Need help with cutting something thick

[juntari]

Hi, I'm cutting out some holes in a helmet I rotocasted. I began with a cutting wheel on a dremel but some areas are too thick for it to go all the way through. Is there an alternative out there someone can suggest? Something like a jigsaw where I can insert the blade in but gentler because a full size one will beat up the thinner parts and I don't want to risk cracking it. So far the only solution I found was using a hacksaw blade without the handle (just the blade in my hand). It works really well except when I need to start making slight curves. I'm building up my tool base so any suggestions would be appreciated, either hand powered or power powered. The thickest part is around 1/2 an inch and in some areas the blade would only be able to travel 2 inches without hitting a wall.

Also, I mixed some ure-fil in the resin and I think the sandy texture is creating a lot of friction on the metal cutting disk. It smokes constantly and after a few minutes the blades are completely worn out. Do you think slowing the speed would make it better or is making it faster better? right now I'm on the 4 speed setting (out of 10)

 

[Pobbrett]

a spiral saw might be just the job such as this
ROTOZIP SPIRAL SAW - SPECIALTY HEAVY DUTY

 

[DaddyfromNaboo]

I am sure that there is a routing tool available for a dremel, and a spiral saw bit.

 

[NormanF]

Coping saw. And there is a bit for Dremel that works like the rotozip.

Sent from my Apple Newton

 

[EyeofSauron]

if all else fails, you can just use the sanding bit on the dremel and sand through it. dirty work, but it will work

 

[pfillery]

If you don't have, or don't want to spring for, the proper bit to rout it out, a small (4 or 5mm) drill bit of reasonable quality can be used as a routing or milling bit if you use it at high speed and if you have a steady hand.

I've used this method to cut things out of 10mm thick acrylic so it should work. You can also buy drill bits with burrs on the shaft to cut slots so it should do the same job. Just remember that the drill bit will pull in the direction of rotation so you need to be steady or use it in a drill press.