Warning about using 40 watt heater cartridges

I feel like I need to forward on some advice I got last night. I had made a comment on Twitter about how great upgrading to a 40 watt heat cartridge is and mentioned that E3D should ship their V6 hotends with them. It's a common piece of advice we give to members here having issues with part cooling fans dropping the nozzle temperature and things like that. Tim (@elmoret) from Filastruder reached out to me via email explaining the reasoning behind the 30 watt cartridge being stock. I have to say, it concerned me to read this knowing how often we advise members without warning. With Tim's permission, here is what he had to say...

"The changeover occurred about 2 years ago. 40 watt heater cartridges were the norm originally as that was really the only off the shelf option from heater manufacturers. Eventually E3D had enough volume to have custom heaters produced, and the more appropriate 30 watt size was selected. In the event of a controller failure 40w heaters can get up over 500C and if you have a sock on, close to 600C. That’s around the melting point of the heater block, and is a fire risk.

There’s really no purpose for 40w heaters, especially with socks. With a sock on, a 30w heater can reach 420C - the E3Dv6 is not recommended for use at temperatures over 400C. If the hotend is having trouble maintaining temperatures due to part cooling fans, it is better to redesign/reposition the fan duct instead. Doing so also results in steadier temperatures and less power consumption as compared to simply using a larger heater."

Now I know some of you will come back with something like "the likelihood of a controller ever failing this way is slim" or "this could never happen with the max temps set in the firmware". HOWEVER, the fact that a chance even exists warrants us informing members of our community of the risk. The very last thing I would want is to have someone install a 40 watt heater and have someone get hurt because they didn't know the potential dangers.

Tim's a smart guy and has given good advice to me in the past. I just wanted to forward on his advice in a positive way so that others can hear. Be safe, be kind, and happy printing!

 

Thanks Danz..............