Curls can be created without heat.
In essence weaves especially do not need curling wands/iron/straighteners everytime as most times the heatless bendy rollers can do all trick,leaving the curls tight or loose or in any way they are desired.
Bendy rollers do not get enough credit, they are featured as bendy foam hair rollers that can be used without heat- which gives it an edge as heat shouldn't be applied to weaves and hair at the barest minimum.
The great thing about the bendy rollers is the fact that they can be used on wet or dry hair to get ringlet curls, bouncy curls, loose curls and so on without just a little turn and bend here and there, they are absolutely easy to use and they pose no harm at all.
If you do not know how to use these before now, check out a detailed tutorial on how to get the best use out of the beauty tool above. Be sure to watch and learn.