Friday, July 15, 2011

Protective Wax Finish for Plaster of Paris


So you've finally finished your plaster of paris masterpiece and would like to give it more of a finishing touch... If you like, you can give it a nice finish and a little protection with this simple turp + wax solution....

Final result of this finish : a solidifying more durable waterproof finish that when buffed produces a smooth waxy sheen that can be further enhanced with oil based paints after...

Final Result : buffed and ready for further oil paint finishes or to be left as is...

If you'd like to learn how to make your very own simple Plaster of Paris model first, check out this post!..

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5 Materials

  1. White candle wax (unless you'd like to try a more colourful effect). I used about 2.5 in x 3/4 in (diameter) candle stick, which covered the top and sides of a 5 in x 3 in x 1 inch sculpture...
  2. Distilled Turpentine - this is used in diluting the wax..
  3. Double Boiler - I would just use an old tin can for the inner pot, for it will contain the wax + turp solution. Not something you want in pots for food, besides the inevitable waxy residue that will be left behind... The outer pot just needs to be big enough to comfortably contain the tin and boiling water....
  4. Old Big Brush - use a brush you don't mind ruining (it would be hard to remove all waxy residue after) and depending on how large your sculpture is, a larger brush ensures faster application of the solution. 
  5. Only 2 ingredients (Wax + Turpentine)
     and a few simple tools are needed...
  6. Oven - to warm your sculpture, preparing it's surface to readily absorb the wax + turp solution. The size of your oven will limit the size of sculptures that can be done with this method...
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....a precautionary note before we begin

Warning
Take Extreme Precautions when handling turpentine near fire (turpentine is Highly flammable). 

Protective gear is always a good idea, especially a mask to protect against fumes.


Needless to say.. Mature Adult Supervision is Required.. :)

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5 Steps

1. Place your plaster of paris sculpture in the oven to warm up (as specified earlier this is to prepare its surface to readily absorb the wax + turpentine solution).
Note* ... Your sculpture has to have thoroughly dried out already or any moisture still retained in the sculpture will get trapped under the wax finish.

The sculpture will be quite hot so
be sure to have some oven gloves on hand


2. While the sculpture is warming up, de-solve the wax in turpentine on a double boiler (about equal parts of each). Do not use direct heat!

Break up the candle stick in to the tin can. 

Pour equal parts of Turpentine in with the broken candle stick.
Best to do this away from the stove...

Boil the water. Only a shallow amount of water is needed..

Once the water starts boiling bring the heat down and place the tin can (already filled with the turp + wax) in to the pot of hot water....

Gently stir the melting wax. Once the wax has completely diluted you can turn off the heat and quickly proceed with the next step.


3. As soon as the wax has melted, remove the plaster sculpture from the oven and place on newspaper near the wax + turp dilution.

Place the sculpture as close as
possible to the heated solution.
This is so the solution can be as hot as possible
when being applied to the warmed sculpture.


4. .... Working fast use an old brush to brush the liquid solution over the plaster sculpture. The solution will absorb quite readily in to the warm plaster. Apply till you feel it to be equally and quite fully saturated. 

Applying the heated solution on to the warmed sculpture which absorbs the solution like a sponge....  

You can then warm the sculpture in the oven again and repeat the process several times till your satisfied 
(I repeated it 3 times). I stopped when the surface began to show signs of being less absorbent... Then leave to dry.

Saturate ever part till the surface gets less and less absorbent.


5. When dry (cool), buff with a soft cloth, the surface will give off a smooth sheen. (if you like the matt look, feel free to skip this step)

Buffing surface with a soft cloth.

And thats it!

Now depending on the look your going for, you can leave it as it is, or rub different coloured oil paint on to the surface to achieve varying effects.. My fav is a raw umber + ultramarine combination which gives the sculpture a nice ivory look.
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As always, I'll be glad to answer any questions or correct any discrepancies found.. just leave a comment!

 Thanks for Visiting!.. :)

p.s View the Dragon Eye Underpainting this sculpture was used as reference for here!


23 comments:

  1. Can I use acrylics instead of oil-based paint after applying the wax coating? I'm making a miniature dragon and I'm on a bit of a stump on what to use.

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    1. Hi kurogitsune110, This wax finish is oil based and applying waterbased acrylic paint on top would not be advisable as the paint will not adhere well or last..

      My advise would be to completely skip this wax finish and just go straight to painting your plaster model with acrylic!.. Acrylic is also great as a finish, it's just different!.. The plaster will probably be rather absorbent at first but you can add more than one layer of paint and finish off with an acrylic gloss medium layer for a glossy effect... Have fun and good luck!.. :)

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  2. Regarding the acrylic finish - I have a bare plaster piece that will ultimately be sprayed a matt olive drab. As the piece will be handled often, I would like to harden up the easily damaged plaster before the final coat of OD green. I used plaster for the job to keep the weight at a minimum but now I want an M&M-tough outer shell. Do I get to do this? Lost in the wood here.

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    Replies
    1. Normal 'painting' acrylic paint will not give the hard coating you require.. I'm afraid I'm not sure of any coating that would give you the protection you need, my only guess is to use a car paint finish of some sort which is usually extremely durable,.. I've never tried this before so you'll have to test this out first to see if it works... Sorry I couldn't be of more help.. All the best to ya! :)

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  3. hi, my POP model is attach with marble plate so what precaution I have to take while heating and applying solution or I can use wooden plate to fix my model on wall.?

