I am trying to do a shell border but we only have Ateco tips here. can anyone help me with which Ateco tip i can use for shell border?

i know you get open star and closed star.the people at the baking shop where i live are so not helpful.

I have the Ateco tips as well and I use the open star tips: tip #18 for a small shell and tip #21 for a larger shell. (Those are the open star tips that came in the kit my mother passed down to me.)

Tip #21 makes a lovely shell. Truly any tip can create a border and size that you may be looking for. The squeeze and release of pressure is what creates and determines the size and look of your shell. I sometimes like a round tip #8 Wilton any med. rounded tip will work (see my pic's) by using the same technique and a 45 degree angle(bag opening faces 3 o'clock in your hand) you are able to make this modern looking shell. Best of luck.