What is the ideal primer sanded smoothness/look?

[pr11111111]

I’m beginning the painting phase and did 3 passes, sanded (600 grit and then 3 more and wet sanded.
It’s very smooth, but I’m not sure how it’s supposed look prior to painting. Also, the grain is coming through which is fine, I just don’t know if it’ll even show up after the paint and gloss coat.
I’m using Duplicolor sandalable primer and will go over with duplicolor color match.

 

[Timbresmith1]

I’m beginning the painting phase and did 3 passes, sanded (600 grit and then 3 more and wet sanded.
It’s very smooth, but I’m not sure how it’s supposed look prior to painting. Also, the grain is coming through which is fine, I just don’t know if it’ll even show up after the paint and gloss coat.
I’m using Duplicolor sandalable primer and will go over with duplicolor color match.
View attachment 1128949 View attachment 1128951

Looks like you’ve got more leveling to do. Should be a smooth matte finish.
Imo, finishes should have fully-filled pores, or almost no filler. The in-between fudge-filled look is too haphazard…the duplicolor coats will almost surely make the primer sink in even more because of the slow solvent evap rate.

 

[dsutton24]

Whatever texture you have in your primer will show through your paint unless you plan on laying on a lot of clear.

 

[pr11111111]

Looks like you’ve got more leveling to do. Should be a smooth matte finish.
Imo, finishes should have fully-filled pores, or almost no filler. The in-between fudge-filled look is too haphazard…the duplicolor coats will almost surely make the primer sink in even more because of the slow solvent evap rate.

Any recommendations for resolving this or just more painting sanding? Is the grit too much?

 

[Timbresmith1]

I think you’re on the right track. If you didn’t pore-fill before the primer coats, You may need to do a couple more cycles of primer if you want a flat finish. I’d probably let it sit overnight, then hard-block with 400 grit- you pretty much need to sand it level with the lowest elevation, or spot spray areas with the deepest pores. That, or a claw glaze to fill pores before adding another primer coat.

 

[pr11111111]

I think you’re on the right track. If you didn’t pore-fill before the primer coats, You may need to do a couple more cycles of primer if you want a flat finish. I’d probably let it sit overnight, then hard-block with 400 grit- you pretty much need to sand it level with the lowest elevation, or spot spray areas with the deepest pores. That, or a claw glaze to fill pores before adding another primer coat.

The body is alder and I saw that it didn’t need filler like other woods. Although, the cross grain is coming through.
Would you recommend a grain filler at this stage or after more primer (I’m probably close to running out)? And what’s the general idea with primer, just to not be painting directly on the wood?

Would the look if I stuck with the current state be similar to this?

Spraying nitro on ash without using grain filler?

If you're not going to use a grain filler on ash be prepared for it to look (and feel) like this I don't know much about accenting or enhancing the grain. I've done it on accident before, before spraying opaque over it. You could try enhancing the grain and then doing some clear grain filler...

www.tdpri.com

 

[eallen]

Unless the primer instructions said to sand to 600 never use more than 320 to 400 grit, or wet sand. Except those finishes that melt or etching into previous layers finishes geneallu attach by mechanical means of the finish molecules grabbing ahold of the micro scratches in the surface. Too fine of scratches from too fine of grit and not enough surface roughness for the hold onto solidly. The solids in the paint layers will fill the scratches. When you finish sand before buffing it will take care of any remaining imperfections.

 

[RickyRicardo]

Alder does not need to be grain filled. I've built and finished quite a few out of it and never had a grain issue. I agree with Eric that 600 is a little fine for a mechanical bind of the following coats. If the shiny spots are gone you have level sanded the primer. What are you using for a sanding block?

 

[stratisfied]

Some people just can't see the surface defects. The primed surface has to be perfect to achieve a perfectly smooth finish coat, especially with lacquer. Try this ... close your eyes and lightly run your fingertips across the surface. You can feel the imperfections and any uneveness in the primer texture easier than you can see it. Primer it again and sand back until no defects show. The surface should be uniform in color and texture. On your final primer coat, rub the body down with green kitchen scotchbrite pad instead of sanding.

Your lacquer won't sink into the grain if you apply multiple thin coats and allow the paint to fully dry between coats.

 

[pr11111111]

Alder does not need to be grain filled. I've built and finished quite a few out of it and never had a grain issue. I agree with Eric that 600 is a little fine for a mechanical bind of the following coats. If the shiny spots are gone you have level sanded the primer. What are you using for a sanding block?

Just a standard hard rubber sanding block.

