Recommendations for a ruined(?) finish

[putnamm]

First mandolin. F5. I'm working on posting pictures but wanted to first explain the situation. I am a pure novice, using the Simminoff book as a first reference but also taking queues from this forum, YouTube and elsewhere. As it's my first instrument, I wouldn't be terribly sad to have ruined the finish. I'm mostly concerned with whether it sounds and plays correctly so I can learn on it.

Here's the situation:
Spruce top. Maple sides and backs. Maple neck with a padauk strip down the middle. Ebony point protectors, peghead overlay. Black-white-black binding made of plastic. I sanded it to 320 after finishing assembly. Dyed with alcohol-based TransTint dyes--the top dyed brown mahogany and everything else dyed dark walnut. (I did not endeavor to attempt a traditional finish, just one that I thought was simple and that I liked the look of.)

Here is the kicker: In looking for a simple finish that I could do in my little shop, I decided on Tru Oil. (Much thanks to the members of this forum for your suggestions in a prevoius post.) In watching YouTube instructions on applying Tru Oil, I came across a gentleman who first prepped a guitar by applying Aqua Coat filler. So, that's what I did. I followed the directions. The can clearly says, "Can be applied before or after staining." I wiped the Aqua Coat on against the grain and wiped off with the grain (again, per instructions).

This basically created a blotchy mess, particularly all over the spruce top. The darker maple pieces were a little better off, but not ideal. But the spruce top was absolutely disastrous.

So I've spent the morning sanding down the Aqua Coat and, by association, much of the dye on the top and also the back. The sides and neck not so much.

So, what did I do wrong here? I'm a novice, as I said, and so if I missed something very obvious that wouldn't surprise me.

Thanks for your suggestions.

Mark

[Bill McCall]

Fillers are typically used on open pore wood which neither maple nor spruce are, but spruce is more porous than maple but not as uniform. I have no experience with the Aqua Coat filler and have no idea how it responds with the alcohol tint.

Typically one would use test pieces of each material, following their predetermined protocol to check how it will appear on the actual instrument. Mistakes are easier to handle in that environment.

I would retint, seal and then apply TruOil on test pieces, but I'm sure others can provide a more in depth answer.

[peter.coombe]

You need to seal in the stain before using Aquacoat. I use shellac, 3 coats does the job.

[HoGo]

You rubbed teh aquacoat and that probably dissolved some of the stain on surface of wood and pushed it into open endgrain. Sealing is best done with spray equipment to prevent this.

[multidon]

As stated previously, grain filler is not necessary on maple or spruce, so you included a step that had no purpose and used a product that nobody here recommended or even is that familiar with. It obviously reacted with the dyes you used in unexpected ways. My advise would be, now that you have sanded it back, re-dye, seal the dye with two or three light coats of shellac, then the Tru Oil.

Hopefully by sanding back you did not remove enough material to affect your graduations too much. If you removed dye you did remove at least a little wood.

Finishing is by far the most difficult thing to learn in the world of luthiers. In the previous thread, I feel badly that I neglected to pass along to you the luthier’s mantra. “Practice on scrap!” Surely you have bits and pieces of maple and spruce lying around, trimmings from your build. Practice finishing those first so you can see exactly how the products you use will behave on your instrument. Had you done that, you would have realized you should not use the Aqua Coat and averted disaster.

Another thing to think about is, you should make certain you are using compatible products. That is, if you start with solvent based products (like your alcohol dye) then you should stick with solvent based all the way through. Likewise for water based products (I am guessing Aqua Seal is water based). In fact some companies that supply finishes for instruments have a whole “system” of sealers and finished that are compatible. However, you don’t need a system. Tru Oil contains solvents, mineral spirits as I recall. So all you have to do is stick to other solvent based products and don’t introduce water based into the mix. Also, Tru Oil has a lot of oil in it, true to its name. Mostly boiled linseed oil and other unnamed proprietary oils. These oils are self polymerizing and become a very hard and durable finish, hard enough to withstand going out on the field on the stocks of hunting rifles. But knowing it contains so much oil (along with the solvent for ease of application and some chemical dryers) brings up another luthier’s mantra to keep in mind- “Fat over lean”. That is, it’s ok to put a product with more oil over top of a product with less oil, but not visa versa. Your dye has no oil. The shellac seal coat has no oil. The Tru Oil, which should be your final coats, has oil. So, fat over lean. Get it?

