Alder body: need instructions from stain to glossy finish

Legatt

Newbie
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3
Hello (Unofficial)Warmoth, I am new to the forum, but not new to building and assembling. I have experience with various finishes, woods, parts, etc. But I want to create a step by step guide for myself, for when my warmoth Alder P Bass body arrives, because I don't want to make decisions I'll regret. So I need your help assembling this instruction manual.

GOAL: Achieve a walnut-colored gloss finish with an alder body, like the following image, but glossier:

dsc03613smaller-jpg.128734


PLAN: To use minwax wipe on poly gloss finish, over minwax walnut stain. Grain fill, wet sand/slurry method.
MATERIALS: Sandpaper of all grits, sanding sponges, a sanding block, wet/dry paper, 0000 steel wool, naptha (for thinning/cleaning) shop towels, and rags.

STEP BY STEP: please tell me if I'm wrong. I don't mind criticism of correction at all!

1. Sand new body up to 400 grit.
1a. Raise grain with naptha to check for sanding errors. Correct any I find.
2. Pore fill with joint compound per this video. I have heard mixed things about alder and pore filling. If it is not needed for a smooth, gloss finish, let me know.
2a. Push joint compound into surface. Wipe off excess. Let dry.
2b. Sand the surface and excess joint compound down to 400.
3. Use minwax dye. Let sink for a bit. Wipe off excess.
3a. Allow to dry. Apply additional coats of dye if necessary.
4. Apply first goat of poly. Apply thickly. Wet sand with 400+ wet/dry sandpaper.
4a. Push sanding slurry into grain.
4b. Wipe off excess poly/slurry. Allow to dry
4c. Lightly sand finish at a grit above 400.
5. Apply next coat of poly, wipe off excess.
5a. Lightly sand finish coat at a higher grit.
6. Repeat until final gloss/coat is achieved.




 
I'm not familiar with Minwax's products, but here are some general "don't do" items I see in your list

1. Don't let steel wool get within 2.6 miles of anything you expect to put a fine finish on. Definitely not in the same building.
2. 400 grit sanding is probably a bit too much. Most finishing schedules recommend between 240 and 320. I prefer 320. Much finer, and you might have adhesion problems.
3. Naphtha won't raise the grain on your wood. Water will.
4. Alder doesn't need to be grain-filled.
5. Slurries won't work with poly. It doesn't remelt like nitro does. Whole different material/chemistry/process. If you leave any sanding residue on the piece before recoating, it'll look like contamination.
6. Poly is a very tough finish that doesn't sand well. Usually with sprays, it's a one-shot deal. With wipe-on, you can do multiple coats, but you're best off having a very good surface to start with than trying to gradually get an even surface through successive sanding/finishing steps.

When you're set up for it, polyurethane is actually a faster, easier, more durable finish than lacquer that returns equally attractive results. But, being set up for it is the trick. It's much more demanding, which is why you don't see a lot of DIY-types using it for guitar finishes. You really need a well-controlled paint shop with plenty of exhaust and filtered make-up air. Lacquer is a lot more work, but it's also much more forgiving and easier to play with. You can shoot that stuff in your garage over several day's time and done right, get professional results.

If you have a problem with spraying (or solvents), there are water-based acrylic lacquers available now that you could shoot in your basement or a spare room without the worries of aerosolized acetone's toxicity, odor or perhaps most importantly, combustibility. I don't have any experience with them, but I suspect you'd get a better finish than you will from any kind of wipe-on process, particularly if you want a nice gloss.
 
Cagey said:
I'm not familiar with Minwax's products, but here are some general "don't do" items I see in your list

1. Don't let steel wool get within 2.6 miles of anything you expect to put a fine finish on. Definitely not in the same building.
2. 400 grit sanding is probably a bit too much. Most finishing schedules recommend between 240 and 320. I prefer 320. Much finer, and you might have adhesion problems.
3. Naphtha won't raise the grain on your wood. Water will.
4. Alder doesn't need to be grain-filled.
5. Slurries won't work with poly. It doesn't remelt like nitro does. Whole different material/chemistry/process. If you leave any sanding residue on the piece before recoating, it'll look like contamination.
6. Poly is a very tough finish that doesn't sand well. Usually with sprays, it's a one-shot deal. With wipe-on, you can do multiple coats, but you're best off having a very good surface to start with than trying to gradually get an even surface through successive sanding/finishing steps.

When you're set up for it, polyurethane is actually a faster, easier, more durable finish than lacquer that returns equally attractive results. But, being set up for it is the trick. It's much more demanding, which is why you don't see a lot of DIY-types using it for guitar finishes. You really need a well-controlled paint shop with plenty of exhaust and filtered make-up air. Lacquer is a lot more work, but it's also much more forgiving and easier to play with. You can shoot that stuff in your garage over several day's time and done right, get professional results.

