Jimmy,
Called em - Yup, all nitro. Good suggestion - it pays to be sure!
-Mark
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| Question for the repair guys - Witness lines in lacquer http://w-ww.luthiersforum.com/forum/viewtopic.php?f=10101&t=18654 |
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| Author: | Mark Tripp [ Thu Sep 04, 2008 10:35 am ] |
| Post subject: | Question for the repair guys - Witness lines in lacquer |
Hi guys and gals, I recently acquired a Collings dread that has had a top crack repaired. The repair is sound and the crack tight and cleated. But there are witness lines in the lacquer running the length of the crack. The finish was not sanded through to bare wood, but the lines are quite noticeable. Can I hit this with some retarder and then spot spray the area and rebuff? Is there another way I should go about this? Should I just live with it? TIA, -Mark |
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| Author: | Barry Daniels [ Thu Sep 04, 2008 11:13 am ] |
| Post subject: | Re: Question for the repair guys - Witness lines in lacquer |
Are you sure its lacquer? What you are seeing is likely not witness lines but the edge of the repair's overspray. A photo would help. |
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| Author: | Mark Tripp [ Thu Sep 04, 2008 11:35 am ] |
| Post subject: | Re: Question for the repair guys - Witness lines in lacquer |
Thanks Barry, Yeah, Collings finishes with lacquer. I'm pretty sure it's not overspray - It looks more like a layer was sanded through. It only shows up in the right light, so it might be tough to get a photo that shows it clearly, but I'll try and get one today in between binding jobs. I FP all my guitars, so lacquer is a bit of a mystery to me! Thanks, -Mark |
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| Author: | Jimmy Caldwell [ Thu Sep 04, 2008 11:40 am ] |
| Post subject: | Re: Question for the repair guys - Witness lines in lacquer |
Mark, You may want to call Collings and check on that finish. I seem to remember reading somewhere that Collings is using nitro for the top couple of coats only. The finish under that may be a type of catalyzed urethane. It's almost impossible to repair without witness lines if the surface of the catalyzed finish is compromised. I may be totally wrong about this, but a call to Collings should clear it up. |
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| Author: | Mark Tripp [ Thu Sep 04, 2008 11:43 am ] |
| Post subject: | Re: Question for the repair guys - Witness lines in lacquer |
Jimmy, Called em - Yup, all nitro. Good suggestion - it pays to be sure! -Mark |
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| Author: | Rod True [ Thu Sep 04, 2008 1:07 pm ] |
| Post subject: | Re: Question for the repair guys - Witness lines in lacquer |
I wouldn't say that it's a witness line as lacquer is an evaporative type finish which burns into each previous layer to form one layer of finish (just like shellac) so there are no bottom layers to create a witness line. What you are seeing is probably the crack in the finish. I would try and drop fill the area with lacquer and let it cure for a week or more. Than level the area with a razer blade (round the corners first though) and than level sand the area. The lacquer should burn into the original finish and fill the crack to make an invisible repair. Whiteish haze, or a chalky look in lacquer is called blushing and it is caused by water or moisture in the lacquer while spraying or spraying in colder temperatures. If this is what you have there are two ways to fix it. First is with a spray on blush remover, this will "pull" the moisture to the surface and flash it off of the lacquer. Don't rub it or anything, just spray on the blush remover. Second you could use some DA (as you FP you will have some of this), put some on a pad, swipe it over the area **DON'T RUB IT** one pass and leave it to flash off, repeat till the blushing is gone. I don't think this is your problem but thought I'd throw it out there just in case. When the crack was repaired, was there no repair done to the finish? Doesn't sound like it. Once you've figured out if it's a crack in the finish or blushing from moisture and have repaired, buff to match the rest of the top. |
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| Author: | James W B [ Thu Sep 04, 2008 5:37 pm ] |
| Post subject: | Re: Question for the repair guys - Witness lines in lacquer |
Rod I`ve heard drop filling mentioned many times,exactly what is this procedure? James W B |
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| Author: | Rod True [ Thu Sep 04, 2008 7:19 pm ] |
| Post subject: | Re: Question for the repair guys - Witness lines in lacquer |
Drop filling is basically using some item like a toothpic, thin paint brush, piece of bamboo skewers, dipping that into the can of lacquer and dropping the "drip" onto the void what ever that may be. Be it a crack, a low spot after level sanding, just drop fill the lacquer, let it cure and than scrape and sand flush. |
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| Author: | Howard Klepper [ Sun Sep 07, 2008 8:40 am ] |
| Post subject: | Re: Question for the repair guys - Witness lines in lacquer |
A photo would help, but I'd say that you are very unlikely to improve things with drop filling. |
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