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Watching paint dry
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Author:  Spyder [ Thu Jul 28, 2016 12:17 pm ]
Post subject:  Watching paint dry
Well, the finish on No. 1 was going very well. Got it wet sanded down to 2000, polished by hand with two grits, and it was looking pretty good. Reflections of lights had fairly clean lines, no orange peel. Still a touch hazy, but not bad. So I was ready to try some power buffing to polish out the rest of the way. Can't wait to string this thing up!

Then I looked close. Sections of the back were covered with tiny pinprick marks it picked up from laying on a towel. AAAAGH!!! [headinwall]

In the pics, you can see where I was after one round of hand polishing. Then I zoomed in the photo, and the little imprints showed up. Finish is spray lacquer over a shellac seal coat. It has been curing in the shop for a week and a half now, temp 77, humidity 43%. And still too soft.

Oh well, I figured patience would be a virtue when I started this, but I never figured on waiting this long for, well, paint to dry. Any ideas on how long I need to leave it this time? Another week? Is there a way to tell without taking a chance on leaving more imprints? Suggestions and sympathetic gripes welcome.
Author:  Rodger Knox [ Thu Jul 28, 2016 12:25 pm ]
Post subject:  Re: Watching paint dry
That's not even close to long enough. You need to wait at least three weeks after spraying lacquer before you wetsand, and longer is better.
Author:  kencierp [ Thu Jul 28, 2016 12:40 pm ]
Post subject:  Re: Watching paint dry
Quote:
That's not even close to long enough. You need to wait at least three weeks after spraying lacquer before you wetsand, and longer is better.


And if its brushing/brush on lacquer even longer.

I think there are many that no longer or do little wet sanding since it tends to soften the coatings.
Author:  Joe Beaver [ Thu Jul 28, 2016 2:16 pm ]
Post subject:  Re: Watching paint dry
I hate it when that happens. To a great extent finishing remains a mystery to me.

What kind of a lacquer finish did you use?
Author:  Don Williams [ Thu Jul 28, 2016 3:08 pm ]
Post subject:  Re: Watching paint dry
You're best off to let it cure for a solid month, and then another week or so after the first wet sanding before you proceed with the rest of the wet sanding, and then wait again at least a week then buff it out... and leave it hanging, don't set it down on anything for a bit.
Don't rush the finish, or you won't be finished!
Author:  James Orr [ Thu Jul 28, 2016 3:28 pm ]
Post subject:  Re: Watching paint dry
Cardinal lacquer is fully cured after a week. What kind of lacquer did you use?
Author:  jshelton [ Thu Jul 28, 2016 3:59 pm ]
Post subject:  Re: Watching paint dry
James Orr wrote:
Cardinal lacquer is fully cured after a week. What kind of lacquer did you use?

Not in my experience. It took just as long as every other brand I've tried and it's way too expensive.
Author:  Spyder [ Thu Jul 28, 2016 4:15 pm ]
Post subject:  Re: Watching paint dry
James Orr wrote:
Cardinal lacquer is fully cured after a week. What kind of lacquer did you use?


I used Duplicolor automotive lacquer. I've used it before on metal parts with very good results. My thinking is if I can find a local source that works well for me, I won't have to deal with shipping charges and delays in the future. So far, the jury is still out.

But I do have it stored properly, I have a board mounted in the neck slot and the guitar standing upside down with that board clamped in my vise. Only issue I have with that is, how do I work around it for the next few weeks while I work on something else? Oh well, patience wouldn't be a virtue if it was easy to get.

But at least I'm getting good help here. I wondered how long it would take, honestly had no idea this being my first gloss lacquer finish on wood. So thanks for the input!
Author:  Barry Daniels [ Thu Jul 28, 2016 5:04 pm ]
Post subject:  Re: Watching paint dry
If it is imprinting that easily at one and one half weeks, then I doubt it will ever get hard. You will probably have to strip it off and do it again with a better lacquer.
Author:  James Orr [ Thu Jul 28, 2016 8:25 pm ]
Post subject:  Re: Watching paint dry
jshelton wrote:
James Orr wrote:
Cardinal lacquer is fully cured after a week. What kind of lacquer did you use?

Not in my experience. It took just as long as every other brand I've tried and it's way too expensive.


It's interesting that you would say that. I finished my last guitar with it, but waiting about a year to level and buff it. However, last week I leveled a test-panel after a week and it was still pretty gummy to sand. I thought it might just be the way it sands, but it didn't feel cured to me, either.
Author:  Joe Beaver [ Thu Jul 28, 2016 9:25 pm ]
Post subject:  Re: Watching paint dry
Cardinal dries very well for me. I level sand in a week, wait another week, or longer if posible, finish sand and buff. I think it is sensitive to the undercoat you use. I only spray it on the cardinal vinyl sealer.

