New guitar incoming for finishing and assembly

ThePrettyDamned

Finish tests part 1 and lessons learned so far.

Grain filler - I've used rustins. Tried both mahogany and teak colour. I prefer teak (on the right) but I had trouble doing it in one pass - I have a feeling I either need to mix it thicker, or apply, sand back and have a second application. Takes overnight to harden so won't work on it till weekend now. 

 
With that said, I think about 90 percent of the pores are filled. I rubbed on a heavy coat with a cloth, then scraped the remaining excess off with a plastic scraper. Seems like an okay workflow but if anyone has better ideas for going under polyurethane I'm all ears!

Moving on to a fun one - I really fancied trying a deep, aqua type colour. I took the light blue and added a touch of green (about 2/3rds blue 1/3rd green) and then added a small amount of white spirit. Now, they say to use cellulose thinners and I do have some, but it's more expensive and I wanted to see it white spirit works. I hope it hasn't destroyed the pigments. 

Anyway... I love this colour. I might just stick with this. I'll need to try sanding it back though. Like the mahogany, this was sanded to 400 grit to remove scratches, then a tack cloth used, then dye application by a small rag. The photo doesn't do it justice. 

ThePrettyDamned

In the sun and slightly different angle to show how the look changes:

 
I like this. I might apply a bit of yellow dye on top and see how that does. 

ThePrettyDamned

Added yellow to see how green looked, then tried applying polyurethane. 

Expecting a poor finish - I wanted to see how sanding sealer affects this process. I've not used sanding sealer on this, but will on the next test piece. I'm aiming for a pretty glossy, smooth finish so applied using a foam brush. Expecting two coats, with the second being thinner, then rub back and use micro mesh/polish.

 

I can already see the finish turn from a beautiful, even coat to a lumpy, bumpy one. I think sanding sealer should help provide a smoother finish. We'll find out in the next instalment!

WezV

if you are doing a stain and sand back, mix up a darker version of your desired colour rather than using black.   It can be near black, but not with actual black pigment

Black pigment can be very heavy and kill the 3D effect. Better in photos, less interesting in real life.  It can also make less figured patches look muddy, which defeats the purpose of trying to accentuate the figure.  The different pigments in the Black can also throw your colour off

I know BigD often says to use black, but he's also been doing those vids nearly 20 years and has a lot of experience making it work.   

Blue/green colours on yellow maple are already difficult to get right without adding black pigment to the mix

ThePrettyDamned

WezV said:

if you are doing a stain and sand back, mix up a darker version of your desired colour rather than using black.   It can be near black, but not with actual black pigment

Black pigment can be very heavy and kill the 3D effect. Better in photos, less interesting in real life.  It can also make less figured patches look muddy, which defeats the purpose of trying to accentuate the figure.  The different pigments in the Black can also throw your colour off

I know BigD often says to use black, but he's also been doing those vids nearly 20 years and has a lot of experience making it work.   

Blue/green colours on yellow maple are already difficult to get right without adding black pigment to the mix

Yes, I've no intention of doing black unless I decide to do a black top for this reason - instead, I would provably use a greeny blue, sand back, then blue on top. But I'm not sure if I'll do that even - I'm very amateur, so simplicity is a good thing for me.

Luckily, the green and the bluey greeny aqua I managed today already looked incredible. Even with the bluey greeny aqua alone, I found myself rubbing over with a rag in white spirits to lift a bit of pigment out, which actually really helped to get a cleaner, 3D finish by reducing how heavy the colour was in those parts that drink it up. 

ThePrettyDamned

Sd90s arrived, got them for a bargain price in nickel. Fit perfectly (but not pressing bushings all the way in until I've sanded and finished the headstock - not sure what I'll do with it though, maybe just some oil). I'll mark and drill screw holes at the weekend, or maybe after work. 

 

ThePrettyDamned

Fully cured first coat actually turned out better than expected. It is already pretty darn glossy and smooth! The issue is the finish sinking into grain - my next test will involve using a sanding sealer, which I hope will reduce this and give a more level surface. I'll still sand this back and apply a second coat (later today) but for now an image at it's least flattering angle. Where it has not sunk it is already pretty darn smooth, and it feels nice to the touch. Well done, rustins. 

