First nitro attempt a failure

[ice man]

I posted some time ago about my plans to refinish my tru-oiled mahogany neck with some stew-mac die and nitro laquer.  I applied the black die, sanded back a soft edged skunk stripe on the back of the neck, applied amber over everything, and began shooting laquer.  After a few coats, I noticed the grains weren't getting filled much (I didn't grain fill).  So thinking the grain was sucking up the laquer, I continued to coat.  After about 15 coats and a few wet sandings, I came to the conclusion that there must have been something in the grain fish eyeing the laquer.  Gave it a good level sanding, wet with naptha, cleaned the neck with naptha and tried one more coat.  Definately fish eyes.  So I sanded back the whole neck with 220, cleaned it with naptha, and re-applied the black die.  I think there must still be tru-oil deep in the grains.  So, what should I do, grain fill and nitro, or would poly cover this stuff up without fisheyes?  I did really well shooting the nitro, it was looking really good, but I'm afraid of more fisheyes.  And if I keep sanding this neck, my Warmoth Pro is going to be a Wizard soon!

 

[jackthehack]

If you could post a reasonable clear close-up picture it would help...

Mahogany grain pores, while visibly tiny can first suck up a seemingly enormous amount of grain filler/lacquer and it's very easy to sand anything filling the pores back out. That being said, just the fact that the pores aren't filled won't cause fisheyes in the lacquer coats, it's more likely you tried applying additional coats before the underlying coats were completely dry, that process can take a LONG time.

If you want a real smooth, mirror-like finish, you need to fill the grain COMPLETELY before shooting any lacquer. This can be very frustrating if you're in too much of a hurry and typically can take at least 3-4 fills before they're completely filled.

You're never going to get the grain filled by shooting more lacquer, unless maybe you wound up shooting a truly ridiculous number of lacquer coats. I typically just shoot about 8 light coats on necks.

 

[dmraco]

poly will fish eye...especially if applied too thick.


oils cause fish eye with poth poly and nitro...I did not think tru-oil was designed to have nitro over it. ( i could ne wrong here)

My guess is there are still oils/contaminates in the grain.  you could try sanding and grain filling like you stated.

Also allow nitro to cure between coats.  I usually waited 12-24 hours based on humidity.

Photos please.

 

[Patrick from Davis]

If there is something there already, you are in for a bit more work.  Nitro can be picky.  I would try dying the neck, letting that dry for at least a day, probably 2-3.  Then I'd use a shellac sanding sealer as an intermediate layer (probably 2 coats with a light sanding after each).  Once that sticks and looks like it has formed a good layer, I would start with the nitro.  Wipe everything down with naphtha before you shoot nitro to remove oils and the problems that they bring.  I would also let the nitro set up for 3-7 days depending on the heat and humidity.  The more heat tends to decrease times, the more humidity tends to increase times.  Patience is only going to help this process.

It sounds like the Tru Oil is not going to play nice, so I suggested the shellac to make a barrier between it and the nitro.  Shellac tends to stick to anything.  Several people have had good luck with the Zinnser Wax Free Shellac Sanding Sealer, and I believe that is Tonars recommendation for shellac sealer.  Good luck.
Patrick

 

[tfarny]

One thing that raises an eyebrow - 15 coats and a few wet sandings? You really shouldn't be wet sanding until you're all done, I think. The most sanding you'll  want to do between coats is just with 320 or so to knock back the orange peel. Is it possible you wet sanded and the neck got damp somehow? That sure as heck would cause fisheyes.

 

[ice man]

Thanks for all of the replies. The picture of the headstock shows the eyes the best.  The other's aren't too good, but I think you can see what's going on.
I'm actually not that upset for some reason, I guess it's better that this happened on the neck and not the body.
I let each coat dry a LONG time, sometimes letting it sit for 3 or 4 days.  I am thinking that when I finish the dye process, I'll grain fill and re-shoot the laquer.

 

[dmraco]

i would say oils in the grain...

 

[Tonar8352]

Welcome to finishers’ school where the best lessons are learned in troubled times. I say that with all sincerity. 

I’m seeing two things.  First it looks as thought you did not put grain filler on which Jack is correct about.  Those pours are pretty deep.  You can eventually fill deep grain by apply finish coats and sanding back but you would have to put a bunch of finish on and sand a lot off to get it level. 

