Shellac as Sealer and Final finish

[mrsamimi]

Hello Everyone, 

 

I am learning from multiple forums here that Shellac is a perfect sealer/finish for almost all surfaces. I am building OCcre Santisima and the hull is Sapelli wood and love the natural color of it so I am going to apply 2-3 coats of clear Shellack and sand in between.

 

My only concern is, I am hearting Shellac has durability issues compared to varnish, like exposure to heat and moisture but wondering for a model ship, we dont out them next to humid areas or extreme heat anyways! Any advice/feedback/experience on Shellac durability issues?

 

Thanks in advance!

[Snug Harbor Johnny]

  I favor shellac in many applications for wood, as shellac has been a proven wood finish for hundreds of years.  Varnish can be durable as well, but can be subject to 'crackling' over time if applied too thick.  Models (and electronics) should be kept in an environment that a human is comfortable in.  Too much heat (as in an attic) can be ruinous.  Cold is not as much of a problem, but accumulation of dust should be avoided - and there are a few ways of doing that, either on display or in storage.

[mikiek]

Just be careful. Shellac and Varnish can be mentioned in posts but can also be very generic terms. Many types of shellac, many types of varnish.

 

Whatever you think you want to use, always try it on some scraps of the material you ultimately want to cover. Your decision at that point should be easy.

[paul ron]

whethere you use varnish and/or shellac, keep in mind its a static model, not furniture thats exposed to usage and needs a protective finish. our ships get a nice finish to look pretty.

 

imho, I'd use one or the other, not both. shellac is alcohol based, varnish is oil based (or water based).. each has a different hardness when cured. the different types can present separation as it ages with expansion and contraction of the wood due to seasonal humidity changes and the difference between how each finish reacts to it.

 

the first thined coat of whatever you use is the "sealer" coat. it penetrates the very surface of the wood to help keep grain from raising and sealing the softer part of wood so it wont soak more than the harder parts in the grain... this will help give an even finish coat. you'll lightly sand between the sealer and finish coat to ultimately allow the final coat to self level evenly.

 

 

Edited February 12 by paul ron

[wefalck]

Not sure, why people differetiate between shellac and 'varnish'. Shellac can be used as a varnish among other applications.

 

A varnish consists of some material that form a continuous coating, e.g. a resin or a oxidising oil, and a solvent that allows to apply this material and vaporises after application.

[paul ron]

well the term of finishing, "varnishing" or "shellaking," has changed over the years and became synonymous although they are chemically different.

 

shellac is a natural excretion of a bug, varnish is made of other resins and has also evolved to polyurethane made of polymers refered to also as varnish. maybe this link can describe the differences.... 

 

https://www.hgtv.com/how-to/home-improvement/what-s-the-difference-between-polyurethane--varnish--shellac-and

 

regardless of what you use, id rather not mix finishes.

 

[wefalck]

The problem is that people confuse 'materials' with 'applications'. A lot of materials can be used for the same application and a lot materials can be used for different applications.

 

Shellac can be used as a cement, as a varnish, as a binder in paints (with pigments added), as sanding sealer (with pumice added), for seals, etc. etc. 

 

I fully agree and have repeatedly said so in this forum, that mixing varnish- and paint-systems can lead to trouble unless you really know what you are doing.

[François de Saint Nazaire]

In France we use Wood filler ( call Fondur) it is an impregnation that penetrates the pores of the wood and follows its dilatory movements. Therefore, it does not crack. The final appearance is a soft satin. Depending on your needs or preferences, you can leave it as is or cover it with a wax or shellac finish

[wefalck]

Again 'fonds dur' is an application, that can be achieved with a variety of materials, such as shellac plus pumice (the basis of classical 'French Polish'), nitrocellulose plus pumice, acrylics plus something as filler etc.