You don’t need another post telling you how to do drywall repairs yourself; there are already hundreds, and tons of videos to. I want to tell you a few reasons why that repair you did, didn’t turn out looking so sweet after all. It’s about light, shadows and mud. For the purpose of this article drywall “compound” and drywall “mud” are interchangeable.
When it comes to light, the angle makes all the difference. If the wall faces the window, then that wall is getting perpendicular light from the window – light is hitting the wall at 90 degrees from the window. Picture a crash test car hitting a brick wall – the car is perpendicular to the wall. Repairs are less noticeable when light hits them straight on.
If your repair wall is beside the window wall, then the light is parallel, or closer to zero degrees. Picture a car scraping a steel guardrail beside the highway – the car is parallel to the guardrail. Any imperfections you have in your repair will cast a shadow when hit by parallel light making them stick out like sore thumbs. This is the situation in the picture shown above when the walls are square to each other.
So how can you prevent ugly repairs on parallel walls ?
1- Feather out your repair compound more
2- Don’t over sand
3- Use the right compound in the right order
Feathering means that each time you apply another coat of compound, you extend it a littler farther than the coat you’re covering. That way you smooth the repair over a larger area to alleviate the bump where the problem was.
Except for the repairs that I have seen that were never even sanded before painting, most people tend to over sand thinking they can make the repair smoother and less noticeable. Instead what happens is that they get a crater look because the repair is softer than the wall surrounding it, and gets gouged out.
So here’s something that should help you avoid problems – knowing how hard the compounds are and when to use them. The first coat applied to a repair or drywall job is typically a 5,20,45 or 90-minute drying time compound, which is mixed from powder. These are used first because they are harder and more durable. After that follows 2-3 coats of premixed “mud”. You should start with the harder compound and work towards the softer, each time covering a larger area. If you try and sand a harder compound that has been applied over a softer, and the application is smaller, your sanding will produce an island of harder compound because the softer compound under it will sand away faster.
This can also happen when you use a spackling or repair compound from one of the small tubs you can buy to fill cracks and holes. If you apply it onto a larger area of finishing mud, it will sand slower and remain while you wear away the other mud.
So save the repair compound for cracks and nail holes and not for filling pinholes where bubbles have formed in the last application of your mud. To fill the pinholes, just water down your compound a bit more so it’s a little runny.
Even more obscure…
As a Handyman I often get small drywall repairs as part of my homeowner’s list. It’s not uncommon to perform repairs in a few hours instead of the few days it would be nice to have. I once replaced a section around a pot light, taped, applied two coats of compound, sanded and primed the repair in 2 hours! The secret there is 5 minute compound and a heat gun to speed the drying. One thing to look out for though is fiberglass mesh. I stuffed a hole with it once and coated with compound. While using the heat gun, the mesh started to melt and bubble in the repair. In that situation a bit of drywall or something less flammable would have been better to stuff in the hole and save my work from getting wrecked.
Following these simple tips should have you repairing those drywall mishaps like a pro!
Fixitgary.com offers quality home repairs and workmanship in Markham, North York, Thornhill, Richmond Hill, Aurora, Newmarket, Stouffville, Uxbridge, Pickering, Ajax, Whitby.