The Clueless German got herself a GR-1SF kit

[ThatCluelessGerman]

Hum..... err.... after polishing it 3 days ago, and not touching it any further, I just noticed these areas today.
It's hard to photograph, the guitar is glossy, but there are matte spots "underneath"? I don't know how to describe it best.

They weren't there when polishing it, but as the gloss is not broken, I don't think these are spots where I polished through? Or are they?





Alas, as I wasn't happy with the finish anyway, I think it's best to go back adding a few hundred coats of poly

Not very motivated...

[ThatCluelessGerman]

Oh, I have another question.... After trying the high gloss finish, I think I don't like it. I'd rather go for a nice semi gloss finish, shiny but not reflective. I don't have any satin varnish, so I'd hope to achieve it with sanding but not polishing. The question is how to do it best. I have some micro mesh sanding paper, would I just go up the grids, to, say, 8000? Or is there a better way? Probably polish it up to high gloss and then knock it down with micro mesh? I don't know.

[JimC]

I've seen this. I assumed I had polished through tru oil into the sealer filler underneath. After careful consideration I decided I couldn't spot the difference from a normal distance and left it. Also I only target moderate gloss not full mirror. But your finish is just poly isn't it? We could speculate that it's an area where the underlying finish isn't fully cured, and so isn't taking a full polish yet, but it would just be speculation.

[ThatCluelessGerman]

Yes, just stain and poly, no sanding sealer or pore filler. After adding a fresh coat of poly, it looks like it's gone, but can't say for sure until it's dry.

[JimC]

My own way of achieving moderate gloss was to stop polishing when I was happy... It depends how moderate, but going to 1200 paper then a moderate amount of hand polishing with t cut (auto abrasive polish) pleased me.

[BigDaddy]

That kinda looks like the 'blushing' that occurs when spraying nitro in high humidity. I.E. The affected area sits within the finish. I'm unaware if the same thing happens with polyurethane (in whatever application method).......but it's very odd that it wasn't there during polishing. If you look across the surface at a very low angle, can you see any step down into those spots? That might give you a better idea of whether it is sanding related.

[McCreed]

I can only add to JimC's speculation. It does appear to be under the surface and all I can think of is possible contamination like skin oil or a solvent of some kind. BigDaddy makes a good observation by comparing it to blushing as well.
I have not encountered this problem with polyurethane either and don't have any solid diagnoses or fix.

However I will raise a point about trying to achieve the satin finish as you mentioned.
I don't want to sound negative or tell you you shouldn't do it, but turning a gloss finish into a satin finish is never going to look like a satin finish. It will always look like a glossy finish that was de-glossed.

This is because a genuine satin clear coat has a small proportion of solids mixed into it that actually diffuse the light and give it that non-shiny appearance. Very much the same way that a satin finish can be polished to a gloss, but it will lack the depth a real gloss finish material (poly, nitro etc) has. It's merely shiny "on top".

As for feel and touch (for instance on a neck) yes, de-glossing will feel similar to satin, but again side-by-side comparison there will be a visual difference.

[Simon Barden]

It's almost as if one layer of poly has delaminated from the one below it, but that's only a guess. Or it may be taht the bottom layer of poly is coming away from the wood itself.

After swearing a lot, I'd probably go and rub those areas back until I thought I'd reached that layer and maybe just polish from there, or maybe then add some more poly and then polish.

[ThatCluelessGerman]

Hey guys,

thanks so much for all your advice and opinions!

Whatever it is, it was not lower than the surrounding areas. Also, the gloss went over it and was not broken, so I don't think it's been sanded through.

Interesting comment about the blushing, I remember it was VERY hot and humid during the days I made the last coats of poly, but I am very sure I didn't see these areas before and after polishing (at least on the day I did it). I polished it and inspected it from all angles to judge if I like the outcome (I didn't). Then I decided to set it aside for a few days as I had some work to do.

I just noticed these areas when picking it up from the wall hanger today.

Also pretty good idea with the skin oils, but I'm pretty sure that's not it, as I'm usually wearing gloves when working on the guitar, even when sanding, because I don't want to have skin contact with the sanding dust (but I never wear respirators, talk about being stupid...).

So what I did today is to rough up the gloss surface and apply another coat of poly. Currently, it looks good, but I can only say for sure if it's dry.

I remember seeing a weird thing on my last build, too - don't know if it's the same - where I would see the different coats of poly after the final sanding. Like if you cut a tree and see the rings. But to a much smaller extend, so I can't say if it's the same. I "fixed" it by covering it with a few more layers of poly and then just lightly removing the dust before polishing.

I think this is going to be my last guitar build for a little while (unless we get locked up again...). I think I'll build an amp next

[ThatCluelessGerman]

Yesterday, I was THIS CLOSE (<->) to throwing this thing out of the window.

After rebuilding the poly and sanding it flat again, I just couldn't polish it again. Whatever I did, it just didn't want to get a nice even surface... It got shiny in some places and stayed matte/milky in some others. I promised it I'd smash it on the wall if it's not playing along.

Today, I found some really old abrasive paste in the tool drawer (I think I bought it in 2013 when my first car got a scratch...) and gave it a go, couldn't get worse, right?

To my surprise, it worked pretty well - compared to how it looked before. Now, the surface is very shiny with scratches. Yep. Nice. But better then before so I'm really not complaining (well, just a little). I had actually hoped for a satin finish, but I don't know how to get there, and I'm too afraid to mess up the poly again.

I think my finishing skills are so bad, I don't even know where to start improving. No matter if I use tru oil, poly or whatever, I just can't seem to get it right.



It was time to remove the tape from the neck. Look how different the poly looks on the binding. Not too sure what to do with the neck binding now. Probably nothing and wait until it gets dirty from playing?



Looks ok from 2 feet away.



Shiny, with scratches! I'm trying to pass it a s a feature.



Pretty desperate try to put something on the headstock. Unfortunately, light paint on a decal looks bad (I tried!), so I went with a shape that I can cut by hand. This MOP sticker sheet is really a b*tch to cut. I think I spent 2 hours cutting this and it's still looking pretty rough. But oh well, now it's on and maybe it will look ok from 2 feet away, too =)