#1
Hi everyone
Sooo some of you may know I'm doing a red/black burst explorer w/ nitro clear... well after a good chunk of curing time after having finished 18 coats of clear, I went ahead and wetsanded, and started the polishing procedure, and I noticed under the light lots of tiny little divots, imperfections of the finish. Almost looks like wood pores? I filled the wood with epoxy before painting, and I also have little divots on the maple cap.
WTF.
So I did a very heavy wetsand, and managed to remove about half the divots... any idea for the second half? They are very tiny, so I'm thinking of re coating with several cans of nitro, with fairly heavy sanding in between. I know nitro re emulsifies when in contact with new uncured nitro, so im hoping i can blend the problem away with 9 rounds of spray/sanding.
I've heard of pinholes happening from shifts of tempature doing spraying/curing. So for what its worth, I sprayed outside in about 40-50 f and brought inside to about 70 for curing.
Weaksauce... its a bit frustrating.
Im sure some of you finishing gods have some good advice!
Thanks
GC
#2
hmm never has this. but then again, I've never sprayed 18 coats of clear either...

I'd say that you probably hae a bit more room to wetsand before you buffer, if you want to give that a try. but i can't really tell what you're talking about exactly. Did you epoxy your whole guitar?

I suppose temperature could make a difference also..

Pics?
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#3
I think you're talking about orange peel, but can't be sure.
Pictures?
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#4
Have you sanded through to the wood?

I would keep levelling it, you will probably remove all the dimples eventually and get a nice even finish. are you using a sanding block?

Is the sandpaper clogging up with clumps of finish? If so it isnt cured enough.




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#5
Probably should've used wood filler vs epoxy! The epoxy could've shrunk more than filler or perhaps even melted a bit when the finish was applied over top.
Moving on.....
#6
The divots youre talking about could have been caused by the weather, but my first question is whether or not you sanded DURING the finishing process ? scuff sanding, followed by level sanding a few days later, is the real key to getting a glass like finish.

I would be very careful spraying nitro again. youll get nasty witness lines.

James ( Roberto Venn grad )
#7
^ You wont get a witness line spraying nitro, nitro blends into the previos layer

2 parts and water bases will give you witness lines.




Quote by dogismycopilot
Absent Mind, words cant express how much i love you. Id bone you, oh yea.

Quote by lumberjack
Absent Mind is, as usual, completely correct.

Quote by littlemurph7976
Id like to make my love for Neil public knowledge as he is a beautiful man
#8
Quote by SFRmagnetic
The divots youre talking about could have been caused by the weather, but my first question is whether or not you sanded DURING the finishing process ? scuff sanding, followed by level sanding a few days later, is the real key to getting a glass like finish.

I would be very careful spraying nitro again. youll get nasty witness lines.

James ( Roberto Venn grad )


I did almost no sanding in between clear coats...
I got my terminology messed up, i used wood filler, not epoxy... i also used it in between paint coats (colored lacquer) as I noticed pores that I had missed.
Last edited by GoldChocobo at Mar 10, 2009,
#9
Quote by Absent Mind
Have you sanded through to the wood?

I would keep levelling it, you will probably remove all the dimples eventually and get a nice even finish. are you using a sanding block?

Is the sandpaper clogging up with clumps of finish? If so it isnt cured enough.


Sand paper isn't clogging. I started to wesand by hand, but then noticed imperfections for doing so and re-sanded with a block.
#10
I'll try to find my wife's camera and get some macro shots for everyone.
Thanks for the help everyone, UG rocks!
GC
#11
Sounds like Solvent "Pop" to me.



When you spray a finish with a solvent based paint such as Nitrocelulose, some of the solvent can get trapped if the paint skins over too quickly.

Then what happens is the trapped solvent, pushes through the surface and leaves a crater behind.

It can be caused in several ways:

- The solvent in the material, is leaving it too fast for the conditions (temperature)
- Not leaving long enough between coats
- Building heavy coats
- Too much air flow, making the paint skin up before the solvent has left the paint
- Leaving the finish too long, then trying to force dry it.

