Sometimes you have to patch cracks on brass instruments. If I can find a new part or can make one, I will do that before I use a patch because patches are usually somewhat unsightly and amateurish looking. But if I have no choice, then I’ll make a patch…but I’ll be a little artistic about it.
For instance, in the above picture, I made a patch on the back turn of a Selmer k-modified trumpet. I cut the patch into the same diamond shape as the braces. While the patch is still obvious, it looks a little better than just throwing a regular oval patch on the crack.
The most useful patch technique I’ve used so far is making a patch that completely circles the cracked tube. If you do it carefully, you can sometimes end up with your patch looking like it was originally supposed to be there.