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    Replies
    1. Hi Nirmal, forgive me if I misunderstand your question, but what I think you'r asking is that you would like to heat your POP model while it is attached to a marble base and what precautions one should take.. Depending on how your model is attached to the marble, I would consider any expansions or contractions of the fixtures holding your model on to the marble that may occur during heating and cooling down. My guess is if they have been fixed in the model internally, this might cause cracks to occur to the POP model, but this is all speculation on my part as I do not know how you have attached your model to the marble. Applying the solution itself I think would not be a problem,.. I'm afraid I would really need to have more information to really help, and even then it would be pretty much speculation. Whenever I am unsure of how materials will react to certain techniques, I usually make small versions so as to test the results first!.. Good Luck!... :)

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  4. Dear Jacqueline,

    Thanks for your article, its very helpful indeed.
    I have one query. I have already added some pigment to the plaster so it isn't pure white. Will this white candle coating result in a whitish layer on top?
    Thanks :)

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    Replies
    1. Hi there,
      The heated turp+wax combo should soak deep into the plaster which I would estimate would result in a deeper overall tone. I don't think there would be any whitish haze at all and if there were, very slight.. The best thing to do is to test it out first to be sure the result is to your liking!.. Wishing you all the best!!.. :D

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  5. This finish is something I'm trying to do on my gypsum plaques. Your result is lovely. I'm afraid to use wax and oil paints because my plaques are shipped - would this affect the piece in that it might stick to the packaging? Also if I used acrylic wax as you ha e mentioned above would it have the same lovely translucent look that you want to run your hands over? Thank you for your help!

    ReplyDelete
    Replies
    1. Hi there,.. The acrylic gloss is clear (yes translucent) with a more hardish plasticy feel about it than the wax and oil paint finish I'd say. The packaging wouldn't stick to the wax and oil finish anymore than it would an oil painting with the right packaging materials. Try wrapping it in something like wax or grease proof paper first (glassine sheets is what is usually recommended for oil paintings if your concerned with the packaging being safe for archival storage) before encasing your piece in any other packaging, and it should be fine... Thank you for your comment!.. Hope that helped!.. :)

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  6. Thank you so much for your response! I really appreciate it. I forgot to ask you if you applied any 'primer' down on the plaster before adding the wax. Usually with acrylic I have to do that so the solvents aren't sucked out into the porous plaster. If I used wax, which just looks amazing, I'm not sure if it will be drawn into the plaster over time. Looking at Venetian plaster sites some put a sealant down first before colour and then wax on top. Thank you so much for your help!

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    Replies
    1. Hi, well the idea really is for the wax to soak into the plaster. That is why the plaster is heated up, so that the heated wax retains it's fluidity to soak even deeper into the plasters surface.. One just keeps applying more layers till there comes a point where the plaster becomes so saturated that the wax just doesn't soak in as much. That's when you'll know it's done and ready to cool and be buffed and finished with the oil paint rub if you like!.. So no, in reply to your actual question, no primer is required for this method.. :) And your most welcome!.. It's my pleasure and all the best with trying it out!..

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  7. Hi Jacqueline, thank you for posting this tutorial!

    So I followed the steps and covered my piece with 'Pure Gum Spirits Turpentine' and white candle wax. I've got a couple questions for you..

    First, after applying the coats my plaster model now has a tan tint to it. Any reason behind this? (See Picture - http://i.imgur.com/hJw76lX.jpg)

    My last question is about the fumes, while melting down the mix it stunk up my whole apartment! I made sure to have proper ventilation, but is there any different solution to this.. like maybe a different mixture? I'm also worried that my model will now stay smelling like turpentine, it is stinky!

    Thank you for the great write up :)

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    1. Hi Blake,

      What a lovely sculpture!.. It looks just as it should after the process, with a slightly enamel look to it. I'm afraid I don't have an answer for you as to why it happens other than conjecture, but rest assure you've got it right. As to the smell of your sculpture (I'd advice ceasing the sniffing!), no worries the smell will dissipate in time just like when painting an oil.. and you're welcome!.. :)

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    2. Oh yes, no I'm afraid I have not experimented with any other mixture. Turpentine as you may well know has notoriously strong fumes and many artists do opt for less noisome alternatives. Perhaps you could try it with some other solvent, like odor-less mineral spirits (though its fumes are still noxious, so just as much precautions should be taken), but I have not tried this before and cannot vouch for its effects.. All the best!..

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  8. Hello!
    First of all, your piece is amazing - I love all the detail!
    I was wondering if you knew of any good ways to seal plaster. I was looking to make some plaster planters and was hoping to a) achieve the look or glazed ceramics if possible and b) prevent staining from dirt water over time. I'm not too worried about water being sucked out of the dirt since the pots will be holding succulents, I'd just rather them not get super dirty over time. Thanks!

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    1. Hi there, I'm glad you like it..
      I'm sorry I really do not have any experience in that area and do not have a satisfactory answer to your question. Perhaps you could hunt out some gardening sites and get some feedback from some gardening pros!.. :)

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  9. Thanks for posting this tutorial! Really helpful :)

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    1. Thanks for dropping by Hannah, glad it helped!.. :)

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  10. Hello, wonderful finish and tutorial! Just one question:what temperature should the oven be?

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    1. Hi Gina, it has been so long I thoroughly can't remember!.. As long as it has warmed through (not too hot that it starts to brown) it should be fine.. :)

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