Thermo bottle used to maintain liquids temperature for longer time.

I use it to keep water cooled in my vehicle for the whole day, and it works great!

The polyurethane foam is one of the bests insulating materials in market.

Step 1: Materials Needed

1 Big plastic bottle (aprox 2,25 litres)

1 Smaller plastic bottle (aprox 1,5 litres)

1 cutter

1 polyurethane foam spray

1 pair of gloves

Step 2: Cut the Bottle Top

Cut the bottle top of the big bottle, so that the small bottle top can fit in.

Step 3: Cut the Bottle Base

Cut the big bottle base, leaving 1 to 2 centimetres to act as a cover.

Be careful! Do not cut the whole bottle base!

Step 4: Make Small Hole in the Base

Make a small hole in the bottle base with a cutter, 1 cm x 1 cm approximately.

Through this hole the excedent polyurethane foam will go out.

Step 5: Fill in With Water

Fill in with water the small bottle, trying not no leave any air inside and making enough presure to the cap.

Step 6: Verify Fit

Verify that the small bottle fits in the big bottle, so that 1 cm is left in the diameter. This 1 centimeter between bottles will be used to fill the polyurethane foam.

Step 7: Fill Top

Fill with polyurethane foam the superior part of the big bottle and then put the small bottle in.

Very important! Use gloves for this step! The polyurethane foam adheres stongly to your skin, and might be difficult to take out.

Step 8: Fill Entire Piece

After fitting the small bottle into the big bottle, fill in the laterals with polyurethane foam. Wait for a few seconds for the foam to completely expand and then execute pressure on the bottom cover. The excess will go out by the bottom hole we did in previous steps.

You can use tape to help you keep the base in its place.

Very important! Still use the gloves for this step!

Step 9: Cleaning

After three hours, proceed to clean the excess of foam, now without gloves in. Only use your hands; polyurethane does not adhere to plastic very strongly, so it will be easy to take out!