Thanks for responding. I ended up using regular fiberglass insulation and it's working fine.
I got my parts from a service place in Oklahoma City, But Andy at Island RV said he might have them. I've used Andy before and he's great plus he's really helpful on this sight.
If your reefer is working good on gas, and you've checked to make sure you have power to the plug in, it might well be your heating element. I think there are some other threads that go into more detail about checking to narrow it down to the heating element.
I did want to let you know what happened with mine. The heating element slips down into a metal sleeve that's welded to the pipes. In a perfect world, you could pull back the insulation, slip the heating element UP and out o the sleeve, replace with a new one and be good to go. But on my 72, perfect world hasn't happened yet.
On mine the heating element had corroded to the sleeve. I was able to pull it about 1/3 of the way up. And even though I used every kind of lubrication known to man, it was not coming out. So here's what I did. I cut open the front of the metal housing box so I could get to the bottom of the sleeve. I then took a screwdriver and hammer and drove the element out the bottom. Problem was that the bottom is one inch from another tube. So every inch, i had to hammer the screwdriver against the element (from the top) then cut off the protruding element end (from the bottom) with pliers, then do it again and again and again.
Good news is, it finally came out. I cleaned out the sleeve, put the new element in, packed it with fiberglass insluation, rivited back the front of the housing and WOW it works great. It worked OK on Gas, but with the new heating element it is perfect. We had looked into a new reefer, but no more!! Just got back from 12 days out west and food did great.
Hope this helps, let me know if there is anything I can do.