Official Luthiers Forum!

This is a great thread! Thanks again to Vijay for his great explanations and information.

_________________
Support the OLF! Bookmark our STEWMAC link Today!
Lance@LuthiersForum.com

I have sprayed five coats of Royal Lac so far on my OM, and it looks very promising. I like the color and clarity, and it goes on nicely from my gun.
The 6th coat is going on later today.

_________________
"I want to know what kind of pickups Vince Gill uses in his Tele, because if I had those, as good of a player as I am, I'm sure I could make it sound like that.
Only badly."

I'll second that, not just for the info but also how it all unfolded. In case someone may misunderstand, my heart goes out to Tim in regards to his problem and I hope that all works out. What struck me was how everyone was so forthcoming and are working together to help. Super.
Tom

_________________
A person who has never made a mistake has never made anything!!!

I have the 6th coat on now, and am pretty impressed still with the color and ease of spraying it. The other thing I've noticed is that after even just a few hours, the ease with which this stuff dry-sands is pretty remarkable. You don't need to apply much pressure, and as long as you don't, the paper won't clog much at all. I'm lovin' it. Still have a good ways to go, and then the long wait before wet sanding and finally buffing.
I will take a couple of pictures soon, albeit reluctantly. I hate showing my shoddy work here with so many great builders present.

_________________
"I want to know what kind of pickups Vince Gill uses in his Tele, because if I had those, as good of a player as I am, I'm sure I could make it sound like that.
Only badly."

Don't be shy, some of has have more time to give to it than others, and some folks have more relevant and suitable background as a leg up.

Well, ok. No laughing...

_________________
"I want to know what kind of pickups Vince Gill uses in his Tele, because if I had those, as good of a player as I am, I'm sure I could make it sound like that.
Only badly."

So I realize that the image color is a bit bright, since the ivoroid looks pretty washed out, and the brick red of the rosewood looks lighter than actual, but I think you should be able to see what I mean about the clarity. The bindings all the way around are pretty much the same color as before the finish. This is a much lighter toned finish than the Epifanes that was on this guitar prior to stripping it back and using the Royal Lac. Coats 7 and 8 will go on over the next couple of days.

_________________
"I want to know what kind of pickups Vince Gill uses in his Tele, because if I had those, as good of a player as I am, I'm sure I could make it sound like that.
Only badly."

Don,
May I ask a few questions:
1) Can you share with us how the softwood top looks? Even and flat with pores not showing or otherwise?
2) Is the finish sinking in compared to the hardwood back and sides?
3) Your technique of spraying?
4) Is Royal-lac 26% or diluted?
5) Time to dry in between coats?
6) How many coats a day?
7) What was your pore fill material and schedule?
I think your feedback will help us all.

Vijay,

I will try to answer those...

1. The top looks great! Nice and even.

2. I don't see any evidence of the finish "sinking in" to the top, but I for one always find that this happens regardless of the finish I'm using. It's happened with nitro, the KTM's, varnish, and shellac based finishes. I think it's more about the top than the finish. The lighter (early) growth rings are very much softer than the darker, winter (late) growth rings, that as the finish shrinks, it forces the soft wood inward a bit, whereas the harder late growth doesn't get pushed in, or as much.

3. I just spray at higher volume and low pressure with a Walcom STM gun with a 1.2 tip. Nothing special about my technique at all. I found that the trick to any finish is finding the right balance of air and material, and getting the right distance away from the work while using the optimum speed of movement. It can be tricky.

4. This is the 26%, undiluted. I have no issues with flow. I may try to dilute at some point to see how it flows, but as of right now it's working well.
5. I'm letting at least a day go by between coats, since the temperature is a little lower than I would like in the shop. Humidity is right around 40-45%.

6. One, or less. I'm not in a hurry.

7. No schedule... I used a combination of CA glue and shellac with pumice. My pore filling leaves much to be desired... but I managed to get it pretty darn level before spraying the Royal Lac.

_________________
"I want to know what kind of pickups Vince Gill uses in his Tele, because if I had those, as good of a player as I am, I'm sure I could make it sound like that.
Only badly."

Just ordered my Royal Lac from Vijay this week. After seeing Robbie's, and now seeing Don's pics, I am very excited to try this finish. I ordered both super blonde and beige as I will be trying to add a bit of color to my Adi top.

Also, Don I think that end graft inlay is awesome!! ( I may have to steal that idea. ;o)

_________________
Guitar Building = Continuous Improvement Process

Thanks Ray. I love the endgraft, I spent a lot of time thinking about the design. I think it goes nicely with the inlay on the fretboard...

