Grain Filler; Sanding Sealer; Primer - what is needed for each type of wood?

[PFDarkside]

I’ve succumbed to the body sale yet again and my second unfinished body will be arriving tomorrow. Depending on how these go I have the itch for a couple of non-sale, custom ordered bodies for finishes.

Regarding the need to grain fill, use sanding sealer and primer, which woods fall into which camps?

Maple - straight to primer?

Basswood/Alder/Poplar - Sanding Sealer then primer?

Ash/Mahogany - Grain Filler, then Sanding Sealer then primer?

What changes above for transparent finishes rather than solid color finishes?

Thanks for the info, I’m planning on a test piece before I do anything to the bodies, but I’d prefer to have a plan going in, not attempt to reinvent the wheel on the fly!

 

[Spud]

I’ve succumbed to the body sale yet again and my second unfinished body will be arriving tomorrow. Depending on how these go I have the itch for a couple of non-sale, custom ordered bodies for finishes.

Regarding the need to grain fill, use sanding sealer and primer, which woods fall into which camps?

Maple - straight to primer?

Basswood/Alder/Poplar - Sanding Sealer then primer?

Ash/Mahogany - Grain Filler, then Sanding Sealer then primer?

What changes above for transparent finishes rather than solid color finishes?

Thanks for the info, I’m planning on a test piece before I do anything to the bodies, but I’d prefer to have a plan going in, not attempt to reinvent the wheel on the fly!

One thing I feel is crucial no matter what type of wood or product you apply is that every guitar body should be rubbed on one’s face to get the best tone possible. In fact, if you are skeptical or unwilling to do this step on a completed or in process guitar you should stop playing.

 

[bagman67]

Leaving aside @Spud's excellent advice, I'd say the following:

For any species, I'd tend to do a wash coat of shellac or lacquer before filling or priming, but that's not strictly necessary for the tight-pored woods.

For alder, poplar, maple, or basswood, you can cut to the chase - primer, sanding, color coat, then sanding (except metallics and metalflakes - don't sand those!), then clearcoats. Scuff sand between color coats and between clearcoats.

I have found that tinted fillers can stain your wood, so I do a sealer coat of shellac before I grain-fill ash or mahogany. Then it's business as usual. Tinted clearcoats (often called toners) can go on over your sealer coat and after fill. But if you want the grain filler to contrast with the toner, as you might see with a dog-hair finish, you would do color then grain fill.

 

[Rick]

And of course there's whole differently methodology if you using dyes and a clear oil based top coat.

 

[PFDarkside]

Leaving aside @Spud's excellent advice, I'd say the following:

For any species, I'd tend to do a wash coat of shellac or lacquer before filling or priming, but that's not strictly necessary for the tight-pored woods.

For alder, poplar, maple, or basswood, you can cut to the chase - primer, sanding, color coat, then sanding (except metallics and metalflakes - don't sand those!), then clearcoats. Scuff sand between color coats and between clearcoats.

I have found that tinted fillers can stain your wood, so I do a sealer coat of shellac before I grain-fill ash or mahogany. Then it's business as usual. Tinted clearcoats (often called toners) can go on over your sealer coat and after fill. But if you want the grain filler to contrast with the toner, as you might see with a dog-hair finish, you would do color then grain fill.

Thank you, so no sanding sealer for the tight grain woods? Would there be any concerns with sanding sealer and leveling first?

Regarding primers, do they need to follow the Lacquer/Enamel/Acrylic as the topcoats or is it less of a concern with primers?

 

[PFDarkside]

And of course there's whole differently methodology if you using dyes and a clear oil based top coat.

Understand. For now I’m doing opaque finishes (solid, then metallic).

 

[bagman67]

Thank you, so no sanding sealer for the tight grain woods? Would there be any concerns with sanding sealer and leveling first?

Regarding primers, do they need to follow the Lacquer/Enamel/Acrylic as the topcoats or is it less of a concern with primers?

If you use shellac as a sealer, you can spray pretty much anything on top of it. Generally it's wise to stay within a family of finish types, and adhere to manufacturer recommendations. Generally I won't put anything but lacquer-based products on top of a lacquer sealer coat, because lacquer can off-gas for some time after spraying, and the chemicals it emits might screw with subsequent non-lacquer coatings bonding to the part.