Best of luck. Hope you can salvage it. But first, not to be redundant, I would practice on scrap first.

[Marty Jacobson]

Have I mentioned that modern waterbased varnishes don't require separate sealing or pore filling? As long as you don't apply the first layers thickly and cause drips or sags, you just lightly scuff sand every few coats and that's it. One big reason I switched to them... Less steps and less materials to keep on hand.

[MikeEdgerton]

This is why they created black (and white) faced mandolins.

[putnamm]

Thank you all for your suggestions and instructions.
Since this is my first instrument, and since everyone here has been so generous with their comments and time, I am planning a more extensive "What I Have Learned" post when I'm finally done. My thought is that maybe other novices will benefit.
But for now I will share that my greatest failings in this project have been (1) an energetic rush to the finish line and (2) an accumulation of methods and techniques from a great variety of sources--without proper testing of those techniques. So this is the result of both, obviously.
The reason I started building a mandolin was to learn to play. Because of the two failings listed above, the mandolin is a Frankenstein's Monster of inexperienced joinery, middling craftsmanship and piecemeal masking of errors. But if the thing doesn't play or sound worth a damn, it's all moot. Therefore, I'm not going to worry further about the appearance of this mandolin. I'm going to finish it, string it and see what it sounds like.
I am not giving up. Far from it. I've learned a great deal from this eighteen-month-long process--an education that I intend to impart on my next instrument. But before I start that one I am going to sit down, make a plan and be sure to proceed with patience and a specific, informed plan.
Thanks again.

[Marty Jacobson]

You are right to prioritize a playable instrument. I spent 600 hours one year learning to French Polish really well, a process I ultimately ended up only using for restorations. Finishing is by far the longest part of the journey to efficient/professional results.

[Jim Hilburn]

This is my #22 which became my main mandolin for about 17 years. I don't remember why but I was unhappy with the first sunburst attempt and sanded it back. I think I did that twice. I was convinced it was a disaster because so much dark stain had permeated the top but once I had re-sprayed the third sunburst it actually came out looking pretty good, more hand rubbed than sprayed. So don't lose hope. The clear coat can go a long way to making a disaster look good.

[Br1ck]

After reading a bunch of finishing threads, and having three different people tell me they loved the natural look of spruce, I left the top Unstained and did the back and sides in Amber. Love the look.

[putnamm]

This is my #22 which became my main mandolin for about 17 years. I don't remember why but I was unhappy with the first sunburst attempt and sanded it back. I think I did that twice. I was convinced it was a disaster because so much dark stain had permeated the top but once I had re-sprayed the third sunburst it actually came out looking pretty good, more hand rubbed than sprayed. So don't lose hope. The clear coat can go a long way to making a disaster look good.

Thanks, Jim. I appreciate it. As I've mentioned, I was not nearly brave enough to attempt a sunburst on this, my first mandolin. I was going for something that looked rustic and maybe a bit worn out. By mistake and with all of the issues I've had with it I think it'll turn out that way! If I'm brave enough to post photos later you will see what I'm talking about. But I'm still not sure I want anyone seeing this thing--EVER. I'm planning to attempt a sunburst in the future but will definitely plan and test that process before execution!

[Steve Sorensen]

The good news is, if you built to the Siminoff plans, your top and back graduations are likely a bit more than 10% too thick . . . everywhere.

Carefully HAND SAND off the finish. As Jim noted, there may be some darker blotches, but you can work with that.

Take your time to achieve a smoother and more subtle 'burst. Tends to be easier the second time anyhow.

After re-bursting, carefully seal the top, sides, and back by wiping on a light coat of TruOil. It will lock in the color and add some smear protection. I start in the center of the burst areas so that I don't accidentally pull dark debris into the light areas. DO NOT overwipe -- single light passes over each area is enough. You will see the wood suck in the TruOil, and lock in the color.

Then you are ready to re-clean the bindings and follow with another coat of TruOil.

My guess is your mandolin will sound 100% more responsive with that 10% less wood. This detour is to your benefit!

Steve

[Jim Hilburn]

I haven't used it but theres Bullseye dewaxed shellac in a spray can. It has some positive luthier reviews. Could be a good way to seal without any chance of finish disruption.

[Marty Jacobson]

Zinsser Bull's-eye dewaxed in a can is basically a one pound cut of blonde shellac which stays good for a long time. If sprayed on very thinly for the first few coats, it will seal the dye in nicely without causing running or blotchiness. I used to use that, now I use whatever waterbased topcoat for that purpose and for all finish layers.

