This is how you can easily make a super & simple gas welding torch with a few household material. This is just an homemade idea so that you can learn how the gas welding actually works.

Supplies

Material Used:

Water bottle
Syringe pipe
Calcium carbide(CaC2)

Tools Used:

Drilling machine
Glue gun

Step 1: Drill the Bottle Cap

Make a suitable hole in the bottle cap enough to join it with the syringe pipe.

Step 2: Connect the Syringe End With Bottle Cap

The syringe pipe is the medium to transfer the acetylene gas which is going to be produced inside the bottle by some chemical reaction.

Step 3: Apply Hot Glue

Hot glue is applied to the inner and outer side of bottle cap to make it airtight.

Step 4: Fill the Bottle With Calcium Carbide

Take an small amount of Calcium carbide(CaC2). Normally It looks like stone which is stored in moisture free area.

Step 5: Pour Some Water

Water reacts with calcium carbide and release inflammable acetylene gas. Be careful while mixing the calcium carbide with water because the process releases an small amount of heat.