The caulk you need to use depends entirely on where you’ll be using it, and what your goals are for the project. The most common use is to keep air and water out, but there are many types of caulk that can get the job done.
Clean up first
Before you can start installing new caulk, you need to clean the surface. That means not only removing dirt, and any other particles present, but also completely removing any old caulk in place.
A caulking removing tool or a wire brush will be vital here. You’ll then want to place masking tape on either side of the surface to ensure a straight edge, but be sure you remove it immediately after applying your caulk.
Now your surface is ready to sell, but you’ll need to prepare the tube of caulk first. The size of the bead you apply depends on how you cut the nozzle on the caulk tube, so do so carefully. Then, puncture the inner seal on the tube with whatever you have handy.
A stiff wire works great. You can now insert the cartridge into your caulking gun and begin sealing. Be sure to apply even, constant pressure to the gun’s trigger so your caulk will exit the tube at an even rate.
Smooth it out
Let’s face it, if this is your first time using a caulking gun, you probably won’t apply the caulk completely evenly and perfectly. That’s OK. Even pros need to smoothing tool, or their finger, to ensure the bead of caulk is smooth and clean.
To fix any mistakes that were made along the way, be sure to smooth the caulk two to five minutes after application. It needs to set slightly, but letting it set too much makes it impossible to smooth out.