What Does Primer Do for Paint? More than You Ever Realized

As I’ve been building my miniature dollhouse, I’ve wondered what does primer do for paint? I mean, is it really necessary? Does it “do” anything — other than give you a white surface to paint on? And, if you check around the Internet, you’ll find that other miniature dollhouse builders are kind of divided. Some say yes, others say no (of course).

Sure, I’ve painted my house before (the inside) but, I haven’t always primed first. Of course, I’m working on drywall, not a miniature dollhouse kit. And, in a miniature dollhouse kit, we’re generally talking about unfinished wood surfaces — but not always.

So, what does it all mean? Do you use primer when you paint a dollhouse? Can you safely skip it? What about those two in one primer paint combos?

What Does Primer Do for Paint?

Other than give you a nice, clean, white surface to paint on, what does primer do for paint? Plenty. Priming your surface, whatever that might be does a lot to help your final paint job. Primer can:

• Seal cracks and pores in unpainted surfaces
• Cover imperfections
• Give the paint something to stick to
• Block out stains and odors
• Makes it so you use less tinted paint 

That’s the easy stuff. There are, of course, other reasons why you should (and should not) use primer on your miniature dollhouse.

When to Use (And Not Use) Primer

Believe it or not, you should not use primer every time you paint. An obvious example is if you’re using an all in one paint and primer product. You can probably skip the priming in that case. However, there are plenty of other situations when you should and should not use primer.

What does primer do for paint on unfinished wood?

Like I said above, primer helps seal wood, so the tinted paint doesn’t seep into pores and cracks. Even if your wood piece looks pristine, it’s still got pores and cracks. This is especially true on unpainted wood (like the kind you’re likely to find in a dollhouse kit). 

The first coat of paint, no matter what kind of paint it is, is going to be absorbed by the wood. That’s just the way it works. There’s no reason for you to waste your tinted paint on that first coat. Starting with a layer of primer allows said primer to absorb into the unfinished wood, letting you use less tinted paint.

Using a primer on unfinished wood also gives you a brighter, truer color when you use the tinted coat. When you paint the final color directly on the unfinished wood not only is some of the tinted paint absorbed into the wood, so is the color. However, starting with primer lets you create a neutral, white surface to paint on (like a canvas) allowing the true color of the paint come through.

For example, here’s what happened when I tested some blue on my dollhouse without priming the surface.

And here’s what the blue looked like with a coat of primer.

I know the lighting isn’t spectacular, but wow. What a difference. In fact, that blue is so bright, I’m glad I added grey.

What does primer do for paint on MDF?

Medium-density fiberboard (MDF) is very common in dollhouse kits. It’s popular in dollhouse kits because MDF is easy to work with and easy to detail. The problem with MDF, though, is that it swells when you add water. I doubt you’ll be watering your dollhouse (though, I wouldn’t judge you if you did). However, if you use acrylic paints (like me), know that those paints are water-based. And, if you add water to MDF, well…

So, you should either seal or prime the MDF with an oil-based primer or sealer before you paint. I suppose if you’re using oil-based paints, you could skip the primer. But, priming will help keep the water (or moisture) out of your dollhouse and help stop the house from warping.

Suddenly, some of the other how to paint a dollhouse tips I’ve read make sense. There’s a whole group that says “don’t prime” or “don’t use too much paint” because you could cause the pieces to warp.

Obviously, too much paint is bad because, well, it’s too much. But, now I get why people worry about warping. It’s not about the paint, per se, as much as it is about the type of paint on the type of wood.

That makes more sense!

What does primer do for paint during a drastic color change?

Sometimes you inherit a dollhouse. Good for you! But, it may not be decorated to your tastes. Perhaps the bedrooms have eggplant purple paint. Side note, my real-life house had a wall like this. My tastes and the previous owner’s tastes are, well, different.

Let me tell you, it took a lot of paint to cover up that purple. In fact, I think it took at least two coats of primer. 

And that’s what primer is good for. Drastic color changes. It doesn’t matter if you’re going from dark to light or dark to darker, you need to prime. Once again, you’re creating a neutral canvas that allows your color to be true. If you skip the priming, no matter what color you choose, your paint will always have a slight eggplant undertone.

Unless you go with eggplant. In which case, you’re probably fine.

What does primer do for paint when you’re painting over other paint?

If you’re painting over something that’s already painted in a light color, you might be able to get away with skipping the primer. But, that’s only if it’s a light or neutral color and doesn’t give your chosen color an odd undertone. Do a test patch first to make sure you don’t end up with weird undertones. 

However, painting right on paint also depends on how good the existing paint job is. If the paint is in good shape, feel free to skip the primer if you want. However, if the paint is chipped, cracking, or peeling, you need to repair those problems first, then prime, then paint.

Also, if the paint you’re going over is an oil-based paint or a glossy finish, you’ll need to prime. Part of the reason people use oil-based and glossy paints is that they’re easier to wipe off and keep clean. Why are they easier to wipe and clean? Because they are less sticky.

Don’t ask me to define “less sticky.” I looked it up and can’t find an answer. I’m sure it’s got something to do with how the paint dries, what resin and binders are used, etc., etc. But, I couldn’t find any “good” information on it. (Side note: future post about paint ingredients on its way.) 

The important point is that glossy and oil-based paints won’t allow your tinted paint to stick as much as you want. Therefore, you should always prime these kinds of surfaces. In fact, you should use a bonding primer. Bonding primers stick to the glossy surfaces and create a “sticky” surface for your tinted paints. 

What does primer do for paint with regards to stains and odors?

Hopefully, no one is smoking or spilling red wine in your miniature dollhouse. But, stranger things have happened. So, you can use an odor and/or stain blocking primer when you want to paint or repaint your dollhouse.

On that note, I’ve noticed that my dollhouse kit was a bit prone to stains while I was assembling it. Even though it’s a brand new kit, sometimes my hands were a bit wet (or something) when I assembled the pieces, and I ended up with a stain. A good reason to prime, if you ask me.

Should I Prime My Miniature Dollhouse?

There are, of course, other reasons to use primer, like on exterior wood, on new drywall, and so on. However, since these scenarios don’t generally apply to miniature dollhouses, I’m going to skip them. If, for whatever reason, you’ve used drywall in your dollhouse, please let me know in the comments. I have questions for you.

The real question is, should you use primer on your miniature dollhouse?

The answer is: maybe. It depends. 

If your dollhouse meets any one of the reasons I’ve outlined above, you should probably use primer. But, if it’s a brand new dollhouse (kit or DIY), you might be able to skip it, depending on the wood.

My suggestion is that you should always conduct a patch test first to see what happens to your tinted paint. Then, if you aren’t happy, prime away. The exception to this is if you think you’re going to stain your wood (like floors or trim). In that case, don’t prime. You’re asking for trouble.

Prime Time

I did prime my dollhouse inside and out before I painted. I did not prime the window frame pieces, and I think that worked out. The stairs are MDF. Honestly, I’ve been testing paint colors directly on the MDF. Now, I think that was a mistake! But I can still prime the rest.

So, that answers all of your “what does primer do for paint” questions. I hope.

Just in case you’re a visual person (or don’t want to reread the whole article), below is a cheat sheet.

Thoughts? Have any of you used all in one paint and primer? I’m curious what your experience is with that and, in general, priming dollhouse pieces.