process of making a reinforced tube including extruding a thin walled tube , encircling the tube with a completely closed layer of helically extending strip coated with heat activatable adhesive material . the tube is then passed through a sizing die heated at its entrance to activate the adhesive while subjecting the tube to relatively low internal pressure to bond the tube to the layer of strips . the integrally connected tube and strips are then passed through pinch rolls which close the tube and maintain the pressure upstream from the rolls different from the downstream pressure . further reinforcing strips and an outer sheath are thereafter provided .