This article describes how to make a trumpet pipe using easy to obtain materials.

Below, you can see an exploded view of all the parts.

This pipe uses the following easy to obtain materials:

Brass Bicycle Horn from Harbor Freight Tools
2" PVC Pipe
2" PVC Pipe End Cap
2" PVC Pipe Coupler
2" to 3/4 " PVC Pipe Reducer
Oak Block
1/2" Copper Pipe (for the shallot)
Copper Sheet (for the shallot)
Solder
1/32" Brass Sheet (for the reed)