Got out to the shop for a bit. Just a little project to add a very small dog door to a security screen door. The HOA limits what designs can be used, so I tried to make this blend in as much as practical.
Cut out a section of screen and made a small frame for it by slitting some 3/16" steel brake line with a small cut-off wheel then notching it to fold around the piece of removed screen. I also used a small piece, to cover the upper edge of the hole. Squeezed the tubing to close up the slit and clamp on to the screen. TIG brazed the cuts in the corners, and the upper tube on. 8 amps did the job with silicone bronze. Used some aluminum strip to cover the cut edges on the sides, held on with a few rivets.

Click image for larger version. 

Name:	DawgDoor 001.jpg 
Views:	485 
Size:	73.3 KB 
ID:	12308 Click image for larger version. 

Name:	DawgDoor 005.jpg 
Views:	512 
Size:	75.8 KB 
ID:	12309 Click image for larger version. 

Name:	DawgDoor 007.jpg 
Views:	535 
Size:	100.4 KB 
ID:	12310

Painted everything up and installed a couple of stainless screws to act as hinge pins in the upper tube.

Click image for larger version. 

Name:	DawgDoor 009.JPG 
Views:	500 
Size:	138.5 KB 
ID:	12311 Click image for larger version. 

Name:	DawgDoor 010.jpg 
Views:	517 
Size:	78.3 KB 
ID:	12312 Click image for larger version. 

Name:	DawgDoor 012.jpg 
Views:	474 
Size:	104.6 KB 
ID:	12313 Click image for larger version. 

Name:	DawgDoor 016.jpg 
Views:	496 
Size:	103.7 KB 
ID:	12314 Click image for larger version. 

Name:	DawgDoor 017.jpg 
Views:	469 
Size:	93.8 KB 
ID:	12307 Click image for larger version. 

Name:	DawgDoor 019.jpg 
Views:	490 
Size:	146.1 KB 
ID:	12306

Came out pretty good. From a distance you can barely tell that is has been modified.