Friday, July 01, 2016

UNDERCONSTRUCTION ::::inexpensive rubber substitute to pour into a mould and create a part

The project to find an inexpensive rubber substitute to pour into a mould and cast a part

What an amazing search that turned into.

Here are sites and clips from the Net that offer inexpensive-casting-materials that cure into rubber-like parts.
Gak (Borax-free Flubber)   
 Pour 1 cup of white glue into a bowl. Add several drops of food coloring until it is the desired color.   Pour 1 cup of liquid starch into the glue mixture. Stir thoroughly. ...   Mix more starch in if it seems too sticky. ...   Store Gak in a container with a good lid.
    1 1/4 cup warm water
    1 cup any white glue
    2 Tablespoons of Borax
    Food coloring (optional)
    Mix 3/4 cup of the water with 1 cup glue in a bowl. Stir this mixture until it is thoroughly mixed together. Set it aside.
    Mix 2 tablespoons of Borax with a 1/2 cup of water in a separate bowl. Mix thoroughly until all of the Borax is dissolved.
    Combine the two mixtures. Stir them together. Add several drops of food coloring until the mixture is the color you want it to be.
    Put the mixture in a plastic bag with a good seal. Close the bag, making sure it is tightly closed. Knead the mixture for a few minutes and your flubber will be done. You can store the flubber in the bag you mix it in.
    1 T. white glue
    1/2 tsp. borax powder (can be found in the laundry detergent aisle of most grocery/department stores)
    food coloring
    3 T. cornstarch
    4 T. warm water
in one cup, combine the warm water, cornstarch and borax. In another cup or bowl, put the glue.

Next, add several drops of food coloring to the white glue and stir well.

Give your water/borax/cornstarch mixture a good stir to combine all the ingredients (the cornstarch has a tendency to settle on the bottom).

Then pour the water mixture into the colored glue.
Stir and you'll see it immediately start to clump together. Stir a bit more until you have one big, slimy glob.
Take the glob out of the liquid and begin rolling it between the palms of your hands to form a ball. It'll be sticky at first, so keep a paper towel handy to wipe off your hands occasionally. Soon a rubbery ball will form. (We found that just using our palms seemed to work better than using our whole hands and fingers.)

 Once the stickiness is gone and you have a nice smooth ball, that's it! You can bounce away!

The balls will flatten out after sitting for a while, but storing them in small plastic containers and then rolling them between your palms again will help the super bouncy balls regain their shape. Keep on bouncing!
    Making Gak (Borax-free Flubber)
Pour 1 cup of liquid starch into the glue mixture. Stir thoroughly. When the glue and liquid starch start to mix, they should become very thick.
 Mix more starch in if it seems too sticky. The starch is what makes the glue stretchy rather than sticky. Be aware that Gak will stick to clothes and carpets, but it comes out very easily with a little warm water and some scrubbing.

 SUPPLIES FOR HOMEMADE FLUBBER    2 bottles Elmers Washable Glue White for a total of 1 cup    1/2 Cup Water {room temperature}    1/2 Cup Liquid Starch    Glitter or food coloring optional    TO MAKE HOMEMADE FLUBBER    Mix glue and water together into one container.    Stir until it is well combined and a smooth consistency. Now is the perfect time to mix in color or glitter.    Next, add this mixture to the liquid starch in a new bowl. <

 RTV (room-temperature vulcanization) silicones
 eHow Crafts Other DIY Crafts Other DIY Projects Homemade Silicone Rubber   
 Homemade Silicone Rubber  By Alex Smith  eHow Contributor
 Silicone must be weighed precicely to come out well.  scale image by timur1970 from    For many years, silicone rubber had to be mixed and heated in very strict conditions in a process called vulcanization, and these conditions were difficult to replicate at home.

 The invention of RTV (room-temperature vulcanization) silicones has changed this, allowing homemade projects to be made out of silicone rubber. These RTV silicones can be purchased at a number of art and industrial suppliers.
 Unformed silicone rubber isn't very interesting, so you usually pour these ingredients into a mold to make a figurine or other shape. 

