Layering vinyl, whether it is regular vinyl or HTV, there are some tricks that can help.
The Knock Out Method
The last project above I did a few months ago and there is a video tutorial on how to do the project at “Design Space – There is Nothing to be Scared of” It is an example of using the knockout method of layering vinyl, which can be used with either HTV or regular vinyl.
Essentially you cut one layer from the other so that the adhesive for all the layers is in contact with the surface. This method lets you do as many layers as you want. The Indians Wall Hanging use three layers but the whole project is just one layer thick
How to Do Knock Out in Design Space
In design space you would line them up where you wanted them, and then slice the top layer out of the bottom layer. After cutting out, when you go to attach the two vinyl layers, the bottom layer is fit first then the top layer is lined up and applied second. This can be tricky, depending on how detailed you project is and how big the pieces are. Be patient and take the time to line them up properly.
If doing HTV make sure you cover the whole design when attaching the second (or third, etc) layer or you could scorch the lower layer.
The Layering Method
The other way to layer vinyl is to simply layer it. It sounds simple but there is a downside for doing it this way. The first two towels were done this way.
Some vinyls do not take well to layering. Glitter vinyl, of either HTV or regular vinyl, must be the top layer and even then, it doesn’t work great. I have only worked with adhesive foil in layers once or twice and it works fine, but it is very unforgiving of mistakes.
The next problem is you are limited to two maybe three layers. The pressure you need to apply HTV gets to be more with each layer. And with either type of vinyl it gets bulky and tends to not stick well.
Remember to cover the whole project with parchment paper or some other barrier when layering HTV so you don’t burn or pull up lower layers.