Interior pipes and barrel prep.

Hi,
 First time poster!
Currently planning a 6" RMH to use in an old unheated room addition.
For the interior exposed pipe, can single wall be used? For three reasons:  since it allows extra heat to escape in the room, the heat at that point is already traveled the length of the mass and shouldn't be that hot, and it is a lot cheaper.
 I know dble wall offers 6" clearance, but is that all?

I need to clean my barrel.  For the pocket rocket, how do you cut into a  metal lid w/o welding equipment?  Is there an alternate lid that can be used?  Does something like Citrasolve work on pain removal??

Thank you!!!

Hi Staci;  Welcome to permies!  No, You do not need dbl wall pipe until you pass thru your roof and go outdoors. Only the outdoor exposed pipe needs to be insulated, your indoor single wall pipe should be apx 130 F ... not nearly hot enough to do any damage.  Barrels can be cut using a chisel or drill holes and use a tin snip. Fire is the best way to remove the paint from your barrel.   Ideally your barrel has a removable lid.  Depending on your location you can fill it with scrap wood and burn it off like a burn barrel on a city  street. I doubt that the paint remover would work.

I agree, the easiest way is to burn it off. I have used citrasolve--or a product like it with some good results, scratch the paint a bit with sandpaper and apply heavily and let it soak a while, then you may have to repeat.  Barrel paint is tough. and it does stink if you burn it  and likely very toxic.

Some people wire brush or sand it off-- wear a respirator, it is messy.

A cheap angle grinder with a heavy steel wire brush attachment works decent in removing barrel paint.
Examples:
https://m.harborfreight.com/catalogsearch/result/index/?dir=asc&order=EAScore%2Cf%2CEAFeatured+Weight%2Cf%2CSale+Rank%2Cf&q=grinders+and+buffers&utm_referrer=direct%2Fnot%20provided

https://m.harborfreight.com/4-12-in-carbon-steel-knotted-wire-wheel-60488.html?utm_referrer=direct%2Fnot%20provided

Hi Staci;  Thought you should know that you can use very thin wall HVAC pipe instead of regular black stove pipe on most of your run. Its way cheaper !  Use regular black stove pipe to leave your transition  area  then go with thin wall until leaving your mass. Depending on its location you could use thin wall up to your roof.  Insulated pipe is only needed when exposed to cold air.  For insurance reasons  any stove pipe going through your roof should be insulated (double wall / metalbestus ).