 Things You'll Need     Paper bucket   Scale   Silicone base   Silicone catalyst     Mixing stick   Mold, cookie sheet or other container   Paintbrush   Hand soap     Set a paper bucket onto a scale and reset the scale to zero.    
 Pour some silicone base into the paper bucket and weigh it. For the most accurate mix, you should weigh the base in either ounces or grams.   
 Add the correct amount of catalyst to the base. Most silicones use a 10:1 ratio of base to catalyst, but check the label on your silicone to make sure. If the ratio is 10:1, simply divide the base weight by 10 to determine the amount of catalyst to use. For example, 74 grams of base requires 7.4 grams of catalyst.     Mix the catalyst into the base completely. Most silicone bases are white, while the catalyst is dark blue or green, allowing you to visually ensure the two components are mixed. Scrape the sides and bottom of the bucket several times as you work. Take your time -- most RTV silicones take several hours to cure.
 Home-Made Sugru by smitty16
Sugru is a whole nother class of silicon because it bonds to most materials, and when it sets this stuff is basically indestructible.

- silicon caulk (you can get this at any home improvement store)
- A paper cup
- A plastic spoon
- Corn starch/corn flour
- Food coloring

 1 to 1.5 cups flour   0.5 cup salt   1 packet unsweetened Kool-Aid powder (more if you want a more vibrant color)   3 TBSP oil   1 cup boiling water    Combine flour, salt, oil and Kool-Aid powder. Add boiling water. Stir together. Knead mixture until it forms a soft dough. If dough is too sticky, add more flour. Mix well and play! Store in a sealed container <

  RTV Rubber Alternative Recipes?
recipe using silicone caulk that I've read on several other forums and I was less than impressed. This recipe called for:

     part GE Silicone 1
     part corn starch
    parts mineral spirits
    a few drops of glycerin
     Your standard hardware store silicone is water catalyzed, meaning it starts to cure when exposed to water, it takes very little water to cure the product, there's sufficient moisture in the air, this is why, when used in the "normal" manner, it cures from the outside in and also why if you apply a thick layer, the inside takes a very long time to cure. In the recipe you have, the cornstarch is very simply just a moisture distribution mechanism, cornstarch is somewhat hygroscopic it contains moisture that it's absorbed from the air and mixing it with the silicone caulk distributes that moisture throughout the mass of the caulk thus causing it to cure evenly rather than form the outside in. Adding a lot of cornstarch causes a rapid cure, adding less should slow it down somewhat. Experiment with the recipe a bit you might find a mixture that works better for you also, add the cornstarch after you're fully incorporated the other ingredients.
 one-part, self curing silicones like caulking and aquarium sealant.

 They are a variant of tin cure and are sold in air-tight tubes. These are further divided into two subclasses based on their catalyst:  
 Acetoxy - these are the typical ones you will find at your home centers etc. They have a strong vinegar (acetic acid) odor while curing.  
 Oxime - are referred to as odorless cure silicones and can be found in some building supply stores but are usually more expensive.   

 The biggest problems with using silicone caulking for molds is that it is rather thick and easily traps air, and that it will not cure properly in very thick applications.

 The way to solve this problem is to get some moisture throughout the silicone. You can't just mix in water, it won't mix well and you'll end up with a mess.

 The two products I have found that work best are glycerine (available at any pharmacy or in the health and beauty department of most chain stores) and acrylic (not oil) artists or craft paint.   

 Start with clear 100% silicone caulk, like GE I or GE II, or DAP 100% Silicone Caulk. Squeeze out the amount you will need into a plastic cup that is large enough to give you stirring room. For each ounce of caulk, add four or five drops of glycerine and a drop of acrylic paint.

 Use a wooden craft stick to stir until you get a uniform color trying to avoid trapping any more air than necessary.    You can use just the acrylic paint, but I like adding the glycerine because it improves the cure and also reduces the adhesive qualities of the silicone, making it easier to remove from the model. You could also do this with just the glycerine, but it is more difficult to tell when you have obtained a uniform blend.    Don't overdo it with either the acrylic or the glycerine as more than a few drops per ounce will result in a weaker end product.

 You cannot thin caulking with these materials without sacrificing a lot of the good characteristics of the silicone.    Once you get a uniform color, you have from 15 minutes to an hour before the product begins to thicken, depending on the temperature and humidity. Working in a cool dry environment will extend your application window. If you are outdoors in southern Florida, in August, work fast.   