Temp and humidity of course play a roll
Author:  James Orr [ Thu Jul 28, 2016 9:38 pm ]
Post subject:  Re: Watching paint dry
Joe Beaver wrote:
I think it is sensitive to the undercoat you use. I only spray it on the cardinal vinyl sealer.


As well as how soon you spray onto the sealer. I had a bit of a learning curve with it. Anyone who's interested can search for "Cardinal," and my user name.
Author:  Joe Beaver [ Thu Jul 28, 2016 10:19 pm ]
Post subject:  Re: Watching paint dry
I agree James. I had to do a few test panels before I was comfortable with it. It is fine stuff.
Author:  kencierp [ Fri Jul 29, 2016 9:01 am ]
Post subject:  Re: Watching paint dry
In my experience -- very slow dry/cure --- no dry/cure is the result of coating chemical incompatibility. I also saw "hazy" mentioned in the OP too. This can be caused by re-coating too soon.
Author:  philosofriend [ Fri Jul 29, 2016 11:35 am ]
Post subject:  Re: Watching paint dry
Everything everyone else said, plus I am leery of any wet sanding that could cause water to touch the shellac seal coats. I would rather use naptha than water as a lube. The naptha needs to have no oil contamination, which you can test by drying a spoonful of it on clean glass and feeling for oil. And never use turpentine or you'll have to strip the guitar to get the oil out (I didn't learn that out of a book).
There are good reasons why most everyone uses exactly the same finishing products that they fought with years ago. Learning new products can have a horrendous learning curve.
Author:  philosofriend [ Fri Jul 29, 2016 11:38 am ]
Post subject:  Re: Watching paint dry
Is Duplicolor nitro or acrylic? Either could work but don't mix types.
Author:  Mike_P [ Fri Jul 29, 2016 4:27 pm ]
Post subject:  Re: Watching paint dry
are you sure those pits weren't there originally?

because they look awfully like solvent pop pits to me, and those are caused by not allowing enough flash time between coats in general.

either way, I looked around and saw quite a few negative comments about this duplicolor product...yeah, it's cheap, and that should be indicative of many things...in the big picture how flashy a product looks is rather secondary to it's ability to last.

also, because it's an automotive product there are probably more plasticizers in it than on instrument lacquers...this is so that when a dent occurs (it is an automotive product) the paint flows into the dent as opposed to shattering off...

and then there is the query of did you use any retarder when applying the product?

if so, that can drastically affect the cure time if you went overboard and used too much...

being that it is an automotive product, there is no associated vinyl sealer to go with it...it is meant for primer, base coat, candy color coat, then clear...finding a compatible vinyl sealer (obviously NOT catalyzed) can only be done by trial and error (e.g. test panels) or by trusting another wood worker who has already done that legwork...

their website states waiting 24-48 hrs for buffing...yeah...right...YOU HAVE GOT TO BE KIDDING ME...you are using it on wood (has grain to sink into etc.) and I don't know of any air dry lacquer that is ready for buffing in 24 freaking hours...even precatalyzed lacquers take 2 weeks to fully cure (not sure about post catalyzed stuff...that's a different animal I've never dealt with)...sure, they can say ready to sand and buff all they want, those are just stupid words from the advertising branch of a big company...and their wait one week before waxing??? again, YOU HAVE GOT TO BE KIDDING ME...waxing should NEVER be done before the product is 100% cured.
Author:  Spyder [ Fri Jul 29, 2016 7:10 pm ]
Post subject:  Re: Watching paint dry
Thanks all for the input. Honestly, I am about lost on this one. I have done things, sanded/scraped back to wood and started over with something else, mixed stuff, probably a mess right now. My intention after last taking it down to wood was to seal with shellac (I mix my own with denatured alcohol), pore fill with Timbermate, more coats of shellac, then sprayed on 9 coats of the Duplicolor acrylic lacquer. To address a couple of comments:

Haze and dimples were not there until recently. Finish was very clear, no haze whatsoever after all coats applied. Haze only showed up after wet sanding, which to me says it needs more buffing. The more I buff, the more the haze goes away. As for the dimples, they were not there until I had my first round of polishing the top. And they were only in a couple of places. So I believe they were caused by pressure on the towel.

So, I think it's time to set this one aside, AGAIN. I was hoping to have it finished this summer, but looks like that ain't going to happen. Still don't know how long it will take the neck to cure, it still has Deft spray lacquer on it, and it still smells strong. I got frustrated with this project and set it aside for two years. Oh well, looks like it will have to sit for some more months.

