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Is this a witness line? If so, how can it be fixed?
http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=30377		 Page 1 of 1
Author:  Dave Livermore [ Sat Dec 18, 2010 5:23 pm ]
Post subject:  Is this a witness line? If so, how can it be fixed?
I'm SOOOO close to having this instrument finished. It IS my best work so far #12 and is a commission to be delivered next Thursday.
That said, as I was doing the final level and buff today, this area appeared in the well cured nitro finish.

What is it? and can I fix it?

Image

Thanks for any help.

Dave
Author:  Haans [ Sat Dec 18, 2010 5:52 pm ]
Post subject:  Re: Is this a witness line? If so, how can it be fixed?
Hard to say, but kinda looks like bad adhesion between coats. If you are not getting it anywhere else, the solution is cellosolve airbrushed over the area, some lacquer airbrushed over that and a tad more cellosolve after. Trick is to not use too much cellosolve or it will take a very long time to dry after you are done building it up.
Author:  Pat Foster [ Sat Dec 18, 2010 5:56 pm ]
Post subject:  Re: Is this a witness line? If so, how can it be fixed?
Haans,

That would work for nitro, but it looks like something other than nitro to me. Dave, what's the finish?

Pat
Author:  Haans [ Sat Dec 18, 2010 6:36 pm ]
Post subject:  Re: Is this a witness line? If so, how can it be fixed?
Pat, if I read it right, it's nitro...
Author:  Dave Livermore [ Sat Dec 18, 2010 6:37 pm ]
Post subject:  Re: Is this a witness line? If so, how can it be fixed?
It is nitro.

I've got til next Thursday. What is celusolove and what are the chances I can get some on a Sunday in Minneapolis?

I could go for adhesion problem as there's a ridge that I can feel around this pocket. It is the only spot on the guitar like this. And of course it is on the upper bout, facing the player.

Can I mask it off and airbrush thin nitro on to it in the absence of Celusolve?

d
Author:  BobK [ Sat Dec 18, 2010 7:04 pm ]
Post subject:  Re: Is this a witness line? If so, how can it be fixed?
Did you use a sanding sealer first? I had an adhesion problem using stew mac's rattle can nitro on my first two builds. For some reason the nitro top coats wouldn't stick to the sanding sealer. Pressing a finger nail into the surface would create something that looked like a half moon which I could easily scrape away. There was no easy solution for my problem.

Bob
Author:  Dave Livermore [ Sat Dec 18, 2010 7:23 pm ]
Post subject:  Re: Is this a witness line? If so, how can it be fixed?
Thanks for the responses.
Will do a re-shoot on the area tonight.

Sealer was Shellac, but I suppose its possibe we're back to that level.
Author:  Mark Groza [ Sat Dec 18, 2010 7:45 pm ]
Post subject:  Re: Is this a witness line? If so, how can it be fixed?
That's a bummer Dave. Looks like it didn't melt down properly. What brand of nitro was it?
Author:  alan stassforth [ Sat Dec 18, 2010 8:04 pm ]
Post subject:  Re: Is this a witness line? If so, how can it be fixed?
Sorry about that.
Did yo z-pxy, vinyl seal, lacquer?
The way I see it, is, beehive
too many different finishes.
A comptability issue.
I'm probably wrong.
But, I'm sticking to my guns.
Water based, oil based, lacquer based, don't mix!!!!
Unless one lets them dry for a month between each coat.
Aaahhhlaan.
Author:  Howard Klepper [ Sat Dec 18, 2010 8:42 pm ]
Post subject:  Re: Is this a witness line? If so, how can it be fixed?
Looks like a sand-through to me, not a witness line.

I've said for many years that sanding sealer is a mistake on a guitar.

There's a really important point to get here, and it isn't about how to lacquer. It's about promising guitars by a deadline. Don't do it. You can estimate completion dates, but do not commit to a guitar being done by such-and-such date no matter what. You must be able to take the time you need to get it right.

As the saying goes (sort of), it can be a week (or two, or three, whatever) late now, or it can be wrong forever.
Author:  jackwilliams [ Sat Dec 18, 2010 8:55 pm ]
Post subject:  Re: Is this a witness line? If so, how can it be fixed?
Many thanks Howard for the great advice about deadlines..
jack
Author:  the Padma [ Sat Dec 18, 2010 10:26 pm ]
Post subject:  Re: Is this a witness line? If so, how can it be fixed?
Well David

Shift happens. Sorry Dave. Brother Howard layed down the sacred word about deadline promises and Haans on how to do the quick fix .