 Adequate cure for handling should take under two hours and it will cure evenly throughout, rather than from the surface inward. Again, heat and humidity will speed things up.    I like to brush on a thin layer first, getting out all the air bubbles and making sure you have good contact everywhere. Then a thicker coat can be spatulated on. Usually about 1/4 inch works for palm sized items, but you can go up to an inch for very large works.   

 Once the silicone has cured, you can make a support shell out of plaster bandages applied a couple of layers thick. This "mother" mold will hold the flexible silicone in place during casting. Again, the bigger the mold, the thicker the mother.   

 Though it is probably not necessary, I like to give my newly made molds overnight to finish curing before I start casting in them.    If you feel you need to thin silicone caulking, xylene is the solvent of choice, but work outdoors and protect yourself from the vapors, they can cause health problems, so read the label. Mineral spirits will also work, but weaken the material and leave it with a greasy feel. Mineral spirits will also slow the cure from hours to possibly days. 

 Also, volatile solvents will result in shrinkage of the finished mold in proportion to the amount of solvent added to the silicone.    I personally like dry mold releases rather than greasy ones. For porous materials like plaster, I like to buff in several coats of Johnson's paste wax, leaving only a micro thin layer on the surface and then allowing it to completely haze over before making the mold.  For non-pourous surfaces, like glass, I take Ivory dish soap and mix it 1:3 with distilled water. Use a soft artist's brush and swish the sudsy mix over the surface of the model while drying with a blow drier in the other hand. The result should be a thin soap film that is relatively dry to the touch.  Petroleum jelly (Vasoline) will also work, but is messy to clean up. I don't like PAM or other cooking sprays. 

 Silicone sprays make great mold releases for everything EXCEPT silicone. They tend to become part of the mold and may actually increase adhesion.  Also avoid petroleum based lubricating sprays. They are messy and make it difficult to brush the silicone over the surface evenly. 

 For really difficult releases, there is a material called PVA (polyvinyl alcohol) sold in craft stores that sell acrylic casting kits used for making clear paperweights and such. Brush it on, let it dry, and then apply a thin film of paste wax. If that won't release it, nothing will. 

 PVA is soluable in water, so don't try to use the soap film for the secondary release.    When making a cast in a silicone mold, a release often isn't necessary as not much sticks to silicone, except more silicone. If you feel you must use a release anyway, silicone spray lube, soap, paste wax, or PVA will all work.  


 Ingredients:     1/4 cup flavored jello   2 tablespoons hot water   1/4 cup white school glue   1 cup cornstarch

    Dissolve 1/4 cup flavored jello in 2 tablespoons of hot water.
    Mix in 1/4 cup of white school glue.
    Add cornstarch 1/4 cup at a time. {You might not need the entire 1 cup.} Stir the cornstarch into the mixture until it becomes a sticky dough.
    Then, you will knead the cornstarch into the dough until it is the consistency you like – it will eventually become less sticky and more like a play dough. If your play dough gets too dry, add a little more water. If it’s too sticky, add a little more cornstarch. {It’s very forgiving.}

 ---------------- I tried this mold material and it is quite good, although it is sensitive to heat. In fact, you can melt it down and re-use and reform it. It feels like a very dense, foamy rubber, flexible, but quite sturdy. I tried to tear a simple mold and couldn't do it. It appears infinitely reusable.   

 If you're going to start mixing this stuff, do it when you won't have any interruptions. Don't get sidetracked or you will regret it. (Trust me on this....)    And don't try to rush things and add all the ingredients at once, or add them in another order. I paid $16 for a gallon of glycerin through my vet & wasted quite a bit.  


 RECIPE for large batch (smaller experimental batch at end of post)   
 4 1/2 pounds dry Gelatin (in flake, grainular or powder form) from a health food store.
 This is the same stuff as plain Knox brand gelatin). SMELL IT before you buy! If it smells like Jello, it's the right stuff.

