Fix a Mirror With the Right Outdoor Adhesive!

One day my husband came home with a curbside find that got me thinking about installing a mirror outside in our garden. A mirror can not only expand a small garden but you get double bang for your buck: it beautifully reflects the plantings around it!

Although the mirror glass was completely detached from the frame, both pieces were still there when he found it! I just had to figure out how to fix it.

The real problem is finding the right adhesive. There are so many choices and lots of things to consider when using a mirror for outside decor. For instance, do you experience wide temperature fluctuations where you live? In our climate, an adhesive has to be flexible enough to withstand extremes in temperature. It also can't shrink too much as it dries - or it can cause micro cracks that can eventually break the glass. Choosing an adhesive for outdoor use can be challenging so in this Instructable we're passing our learnings along to you!

You Will Need:

• Metal frame / mirror (be on the lookout for curbside finds and garage sales)
• Paint suitable for metal (we used PPG Break-Through)
• GE Silicone II
• DAP Alex Plus
• Utility Knife
• Caulk Gun
• Disposable gloves
• Paper towels
• Plastic cup filled with water for cleanup
• Corrugated plastic for backing
• Fine grit sandpaper (220)
• Paint scraper
• Mirror cleaner

If you find a metal frame that's missing the mirror, have one cut to size at a mirror and glass company or, if you're handy with a glass cutter, cut one yourself. Just remember to cut it narrower than the framing space so it fits into the opening. I usually cut 1/8" smaller in length and width so there's 1/16" play on each side.

Painting the frame is so much easier without the mirror in it. Set the glass aside somewhere safe for the time being.

I chose to use a paint from PPG called Break-Through. It dries very quickly, adheres well to metal and is flexible to resist cracking and peeling (one of my biggest pet peeves)! Best of all, it has low VOCs (Volatile Organic Compounds) so is environmentally friendly.

Prep the Frame

The metal frame was cleaned with soapy and dried it thoroughly. It was also given a light scuff with 220 grit sandpaper and wiped again. I thought it was best to leave the metal bare in the back channel (where the mirror will go) so the adhesive would stick better. Green painters tape was applied around the inside of the frame to protect from overspray.

My husband used a sprayer to apply the paint. Once dry, I removed the painters tape to prepare for adhering the mirror.

Cut Backing

Measure the width and height on the back of the frame and cut a piece of corrugated plastic for the backing. The corrugated plastic is the same type of plastic that’s used as signage. It will prevent the back of the mirror from being scratched from plant materials growing around it.

While the frame was still empty, we took advantage of the fact that it weighs a whole lot less without the glass. We tried it out in different spots in the garden to see how it would look.

Once we decided where it would look best, we marked it and then predrilled holes. We screwed in the vinyl covered hooks you see in the lower left of the first picture to hang the mirror on the fence. The hooks allow it to easily lift off for storage in the winter.

We took it down until we were ready to attach the mirror.

After researching the pros and cons of different glues and adhesives, I settled on not one but two sealants. The first was GE Silicone II to hold the mirror to the back of the frame and seal in the plastic backing. GE Silicone II is what’s called a neutral cure silicone, meaning that it’s non-acidic (so shouldn’t corrode the silver backing of the mirror) and is superior for outdoor applications (it can be exposed to water in only 30 minutes). The only drawback is that because it’s 100% silicone, it's almost impossible to smooth it out nicely. That’s why I chose a different caulk to seal around the front of the mirror.

The purpose of the second caulk is to seal the gap between the metal and glass on the front of the mirror so it has to look flawless. I chose DAP Alex Plus. It’s an acrylic latex caulk plus silicone that can easily be smoothed with a finger dipped in water for a neater seal around the front. You can't do that with 100% silicone! We purchased a clear formulation; it’s goes on white but becomes clear as it cures in 7 – 14 days. The drawback with this product is that it's not waterproof until it cures so you will have to tuck it away when rain is forecast for the first two weeks. I decided that was an ok tradeoff to get a clean seal around the front of the mirror.

Clean the glass well so there’s no dirt to resist the caulk. If there's any old caulk that happens to be on the mirror, carefully scrape it away with a paint scraper (as shown in the third picture). Use either a commercial product or a solution of vinegar and water in a spray bottle for the front (mix 2 cups of water with 1/4 cup of vinegar). For the back, I used plain soapy water (I didn't want anything acidic touching the silver backing).

Carefully insert the glass into the frame, mirror side down.

Starting with the GE Silicone II, cut off the tip of the tube of caulk on a 45 degree angle with a utility knife.

Use a stiff wire that’s long enough to pierce through the seal; our caulk gun happened to have a piercing tool on it, so we used that.

Put on disposable gloves. Load the tube into the caulk gun, depress it over a paper towel first to make sure you pierced the seal and the caulk is flowing. We actually didn’t pierce the tube properly on our first try and when I forced the caulk gun, the caulk exploded out the back end and oozed all over the gun; oops! We were too busy wiping away silicone to get pictures of the mess but lesson learned: if the caulk doesn’t flow easily, don’t force it – take the tube out of the gun and try piercing it again.

Start in one corner and run a bead around the perimeter of the mirror.

Smooth it with a gloved finger to ensure it makes contact with the mirror and frame. It doesn't matter if you are messy with this step because the corrugated plastic backing cut earlier will go over top.

We let it set up only a few minutes so we could still press the backing into the silicone. Don't let it dry too much or it won't sit flat against the mirror.

Set the plastic backing into place. Apply another bead of caulking around the plastic backing. Once again, smooth it out with a gloved finger.

Let it dry for at least a day, then flip it over so it's right side up. I put painters tape along the metal frame and also around the mirror, leaving a slight gap so the caulk could make contact with the mirror but still be neat and discreet. The second picture shows a closeup of the gaps we’ll be filling.

This is where I switched over to the Alex Plus. Once again, cut the tip at a 45 degree angle and pierce through the tip to puncture the seal.

Fill a plastic cup with some water. Since Alex Plus is latex, the bead can be smoothed with a finger dipped in water (no need to wear gloves this time). I placed paper towels over the mirror so I could wipe off the caulk as I smoothed it.

Like the previous step, position the caulk gun in one corner and run a bead of caulk around the perimeter. At this point the caulk will look messy. Dip a finger in water to smooth the joints. As you smooth the caulk, you want to push it towards the metal in such a way that the gap is filled between the metal and the mirror. Use the paper towels frequently to wipe the excess caulk from your finger and re-dip in water as necessary.

Ensure all the gaps are bridged and there are no bare sections (if not, apply more in those aresa with the caulking gun and smooth caulk again). When you are satisfied, lift the painters tape.

Let the caulk dry for at least another 24 hours before hanging outside.

Since the hooks were already in place, all we had to do was hang it. Look how beautifully the mirror reflects the rest of the garden – and our newly blossomed day lilies!

As I mentioned earlier, although the GE Silicone II is rain ready after 30 minutes, Alex Plus takes 7 – 14 days to cure. For the first two weeks, if rain is forecast, I plan to take the mirror down during those periods and temporarily store it in the garage so the Alex Plus has a chance to fully cure before being inundated with water. It's a bit of an inconvenience, but why take chances?

With the right adhesives, we were able to fix the mirror and repurpose it in the garden. It will last for many seasons to come! Isn't it amazing how much nicer the fence looks with the mirror now?

The mirror wasn't the only thing we hung on the fence. To balance out the mirror, we had one more creative trick up our sleeves. To see what else we did, follow us right here on Instructables or on Birdz of a Feather so you don't miss a future post! You can also follow us on Pinterest, Facebook, our YouTube channel and on Instagram.

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