I also see the fisheyes on the headstock.  When did you first start noticing them?  If it was right away then your stain is causing the problem, if it was after several coats and level sanding there is something else going on. 

Which lacquer are you using?  Spray cans or spraying it with a spray rig?
If it is a spray rig what kind?
How are you thinning the material?
How are you cleaning the surface after you sand?
On the wet-sand did you use tap or distilled water?
What kind of sandpapers was used?

Let us know and we might come up with some ideas to help you out.

 

[Mor Paul]

Look! It's the finishing Jesus, come to save us from our sins!

Really, Tonar is the man for finishing.

 

[DangerousR6]

I must have lucked out on mine cause I never grain filled it, just started shooting the Deft Satin Nitro. Letting it dry 24 hrs between coats and level sanding about every 4 to 5 coats. I used about 2 cans on the neck, and it came out smooth as glass... :icon_biggrin:

 

[ice man]

Welcome to finishers’ school where the best lessons are learned in troubled times. I say that with all sincerity. 

I’m seeing two things.  First it looks as thought you did not put grain filler on which Jack is correct about.  Those pours are pretty deep.  You can eventually fill deep grain by apply finish coats and sanding back but you would have to put a bunch of finish on and sand a lot off to get it level. 

I also see the fisheyes on the headstock.  When did you first start noticing them?  If it was right away then your stain is causing the problem, if it was after several coats and level sanding there is something else going on. 

Which lacquer are you using?  Spray cans or spraying it with a spray rig?
If it is a spray rig what kind?
How are you thinning the material?
How are you cleaning the surface after you sand?
On the wet-sand did you use tap or distilled water?
What kind of sandpapers was used?

Let us know and we might come up with some ideas to help you out.

I did not grain fill, and thought the grain was sucking up the lacquer.  It was apparent after a good level sanding that they were indeed fisheyes, and something was repelling the lacquer.  I'm using Stew Mac nitro in a rattle can. The die I am using is also Stew Mac water based die.  I never used water to wet sand, only naptha, using 320 I think.  Would tru oil deep in the grain repell the lacquer?  I'm thinking that is what's going on.

 

[Tonar8352]

I suggest that you level sand with 320 dry.  And then spray it with a couple of light coats of Zinsser Seal Coat.  Sand real lightly after these coats and then hit it with one wet coat of the Seal Coat.  Lightly sand that coat and then spray 2 dry coats of lacquer.  Hold the can 12 inches from the surface and mist it for your dry coats. Lightly sand after your second coat and then start putting wet coats on again.  If it is still getting fisheyes at this point you are going to have to strip it and redo it.  Good luck, let us know how it goes.

 

[bpmorton777]

Does the seal coat come in rattle can? sounds like he doesnt have spray equipment.

Brian

 

[Tonar8352]

My source does not have it in spray cans.  You can get an air charger to spry it through or in a pinch it brushes fine.

 

[DangerousR6]

Does the seal coat come in rattle can? sounds like he doesnt have spray equipment.

Brian

Lowes has Zinsser in spray cans..

 

[ice man]

So use the sealer instead of grain filling, or apply the sealer as stated after grain filling?  I'm almost ready to grain fill.

 

[bpmorton777]

grain fill then sealer.

Brian

 

[ice man]

Alright, I'll get busy.  Thanks for all of the replies.  I'll keep ya posted.

 

[Rick]

The back of the neck doesn't look bad, and with use the imperfections will wear off .... but how to fix the headstock?  I don't know.

If it were me, I would've filled the grain and then applied tru-oil.  That tru-oil is idiot proof.

 

[big bob]

I suggest that you level sand with 320 dry.  And then spray it with a couple of light coats of Zinsser Seal Coat.  Sand real lightly after these coats and then hit it with one wet coat of the Seal Coat.  Lightly sand that coat and then spray 2 dry coats of lacquer.  Hold the can 12 inches from the surface and mist it for your dry coats. Lightly sand after your second coat and then start putting wet coats on again.  If it is still getting fisheyes at this point you are going to have to strip it and redo it.  Good luck, let us know how it goes.

I was going to suggest either spray shellac or deft sanding sealer, but seal coat would be better  +1