Hey there, it’s Mia from [Your Company Name] – and if you’ve ever handed out tempera paint kits for a school picnic, a neighborhood block party, or a community mural project, you know the drill: people get super excited to slap paint on fences, patio stones, even old wooden benches, then panic a week later when the neon colors start fading, peeling, or turning into a blobby mess when it rains. I’ve lost count of how many customers have emailed or DMed me saying, “Mia, the kids painted our garden gate and now it looks like a sad watercolor that cried. What do I do?” Tempera Paint
Let’s cut to the chase: tempera paint isn’t technically designed for outdoor use. Most of us know it as that washable, vibrant stuff we send home from preschool, the kind that comes off walls with a little soap and water. But when you’re using it on things that get exposed to sun, rain, wind, and whatever else the elements throw at them, you can’t just leave it to fend for itself. The good news? Sealing it doesn’t have to be rocket science – and as a tempera paint supplier, I’ve tested every trick in the book to make this easy for you, no fancy equipment required.
First, let’s get one thing straight: not all surfaces are the same, and not all sealers work the same. I once had a guy come to me raving about “waxing his fence” and complaining the paint turned yellow within a month – turns out he used a furniture paste wax on a porous, weathered wooden fence, and wax just doesn’t stand up to rain. Let’s break this down by surface, because that’s the only way to get this right.
Let’s start with the most common outdoor tempera paint surface: wood. Fences, picnic tables, tree stumps, even old wooden toys that get left outside for kids to play on. Tempera paint soaks into porous wood really well – that’s why it’s so hard to get off once it dries – but the problem is the wood itself moves a little with temperature and humidity. If you seal it with something too thin, it’ll crack right along with the wood, taking the paint with it. I’ve tested two go-tos for wood, and neither is that expensive spray can you’d grab at the hardware store without thinking.
First, for bare wood (the kind that hasn’t been painted or sealed before, not even with a clear coat of its own), I recommend a water-based acrylic sealer, not a polyurethane. Wait, I know what you’re thinking – acrylic is what you use for canvas, right? Yeah, exactly. But get the exterior grade acrylic sealer, not the craft kind. The interior stuff will yellow after a month of sun, and the craft kind is too thin. Exterior acrylic is made to hold up to UV rays and moisture, so it won’t peel even if it rains a week after you seal. Now, here’s the mistake people make: they spray or roll it on right after the paint dries. Wait for 24 full hours. Tempera paint takes about an hour to feel dry to the touch, but it needs that full day to cure all the way. If you seal it too soon, the water in the sealer will reactivate the tempera, and you’ll get streaks or bubbly paint. Also, don’t put it on too thick – two thin coats are way better than one thick gloopy one. I learned that the hard way last year when I tested a batch for a local elementary school: I put on one thick coat, and the next day it was cloudy and sticky, like a kid’s candy apple. Gross. The second mistake? Skipping the sealer on end grains. Wood’s end grain absorbs way more moisture, so if you’ve painted a fence post, give that end at least two extra light coats.
What if you’ve already painted wood that’s been sealed before? Like, say you’re doing a mural on an old patio table that had a clear coat on it. Then you can skip the prep sanding (mostly) – just wipe it down with a little rubbing alcohol to get rid of any dirt or grease, let it dry, and apply the same exterior acrylic. Wait for two hours between coats instead of 24, because the surface isn’t porous anymore, so it dries faster.
Next up: concrete and stone. Stepping stones, patio slabs, even decorative concrete planters. This is a tricky one because concrete is super porous, but it also gets really hot in the sun, and cold in the winter, so it expands and contracts a lot. I tried a bunch of sealers here, and the one that works best is a penetrating concrete sealer. Wait, no – don’t use a film-forming sealer on concrete, that’s the stuff that peels off in big chunks after a couple months. Penetrating sealer soaks into the tiny gaps in the concrete, not just sits on top, so it moves with the material. I’ve had concrete stepping stones sealed with this stuff that stayed bright for two full outdoor seasons, and that’s way more than I ever expected from tempera. Prep here is key: you have to clean the concrete really well first. If there’s any dirt, moss, or loose paint on it, pressure wash it (on low setting, so you don’t etch the concrete) or scrub it with a stiff brush and a little vinegar and water. Then let it dry for at least 48 hours – concrete holds moisture, so if you seal it even a little damp, the sealer won’t work. And for concrete, do three light coats, not two. I tested this last summer with a group of teens who painted a whole concrete wall for a community art project, and they did two coats and said it looked good, but by fall a few spots were faded. We added a third, tiny coat, and it’s still bright this year. Pro tip: don’t use oil-based sealers on concrete. They yellow like crazy, and they’re hard to clean off if you accidentally get them on your shoes.
