Giant Indoor Bubble Blower (One-way Valve)

Simple one-way valve bubble blower inflates giant soap bubbles with your lungs! This is a great way to make big bubbles inside since it's small and much less messy. These directions are for the valve blower only, many soap recipes can be found here on Instructables. Soap Bubble Wiki also has great recipes.

Materials

Plastic drink bottle and cap. Avoid fizzy drinks because the pressure deforms the cap. You'll want a cap that's nice and flat.
Stiff plastic foil. Thick potato chip bags and other plastic food packaging work well. You'll want something thats un-crumpled, smooth, flexible and springy. This will form the valve.
String / yarn that absorbs soap. Shoelaces work great!

Tools

Scissors
Hot glue gun (low temp)
Sharpie
Something to make holes in the bottle-cap. You can use an awl, X-Acto knife or drill.

This is a quick project using cheap abundant materials and simple tools. You might need to make a few to get the hang of it. I recommend having a few bottles on hand for practice.

Step 1: Preparing the Bottle

Mark a line around 3.5 inches down from the top of the bottle cap. Don't make it too short otherwise your hands might pop the bubbles later. I like propping a sharpie to the right height and rotating the bottle.

Once the line is drawn, trim the bottle to the line and recycle the bottom. If the bottle is thin enough you can use scissors for this.

Glue the string to the edge of the bottle using a low temp glue gun. If the glue is too hot you can burn your fingers and melt the bottle. Trim the string once it makes a complete loop. Make sure it's glued all around and is not messy since the bubbles will form here.

Step 2: Making the Valve

Determine the size of the plastic gasket. I used a penny to trace the circles. The gasket must fit inside the bottle neck without touching.

Selecting the right material for the gasket is important. You'll want a flexible-smooth-thin-springy plastic. The popcorn bag I'm showing is a little too thin but still worked and was what I had on hand. Trace an area thats wrinkle free and perfectly flat. Cut out the circle. Remove any oils that might remain on the plastic disk. Once cut the circle should be perfectly flat.

Mark holes on the bottle cap for drilling. The larger hole in the center is for glue and the smaller holes are where the air flows through. Carefully drill the holes. I used an X-Acto knife but this can be dangerous.

Clean up any burrs around the holes. The bottle cap must be smooth and perfectly flat for the seal to work.

Place the plastic gasket on a flat smooth surface and center the bottle cap directly over it. Make sure the gasket covers all the air holes.

While pressing down on the bottle cap, place a dab of hot glue in the center hole to attach the gasket to the bottle cap. Press down on the bottle cap for 30 seconds while the glue is drying to make sure the gasket attaches perfectly flat.

Test the gasket! Place the inside of the bottle cap to your mouth and blow. Air should flow freely. Now try sucking. If the gasket is made correctly air should not flow in this direction.

Step 3: Assembly

Center the gasket on the top of the bottle. The plastic gasket should not touch the sides of the bottle.

Once centered, tack the bottle cap in place using hot glue, then seal the the two together completely from the outside using more hot glue. Be careful not to get glue on the inside where the gasket is.

The bubble blower is complete! Test the valve once again. You should be able to blow air through the bottle cap, but not the other way. It's time to make bubbles!

Step 4: Making Bubbles!

There are many recipes on Instructables for giant soap bubble mixes using easy to find ingredients. Soap Bubble Wiki also has great recipes.

Place the bubble soap in a bowl or small dish. Dip the string end of the bubble blower into the liquid. When you pull it out you will see a bubble film across the string.

Take a deep breath and blow through the bottle cap. The valve allows you to make big bubbles using multiple breaths without letting air escape the bubble. It's kind of like a bubble pump!

If you have long hair you might have to tie it back so it doesn't pop the bubbles. Try to keep your hands out of the way too.

Once the bubble is as big as you want it, pull the blower up quickly to release the bubble. You can also catch bubbles that are in the air by gently touching the string end of the blower to the bubble. This is how you can make connected bubbles like shown in the photograph.