]

On the acetone, it might help but I have not stripped back a Warmoth finish in the way you are doing so we are flying somewhat blind. But it does look a little like some "natural" colour grain filler I used in an Ash body but that faded away with the rest of the finish process. It may be that the Walnut stain might even colour it rather than having to remove it.

It will need a little experimentation but judging how well you have done so far I am confident you will prevail...

 

[PhilHill]

I agree with stratamania, it's probably grain filler. Hard to find info about removing old grain filler, you could try acetone or mineral spirits, there's nothing else on the body right now that it could harm really other than cutting the tru oil you've put on.

 

[Dazkeirle]

Well, as we say over here, proof is in the pudding.

I spent 5 mins with a stiff-ish paint brush and a big old bottle of Acetone in just one area.

Before:

After:

Definitely an improvement. Looks like I have my work cut out.

I'll probably give it a bit more of a sand just to remove as much of the tru-oil / filler and then with a big glass of whisky I'll spend a couple of evening poking it out while getting high on acetone.

I love all the little challenges this thing throws at me. Baked in white filler was not something I saw coming (as the grain was filled black).

I guess warmoth do it two stage, some kind of putty first or something.

 

[stratamania]

Ah good.

Here are some possible grain filler candidates to check out.

https://www.rothkoandfrost.com/search/grain-filler

 

[Dazkeirle]

Well acetone isn't going to do it so I think I'm gonna take your advice and get some filler.

I'm a little concerned that the filler will just fill over grain and leave the white bits which could be flush now but I guess only one way to see.

I've now just given the body a sand back, I've taken several steps back, I'm now back at 100 grit with a lot of scratching to remove.

Oh well, it's a Bank Holiday after all, what else would I be doing. Won't take long to get back to 240.

Which colour is would you think works best? I kind of dig the medium oak.

 

[Hendrix]

Right now SS is basically a meme, and the Blurple Nebula is the guitar equivalent of Yeezys. Give it a few years and the pickups will gets sold on.

I'll keep my eye out for you, I've bought and sold probably 10 sets of PRS pickups in the last 1-2 years.

thanks ,

although SS got so many  meme and hater , but it selling OK well to keep PRS busy, for the price of Fender American ultra , you got  the build quality of CS and PU JM loved  .

 

[VinceClortho]

I wonder if something like scrubbing with a stiff bristle toothbrush could help dislodge the white gunk?

 

[Dazkeirle]

:guitarplayer2:

I wonder if something like scrubbing with a stiff bristle toothbrush could help dislodge the white gunk?

Nope. I've actually sanded back smooth now and the white that remains is hardcore.

Even if you stick a pin in and try to scrape it out, it's really in the there.

I can see that it is indeed in the deeper pores so a grain fill should solve the issue.

I was hoping to get away with not having to add the dark back into it but cest la vie, it still looked great with them (like the very first picture).

On the plus side this will make the oiling much easier and I won't need to mess around with the a true oil slurry.

Also means I can work out a couple of scratches I caught when it was oiled.

So, all useful steps on this journey. I didn say I had no experience lol how was I to know warmoth uses black grain fill over white grain fill?

 

[stratamania]

Maybe the medium oak or rosewood filler.

 

[Hendrix]

So, all useful steps on this journey. I didn say I had no experience lol how was I to know warmoth uses black grain fill over white grain fill?

As the white spot on koa is so strong, I suspected it is epoxy clear pore filler .
Sanding made it become white.
It better to use clear pore filler on koa , as it like Quilt Maple , reflects light different on different angles you look at it .
I have brought a unfinished Koa neck , it got a small black spot on back , I print it out as the colour around it , can’t really tell it there in one angle but can see it in another angle , even it all matte without clear coat.

Don't want to post too much photo here , can view it in the album:

https://www.facebook.com/pg/SmarTechDIY/photos/?tab=album&album_id=116414566725464

 

[Dazkeirle]

So, all useful steps on this journey. I didn say I had no experience lol how was I to know warmoth uses black grain fill over white grain fill?

