low area on doublewall top.

[king drake]

Hi guys,i been looking at this great site,for about 10 years,a member around 2 years.I bought a 1970 two wheel drive jimmy, off ebay 9 years ago.with a little work from myself and a couple local shops,im starting to see a little light at the end of a 100 mile tunnel,which bring me to the top,a job i might tackle myself, depending on the information i get back,i have a few low area i like to fix,are have fix.I like to know what is the best way and the best material, to use to fix this problem,i have a few small chips and cracks also.