_________________
"I want to know what kind of pickups Vince Gill uses in his Tele, because if I had those, as good of a player as I am, I'm sure I could make it sound like that.
Only badly."

Very nice work.

Also, I think you have a much better stash of wood than the average bear. Holy nice stuff! We'll done.

_________________
Guitar Building = Continuous Improvement Process

Better stash? Not really. I have a few pieces that I like, and I lucked into some of it, but I know several folks who have stashes that make mine look paltry indeed.

It helps to have a CNC... all the work on the fretboard and headstock was done on the CNC, including the binding ledges, tuner holes, truss rod slot etc.

_________________
"I want to know what kind of pickups Vince Gill uses in his Tele, because if I had those, as good of a player as I am, I'm sure I could make it sound like that.
Only badly."

Don, I can see how you could cut the pockets for inlay with a cnc, but are you cutting those tiny thin parts to inlay into the pockets on the cnc as well? I just recently got a little router cnc with a 12x13 table, but don't have much experience with it yet,
Mike

Sorry for the inadvertent thread highjack, thanks to Don for catching it below!

Mike, we're probably diverging too far off the path of this topic, so I'm sending you a PM...

_________________
"I want to know what kind of pickups Vince Gill uses in his Tele, because if I had those, as good of a player as I am, I'm sure I could make it sound like that.
Only badly."

back to the subject at hand...

I noticed a bit of graininess and slight pinholes in the last coat, so I increased the volume a bit, tightened the pattern, and slowed down. The 7th coat going on right now is going on much more smoothly and more glass-like.
Lovin' it so far.

_________________
"I want to know what kind of pickups Vince Gill uses in his Tele, because if I had those, as good of a player as I am, I'm sure I could make it sound like that.
Only badly."

Tom,
I did seal one or two tops with a very thin skim coat of West epoxy. On early guitars I had similar shrinkage problems into the soft wood on the tops. Vijay suggested sealing one or two tops with epoxy to see if that made any difference but it did not. I still experienced finish shrinkage into the softwood.

Its worth mentioning that all of these guitars, during the spraying and curing process, were subjected to 95* - 105*F constant temperatures between coats and for final curing. This may or may not have had some bearing on my problem?

Of the four guitars that have cracked tops, three were subjected to the extreme cold temperatures. The fourth guitar was put in its case and then stored in the shop at ~70*F. Most all of the cracks were along and parallel to the tops grain lines. However a few cracks did transverse across the grain.

All of the finish cracks were on the softwood tops but none have any cracks in the sides and backs.

Robbie,
I did several free plate tests panels on Spruce, Walnut and Rosewood prior to using RL on my guitars. I subjected them to several days in my deep freezer and then I would remove them and immediately hang the samples beside my wood stove in the shop which is about as extreme of a temperature swing that I could produce. None of the free plate samples cracked or showed any signs of shrinkage in the finish. I wonder if there is any effect of the top being secured around the rim of the body as compared to a free plate. Perhaps this limits the way the softwood top can expand and contract differently than the way my free plate samples did?

_________________
tim...
http://www.mcknightguitars.com

Robbie,
I did several free plate tests panels on Spruce, Walnut and Rosewood prior to using RL on my guitars. I subjected them to several days in my deep freezer and then I would remove them and immediately hang the samples beside my wood stove in the shop which is about as extreme of a temperature swing that I could produce. None of the free plate samples cracked or showed any signs of shrinkage in the finish. I wonder if there is any effect of the top being secured around the rim of the body as compared to a free plate. Perhaps this limits the way the softwood top can expand and contract differently than the way my free plate samples did?[/quote]


Tim,

This one has me stumped as I am not able to reproduce the issue on my end. However, it could be an apples to oranges comparison here because I did not use epoxy as a filler on the spruce but rather applied it over raw spruce, my spruce sample boards were thick but the rosewood samples were thin, I was using a version of Royal Lac with fewer solids and I wiped it on instead of spraying. Any one of these factors could change the entire equation. I wonder if not subjecting the guitars to the temperature/humidity extremes might have kept the finish from checking?

100 F might be a bit high, causing the solvent to release too quickly.
I've had Shellac bubble badly when the sun shines (not very often here!) through the window and hits a freshly polished guitar.
It's releasing the solvent too quickly. But these are bubbles and the problem appears not long after polishing.
I still think it may be better to let the solvent release a bit on the slower side, below 85 F. In any case it won't do any harm and it is playing it safer.

