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Sodium silicate, also called waterglass is an interesting compound that is used in a variety of things. It is a glue, a high heat cement or refractory, used to preserve eggs without refrigeration and sealer for concrete. My interest is to use it for a refractory in a high heat forge. It is commercially available but locally I was unable to find it in the concentration I needed. So I found some videos and information online and made my own.

I was successful, so I thought I would share my experience.

Warning, this involves using a caustic ingredient and heat so wear appropriate safety equipment, face shield, gloves and work in a well ventilated area.

Step 1: The Materials

You will need the following:

200 grams Sodium Hydroxide - commonly known as lye, you need the pure form, some drain cleaners are made from this, soap makers also use it.

300 grams Silica Gel - Found in those little do not eat packs that come with electronics, also used as cat litter.

500 ml Water

Heat Source - butane burner, camp stove, etc.

Long Stir Stick

Stainless steel bowl or pot

Well ventilated work space

Step 2: Video of the Whole Process

Here is a video of the whole process.

Step 3: Written Steps

Here are the steps:

Add the lye to the water, this will generate lots of heat and fumes, do this in a well ventilated area.

Once mixed add a little silica gel to the mixture, this will react and create more heat and fumes, stir to mix.

Keep adding a little of the silica gel at a time to the mixture until it is al combined. It is ok if the silica gel does not dissolve.

Heat the mixture over your heat source until it boils and keep stirring. If it starts over boiling, turn down the heat. Keep stirring and eventually it will become a clear thick syrup. If the silica gel has coloring in it, it may have a tint to it, which is perfectly ok.

Let cool and store. It can be diluted with water depending what your application is.

Here is the original video that I used as reference

https://www.youtube.com/watch?v=-Mx1-o1_MWo

<p>What I see commercially available is something like 40% solution... What is concentration of your end product? 100% and if so do I just add water at the end to make a 40% solution?</p><p>Thanks</p>
But! I skimmed the bits off and it made a perfect adhesive! Just barely stuck my front insulation to the inside of the lid. Thanks a lot.
Bits.
So.... I've got floating bits in my solution.
Fantastic information! I recently built a forge and I'm looking for a way to make my sodium silicate. I'm going to use it to glue the insulation to the door.
<p>What is the shelf life? Do you use it on top of high temp blanket? Does it harden when painted on?</p>
<p>To be honest I'm not sure of shelf life, I think it would be stable for sometime if you keep it out of moisture. As a refractory you mix it with an perlite, still need to experiment with it to see how well it holds up. It does dry hard but it takes a while.</p>
Are you going to use it as a refractory element in a forge? If so, how and why?
<p>I am going to use this in a foundry that I am making as an added layer of insulation between my ceramic fiber blanket and my heat source. I am going to make it into a fire brick by mixing it into sand and perlite. There are several videos around the internet that can help you figure this part out.</p>

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Bio: http://www.youtube.com/c/AndrewWorkshop
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