[putnamm]

I have decided that I do not have sufficient shop space to safely or effectively do spray finishes. So I'm going to have to stick to hand applied finishes. But I appreciate all suggestions.

[Jeff Mando]

I have decided that I do not have sufficient shop space to safely or effectively do spray finishes.

FWIW, Dan Erlewine (StewMac) does minor finishing outdoors in good weather.....

So do I......

[Marty Jacobson]

If you're not going to be spraying a light seal coat, you should use a clean lint-free rag and really burnish off all surfaces and nooks. You want to clean off all dye particulate that's not in the wood, since that's mostly what causes the bleeding and splotchiness.
You might consider Waterlox, it's basically foolproof to apply and provides protection to the instrument after two coats or so. Pretty similar to Tru-oil, maybe a little harder.

Be aware that when using drying oil varnishes and rags there is a very real fire risk. Rags soaked in oil together in a trash can are nearly guaranteed to catch on fire as the curing reaction is exothermic.
Spreading the rag out over the edge of a metal trash can reduces risk considerably, but be careful since the oil can drain off and soak dust or paper towels in the trash can. So I always use excess oil to polish up my workbenches until the rag is just damp, then lay it out on a stone or over the edge of the trash can.

[putnamm]

Thanks, Marty. I will look in to Waterlox.

I always spread my rags out and let them breathe/dry at least overnight before disposal. That is a great tip. Thank you.

[multidon]

Waterlox is a bit different from Tru Oil. Tru Oil does not contain resins, so it is not technically a wipe on varnish. All of the protection comes from the catalyzation of the oils. Waterlox contains resins, which makes it a wipe on varnish. I’m sure it’s a very fine finish. It’s make up would make it more similar to Homer Formby or Watco Danish Oil than Tru Oil. One thing all wipe on finishes have in common is their ease of use. No matter what formula or manufacturer what they are going for is to be goof proof. I like to make my own. Equal parts of 100 percent tung oil, mineral spirits, and oil based violin varnish is a great combination for me.

[belbein]

my greatest failings in this project have been (1) an energetic rush to the finish line and (2) an accumulation of methods and techniques from a great variety of sources--without proper testing of those techniques. So this is the result of both, obviously. ...
... a Frankenstein's Monster of inexperienced joinery, middling craftsmanship and piecemeal masking of errors. .

I cringed every time you talked about "failings." None of what you did are failings. They're successes. They're successes because you tried, and successes because you got in the game. You didn't produce a Peter Coombe or Marty Jacobson quality instrument. But you produced a damn sight better instrument than if you'd sat on your butt and just wished you could do something. My father was a research biochemist, and when his experiments didn't work out, he felt like he'd had a success because he learned something he hadn't known before.

So: Learn from your mistakes, sure. But don't castigate yourself for making mistakes. There isn't a single person here who hasn't screwed up royally, and learned from it. That's how you get to be an expert: by continually screwing up--as long as you learn from it.

(And by the way, I use exclusively French Polish as a finish. It's easy (I'm sure I don't do it as well as Marty). I love the look. And it forces me to slow down.)

[John Bertotti]

I cringed every time you talked about "failings." None of what you did are failings. They're successes. They're successes because you tried, and successes because you got in the game. You didn't produce a Peter Coombe or Marty Jacobson quality instrument. But you produced a damn sight better instrument than if you'd sat on your butt and just wished you could do something. My father was a research biochemist, and when his experiments didn't work out, he felt like he'd had a success because he learned something he hadn't known before.

So: Learn from your mistakes, sure. But don't castigate yourself for making mistakes. There isn't a single person here who hasn't screwed up royally, and learned from it. That's how you get to be an expert: by continually screwing up--as long as you learn from it.

(And by the way, I use exclusively French Polish as a finish. It's easy (I'm sure I don't do it as well as Marty). I love the look. And it forces me to slow down.)

You're giving some people to much credit. I know plenty that never learned from their mistakes. So funny and sad to watch them repeat the same mistakes over and over and over. Otherwise I agree 100%.

[putnamm]

Thanks again to everyone. And thanks to those of you who recommended Tru Oil. I've been please with it so far.

One question: I've gotten seven thin coats of Tru Oil to build up nicely. I've noticed in certain areas there may be a fiber or tiny speck of something that got caught in the Tru Oil as it cured. What's the best way to deal with this? Wet sanding? Steel wool?

Thanks.