Issues with Shellac Finished Hull

[mrsamimi]

Hello Everyone, I am building Occre Santisima Trinidad, I used Shellac, Zinsser Bulleye Sealcoat and applied 4-5 coats as sealer and finish for the mahogany hull, I love the outcome, Let each coat dry for 4-6 hours and final coat for 3 days.

 

The issue I am facing is, after setting the model upright on Occre workbench, Although the cloth is soft, after a day it left some marks in finished Hull, can be seen like a missed spot or worn off, where the pressure is applied, what should I do? Is this normal? Should I apply another coat or two and let it dry longer? Or should I use Poly or maritime Varnish on Shellac, my product is wax free so I think you can apply any Varnish finish on it, anybody else experienced something like this?

 

Any help or comment would be appreciated!

[AON]

I think you need to sand those spots, finishing with very fine grade sandpaper (320 grit), and after a through cleaning, re-apply the shellac in those areas.

 

[mrsamimi]

Thank you, the problem is, it happened again, I still have quite a lot of work left on masts and sitting the model upright will cause the same thing, Can I prevent this? Is this normal with Shellac or I am doing something wrong?

[RossR]

I have use shellac and never experienced anything like that.   I use shellac flakes dissolved in denatured alcohol, so I can’t speak to the premixed shellac.   You may be able to brush some alcohol the spot.  Shellac should dissolve and then brush the shellac to “fill in” the area that appears to be missed.  I would test it on some scrap wood first.  

[bruce d]

1 hour ago, mrsamimi said:

Hello Everyone, I am building Occre Santisima Trinidad, I used Shellac, Zinsser Bulleye Sealcoat and applied 4-5 coats as sealer and finish for the mahogany hull

To be clear, did you put on the Zinser first or the shellac?

Edited Friday at 09:59 PM by bruce d

[RossR]

I assumed Zinser was the brand of shellac   please ignore my previous advice if is a product other than shellac.

 

[palmerit]

I’m no expert, but is the shellac new? I’ve been reading that it can “go bad” in a year. 
 

I’ve used some recently that bought a year ago and after applying it’s gotten tacky, unlike before. I’m switching to using flakes next time, dating my jars and making them in small quantities. I’ll see if that helps. 

[Y.T.]

Either the Shellac you have is too old so will never dry up. This substance is organic so can be after its best before date a few years OR  you applied way to many layers of thick Shellac and they are unable to dry up. 

[mrsamimi]

Zinnser is the brand, I purchased it two weeks ago, so it is nee but I kept it in a transparent plastic container between coats , maybe that is the reason! Never really hardened apparently maybe it is a bad batch

 

it is this

 

https://a.co/d/0NGGNJb

[Loracs]

This is great... at least you are not dealing with multiple product interaction.  I would try with @RossR suggestion.  Try to reproduce it on a scrap wood and then see if it can be solved that way.  Far less risky than trying to fix on the ship first.

Edited Friday at 11:01 PM by Loracs

[mrsamimi]

Gurus, if I have bad Shellac ir too thick of a layer, of course on option is to clean up with alcohol and reapply, but Can I sand down with 600 grit and reapply? Or has to be cleaned with alcohol?

 

I am also asking you all if a final coat of Poly can fix this issue and hardens Shellac and hardens itself?

Edited yesterday at 02:17 AM by mrsamimi

[RossR]

I did a little looking online and I saw some versions of Zinsser shellac it is recomended that the shellac be diluted to a two pound cut.  A 2 pound cut is pretty standard but if the shellac out of the can was heavier than that and you applied several layers you may have just applied a very thick layer of shellac that is easily damaged.  I usually apply two coats of 2 pound cut with a sanding using 00 steel wool after each coat.  It leaves a nice finish on the wood, but there is no visible layer of shellac like you would get with lacquer.

 

[paul ron]

my experiance with shellac flakes in alcohol, doing french polish on furniture, if the cut is too heavy, or too many coats, it takes alot longer to cure. the alcohol evaporates fast leaving the shellac resin behind, it will feel dry. but its still in a fresh state maybe a bit tacky for a few days but does fully harden, then i can recoat. 

 

the best thing in your favor... you can strip it very easily while its fresh just using alcohol to wipe it down. it may need a light sanding or 000 steel wool rub out. i dont do that because i dont like the residual steel wool or sand on my new shellac... i gently rub it out with my clean dry hand. my tough skin is better than sanding and doesnt gum up.

 

though my choice for ships... clear semi gloss or matt acrilic spray. it lays evenly and has a polished wax finish. not gloss, not flat... right in the middle. 

 

btw, when making shellac, check if the flakes you got are dewaxed or not. you have to let the wax settle, then skim it so you dont get wax in your batch, which makes it too soft.

 

https://kmtools.com/blogs/news/all-about-shellac-finish

 

 

 

 

 

 

Edited 14 hours ago by paul ron

[LoydB]

My shellac experience is also furniture + French polish. I can't really recommend any premixed shellac, as you are finding out. The good thing is, you can remove it easily.