Archive for January, 2003

resin to fiberglass ratio

January 29th, 2003 No comments

resin to fiberglass ratio

A strong, affordable and easy to use casting material for artists body casting

If you casting in plaster or professionally or as an amateur, you've probably been using plaster of Paris or gypsum plain more solid cement such Hydrostone, Hydrocal or even the system very strong cast Forton MG.

All these materials have their advantages and specific use. Like me you've probably discovered that Forton MG is by far the most robust material and it has indeed become the norm in the body casting life casting and industry allowing artists to make songs sound and light.

However Forton casting system is a property and as such is quite expensive. artists casting life three major cost centers: alginate, casting material and advertising … Keep your costs down without compromising quality must be high on the priority list of all professional studios. So I experimented with various alternatives to costly system and Forton now set at a casting mixture which is much cheaper, almost as strong and in many respects, easier to use than Forton.

My formula
I have been using a mixture of PVA glue diluted in water as a sealant for some of my pieces. It occurred to me that if I was soaked with this mixture of plaster I could get a cast material with new properties, always curious to find better, cheaper, faster ways of doing things, I experimented with plaster of Paris and with the mixing ratio Hydrocal different but have since settled with Hydrostone.

I mix the PVA glue with water at a ratio of one to one and soak in the volume of liquid, a maximum of two volumes of Hydrostone. I mix gently by hand and then mechanically for 5 minutes as you would for Forton Hydrostone or plain.

It is easy to mix and you'll quickly get a smooth paste. I never had the small lumps often appearing in a mixture of Forton. Overall it is easier and faster to mix Forton.

The pot life of the slurry is just 5 minutes … is more than sufficient to apply a first coat, even in a large pan. mix with water is very cold slow your curing time. A second batch can be mixed and applied immediately. I paint on the alginate or silicone mold. It is a pleasure to work with. It is much heavier and sticky than anything else, I was used before.

My Parts are constantly arising from a very high quality with none of these air bubbles exasperating pin holes, cracks or fine, "runneth" that the casting materials are often more liquid production. One troublesome aspect of Forton when casting a mold is that alginate is flowing nearly half an hour after you have often a very thin layer of the first specifically on the vertical part of the mold .. This first layer is very fragile and sometimes crack when applying the second layer, especially when the skin does not hold well in alginate mother mold. No problem, for example with this formula. The mixture is much creamier than plain or Forton Hydrostone and you can easily create a layer thick, even against vertical walls or overhanging parts and cons undercuts. I was able to throw a torso while 15 minutes where a similar mold would have taken me over an hour with Forton. Several times, when the fiberglass reinforcement is not necessary, I was able to distribute in a single layer.

Demolding time is approximately two hours. As the plaster it as warm as it cures and is fully developed when he cooled again. full strength is reached after 24 hours and it is fully cured in a few days depending on humidity.

I could not test the comparative strength for the lack of a suitable test rig and methodology. It can obviously be strengthened fiberglass to increase the impact resistance as you would with a casting Forton.

Show simple test that he will become as resistant to scratches Forton once it has fully healed.

Cost Comparison
This is my formula that really shines and completely surpasses Forton MG.

22 kg of powder GSF Forton (modified Hydrocal) and 10 kg of resin VF812 will cost me $ 497 here in New Zealand. This is including the required amount of the accelerator but excluding any other agent.

To make a batch equivalent of my formula I need to buy 22 kg of standard Hydrocal and 5 liters of PVA weatherproof (I use Aquadhere Selley, in the United States a similar product is Weldbond.) There is no need for an accelerator and not everything that costs me $ 146.

Weight for weight my formula is more than 70% cheaper that Forton. Since you will probably use a little more material you would Forton, probably 60% cheaper. This is still an economy highly important. You can report these savings to your customers and become more competitive or chose to increase your margins, in both cases, it will be a positive effect on your results without compromising the quality and robustness of your product.

Other use.
The skilful sculptor will immediately Another use of such material. If you build silicone molds around the mother or urethane molds, this recipe will build thinner, mother molds lighter and stronger much faster than using standard plaster of Paris and much cheaper and much faster than using Forton.
This is probably not appropriate for casting small hollow because it is too sticky to be slushed a mold. It is also too thick to be poured into a narrow mold. But it can be done runnier reducing the rate of mixture of 1 to 1.5 instead of 1 to 2.

Same so modern PVA glues are often advertised as waterproof and weatherproof, I would still use a good paste modified Forton Works designed for permanent outdoor display.

For all other applications, it will be very easy to implement within a open mold, it does not work on the side walls and can be grown in small towns like fingers or nipples.

Do try … You'll like it. I am no longer using Forton, but for most jobs and where weight is concerned.

On author.
Olivier Duhamel is a sculptor specializing in New Zealand bronze figurines. It is also the name behind the studio casting Bodyscape life and the author of the very respectable " Boobs Casting Manual ", published title = "">. This article may be freely reproduced, provided it is not modified and that the paragraph is included. Forton MG is a registered trademark of Forton BV, Netherlands. Hydrocal, Hydrostone are registererd trademark of USG Corporation

About the Author

Olivier Duhamel is a New Zealand sculptor specialising in bronze figurines. He is also the name behind the Bodyscape life casting studio and the author of the very respectable “Boobs casting manual” published on This article can be reproduced freely on the condition that it is not modified and that this last paragraph is included.

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