So whats left to say other than you may be real lucky in that its only on that one area. My experience
is 50/ 50. I know you don't wanna here this but the layer that is separating may in time start to show up elsewhere. Because of this happening to me in past experiences, I would simply tell the client "sorry dude, I'll call you when its ready" then proceed to strip and refinish. Why?... because its the right way to handle layer separations like this. Truthfully, it is better to siss the client off now than having them bring it back with an attitude of poor quality taking seed in their head. Well to me it is.

Oh and Dave, please stay away from sanding sealers.


blessings
Author:  Dave Livermore [ Sat Dec 18, 2010 11:02 pm ]
Post subject:  Re: Is this a witness line? If so, how can it be fixed?
Howard, you are a wise man.

I'm in a good position in that the customer is in no hurry either. I had projected it being done by late summer. But, since he wanted a body style I'd never done before, I spent the summer making a prototype (which turned out GREAT.) Then I thought we'd have it done by October, but that came and went and I said it would probably be done by Christmas.
He's in no hurry and isn't bummed. I would just like to get it to him when we make the trek to South Dakota next week as we only get out there a few times a year. Delivering in person and driving it out is way safer than shipping it in the dead of winter.

If it starts getting funny a few months down the road, I'll take it back and re-do it. Or build him another one. He understands that I'm new to the trade and SOMETHING isn't going to be perfect. He also knows that the guitars he played last easter were of a quality and price that he really wanted hanging on his wall.


As for the sanding sealer, I don't use the stuff and haven't since my very first build a dozen guitars ago.
The pores are filled with an egg white/sawdust slurry and then I sand back and rub some shellac on before spraying nitro.

I sprayed about four coats of nitro on the spot in question tonight (30 mins apart.) I'll wait as long as I possibly can and sand back and buff it on Wednesday night or Thursday morning. I know that is pushing it, but the area is so small I doubt it will be that big of a deal. It'll all be set up and ready by then anyhow.

It could very well be a sand through that went only to the shellac. I sanded through in a few other spots to bare wood and drop filled those. All on the sides. All where I should have sprayed a little heavier and didn't.
The whole thing should've had another two coats put on, but I was out of time and just leveled and buffed without them.
Live and learn.
Author:  Michael Smith [ Sun Dec 19, 2010 12:57 am ]
Post subject:  Re: Is this a witness line? If so, how can it be fixed?
I did one like that by overheating with the buffer.
Author:  Haans [ Sun Dec 19, 2010 5:12 am ]
Post subject:  Re: Is this a witness line? If so, how can it be fixed?
Dave Livermore wrote:
It is nitro.

I've got til next Thursday. What is celusolove and what are the chances I can get some on a Sunday in Minneapolis?
d


I've got some, but you have to get here before noon. Bring the guitar and we can take a look at it. Email me if you want to come over.

Hans.
Author:  Kim [ Sun Dec 19, 2010 6:31 am ]
Post subject:  Re: Is this a witness line? If so, how can it be fixed?
Haans wrote:
Dave Livermore wrote:
It is nitro.

I've got til next Thursday. What is celusolove and what are the chances I can get some on a Sunday in Minneapolis?
d


I've got some, but you have to get here before noon. Bring the guitar and we can take a look at it. Email me if you want to come over.

Hans.



Ur a Class act Haans [:Y:]

Cheers

Kim
Author:  woody b [ Sun Dec 19, 2010 7:30 am ]
Post subject:  Re: Is this a witness line? If so, how can it be fixed?
Michael Smith wrote:
I did one like that by overheating with the buffer.


That's what I was thinking. Take your time repairing it. Another week or 2 is better than a bad repair.
Author:  Dave Livermore [ Sun Dec 19, 2010 9:27 am ]
Post subject:  Re: Is this a witness line? If so, how can it be fixed?
Thanks for the offer Haans, but I'll be in church playing for my kids' Christmas program.

I used an airbrush and thinned nitro and shot it last night, so I'm good.

Dave
Author:  Haans [ Sun Dec 19, 2010 10:18 am ]
Post subject:  Re: Is this a witness line? If so, how can it be fixed?
Figured that, but thought if you were desperate...
Hope it works for you, but I fear you may get the witness lines now. I've got a quart of cellosolve, so if you need an ounce, let me know. An ounce goes a looooong way.
Author:  Dave Livermore [ Sun Dec 19, 2010 12:11 pm ]
Post subject:  Re: Is this a witness line? If so, how can it be fixed?
There won't be any witness lines from spraying....
because that's what I was praying for at church this morning.
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