 

ThePrettyDamned

Sanded back, applied second coat and now dry. Looks much better, but still some sinking going on. Hoping sealer helps!

 
 
In mahogany-land, my first attempts went well. This is one coat, almost fully dry, maybe another hour to go. Thinner piece was first try, thicker piece second. Grain filler and sanding sealer applied, has definitely helped provide a more level finish with far fewer pin-pricks! 





The finish was thinned with a tiny splosh of white spirit to help the foam brush take it up. The brushes work well, minimal bubbles and a very even coat (that continues to self-level). The second piece isn't flawless - there are dust spots and some pin picks - but my goodness is it exceeding what I thought possible in a garage with cheap polyurethane.

RickLucas

Re grain filler, I have had great results with zpoxy finishing resin. I used it on a limba body and it came out flat as a mill pond.
Imgur: The magic of the Internet

ThePrettyDamned

RickLucas said:

Re grain filler, I have had great results with zpoxy finishing resin. I used it on a limba body and it came out flat as a mill pond.
Imgur: The magic of the Internet

Thanks, I'll check it out. I think the results I have with rustins are actually acceptable - however, it is really hard! I noticed that sanding it back - instead of getting back with 400 grit, I wound up needing 240 grit to get it off in a sensible time. Hopefully means it won't shift anytime soon - the result I got on my second test piece is excellent, and it's still only the first coat. Second should go on tomorrow and I expect it to be pretty darn gold. Dust bunnies will be a bigger problem.

The maple is the trickier bit. I'll be testing the sanding sealer on the maple tomorrow, to see if that reduces the sinkage. 

ThePrettyDamned

Next maple test.

 
Yuk! What a horrible, sickly slime green. Very yellow and nasty. 



Sanded it back and went with light blue, followed by a darker royal blue. 



Very hard to capture, so I video'd it. Didn't help much.

https://i.imgur.com/mjAl7Yx.mp4

Sealed it and applied a thinned polyurethane. Photo to come in a while after food. 

ThePrettyDamned

After cellulose sealer and a cost of thinned rustins, about 10 percent white spirit, which does make it much thinner and easier to apply. This is still wet, so it won't come out this smooth (and there is already a dust spot or two) but after one hour nothing looked to be sinking too much, so I think the cellulose sealer has done what I hoped it would - fill in some of those thirsty pores!

 


That colour is amazing. I think, though, I might not bother with the green. It adds unnecessary risk to my limited skills and resources. As such, I'll likely finish with light blue, then apply royal blue on top until it has reached the deep-ocean hue I'm looking for.

As for the mahogany, well... They looked fantastic. I rubbed them back and applied a second coat - one got unthinned rustins and the other got thinned. Findings were interesting, I am looking forward to seeing how they dry. However:

- unthinned did not go on as nicely and I believe it won't self-level as well as the first coat.
- the thinned finish was hard to not apply too much and there will be runs in the finish.

As such, I'm going to need to grain fill and finish a couple more pieces to work out how best to top-coat. Maybe one slightly thinned coat is enough - @WezV @Andyjr1515 I don't suppose you have any thoughts on this? The tin recommends 2-3, so I will continue perusing a second, more even coat but the first one bridged a fine line between a beautiful gloss (that probably could have been polished) and looking like real wood, with some grains of sinking in the finish. 

So interesting to put all of this to the test. Pros make it look so easy. 

normula1

That's really nice

ThePrettyDamned

Final coats applied to mahogany, and a second to the blue maple. All look great, and it's given me a really good opportunity to practice level sanding the finish before the final coat - it's a lot of slow, methodical work but the latest coats went on beautifully. 

So... Final improvements to the finish:

- three polyurethane coats applied (level sand between them as best possible, especially between the second and third coats). 
- wet sand after a month of curing from 1000 grit to... Well, as high as I like, but probably at least 4000 grit and maybe up to 12000 before final polish. This will, hopefully, help with some of the inevitable imperfections and surface dust-bunnies.

I cannot avoid dust. I'll either be finishing in a small garage or outside where there is dust and wind. I hope that I can sand most out between coats and hope wet sanding is successful. I'll not do that on the guitar until I've tested, of course...

