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Homework: Magic setting compound comes in a bag

When preparing to plaster drywall, consider a product

When preparing to plaster drywall, consider a product that you can mix yourself. Credit: iStock

Regular pre-mixed drywall compound that comes in a bucket at home centers is not your only choice when you finish drywall. You can purchase a similar product you mix with water at home. It sets up much faster than pre-mixed compound, and it offers a great alternative if you need to make fast repairs. It's both a joint compound and topping compound in one product.

Pre-mixed compounds that you've probably used before get hard as the water leaves the material. It's much like paint. But think of the dry joint compound much like you do epoxy. You mix the dry compound with water and you start a simple chemical reaction that allows the compound to get hard in as little as 20 minutes.

This magic in a bag allows you to tape, second coat, third coat and sand drywall in less than four hours. So start to finish, you can completely finish new drywall and have it painted in just eight hours.

DEGREE OF DIFFICULTY: Three Hammers out of Five

Step One: The magic bag of powder is dry-setting joint compound. It's made by the same companies that manufacture the pre-mixed joint compound you see in boxes and buckets. This setting compound comes in different set times from 20 minutes up to 90 minutes.

Step Two: If you've never used these fast-setting compounds before, start with the one that sets in 90 minutes. You'll need that time to practice.

Step Three: Stop and read all the written instructions on the bag. Follow them to the letter. Pay close attention to the part about retempering or adding water to the compound as you're working with it. These dry setting compounds don't react to additional water like the pre-mixed compounds do. You can't add water to the dry setting compounds once they start to stiffen up.

Step Four: The first time using this material, only mix up about one quart. That's not much. You should practice with this on a scrap piece of drywall. With a little practice, you'll get the hang of it.

Step Five: Mix the product with cold water to start. Warm or hot water will cause the product to get hard faster. You can use this trick once you master how to apply and finish it before it hardens in your pan or bucket. Mix it to the consistency of warm cake icing.

Step Six: You use this product exactly as you would pre-mixed joint compound. You just need to be aware that you should only mix as much up as you can use in half the time it says on the bag. If you have purchased the compound that sets up in 45 minutes, then you only mix up as much as you can apply to the wall or ceiling in 22 minutes.

Step Seven: One of the benefits of using this compound is that it can be wet-sanded. It can be finished much like hard-coat plaster or concrete where the compound is troweled as it's getting hard. This means there's no need to have dust clouds swirling around inside your home caused by endless sanding of traditional joint compound.

Step Eight: The wet sanding or troweling process requires practice, as you must do this at a specific time when the compound is hard enough to react to the pressure of the trowel, but not so hard as it's completely set up. It's just something you have to experiment with. If you mess up, no worries as the dry-setting compounds can be sanded like traditional joint compound. In fact, they have one that's branded as Easy Sand.

Summary: These dry-setting joint compounds are ideal for rapid repair projects that have to be done in a day or less. Try using them and keep a bag on hand in case of an emergency. Keep the bag sealed tightly and store any opened bag in a cool, very dry location so humid air doesn't invade the bag and cause the material to harden in the sack.


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