I could use a tool like this. I have an '81 westy that I brought to 
wisconsin from Denver. The body is very clean because of the dry climate 
it has been in up until '91. Well, the mid-west is humid and hot and the 
winters are salty. Anyways, I have noticed rust forming at the body seam 
right above the propane tank ( or below the hook-ups). It seams to be 
rusting from the inside out. Now I do not know where the water is coming 
from. I even siliconed a seal on the inside of the hook-ups, but that did 
not make a difference.
 I came to the conclusion that it is condensation 
forming from the humid weather in Wisco. I tried that rust neutralizer 
stuff and have even sanded and painted, but it still comes through. I can 
sorta access the bottom half of the area from underneath,  but the top 
half I need to get to from inside. This means removing the 
sink/stove/fridge unit to access the hollow panel.
Does anybidy have any suggestions?