 Don't accept cornstarch -- some clerks don't know the difference. 
 9 cups of cool water (2.25 qts.) 
 13 cups Glycerin (3.25 qts or 9 lbs) (check with your veterinarian) 
 1 lb. glucose (a similar product is corn syrup-- use a 16 oz bottle) 
 1 oz. Denatured Alcohol (from hardware store)   

 Put the measured glycerin into a pot over LOW heat & start it heating.
 You do NOT add it to the gelatin unheated.   
 Pour the water into a large cooking pot & add the gelatin. Start mixing immediately & keep mixing until all the water & the gelatin are thoroughly mixed together (I used my hands).

 DON'T STOP mixing or it will separate & congeal in layers. When ready, the mess should be consistent in quality. If you do have to stop, cover the pot with a damp towel.    Place the pot of gelatin over LOW heat & start stirring when it begins to melt, and keep stirring until the gelatin is all melted and free from lumps.

 Then add the heated glycerin and stir until well blended. Then add the glucose and continue to mix until it is fully incorporated.   

 REMOVE AWAY FROM THE STOVE ENTIRELY. Now add the alcohol and stir until thoroughly blended with the rest of the mixture. It is now ready to use, & should be formed while warm


 1/3 SIZED RECIPE FOR TRIAL -- it still makes quite a bit

1.5 lbs gelatin
3 cups cool water
4 1/3 cups glycerin
1/3 lb glucose (corn syrup is a good substitute - use 1/3 of a 16 oz bottle)
1 Tablespoon denatured alcohol

How to make silly putty with corn starch - Know About Life

How to make silly putty with corn starch2014-08-22

PlatSil Gels - Polytek
> Polytek's PlatSil

How To Make Slime with White Glue and Borax | GAK ------------------------------------------------------

How To Make Slime with White Glue and Borax | GAK

In one bowl mix 1/2 cup (4 oz) glue and 1/2 cup water. Add food coloring if you want colored slime. In the other bowl, mix 1 teaspoon borax with 1 cup water until the borax is dissolved. Add the glue mixture to the borax solution, stirring slowly.

6 Recipes to Make Slime for Kids! - Tip Junkie › Crafts

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Making slime using white craft glue, food coloring and borax on this Kiddie Craft on Emmymade. Subscribe: ...

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Slime Party - Elmer's Glue Borax Recipes - The Lab › Home › Experiments

Steve Spangler Science

Just vary the quantities of each ingredient to get a new and interesting batch of goo. This recipe is based on using a brand new 8 ounce bottle of Elmer's Glue. Go ahead… add a drop or two of food coloring. Measure 1/2 cup of warm water into the plastic cup and add a teaspoon of Borax powder to the water.

Liquid Starch Slime Quick and Easy Slime - Little Bins for Little Hands

Nov 26, 2014 - Have you ever wanted to make slime but thought it was hard? Our liquid starch slime recipe is so easy and quick. Perfect slime for science and ...

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Jun 17, 2015 - Borax slime is an easy way to make homemade slime for sensory science play. Our 3 ingredient borax slime recipe will have you making cool ...

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Follow this easy-peasy homemade slime tutorial for some serious fun in the kitchen! ... This is a fun project for kids, just supervise and make sure they're old ...

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Jun 13, 2013 - For the simplest of all slime recipes, all you need is cornstarch. Just dump some into a bowl, add some water, and start mixing. Keep adding . ====== Make a silicone mold from common household materials in your kitchen in 1 hour ====== How to Make Play Dough | Science Projects - YouTube ===== How to Make Modeling Clay at Home


glycerol (ordinary drugstore variety) and 12.0 g (4 tsp) gelatin

Combine 3.0 g (1/2 tsp) glycerol (ordinary drugstore variety) and 12.0

g (4 tsp) gelatin (ordinary supermarket unflavored gelatin) with 60 mL

(1/4 cup) hot water. You can feel free to experiment with adding

small amounts of food coloring, as well, if you would like.

[This formula can be scaled up for larger amounts.]

Mix all of the ingredients together in the amounts above, and stir.

Keep mixing until there are no clumps, and heat the mixture to 95 C or

to when it starts to froth (whichever comes first). Stir the mixture

while you are heating it, and once it is at the right temperature (or

starts to froth), remove the heat and keep stirring. Scoop out excess

froth with a spoon, and make sure there are no clumps.

Pour the hot clear liquid (in the bottom of the mixture) directly into

molds of the desired size and shape. When dry, remove the objects from

the mold and trim as needed.