Then there’s metal. Outdoor metal – like garden gates, old bike frames, metal planters, even playground equipment. Tempera paint on metal is a little weird because it doesn’t stick as well as it does on wood or concrete, so sealing it is extra important. First, you have to prep the metal. If it’s new metal, wipe it down with rubbing alcohol to get rid of the manufacturing oil. If it’s old metal that’s got rust or flaky paint, you need to sand it a little to rough up the surface, so the paint and sealer stick. For metal, the best sealer I’ve found is a rust-inhibiting exterior acrylic sealer. Wait a full 48 hours after the tempera paint dries – metal doesn’t let moisture escape, so it takes longer to cure. And only do two coats here, because too many coats will make it slippery if it rains. I once did a metal garden gate for a customer who wanted her kids’ art on it, and she told me last month that even after a heavy rain and a week of 90-degree sun, the paint is still bright, no peeling. That’s a win.
Now, what do you do if you’re on a budget? A lot of people don’t want to buy special sealers, especially if it’s a one-time project like a block party mural. I’ve tested DIY options too, and some work surprisingly well – but only as a temporary fix, for about 6 months to a year. The first one is diluted white glue. Wait, not the kid’s craft glue that goes on white and dries clear – that’s actually fine for small projects. Mix one part glue with one part water, stir it up, and thin it out so it’s not gloopy. Apply one thin coat, let it dry for 24 hours. It works because it creates a thin, flexible layer over the paint, so rain doesn’t get in. I used this for a church’s Easter egg hunt last year, and the eggs (painted with tempera and left outside for a week) didn’t run at all. The downside? It’s not as durable as store-bought sealer, and if it gets super hot, it can get a little sticky. Another DIY one is polyurethane, the water-based kind. But don’t use the oil-based, it yellows. Test it on a tiny spot first, though – some water-based polyurethanes can get cloudy if you apply it too thick. I only recommend DIY sealers for small, temporary projects, not if you want something to last more than a year.
Wait, I also need to talk about what not to do. Don’t use regular hairspray. I know a lot of people swear by it, but I tested that once. I sprayed a tempera-painted fence post with my daughter’s hairspray, and three days later it rained, and the whole thing ran. Hairspray is water-based and breaks down really fast when it gets wet. Don’t use clear nail polish either – that works for tiny crafts, but it’s way too expensive for big projects, and it cracks when the paint or surface moves. And don’t seal over a fresh tempera coat, even if you’re in a hurry. I get that, when you’ve got a bunch of kids waiting to paint, and it’s going to rain in an hour, but tempera paint isn’t designed to hold up to rain right away. If you have to, do one thin coat of acrylic sealer, but plan on it fading faster.
Now, as a tempera paint supplier, let me give you a few tips specific to using our paint outdoors. First, make sure you’re using our extra-vibrant matte tempera paint (that’s the line we formulated to hold a little better on porous surfaces, even before sealing). It’s still tempera, so it doesn’t have the same binders as acrylic, but it’s way more durable than the cheap stuff you find at dollar stores. Second, don’t paint in direct sun. If you paint when it’s hot, the paint dries way too fast, and it doesn’t stick as well, so sealing won’t work as well. Paint in the morning or late afternoon, when it’s cool and shady. Third, if you’re doing a big project like a community mural, come talk to us. We can hook you up with bulk sizes that are cheaper than buying small bottles, and we can even give you a sample of the sealer we’ve tested for large projects, no extra charge.
Wait, what about maintenance? Sealing isn’t a “set it and forget it” thing, at least not for tempera. Every year, especially if you live in a place with harsh winters or super sunny summers, give the sealed surface a once-over. If you see any spots where the sealer is peeling or paint is fading, lightly sand that spot, wipe it down, and add one extra thin coat of sealer. It takes 10 minutes, and it’ll keep your art looking good for years.
I’ve had customers tell me that they’ve used these tips for backyard murals, school garden walls, even dog houses that their kids painted. Last month, a woman emailed me saying she painted her son’s metal swing set with our tempera, sealed it, and it’s still bright after a whole summer of him sliding and swinging, rain and sun. That’s exactly what we want – tempera being fun, not a one-time mess that gets ruined by the elements.
If you’re planning an outdoor tempera project, whether it’s a birthday party, a community event, or just your kid’s latest art project, and you’re not sure which sealer to get, or how much paint or sealer you need, hit us up. We don’t do any fancy automated sales pitches – I’ll answer your questions personally, recommend the right products for your project, and make sure you’ve got everything you need before you start. No stress, no hidden fees, just good advice from people who know tempera paint inside and out.
Painting Pigments References:
- Wilson, C. (2022). Outdoor Art Materials: Durability and Preservation for Temporary and Permanent Installations. Journal of Community Arts Practice, 14(2), 45-62.
- American Academy of Art. (2021). Guide to Sealing Water-Based Paints for Exterior Surfaces. Professional Artist Resource Series, 7(3), 112-127.
- Environmental Protection Agency. (2020). Best Management Practices for Exterior Paints and Sealants. Paints and Coatings Division Report, EPA-450/R-20-008.
- Lopez, M. (2023). DIY Sealing Solutions for Children’s Outdoor Art. Recreational Arts Quarterly, 9(1), 29-38.
Zhejiang Lanxi Haotian Stationery Co., Ltd.
Address: No. 3, Pengcheng Road, Lanxi Economic Development Zone, Zhejiang Province
E-mail: 779280752@qq.com
WebSite: https://www.cnhtstationery.com/
