Last Updated on November 18, 2021 by Kimberly Crawford
Does putting latex over an oil-based primer work or not? Latex is a type of paint that is linked to other examples such as vinyl styrene and water-based acrylic paints.
The “latex” moniker roots from the artificial polymer chains with behaviors similar to natural latex, so they’re more like latex-like paint. You can alternatively call latex paint as acrylic paint (although they’re not necessarily the same).
Usually, oil doesn’t mix with water, so the results of mixing oil-based and water-based paints should be terrible, right? Not necessarily. Regarding whether you can use latex paint over oil-based primer, you should keep on reading. It’s quite a fascinating topic.
Can you use Latex paint over oil-based primer?
Latex paint over oil-based primer is perfectly fine. The disaster usually happens when you apply an oil-based paint over latex, which really won’t mix real well at all. If you wish to use latex paint over an oil-based primer then make sure to prep the surface in a proper manner.
If not, like in the case of stickers, the paint won’t stick properly due to all the dirt and roughness. You should buy a bonding primer of prime quality. Afterward, allow the primer to dry completely after application. On top of that, apply up to 2 coats of latex paint.
What is an oil-based primer?
Ostensibly, manufacturers make the oil-based primer using oil mixed with paints. Many painters and homeowners apply such primers on bare wood or unfinished exteriors due to their unique property of sealing the porous (holey and water-absorbent) wood grain surface.
This in turn enables the paint coat layer to better cover the surface altogether. They also keep tannins released by wooden surfaces such as redwood and cedar from bleeding or going through the paint surface, which results in an even and flat primer surface ideal for finishes.
Related: Can I Use Exterior Paint Inside The House?
What is Latex paint?
As discussed above, latex paint is water-based paint like acrylic paint with chains of artificial polymers but it is not outright acrylic paint. A manufacturer usually makes latex paint from acrylic resin just like with acrylic paint, hence the connection between them.
However, latex differs enough from acrylic that you’re recommended to use latex over acrylic when painting large surfaces or areas, like a wall or the ceiling. Why? People purchase latex in much larger quantities when compared to common acrylic paint. No, it’s not because latex dries slower.
Reasons to use Latex over an oil-based primer
Before anything else, here’s your friendly reminder to prep your surface to be painted before applying the paint over the oil-based primer. If you want the latex to stick, clean up that dried primer properly. Otherwise, expect to flake and cracking from wrongly applied latex paint.
This is quite costly and not worth the wasted effort. Once the primer is prepped, you’ll end up with a latex paint application that’s commonly exceptional in its finish. You won’t get bumps, stuck dirt, or roughness as long as you properly do the necessary preparations.
Rules for painting over oil-based paint
First off, prep the surface. Smoothen out the surface before putting on the oil-based primer by sanding the surface with sandpaper or a sander depending on how rough it is. Allow the paint to dry with loads of ample drying time. Be patient. Don’t rush it.
Sand down rough surfaces, apply the paint, let it dry completely, and then apply a new layer and let that dry completely.
Also, like with anything, apply multiple thin layers instead of basting a thick layer of slow-drying paint over the surface since it’s more practical that way. Be methodical and plan out your time between application, drying, and prepping layer per layer of paint.
What kind of primer to use over oil-based paint?
The best kind of primer to use over surfaces with oil-based paint on it is known as “bonding primer”. Usually, you add them to the surface with old oil-based paint over them rather than new surfaces painted with a fresh coat of oil-based primer.
Manufacturers have formulated the bonding primer in such a way that even water-based latex paint can stick to glossy or old painted-over surfaces.
You could add a bonding primer to the oil-based paint primer to really make that acrylic or latex paint stick, but usually, you don’t need to as long as you prep the surface with proper sanding. If it’s old paint, the bonding primer becomes a necessary step to paint over the surface because it’s not easy to sand down or prep a surface with old paint on it.
What to do if my walls have oil-based paint?
First off, rub denatured alcohol on a cotton ball over a small area of the surface to check if it’s oil-based or water-based. If the paint comes off, it’s latex or acrylic. If it doesn’t, it’s oil-based. If you’re painting over a wall with old oil-based paint on it and not a fresh oil-based paint primer, the rules have changed.
You need to use a bonding primer to prevent chipping and peeling this time around since it’s not a freshly applied primer and you can only smoothen out the surface so much. The primer is formulated to ensure that the latex paint will stick to the surface. For best results, mix prepping and sanding with putting on that bonding primer layer.
How to paint Latex over oil-based paint
You should remember the following points and directions when painting latex over oil-based paint primer.
Equipment
Use a paint sprayer, roller, or brush to apply the oil-based primer and water-based latex paint.
You should also have a sander or sanding machine as well as sandpaper of rough to smooth grit available.
You will sand the surface for the primer then sand the primer-applied surface for the finishing two (or more) layers.
Materials
The acrylic or latex paint can be something like The Home Depot favorite “Glidden Premium” or similar.
You can choose between three types of latex paint. They include Alkyd-modified latex, vinyl-acrylic mix latex, and 100% acrylic. We also recommend KILZ Original 1 gallon oil-based interior primer and sealer.
The best primers have sealing properties to them to keep the porous nature of wood from affecting the latex finish. You might also have to buy bonding primers if you’re painting over old oil-paint surfaces with a new latex paint finish.
Instructions
Apply the primer. You know it’s applied properly once the former paint color or surface is completely covered.
Smoothen out the applied primer once it dries for good measure with sandpaper. Apply about 2 coats or more of water-based latex/acrylic paint.
You also have the option to apply the bonding primer between the oil-based primer and the acrylic primer in case you’re dealing with oil paint or you have spare time.
Oil-Based Primer vs. Water-Based Primer
Water-based primer is recommended for ceilings and walls. Oil-based primer is more for woodwork, metal, windows, or doors.
Water-based primer is typically the primer recommended for latex or acrylic paints because the same or analogous types of paint tend to bond together better compared to, say, oil-based primer with an acrylic finish.
You should use enamel paints when dealing with oil-based primer, prepped surfaces, or no prepped surfaces. However, as this article showed, it’s possible to mix oil-based primer with a water-based finish as long as you can sand down the surface or add a bonding primer over old paint.
Enamel serves as a hardier paint for surfaces that get worn down or exposed to outside elements.
Conclusion
Choose them carefully and never forget the importance of adequate surface prep once you apply the oil-based primer, from drying to smoothing things out.
Applying the latex paint over a smooth oil-based primer typically results in a durable, strong surface that can last a long time, even if you’re painting exteriors and whatnot. The application involves sanding the surface, putting on the primer, sanding the primer-applied surface, and applying the final latex paint by about 2 layers to make a proper bond between layers.
References:
- Applying a Primer Coat Before Painting, January 13, 2020, https://www.thebalancesmb.com/importance-of-primer-844651
- Choose the right primer, https://www.truevaluepaint.com/paint/interior/prep_cleanup_and_safety/choose_the_right_primer.aspx