After examining my guitar today in preparation for coat number 8, I felt I was getting a bit too much orange peel and decided to forego the eighth coat and started the leveling process in preparation for the final coats. I think the finish definitely needs a few days, or at least a couple of days before dry sanding, but I found that wet sanding with 400 grit paper worked pretty well. I found a couple of tiny specs of dirt embedded in the finish on the top and had to pick them out with a scalpel. I guess I'm now testing the finish for drop filling as well...
Oh... seven coats was plenty for sanding back with the higher solids mix.

I did find that the finish did "sink in" to the softer early grain of the spruce top (as expected) but not any more than any other finish I've used. It was negligible, but a few days more drying time may reveal further shrinkage. Certainly, after the last coats and a month or so wait there is bound to be more but I don't foresee any issues. I actually like the look of it...

_________________
"I want to know what kind of pickups Vince Gill uses in his Tele, because if I had those, as good of a player as I am, I'm sure I could make it sound like that.
Only badly."

Robbie O'Brien wrote:
Tim,

This one has me stumped as I am not able to reproduce the issue on my end. However, it could be an apples to oranges comparison here because I did not use epoxy as a filler on the spruce but rather applied it over raw spruce, my spruce sample boards were thick but the rosewood samples were thin, I was using a version of Royal Lac with fewer solids and I wiped it on instead of spraying. Any one of these factors could change the entire equation. I wonder if not subjecting the guitars to the temperature/humidity extremes might have kept the finish from checking?

My take:
The major difference that increased atomization (Tims’ method) would cause is change in the amount of solvent left in the coating when it first lands on the part. More atomization will result in a higher solids wet film. Depending on the molecular weight and on how thick the film is built up, it can slow down the rate at which remaining solvent gets out of the film and also the rate that cure occurs. Once a new coat is laid down over it within a short period of time, it slows it down further. I believe if a wet film is laid down with more time in between coats and curing time increased, it should work well for Royal-lac to cure properly. In its present formulation, it cannot be pushed too hard. It needs more time to cure. I am working on a formulation that will cure faster. Results are encouraging so far!
Tim also mentions; "The fourth guitar was put in its case and then stored in the shop at ~70*F."
I believe that this guitar was still in its curing stage when it was put in a closed environment. Definitely not good for curing.

I've decided to reduce the 26% mixture down a bit to try to eliminate the orange peel I'm getting when spraying the Royal Lac. I was reading Brian Howard's article in Guitarmaker magazine about spraying, and it would seem that it needs to be reduced further. I'm also going to try playing with the pressure and settings on my gun some more as well.

_________________
"I want to know what kind of pickups Vince Gill uses in his Tele, because if I had those, as good of a player as I am, I'm sure I could make it sound like that.
Only badly."

Vijay from shellac finishes sent me some spray cans of Royal lac as well as regular Royal Lac but with a higher solids content than the original formula. I am doing some testing for him by spraying the rattle can version on pieces of spruce and rosewood. The rosewood was pore filled using the shellac and sawdust method I showed in my Luthier Tips du Jour Mailbag video yesterday. I sprayed 3 light coats from the rattle can this afternoon at about 5 to 10 minute intervals. I noticed that this dries very quickly and goes on very thin and smooth due to the rattle can formula.
I also sprayed three light coats from my spray gun using a 1.0mm tip. These were also done at 5 to 10 minute intervals. Due to the higher solids content and this being build coats I got a bit of orange peel. I will thin the product as I get closer to my final coats.

Due to the way I hold guitars while spraying I would not be able to apply coats as quickly. It would have to be drier to the touch unless I hung the guitar while spraying. Certainly this can be done.

This may seem a dumb question, but I've seen all the comments on why this shellac doesn't have the negatives (or impossibility) of spraying shellac. What I am not sure I understand is what the perceived benefit over lacquer. What is it that spraying this over, say, Mohawk Piano Lacquer gives you?

Update:

I now have 11 or 12 coats on the guitar (I lost count...) and the top and back both seem to have plenty of finish on them, while the sides seem to have thinner coats. Not sure why that is, except that I have been a little more conservative when spraying the sides due to the tendency of the finish to want to run a bit. I'm going to do a 2-3 more coats on the sides and maybe one more on the top and back and call it a day. I went through more of the finish than I was expecting to in the process, but that's ok. I expect to get perhaps 5 or 6 instruments out of a gallon which is perfectly acceptable to me. I wish I had a better "true" hvlp setup, but my compressor and conversion gun do the trick.

On another note: I hope that the final wet-sanding can take out cat hair...

_________________
"I want to know what kind of pickups Vince Gill uses in his Tele, because if I had those, as good of a player as I am, I'm sure I could make it sound like that.
Only badly."