Is that responsive to your question?

 

[PFDarkside]

If you use shellac as a sealer, you can spray pretty much anything on top of it. Generally it's wise to stay within a family of finish types, and adhere to manufacturer recommendations. Generally I won't put anything but lacquer-based products on top of a lacquer sealer coat, because lacquer can off-gas for some time after spraying, and the chemicals it emits might screw with subsequent non-lacquer coatings bonding to the part.

Is that responsive to your question?

I think so. I’m planning on Dupli-color Lacquers for the first, so I was thinking Deft Lacquer Sanding Sealer. For the second I might use the Roth Metal Flake line, but I need to check on the type of paint it is. They recommend SEM Primer which is acrylic, what’s the appropriate type of sanding sealer under Acrylic?

 

[bagman67]

I'd check with the manufacturer, to be safest. As I said, shellac is pretty much a universal interface coating, and you can use it safely with just about anything. Zinsser makes a white, shellac-based, water-borne primer under their 1-2-3 brand, which you could experiment with. It's available everywhere, and probably less expensive than whatever the specialty hotrod paint makers recommend.

Whatever else you do, pick up some scrap wood of the same species as your body, and work out your finishing schedule there before you start applying coatings to your expensive Warmoth part. It is far better to make your mistakes and do your swearing early in the game on cheap wood, and then approach the actual part with a zen mind and the confidence of actual knowledge about what works and what does not.

 

[PFDarkside]

I'd check with the manufacturer, to be safest. As I said, shellac is pretty much a universal interface coating, and you can use it safely with just about anything. Zinsser makes a white, shellac-based, water-borne primer under their 1-2-3 brand, which you could experiment with. It's available everywhere, and probably less expensive than whatever the specialty hotrod paint makers recommend.

Whatever else you do, pick up some scrap wood of the same species as your body, and work out your finishing schedule there before you start applying coatings to your expensive Warmoth part. It is far better to make your mistakes and do your swearing early in the game on cheap wood, and then approach the actual part with a zen mind and the confidence of actual knowledge about what works and what does not.

Thank you again, and yes, that’s the plan! I almost wish I could get the trimmings from Warmoth to practice with. I’ve practiced getting even coats on some scraps and my technique has improved. My biggest concern is getting a smooth and even primer coat to lay the color on. My other concern is sanding the orange peel without really knowing the depth of the clear.

 

[DuckBaloo]

Sanding sealer and primer both do the same job — good adhesion to raw surfaces and high solids for fast build up. Use sanding sealer on transparent finishes, use primer on opaque finishes. You never need to use both. Use the sealer or primer that is compatible with your other coats, preferable within the same system.

Wax-free shellac is like the rosetta stone of finishes, it sticks to just about anything and just about anything sticks to it. Using a shellac sealer coat to start will often off-set any ill effects due to chemicals left on the body. It also helps as any in-between coat in different kinds of finishes. It, however, is not a durable finish for top coats. That's just something to take into account when deciding on a finishing technique. Generally always use the wax-free shellac, once you've added wax to a surface, you limited any finishes that will work over it.

My biggest concern is getting a smooth and even primer coat to lay the color on.

You apply a 3-4 coats of SS or primer and sand smooth, as you sand through (and you will), apply more coats, and repeat. It's taken me as much as 12 total coats to get smooth.

My other concern is sanding the orange peel without really knowing the depth of the clear.

This is why we spray 10-12 coats of clear.

 

[triple jim]

They recommend SEM Primer which is acrylic, what’s the appropriate type of sanding sealer under Acrylic?

To complicate things, acrylic can be lacquer or enamel.

 

[PFDarkside]

To complicate things, acrylic can be lacquer or enamel.

Do you want to fill in my gaps of knowledge here here?

 

[Spud]

To complicate things, acrylic can be lacquer or enamel.

Or waterborne, or solvent

 

[PFDarkside]

Ok, how will this work as a base coat? Wax free shellac sanding sealer.