In the mean time, I think I'm going to get back to number 2. The box is pretty much done on it, just needs the final neck carving, frets and fret board, then it will be ready to finish. My plan for it all along was a satin finish with shellac, so who knows. It might even get completed first.
Author:  dzsmith [ Fri Jul 29, 2016 7:20 pm ]
Post subject:  Re: Watching paint dry
Phil,
I browsed your website.
Your dulcimers look outstanding!
You might look into Tru-Oil as an alternate finish to shellac or lacquer.
Dan
Author:  Spyder [ Fri Jul 29, 2016 8:29 pm ]
Post subject:  Re: Watching paint dry
Thanks Dan, I appreciate that! My dulcimers have my standard finish, which is a pseudo French polish. Not a true gloss, I've never been able to quite get there. But I can get a very nice shiny satin with shellac. That's what I have in store for No. 2, as the wood on it doesn't have the figure as for No. 1.

I have heard good things about True Oil, but have never tried it. How long does it take to cure, start to finish? I'd like to try it some time.
Author:  Ken Franklin [ Sat Jul 30, 2016 3:43 am ]
Post subject:  Re: Watching paint dry
Spyder wrote:
James Orr wrote:
Cardinal lacquer is fully cured after a week. What kind of lacquer did you use?


I used Duplicolor automotive lacquer. I've used it before on metal parts with very good results. My thinking is if I can find a local source that works well for me, I won't have to deal with shipping charges and delays in the future. So far, the jury is still out.


If you like using local automotive finishes you might try Dupont Chroma Clear.
Author:  dzsmith [ Sat Jul 30, 2016 2:51 pm ]
Post subject:  Re: Watching paint dry
Spyder wrote:
Thanks Dan, I appreciate that! My dulcimers have my standard finish, which is a pseudo French polish. Not a true gloss, I've never been able to quite get there. But I can get a very nice shiny satin with shellac. That's what I have in store for No. 2, as the wood on it doesn't have the figure as for No. 1.

I have heard good things about True Oil, but have never tried it. How long does it take to cure, start to finish? I'd like to try it some time.

Phil,
I've done a few solid bodies using Tru-Oil.
I was able to apply 4 coats a day.
I probably put on 20 coats or so. What worked best for me was to apply it with a cloth, wait a few minutes, and the try to wipe it all back off. It needs to go on thin.
It smells good, and is a pleasure to apply.
It really makes figure and grain pop.
There's plenty of you-tube videos on using it.
My finish of choice is nitro lacquer because I like the mirror-shiny finish.
I have yet to make a satin finish look good, still trying.
Regards,
Dan
Author:  Spyder [ Sat Apr 08, 2017 6:38 am ]
Post subject:  Re: Watching paint dry
Hello everyone, I'm back! hard to believe it has been nine months since I was last here, expressing my sorrow over my inability to put down a good glossy finish. Just thought I'd rejoin the group discussion with a little update.

I decided to let the guitar sit for a while to cure. I figured 3 months should do it. So I clamped the false neck in a vise and let it sit in the shop while I moved on to other projects. Around early December, it looked great. Even found me a small hand held buffer, had that thing looking pretty good. Not perfect, but close enough to call it done. So I moved it into the house to keep it from getting damaged while working on some big stuff.

Last night, I picked it up again. It had sat resting against a white plastic bag, of the normal tall kitchen garbage variety. Guess what? That bag dissolved the finish. Imagine the dimples in the first photo of this post magnified many times over. In short, the finish is ruined. I will now be taking it back to bare wood and starting over.

Not even sure why I'm writing this at this point. My first guitar is now in its 5th year without completion, some sort of a sad record I suppose. Guess I am just curious, has anyone else had this problem? I will be starting over from scratch on the learning curve for gloss finishes. Does the stuff Stew Mac sells hold up better than this?

Thanks for your patience!
Author:  Clay S. [ Sat Apr 08, 2017 7:19 am ]
Post subject:  Re: Watching paint dry
Hi Phil,
If you want to do a gloss lacquer finish my suggestion would be to buy Mohawk's stringed instrument lacquer, or some other version of nitrocellulose lacquer. One reason nitro is prefered by many is it is relatively easy to apply and finish.
Did you try the Birchwood Casey Truoil? It is an oil-varnish finish that is usually ragged on. I knew a gunstock maker that used it, and after applying numerous coats built a high gloss finish with it. I have used it, building less coats, for a semi gloss finish.
Author:  RustySP [ Sat Apr 08, 2017 7:21 am ]
Post subject:  Re: Watching paint dry
Hi Spyder,
I'm sorry to read about your troubles and I'm sure it must be heart breaking.
Your post reminded me of an article I read in Frank Ford's
frets.com "Vinyl is Your Enemy".
Vinyl is a type of plastic and so are trash bags, I think that's what happened. Good luck friend.



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