I have been wanting to learn a little about different symbols on blueprints pertaining to welding. The part I am questioning now are the little triangles, what are they for, some empty, some colored in, and sometimes they are back to back with a little colored in triangle ahead of them. If there is a site that you know of or a good book you know the title of, I would appreciate it if you could share that info.

Also I have heard that there is a little formula on finding a good starting point for the current. Is there such a formula and what is it? Say if I was going from a 7014 rod down to a 6013, how would I know a good spot to start the heat.

One more thing is there any site or list that has good info on welding rods, like what they are good for, and reccomended applications, ect. For example where I work, they use 7014 1/8 rods to do all their 1/4-1/2 hor and vert welds, where in the past all i have ever seen used is 7018's.

Any info given would be greatly appreciated,

thanks,
Otis Lentz