I haven't seen anyone mention this, so here's a quick tip: you can use an Andrewsarchus to tame a Voidwyrm. The saddle does a great job of protecting the rider.

1. If your cluster has Fjordur, try taming an Andrewsarchus first. Equip it with the highest armor saddle you can get (or make sure it has a massive HP pool), and pack a ton of ammo.

2. Mount the Andrew and use the minigun to melt the Voidwyrm's health down. Make sure to use your HLN-A to scan and monitor its exact HP.

3. Once it's low enough and you've confirmed the area is clear, dismount the Andrew and back away a bit so the Voidwyrm keeps aggro on your tame. From there, you can just proceed with the normal taming process.