When I spackle, I'm always eager to start painting, so I'm always checking back impatiently to see if the spackle is try yet. The problem is that it can be hard to tell, and I'm often tempted to try sanding it down before it's really dry. If you've ever tried this you will know that it makes a mess of both your sandpaper and your spackle job. My first tip is a great solution to this problem.
Tip #1 - Buy the spackle that starts out pink dries white, so that you can easily tell when it's dry!
I have spackled many times over the years, and my next tip is something that it took me a long time to learn. You see, I was taught that the appropriate tool for spackling is a putty knife, and that one with a wider blade is better. It is true that a putty knife with a wide blade (at least 4") is a great tool for smoothing out the spackle, but I know of a much better one for applying spackle in the first place. And best of all, it's free!
Tip #2 - Apply the spackle with your finger (especially for nail holes and other small patches).
Using your finger enables you to push the spackle right into the hole that you're trying to fill, without getting it all over the wall around the hole. You will have to rinse your finger off afterwards, but spackle is water-soluble, so it's easy to clean off. Apply your layer of spackle, and then run the putty knife over it once to clean off any excess.
Wait until it's dry (no longer pink!), lather, rinse and repeat. Unless it's a very small hole, it will probably take 2-3 applications of spackle to fill it so it's flush with the wall, because spackle shrinks a bit when it dries. That brings us to our next tip.
Tip # 3 - Apply several layers of spackle if you need to fill a hole more than 1/4 inch (about 0.5cm) deep.
Spackle is cheap, and that's a good thing given my next tip. Spackle that has started to dry out, or that has bits of dry, crunchy stuff (like dried plaster or bits of paint) in it is terrible to work with. The same goes for a putty knife with bits of dried spackle or other crud on it. This tip will hopefully prevent this problem.
Tip # 4 - Never ever put spackle that you've scraped off of the wall back into the tub of spackle.
Wipe it off the blade of the putty knife with your finger or a cloth, and throw it out or wash it down the drain (water-soluble, remember?). Also, be sure to wipe off the blade of your putty knife whenever the spackle on it starts to dry, or when it gets crusty. Otherwise when you clean off the excess spackle with the knife, you won't end up with a smooth surface.
If you're patching a larger area, you may want to sand between layers of spackle to remove any imperfections in your previous layer (due, perhaps, to laziness in cleaning off the putty knife) before adding more spackle. However, following these tips will minimize the amount of sanding you will have to do, and the number of layers of spackle that you will have to use. It's still a good idea to give your spackle a quick sand before you paint it though. But, after the sanding and before the painting, there is an important step that you must not skip.
Tip # 5 - Always prime over spackle before you paint.
If you are not planning to prime a wall before you paint it, and there are just one or two little nail holes that you need to patch, you may be inclined (like me) to skip priming all together, and just get on with the painting already. You must resist this urge. You don't have to prime the whole wall, but you do have to prime anywhere you have spackled. Unless I'm painting over a dark colour, spot-priming is usually what I do for areas that have been spackled, and anywhere where there's a stain that might leach through to the next layer that I can't clean off.
If you don't follow this advice and paint without priming, when the paint dries you will be disappointed to discover that the sheen (how shiny it is or isn't) will be different where there is spackle underneath the paint. This sounds like it might not be that noticeable, but it really is, so save yourself the hassle of having to prime over the new paint and then paint again over the primer, and spot prime over any spackled areas before you paint.
Please share your spackling tips in the comments section! For tips on choosing paint colours while you wait for your spackle to dry, check out this post.