Top coat over shellac


trz
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So, I've sprayed two coats of amber shellac on my bookcases. Why shellac? Because I've never worked with it before and wanted to try spraying some! Amber, because two coats gave me just the color I wanted.

Now that that's done should I top coat it and if so with what?

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Bookcase = something durable

 

New to spraying = something easy to shoot that’ll lay-down well

 

From previous posts, not a lot of oomph at the tip = something that atomizes fairly easily

 

 

I’d shoot pre-cat solvent lacquer

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==>And I would wipe on some poly.

Excellent choice... I would have gone that way, but figured he wanted to keep spraying... Of course, the other advantage of a catalyzed lacquer – you can finish the project in an afternoon and have books on the case the next day... Wipe-on poly/varnish/etc -- it's another week or so... The upside of poly -- spraying bookcases can be a bit of a challange...

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Correct you are, I would like to keep spraying, I won't be putting any books on them for awhile, so drying time is not an issue.

I'll have to look into the water based poly and the lawuer options. Mot sure which would be better for a noob sprayer to start with!

Again , thanks

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Based on your other spray threads... WB isn't in the cards until you up your air supply... Solvent-based, shellac, et al are about your only options... Shooting poly is absolutly out of the question...

 

==>drying time is not an issue.

Not so much dry time, but cure time... It normally takes three weeks to a month for wipe-on varnish/poly/oil blends to cure... No cure = no books.

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I have a couple bookcases and a few other pieces that I only finished with shellac.  They are holding up fine (through plenty of use and 2 moves).  

 

 Is there a reason you are looking for a different topcoat?  Shellac has been used for a long time with nothing (save some wax) on top. If you want a different sheen you can sand it a bit with 600 or something, or just apply some wax, and buff to the sheen you want.

 

Additionally while many people report not having issues applying another finish on top of waxed shellac (which is what Zinnser Amber is), there is at least a theory that another finish will not stick well.  I usually buy the seal coat or mix my own, so I can't provide any experience to that notion.

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==>I wanted the amber color!

Amber Transtint: http://www.amazon.com/TransTint-Dyes-Honey-Amber/dp/B001DSZ4MM  added to dewaxed is the ticket -- a couple drops is all you need...

 

On wax, lacquer bites into just about everything... But if it worries you, shoot a coat of dewaxed over it, then topcoat...

 

As for shellac alone -- yea, it tends to be aok for decorative bookcases, but if you take/remove books frequently -- say a student -- then shellac won't hold up... The scratches will [mostly] be hidden by the books, so it's up to you... One thing, shellac takes between a week and a month to cure.... and no cure = no books.

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==>I wanted the amber color!

 

 

On wax, lacquer bites into just about everything... But if it worries you, shoot a coat of dewaxed over it, then topcoat...

 

 

 

Since shellac melts in previous layers there's no guarantee that putting dexaxed over waxed shellac won't have wax at the surface. Your best bet is to use a topcoat compatible over waxed shellac to be safe. Poly does not like waxed shellac but I've heard that Waterlox will work just fine over it. Personally I like to plan ahead and never use waxed shellac if something is going over it. 

 

But like Josh said, shellac will be a fine finish for a bookshelf and will be ready to use the next day. 

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\ One thing, shellac takes between a week and a month to cure.... and no cure = no books.

 

That is some good advice.  Dry does not equal cured.  I built a small gaming table and sprayed it with amber shellac (from flakes).  I put it into service after a couple of days and right away it sctratched a little.  But since then, no new scratches and it has been surprisingly durable and water ring resistant.   If it were my bookshelf, I'd wait 2 weeks, put it into service, and if in a year you are finding it is not durable enough, you can scuff sand and top coat.  

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==>will be ready to use the next day.

No it won't... Been there, done that -- doesn't work. It needs time to cure prior to adding books. I learned that the really hard way...

 

==>melts in previous layers there's no guarantee that putting dexaxed over waxed shellac won't have wax at the surface

True, but it's more like 'bite-in' not 'melt-in'... The top layer really will be the new coating... That's the point of barrier coating and locking-in color layers... Can some wax make it to the top -- maybe... Is it likely at all? No.  But the point is well taken --- plan the finish schedule in advance and pick compatible finishes...

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Original plan was to only use the shellac , but the decided to throw it out here to see if it was "better" to top coat it! If it isn't necessary Ill be satisfied with the shellac and save the experience top coating with other products for another project.

Hopefully by then I will have a better sray system.

I do need to smooth the shellac out a bit cuz it's a little rough!

The book shelves are more of a home library where my wife can put her hundreds of books, so they won't be moved on and off the shelves frequently.

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  • 5 years later...

@Kezzie, shellac is prone clouding from moisture, are you seeing white-ish rings or clouds where the vase was?  If so, these can sometimes be removed with warm air, as from a hair drier on a medium setting. Failing that, shellac is relatively simple to repair, as a new coat "melts" into existing coats. You would only need to sand away the damaged area, not the entire surface.

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Sanding with a high grit, 400 or higher and very light pressure.  Then with a folded pad of old tee shirt wipe on the shellac to kind of feather or blend the wet shellac into the finish.

If it were me I would want to do this with shellac made by mixing de-waxed shellac flakes and denatured alcohol, not a can of store bought shellac.

This is a pretty simple repair for a pro and I wouldn't think it would cost to much, so if you are uncomfortable with any of the information above you might take it back to the shop that restored it.

Shellac is a beautiful finish but you need to use a trivet under anything that can let moisture to get on the finish.

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  • 2 weeks later...
On 6/7/2015 at 11:35 AM, Trip said:

Based on your other spray threads... WB isn't in the cards until you up your air supply... Solvent-based, shellac, et al are about your only options... Shooting poly is absolutly out of the question...

 

???  Can you elaborate on this?  I am pretty new to spraying and I have shot several cans of Varathane WB Poly through my LVLP gun using a compressor with less than 7 cfm capacity. No thinning. No Problem. Good results.

Dang! I just noticed the age of this thread. Oh well. Maybe someone can clarify.

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19 hours ago, Wimayo said:

???  Can you elaborate on this?  I am pretty new to spraying and I have shot several cans of Varathane WB Poly through my LVLP gun using a compressor with less than 7 cfm capacity. No thinning. No Problem. Good results.

Dang! I just noticed the age of this thread. Oh well. Maybe someone can clarify.

You have to chase down the specific trz posted at this time in 2015. Try searching his posts. I don’t own 7 CFM and run roofing guns in summer. I’d have to upgrade to spray most things. 

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