Although I am not able to do your sig justice in this I have cut the image from your Tee so that it would be easier for the next artist to work with:
Under Spoiler is the cutout on white background to make it easier to select with magic wand.
Spoiler!
It looks like crap this way, but you wanted a black background anyway, right? It will look the same as the above on black (or better) when the artist is done.
I made a couple guesses and took a shot. lol, no worries - you won't hurt my feelings if you don't like - PM me (without reply in thread) and I'll delete this post, no problem.
Grandpa you have improved by a big majority mate. If this is just another one of your hobbies then you must be a data machine.
If your interested in joining a GFX website go here. They have alot of good tutorials and vary from photography- hand art- sigs- photoshop - html coding-jav alot of stuff.