I have a question for step 3. A 25% w/w solution would be 25% sodium silicate and 75% water, correct? Also, once the inside of the tube is rinsed, is the excess that is poured out unusable for the future, or can you continue using this to coat more tubes?
Edit: A fun fact! Now that you are done and have all of this calcium chloride left over, you can use it to make pine cone fire starters That Burn Blue!. That is what I will be doing with my leftovers .
Step 3. get a cheap 1 qt pitcher, put in 1/4 of the volume with Skylighter (the only one I used) waterglass. fill the rest with water and stir well. Get a cheap plastic pan and pour the 25% solution into the tubes over the pan as some of the tubes will leak. Fill all the way to the top of the tube. After a few seconds pour solution out of the tube. Repeat for up to 100 tubes. After the tubes are dry rinse with plain water to remove the salt from the tube.