Ask Eli - Using A Hair Dryer On Drywall Repairs?

Question:

Can I speed up a sheetrock repair by blowing on the drywall mud with a hairdryer? - JR

Answer:

Yes you can use a hair dryer or a heat gun to dry the mud on a sheetrock repair faster.  It is best to let the repair dry a little slower, but if you are in a hurry you can use a hair dryer or a heat gun to speed up the process.  When drywall mud (or joint compound) dries it shrinks a little, and if you dry it too fast it can sometimes crack.  This is fine and won’t hurt anything, but it does mean you will have to fill the crack with more mud. I prefer a hair dryer to a heat gun. The heat gun puts out hotter air but the hair dryer puts out more air. More air movement with heat will dry it faster.

Here are some suggestions for speeding up the drying process:

I would suggest using a setting compound or hot mud if the joint compound needs to be thick. Using a hairdryer on regular joint compound that is thick can dry the surface of the repair while the joint compound beneath it is still wet. The wet joint compound will continue to disperse the moisture through the dried compound over it. This could end up making your repair take longer to dry fully. The wet mud underneath can also shrink when it finally dries leaving your repair indented. If you need the joint compound to be thick you should either use hot mud or give it plenty of time to dry completely

With hot mud you do not need to use a hair dryer or heat gun to speed up the drying process.  Hot mud does not dry, but sets up like concrete.  It also does not shrink which means it needs fewer coats. For a smaller repair I like to use a 20 minute setting compound which means it starts to set up in 20 minutes. You don't have much time to work with it but then you can get the job done fast.

Regular drywall mud has to dry, which means that the moisture in the mud has to evaporate out for it to harden.  By heating it up with a hair dryer, you can speed up the evaporating process. Don’t ever leave a hair dryer or heat gun running unattended! I have seen people prop them up against walls or on chairs.  Once I even saw someone use masking tape to tape a hair dryer to the back of a chair and leave it running while he went and worked on something else.  If you can’t hold the hair dryer then find another method to speed up the drying process that is safe.

If you need a repair to set up faster and you can’t stay and hold a hair dryer, there are some other options you can consider.  One is to use a space heater.  Set it on the floor below the repair and pointed at the wall.  The heat will hit the wall and then go up it.  I don’t recommend putting heaters on chairs because the vibrations created by the fan motor can sometimes cause them to move around and they could fall off.  You can decide if it is safe in your situation but I cannot recommend it here. 

If you don’t have a space heater you can also use a fan to speed up the drying time.  Air movement will help dry the repair almost as fast as heat will.  If there is no air movement, then when the moisture evaporates out of the mud it will prevent more moisture from evaporating behind it.  If the moist air is constantly moved away from the repair then moisture can constantly be evaporating out of the repair.

A hair dryer is an excellent way to speed up the drying process on a drywall repair.  It is a method that I sometimes use myself.  Just make sure you are doing it safely.

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