If you MUST paint in 45F...please use a heat gun to warm the body up before you take it out to paint it.

Also, warm your paint up too.
#12
Quote by Skeet UK
Sounds like Solvent "Pop" to me.



When you spray a finish with a solvent based paint such as Nitrocelulose, some of the solvent can get trapped if the paint skins over too quickly.

Then what happens is the trapped solvent, pushes through the surface and leaves a crater behind.

It can be caused in several ways:

- The solvent in the material, is leaving it too fast for the conditions (temperature)
- Not leaving long enough between coats
- Building heavy coats
- Too much air flow, making the paint skin up before the solvent has left the paint
- Leaving the finish too long, then trying to force dry it.

If you MUST paint in 45F...please use a heat gun to warm the body up before you take it out to paint it.

Also, warm your paint up too.


Sounds possible. Then again it could be a crappy pore filling job... I'm noticing also the surface is not perfectly flat... like wavy sort of in certain area's. I'm guessing this is a ****ty filler job.
*sigh* how frustrating, especially on a $900 warmoth
#13
If you havent hit the wood yet I would keep going with a block, it may level out.




Quote by dogismycopilot
Absent Mind, words cant express how much i love you. Id bone you, oh yea.

Quote by lumberjack
Absent Mind is, as usual, completely correct.

Quote by littlemurph7976
Id like to make my love for Neil public knowledge as he is a beautiful man
#14
Quote by GoldChocobo
Sounds possible. Then again it could be a crappy pore filling job... I'm noticing also the surface is not perfectly flat... like wavy sort of in certain area's. I'm guessing this is a ****ty filler job.
*sigh* how frustrating, especially on a $900 warmoth


Did you just pore fill once? you also didn't mention the type of wood. Things like ash and mahogany have large pores and might need a couple pore filling treatments. Also did you level sand the body before you started finishing it? That could be why your surface is wavey.
#15
It is on mahogany body.
I pore filled several times over, and I did sand it down to get rid of the filler high spots, though then again I probably didn't do a good enough job.
You guys think if I could keep block sanding it down it will level everything out? Its pretty thick (once again, 18 coats)...
If worse comes to worse, I can sand it to the wood, and just re do everything.... then again, re doing that burst I don't think is happening... the front seems more or less fine, maybe I can just repaint the back/sides.
#17
Quote by GoldChocobo
It is on mahogany body.
I pore filled several times over, and I did sand it down to get rid of the filler high spots, though then again I probably didn't do a good enough job.
You guys think if I could keep block sanding it down it will level everything out? Its pretty thick (once again, 18 coats)...
If worse comes to worse, I can sand it to the wood, and just re do everything.... then again, re doing that burst I don't think is happening... the front seems more or less fine, maybe I can just repaint the back/sides.


Without pics it is hard to say what happened, which is why I suggested solvent pop.

Really speaking. You should grain fill, sand, grain fill, sand etc.

Then scuff to 220-300 and prime it.

Then do a guide coat of black or contrasting colour.

Sand that with a block.

This will reveal pits and low spots, which you can then see to.

Then two more coats of primer and and a guide coat if you like, then block it again before you start on the colour.
#18
Quote by PainIsPower
Nitro will just remelt into it's self, so if you are getting worried about rubbing through into the finish, put some more coats of Nitro on it, and then let it harden and keep sanding. Eventually you'll get the nitro perfectly flat. Also, how long did you cure it for?


sprayed nitro over the course of 2 weeks, after which I let cure for 5 or so days? I know that seems very quick, but it had hardened nicely... no "fingernail" dents or solvent smells.
Im gonna do exactly that... spray/sand etc till its flat.
#19


mind the heavy buffing i was doing... still looks very scratchy. Keep in mind this is a CLOOOOSE picture.
Last edited by GoldChocobo at Mar 10, 2009,