Yes you can, however it will not be truly water proof.  If you want the best article on varnish types look at Jackies (it is in the article section of the site)  She did a fantastic experiment with different varnishes to see what happened over time.

Thank you for the replys >
I read Jackies article , about the varnish experienced.
Thank you Jackie , i found you did a wonderfull job , of investigation .
I want to cover Rita , with a good varnish , wich one is the one , almost everybody uses .
She is going to be indoors ,and i want to sell it ,so i realy want to use the right product .
Some of the finish i give her on the scales , is a product called Patina (this comes in diferent tones ),and another thing called BETUN DE JUDEA , for and antiquing look .
My brushes first i washed them with soap and water and then i had to use solvent .
So i am a little scared , of using the wrong varnish.
The products i described , the names are in Spanish , they are like a wax , and they smell like turpentine.
Is the first time i apply this to something , but they look very nice .
I am willing to receive all the advices .
Thank you again .
Maria .

Thank you Jackie :

I would do as you said .I mentioned the patina of betun de judea , are you familiar with this ? And if it last enough ?
Is your Elephant in your book ? do you make it with chicken wire ?.
I realy wish i could learn how to be good with the wire .
The books i have , i wish they have more step to step pictures , and tricks of how to bend it .
Gracias .
Maria .

Jackie:
I try to bought your book , but Pay Pal does not work in CR , is any other way ?
Thank you .
Maria .

I'm glad you have managed to purchase my e-book now Maria.

If anyone else has any difficulties, just let us know.