Find a nice electrican and he could "rig" something with the stove plug. Will not be code. Use only one leg of the 220 from the range. So when you want to roast, pull out the range put in your roaster plug. Ask for some #6 SO cord to run outside. If you could run 220 this roaster on 220 it would be to code and safe, at 110 not code but it will work. Would be very supprised if this could not be converted to 220. Almost all motors can be changed by changing the order of wire conections. Look on the name plate if the motor says beside voltage 110/220. Then its very easy for you to change to 220. Takes 5 min and no tools. For the heating element I do not know how to do that, you would have to buy new heating coils rated for 220 I would think. People who built it will tell you how to convert. A commercial electrican could do all this work for couple hundred bucks you would have to buy parts. Parts would be in the hundreds also. Do not ask a residential electrician they are cheeper but do not understand this kind of work.
