First of I am new to this site so I apologize if this has already been discussed.
I am currently making a coat of plates. I have had no problems with the metal as i am a welder. But I am using canvas over leather for my outer material. So my question is how many layers of canvas would be appropriate to use? as of right now I only have one, is this enough? or will i need to add more layers?
Thank you.

I think the most common historic method would be to use canvas as a base material, and then add a covering of something else. In the cheapest examples we have two layers of hemp canvas, with slightly higher grades using fustian or buckram as a cover over the hemp, and richer versions using silk, velvet, or leather. Most of the Wisby finds are believed to only have used a single layer of thicker leather, without fabric beneath, though some evidence contradicts this.

So, a minimum of two layers of fabric.