As the white spot on koa is so strong, I suspected it is epoxy clear pore filler .
Sanding made it become white.
It better to use clear pore filler on koa , as it like Quilt Maple , reflects light different on different angles you look at it .
I have brought a unfinished Koa neck , it got a small black spot on back , I print it out as the colour around it , can’t really tell it there in one angle but can see it in another angle , even it all matte without clear coat.

Don't want to post too much photo here , can view it in the album:

https://www.facebook.com/pg/SmarTechDIY/photos/?tab=album&album_id=116414566725464

Oh christ, I think I follow what you're saying, that these white spots, at least those that are flush with the body area actually clear epoxy that have become white through sanding.

Fuuuuu.....

Ok I guess my plan of action is then to finish this guitar with sanding, once to 400 grit or so to use a grain filler (medium mahogany I think) to fill anything below the surface in pores.

Then to step up the sanding to an incredibly high grit (going through the papers and even finishing with micromesh.

This I think would probably make some of the white smooth and clear again that are sat on the surface, probably what I'm seeing in the horns, the equivalent of burnishing and so polishing back to clear.

Then whatever is left I suppose I've got to deal with and from your post it looks like you're recommending painting them out.

Defo a possibility but there are thousands, it's gonna be quite involved.

Hmm this is daunting, I'm gonna need to buy more whisky.

 

[PhilHill]

So, all useful steps on this journey. I didn say I had no experience lol how was I to know warmoth uses black grain fill over white grain fill?

As the white spot on koa is so strong, I suspected it is epoxy clear pore filler .
Sanding made it become white.
It better to use clear pore filler on koa , as it like Quilt Maple , reflects light different on different angles you look at it .
I have brought a unfinished Koa neck , it got a small black spot on back , I print it out as the colour around it , can’t really tell it there in one angle but can see it in another angle , even it all matte without clear coat.

Don't want to post too much photo here , can view it in the album:

https://www.facebook.com/pg/SmarTechDIY/photos/?tab=album&album_id=116414566725464

Oh christ, I think I follow what you're saying, that these white spots, at least those that are flush with the body area actually clear epoxy that have become white through sanding.

Fuuuuu.....

Ok I guess my plan of action is then to finish this guitar with sanding, once to 400 grit or so to use a grain filler (medium mahogany I think) to fill anything below the surface in pores.

Then to step up the sanding to an incredibly high grit (going through the papers and even finishing with micromesh.

This I think would probably make some of the white smooth and clear again that are sat on the surface, probably what I'm seeing in the horns, the equivalent of burnishing and so polishing back to clear.

Then whatever is left I suppose I've got to deal with and from your post it looks like you're recommending painting them out.

Defo a possibility but there are thousands, it's gonna be quite involved.

Hmm this is daunting, I'm gonna need to buy more whisky.

My ratio varies, sometimes it's two parts guitar to one part whisky, sometimes it's three parts whisky to one part just looking at the guitar and cussing.

 

[Hendrix]

I not recommending painting them out. I mean if full it with color , it can become different color under different angles look at it .

the "white" epoxy will become clear coat once transparency coat put on it .

poly type of  transparency coat is kind of  epoxy can mix with it .

in this video
https://youtu.be/DRvSX7YYXJg

some 3D print  transparency resins mix sculpture , I too lazy to polish it to become transparency , it look  "white" after sanding , I just put on a  clear coat , it become transparency .

 

[Dazkeirle]

I not recommending painting them out. I mean if full it with color , it can become different color under different angles look at it .

the "white" epoxy will become clear coat once transparency coat put on it .

poly type of  transparency coat is kind of  epoxy can mix with it .

in this video
https://youtu.be/DRvSX7YYXJg

If that wee the case though the tru-oil would have reacted in that way and would have filled those scratches and made it clear, it didn't.

I don't think this is clear, it's uniform in colour top and back. I've worked with quite a bit of epoxy in my time and it would look different to this if it were clear and sanded white. I picked a larger one out and looked at it, it's pretty uniform white.

