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FP color problem on cedar top
http://w-ww.luthiersforum.com/forum/viewtopic.php?f=10102&t=12287		 Page 1 of 1
Author:  Jebarri [ Fri Jun 01, 2007 7:27 am ]
Post subject: 
Hello everyone,
I'm having a problem when I put the wash coats on my cedar tops, I am
doing the application based on the Milburn tutorial.
Anyway, when I rub the first wash coat on it soaks in (more where I first
touch the cloth down and less as the cloth dries out) and when I come
back over the aria that was dryer with a reloaded cloth it stays lighter in
color
The color doesn't seem to even out if I go over it again.



Has anybody had this problem? Any ideas on how to fix it?
It seems like if I had a way of applying a even wash coat that didn't dry up
like the cloth does I might not have this problem, maybe if i used a
brush???
Any help on this issue would be greatly appriciated
Author:  Bruce Dickey [ Fri Jun 01, 2007 9:01 am ]
Post subject: 
Jeb, I'm a nitro guy myself. My guess is you just need to keep at it and it will even out as the coats of shellac build. Good luck, how about backing off that puppy and giving us a full shot of what you are working on, looks nice, what I can see... bd
Author:  crazymanmichael [ Fri Jun 01, 2007 10:32 am ]
Post subject: 
i am not familiar with the milburn method, but i assume you mean the wash coats on the binding ledge and surrounding areas. the thinner wash coats have penetrated more than your later higher concentration coats. i don't think there is any fixing this. if you were going to use shellack you should have given the whole thing a wash coat, or have sanded back to bare wood before trying to build the finish.

i think that that is your only solution now.

Author:  Jebarri [ Fri Jun 01, 2007 11:32 am ]
Post subject: 
Bruce, I guess I'll do some experiments on a scrap and see if it goes away,
Here is a full shot with just the wash coat and one of the back with the
first bodying session (no issues on the back or sides)






Michael, I did a 2lb cut over the whole thing doing the binding/purfling
etc. first, in a single pass to avoid staining.
When I first noticed it I ended up sanding the whole top back, started
again and it did the same thing but, at least I was able to figure out what
was happening.
Author:  Martin Turner [ Fri Jun 01, 2007 11:45 am ]
Post subject: 
The top will look a bit patchy in places after wash coats. Nearly always happens with my spruce tops. Once a few body sessions are completed things look fine.

Youre probably already doing this but before applying wash coats to the top run around the bindings with a few coats of shellac to seal off same and prevent dark coloured wood bleeding onto the spruce top.

Author:  crazymanmichael [ Fri Jun 01, 2007 12:52 pm ]
Post subject: 
well, there goes my theory.
Author:  SimonF [ Fri Jun 01, 2007 3:47 pm ]
Post subject: 
Is it possible that you have some residual glue on that area? If you are
positive that is not the case, then you should be fine.
Author:  Colin S [ Fri Jun 01, 2007 8:40 pm ]
Post subject: 
It'll almost always be patchy for the first few coats on the top. I have literally just finished the FP on the Italian spruce top on my new OM (I like to glue the bridge on and do an initial set-up so I can tune the top thickness before I FP it) and for the first few coats that looked patchy but now after the bodying and glazing it's just fine. I'd keep going with the bodying. If your still not happy, it's the easiest thing in the world to sand it back and start again. My guess is you won't need to.

Colin
Author:  Jebarri [ Sat Jun 02, 2007 4:41 am ]
Post subject: 
Thanks everyone for your help.
I have already sanded back the top and, it seems it would be a evener
application if I used a brush to apply the first wash coat, (maybe I'm wrong).
Hopefully what Martin and Colin said is the case but... just to be safe would
brushing it on work?
I would test it on a scrap first but just wanted to know if there were any
foreseeable issues.
Thanks
Author:  KenH [ Sun Jun 03, 2007 3:30 pm ]
Post subject: 
I had a similar situation with a walnut back and FP. The darkened stains didnt go away until about 2 weeks after I finished the guitar. I had left it hanging up like yours for those 2 weeks with the back facing away from me and when I picked it up again, it was gone. I still cant explain why it looked like that or why it stained. I am glad it dissappeared though!
Author:  Jebarri [ Mon Jun 04, 2007 10:01 am ]
Post subject: 
Ok, after I sanded it back I brushed on the first 2 wash coats, now there
aren't any noticable spots
Thanks for all your help, GREAT FORUM!
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