If you have a problem with spraying (or solvents), there are water-based acrylic lacquers available now that you could shoot in your basement or a spare room without the worries of aerosolized acetone's toxicity, odor or perhaps most importantly, combustibility. I don't have any experience with them, but I suspect you'd get a better finish than you will from any kind of wipe-on process, particularly if you want a nice gloss.

I have a garage I can clean up and set up for spraying though I am not eager to try. What kind of lacquer products are you referring to, like reranch nitro?

I'd be interested in hearing more.
 
Legatt said:
I have a garage I can clean up and set up for spraying though I am not eager to try. What kind of lacquer products are you referring to, like reranch nitro?

Not eager to try what? Cleaning the garage or spraying a finish? :icon_biggrin:

If you're not eager to spray a finish, maybe you shouldn't. Lacquer finishes are not a trivial project. That's why they cost so much, and why many OEMs stopped doing them. There's a good article with enough detail to get you from start to finish here if you wanna see what you're in for.

Reranch is the DIY guitar guy's go-to finish supplier, if you don't have or don't want to buy a spray rig. They make a good product and their business sorta revolves around the DIY guitar builder market. The only problem with going the "rattle can" route is you don't have any control over the mix, and sometimes you need that. Temperature and humidity will have a surprising affect how the stuff behaves, and where you are in the process may change viscosity requirements. But, once a can is mixed and pressurized, you're pretty much committed to using it as-is.

Speaking of cans, I don't know what your budget is, but you can easily go through 4 or 5 cans of finish because there's actually a lot less material in the can than it seems. The majority what's in there is reducer, propellant and dead air space. What looks like a 24oz can might only have 3 or 4 ounces of actual finish. That's probably all you need for a color coat, but there are a lot more clear coats and each one gets partially sanded away, so you'll chew through clear like it's free. Plus, no matter how good the can is, it's never going to be as good as a proper spray rig. You have no fan/flow/pressure control.

Unless you're independently wealthy, it makes no sense to get a spray rig for a single guitar, but if you think you might do this several times, it's worth looking at a small HVLP setup. You can be done for under $400 including supplies/materials for your first finish, so you only need do about 3 bodies before it's free. I use one of these Earlex rigs, and get results like this...

IMG_2929_Sm.JP
 
Cagey said:
Legatt said:
I have a garage I can clean up and set up for spraying though I am not eager to try. What kind of lacquer products are you referring to, like reranch nitro?

Not eager to try what? Cleaning the garage or spraying a finish? :icon_biggrin:

If you're not eager to spray a finish, maybe you shouldn't. Lacquer finishes are not a trivial project. That's why they cost so much, and why many OEMs stopped doing them. There's a good article with enough detail to get you from start to finish here if you wanna see what you're in for.

Reranch is the DIY guitar guy's go-to finish supplier, if you don't have or don't want to buy a spray rig. They make a good product and their business sorta revolves around the DIY guitar builder market. The only problem with going the "rattle can" route is you don't have any control over the mix, and sometimes you need that. Temperature and humidity will have a surprising affect how the stuff behaves, and where you are in the process may change viscosity requirements. But, once a can is mixed and pressurized, you're pretty much committed to using it as-is.

Speaking of cans, I don't know what your budget is, but you can easily go through 4 or 5 cans of finish because there's actually a lot less material in the can than it seems. The majority what's in there is reducer, propellant and dead air space. What looks like a 24oz can might only have 3 or 4 ounces of actual finish. That's probably all you need for a color coat, but there are a lot more clear coats and each one gets partially sanded away, so you'll chew through clear like it's free. Plus, no matter how good the can is, it's never going to be as good as a proper spray rig. You have no fan/flow/pressure control.

Unless you're independently wealthy, it makes no sense to get a spray rig for a single guitar, but if you think you might do this several times, it's worth looking at a small HVLP setup. You can be done for under $400 including supplies/materials for your first finish, so you only need do about 3 bodies before it's free. I use one of these Earlex rigs, and get results like this...

IMG_2929_Sm.JP

Not eager to do EITHER!  :laughing7:

(Also that is a phenomenal finish you got there. Better than a factory, at least from this angle.)

Truthfully, I know nothing about lacquer and I don't really want to go through seven cans of spray. Nor buy a rig (I don't do many bodies).

From what reading I've done since last night, the biggest issue with wipe-on stains is that they blotch on less porous woods, like alder or maple. Do I have that right?\

If so, should I apply a conditioner to the wood for better and more even absorption?
Would cutting the stain work? Thinner, quicker drying coats, less time to penetrate?
Or how about alcohol dyes? Would alcohol-based leather dye, like fiebing's, work? Those are extremely easy to cut?
How about gel dyes? Do those change what finishes I can use after?

The appeal of danish oil is that I can get it tinted, and that it can make a sanding slurry which in THEORY should even out the coat. But clearly it has problems...
 
Alder needs a "conditioner" before you stain to mitigate blotching. Then, you don't need anything special stain-wise. I'd use alcohol if it was me, just because it has a much lower surface tension than water so it won't bead up or anything funny like that.
 
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