It could of could be epoxy that's uniformally clouded through the process somewhere, but tbh I think it just looks like white filler. I still think the process is sand to 400, then use some grain filler and see what I'm actually working with. It may be that this is actually enough.

I think this is like some kind of heavy duty putty they use as a deep grain filler before they move onto the darker / thinner top grain. I've just worked away quite a bit of wood so I'm down to that.

Picking them out isn't really an option, there are too many tiny ones and they take too much effort / damage too much wood to remove.

Painting them out could be. I'd need a very steady hand and a lot of time (and my trusty warhammer brush), but it could be done. I think a last resort though after I've entire tested grain filling and sanding. I have a feeling that may be enough to get rid of 99% (as most of it is indeed in the grain which is why is hasn't shifted up to this point.

Through all this planning this assumption is where I come unstuck, I really just thought it was end grain and was gonna just suck up the colour / oil of tru-oil and disappear.


some 3D print  transparency resins mix sculpture , I too lazy to polish it to become transparency , it look  "white" after sanding , I just put on a  clear coat , it become transparency .

tbh I just used a small pin to pick one of the larger out, no easy feat.

I don't think this is clear, it's uniform in colour top and back. I've worked with quite a bit of epoxy in my time and it would look different to this if it were clear and sanded white.

It could of could be epoxy that's uniformally clouded through the process somewhere, but tbh I think it just looks like white filler. I still think the process is sand to 400, then use some grain filler and see what I'm actually working with. It may be that this is actually enough.

Picking them out isn't really an option, there are too many tiny ones and they take too much effort / damage too much wood to remove.

Painting them out could be. I'd need a very steady hand and a lot of time (and my trusty warhammer brush), but it could be done. I think a last resort though after I've entirely tested grain filling and sanding. I have a feeling that may be enough to get rid of 99% (as most of it is indeed in the grain which is why is hasn't shifted up to this point).

Through all this planning this assumption is where I come unstuck, I really just thought it was end grain and was gonna just suck up the colour / oil of tru-oil and disappear. As the tru-oil didn't do anything, i'm fairly sure that it isn't scratching. Agree with you, that should have filled those tiny scratches and made clear.

 

[Dazkeirle]

I think we all know where this is gonna end up so probably best to just get started.

I'll aim for 2cm squared per day.

Fml

 

[Dazkeirle]

[youtube]https://www.youtube.com/watch?v=E6Aqt53eBPY&feature=youtu.be[/youtube]

Like this. (Sorry was accidentally marked as private before)

 

[stratamania]

A labour of love indeed...but the results are going to pay off I think...

You might not want to go to micromesh levels before getting tru-oil on as it will be difficult for the finish to key onto wood that is too smooth. I would aim for around 400 - 600 after the grain filling and then move onto the tru-oil after you have built the layers up then of course you can go to much finer grits before polishing.

 

[Dazkeirle]

A labour of love indeed...but the results are going to pay off I think...

You might not want to go to micromesh levels before getting tru-oil on as it will be difficult for the finish to key onto wood that is too smooth. I would aim for around 400 - 600 after the grain filling and then move onto the tru-oil after you have built the layers up then of course you can go to much finer grits before polishing.

Yeah that was more for if I were going to attempt to make the epoxy clear, I was spit balling.

Now I'm removing it all there's no point in doing that.

I'm gonna see how I get on removing all this. If I can clear 99% of it I'd like to really try and get away with not having to use a dark grain filler at all and just stick with it clear. I think dark may change the look of a little.

In which case I think the plan is back to sand to 320, grain fill with clear sander sealer, then get it to 400 and then start working the tru oil once flat.

 

[PhilHill]

[youtube]https://www.youtube.com/watch?v=E6Aqt53eBPY&feature=youtu.be[/youtube]

Like this. (Sorry was accidentally marked as private before)

That's Dedication!..........Or serious OCD.........What's the difference, I salute you Sir! :headbang: :headbang: :headbang: