Grain Filler/sealer Issue

[Mickguard]

Here's the latest issue I've come up against:

I grain filled/sealed the guitar, then sanded that back. It LOOKED okay, that is, when I inspected it, it looked flat, couldn't find any issues with it. And even when I wet it down to clean the dust away, it looked okay.

BUT, as soon as I sprayed the primer coat (to the back of the guitar), I found a couple of areas of drip or smear...at any rate, you could clearly see the grain filler. So I had to sand back the back of the guitar and spray again.

Then it was time to spray the color coat --there's no primer on the front of the guitar, so the color will be a little transparent.

This time, I inspected the front really carefully, held it up to the light, etc, etc. It really looked good to go.

But of course, as soon as I had the color on I found a pretty large area of sealer drip/smear. I'll have to sand back at least those areas now and spray again.

Now here's the big question-- for the neck, I've decided not to use any color. I'm just going to spray clear coats on there. But I'm worried that as soon as I spray the clear, I'm going to discover more bits of drip/smear --so how do I locate those areas BEFORE I spray?

[Mattia]

Get some Naphta, wipe it on, and it should show up any flaws. What kind of products are you using? How would you get a drip and/or smear that's not visible prior to coating?

I'm not quite getting what's going on here; I tend to seal (shellac, wiped on), pore fill, sand level, one more quick seal coat (shellac, again), and that gets me a good surface. Evaluating it post-level sanding has worked for me every time, save for a few moments where I missed a pore, and needed to re-fill it.

[Mickguard]

Get some Naphta, wipe it on, and it should show up any flaws. What kind of products are you using? How would you get a drip and/or smear that's not visible prior to coating?

I'm not quite getting what's going on here; I tend to seal (shellac, wiped on), pore fill, sand level, one more quick seal coat (shellac, again), and that gets me a good surface. Evaluating it post-level sanding has worked for me every time, save for a few moments where I missed a pore, and needed to re-fill it.

←

I'm using the only thing that I've been able to find-- it's called a "Bouche Pores" (which pretty much means grain filler) and on the back is also calls itself a 'Fond Dur' (sealer).

I put on two coats, then sanded it back. And like I said, it looked all right. But it was only when I put color over it that the drips showed up.

So I'm willing to entertain the possibility that it's actually the color coat that's doing this-- maybe I'm spraying too much (I think I'm going light, but maybe I need to make even lighter passes?)

Back to the drawing board!

[Setch]

Define 'drip'.

IMO, if you've sanded back, a drip will not appear any different to the rest of the sealer, since it should be sanded level with an sealer surrounding it. Are the drips proud of the surrpunding area? A different colour? Do they effect the way the finish is absorbed?

what exactly causes them to 'appear' once finish is applied?

If you're still getting visible pores, ditch the 'mystery' product and use a 5 minute epoxy instead. That's guaranteed to work.

[Mickguard]

It wasn't the sealer, it was my heavy trigger finger....I wasn't spraying lightly enough, and so the paint was sloughing a bit --not really dripping, more like sagging...I'm guessing because the paint is at room temperature but I'm spraying in an unheated garage.

At any rate, I sanded back and resprayed, it looks much better now....not exactly factory finish, but once the clear coats are on, it should look just fine.

Every step is a learning experience...