Anyway, I'm happy with the finishing plan. I'll finish the body first, and hang the guitar by the unfinished neck - then I'll finish the neck separately, and will be leaving that with a satin sheen for comfort. I'll mask off the body for a clean, crisp line between the glossy body and the satin neck (like the modern Jackson Soloists). By finishing separately, I hope to reduce lines in the finish (if I do the top, back and sides separately there will be a clear line between them where the finish has cured and won't "melt" together). 

For the neck finish, I'll likely use a similar technique to the body, but rub back with a green, red, orange and finally white abrasive pad - I tested these the other day, and they leave a gorgeous, super smooth satin sheen finish that I'm tempted to do to my strat and jazzmaster.

Plan for this week! 

Drill and fit tuners (this is scary, but I've managed before - I just hope I get them on straight enough!) 

Drill volume and 3 way switch holes. I won't have a tone - I will just have two volumes and a three way switch. I have seen images online of the standard layout, but I may change this slightly. This is terrifying - I've never drilled these before. I think, from having done some reading and you tubing, the smartest method is to mask off the area, mark out and then drill slowly to avoid damage.

Terrified of this. Measure 200 times, drill once. 

ThePrettyDamned

Just thinking about applying the poly finish. I wonder...

Should I finish the back and sides first, then the top? As the guitar has binding, it might help disguise any witness line that would exist, and I could even have a final coat that runs from the top onto the sides. 

Or is this madness? It would greatly streamline things and, probably, reduce the amount of runs. I am expecting the sides to be really difficult to get a good result on due to runs and the difficulty of sanding the sides... Hmm. 

WBT2079

Could I ask which sealer and poly finish you are using? Thanks. 

ThePrettyDamned

WBT2079 said:

Could I ask which sealer and poly finish you are using? Thanks. 

Chestnut cellulose sealer from a rattle can, then rustins polyurethane brushed on from a tin.

Edit: the goal of the sealer is to provide a barrier between the stains and the poly. It also helps seal up any remaining small pores, and provides a smoother surface for the finish to adhere to. Seems to work, as brushing on the poly (which is solvent based) has not disturbed the stain at all. 

The sealer is lubricated - so it's really really easy to safely rub back with 400 grit and very little pressure,basically "de-nibbing" rather than flatting back. It should already be pretty flat at that stage. 

WBT2079

Thanks for the info. 

ThePrettyDamned

So, work has been pretty busy and tiring recently and I don't fancy drilling until I'm better rested. However I've spent some time pencilling the body, marking issues to be resolved before finishing should begin. I'll not address them until drilling and dry-fitting has been done (as I'll likely create a new ding somewhere...) but most will be sanded out while a couple may require some filler to be used.

I will, in the first instance, try steaming them out with a wet cloth and soldering iron tip. This has been discussed to death on here so I'll not describe it.

As I'm looking for the best possible finish I can do, I really want to get everything sorted as much as possible, and be very particular about this. Grain filler is not recommended for actually filling imperfections beyond pores and the like. 

ThePrettyDamned

Today, I found a spare 30 minutes on lunch and tried wet sanding for the first time. I've never done this before, and was a bit scared of trying it on a guitar.

Anyway, first attempt - I split one half up to 2000 grit, and the other to 12000 grit. I started at 400 grit to level the finish as best I could (it's not flawless but it is pretty good) then worked up from 1000 to target. 



Pretty obvious which side is 12000 grit! This is after application of Halfords car polish. It's not as deep a gloss as it was, but the finish looks better - and it feels absolutely sublime.

Going up to 2000 grit was also a worthwhile task - it feels super, super slick and I'll likely do this on the neck, while putting the body up to 12000 for a smoothest, glossiest finish I can muster. Now there are no surface dust spots - only the odd pinprick, which I am more than happy with.

I then tried to repeat this on the maple, up to 12000 grit - I left the green piece as it was and... Well... It didn't go well.


My guess is that, as I was using the same piece of cloth to wipe dry as I did for the previous piece, I was not fully clearing debris and so, although it has a nice sheen, there are clearly visible scratches. I'll need to do this some more as I'd be really disappointed at that finish (from a couple of feet away it's a nice mid-gloss but as soon as you are inspecting it, it is clearly scratched). The other thing I did differently was use circular motion on this piece. Bad idea - the scratches follow that swirly motion! 

If anyone has tips, I'd be grateful. I'll go out in a bit and finish a new piece of maple to further test.