 

[Sea Devil]

It's supposed to look absolutely perfect. If you have the slightest doubt, turn on the bright lights and get a little crazy with it. Being a fanatic about your primer coats will make final finishing a breeze.

 

[FTDude]

Use a guide coat to be sure the surface is flawless. Common in autobody but also applies to guitars.

What is a Guide Coat

A term some of you may have heard of is a guide coat. This 67 Camaro is in the final steps to prepare it for paint. Click on continue reading to understand what a guide coat is and how we use it to achieve a show quality finish on this, or your classic car.

www.renownauto.com

 

[chaosman12]

the white sanding dust leftover from wet sanding make it hard the tell the state of the surface from the pictures.

Anyway, you need to learn for yourself how to inspect the surface:

Use damp paper towels and wipe off ALL of the white dust. You may have to repeat several times until it is all gone. As others have said 600 grit is way too fine for leveling the surface. 600 and higher is for removing scratches from the previous grit. It does not remove enough to level out any ridges etc.

Use 320 grit with a block. Using minimal pressure glide the block over the surface. High spots will become quickly visible.

Hold a flashlight nearly level with the surface to help you see the high and low spots

If the high spots and valleys seem large. (depth wise) use 180 or even 120 to get everything level. Then move up the grits in order. For example 150, 220, 320.

 

[Supertwang]

At this stage 220 grit is your friend. Ur not ready for finer grit until the entire guitar body can be sanded to a matching smooth flat luster with 220 grit.

 

[David Menke]

I’m beginning the painting phase and did 3 passes, sanded (600 grit and then 3 more and wet sanded.
It’s very smooth, but I’m not sure how it’s supposed look prior to painting. Also, the grain is coming through which is fine, I just don’t know if it’ll even show up after the paint and gloss coat.
I’m using Duplicolor sandalable primer and will go over with duplicolor color match.
View attachment 1128949 View attachment 1128951

Not sure about what type of primer you are using, but suggest you look at https://www.reranch.com/basics.htm for information on guitar finishing.
Typically the best way is if the instrument is swamp ash or a wood that was a lot of pores, use a wood filler first. Then a sand and sealer. Next light coats of the paint you want. To do candy finishes, there is info on what paint to use first (light coat) then to start spraying the finish coat, but again this may not be necessary. Multiple light coats is the best with same color paint. NO color primer is really necessary. Alder painting is a bit easier, you will not have porous wood, and no need to fill. Sanding prior to painting, so the paint will stick to the body should be smooth 220 or 320 grit. Later on, final sanding up to 3000 grit. Most often these smooth grit paper can be found at automotive stores or online stores.

 

[61fury]

Just a standard hard rubber sanding block.

A smaller rectangular pencil eraser might give you better control when sanding. I usually use BINS pigmented shellac as a primer.
This time I'm doing a dark blue guitar so I tried the Duplicolor gray primer. Mainly so when it gets chipped the spot wouldn't be bright white.
The Duplicolor went on like dust, sanding it showed every mark of the sand paper. It was grainy and uneven, much like your guitar.
Probably user error but I went back to BINS, which sands smooth and even.

 

[stratisfied]

Frosted'matte glass is as close as I can come to describing a properly prepared primer surface.

 

[Silverface]

With all lacquer products (lacquer is not paint and isn't applied like paint - so I'm hoping your "passes" were very light and you essentially applied 2 coats) I never wet sand between coats. It's unnecessary. Using a rubber block (and it's helpful to have a set of curved ones as well) I dry sand with 320 and wipe everything down with tack cloths. Tack cloths are specifically designed to pick up residue and leave nothing on the surface.

That body looks like there was moisture on the surface, the surface (or primer) was contaminated with something, or the humidity was too high during application or drying.

Was the wood tested for dryness prior to coating?

I suggest fogging some blush reducer over the surface (never directly sprayed at the surface) and see if any of the white color goes away. If so, it's moisture contamination and/or a humidity issue.

Other than that I feel you'd have to sand it bare, test it for moisture with a moisture meter (a $15-20 tool) and start over.

I would not add any primer or other coating to it.

 

[Sea Devil]

The last time I finished a guitar, I spent a few hours a day over about four days sanding and prep-coating the body. It took only one day to spray the color and clear.

Primers are a good idea even if they're not strictly necessary. An evenly colored substrate makes it easier to achieve an even color coat, and with less material. I suppose it helps with adhesion as well, but the main purpose of a primer coat, IMO, is to make the surface as close to perfect as possible -- as smooth as a Canova sculpture made of Carrera marble. Fetishize its smoothness and flatness, look at it under a 150 watt light from an inch away, make it perfect. You'll be glad you did.