What Is A Bonding Agent? When Would You Need To Use It?
Used For Fortifying Or Strengthening Hypertufa Recipes Or When Adding One Layer Upon Another Layer
If you are adding another layer of ‘tufa to a partially cured, or even totally cured layer of hypertufa, then you will most definitely want to mix in some bonding agent into your recipe. In addition, if you want a relatively easy way to strengthen your hypertufa recipes, then the use of a bonding agent is an acceptable way to accomplish that.
A bonding agent is pretty much what I’ve just explained … it’s a substance or additive that helps make your ‘tufa (or concrete) recipe stick or adhere to an existing layer.
Commercially made bonding agents are located in the cement products isle at stores like Home Depot or Lowe’s.
A DIYer’s “Homemade” Bonding Agent
Since commercially made bonding agents can get a bit pricey, many frugal do-it-yourselfers have discovered that Elmer’s brand White Glue or Wood Glue can be substituted with great success (and again, you’ll save a little money, too). The basic chemistry of the Elmer’s brands is almost identical to the commercial bonding products.
Amount To Use In Your Hypertufa Recipe
The amount you’ll need to use is not set in cement (not to make a pun!) but in general … for every 10 cups of dry mix ADD approximately ¼-cup of bonding agent. I highly suggest you add it into the water that you’ll use to moisten your dry mix; make sure to mix the liquids together very well.
NOTE: I’ll mention that it has been reported amongst concrete crafters that the maestros “Little and Lewis” use Elmer’s "Carpenter’s Wood Glue" as their bonding agent. I’m just passin’ along some tips!
Your main concern is that whatever product you use, it must be WATER soluable. Do not use urethane glues such as “Gorilla Glue”. You’ll have very bad results because urethane based glues expand as they cure.
The only other step you want to make note of if you’re using a bonding agent is to first thoroughly WET the surface of your hypertufa object before you apply the new layer. Hose it down or spritz it well with water … get it really wet. This helps your new layer adhere even better.
That’s about it! There’s nothing complicated about using an additive of this type.