I love that lil horz propane tank. What is the cap on it? Where can we find em?
It is a DOT rated horizontal tank manufactured by Manchester. They were used on some vintage travel trailers and sometimes on boats (until boaters wised up and realized that propane will collect in the bilge and is a potential bomb). The tanks were in the Manchester catalog until just a fews years ago. I do not know if there are any current sources for new tanks.
I kept my eye open in marine salvage yards and in old time trailer supply places. I finally found one, about 3 years later, used but not abused, in a dusty corner of a trailer repair shop in Costa Mesa CA. $25, I think. I had the tank purged, de-scaled, and pressure tested. Then I stripped it, primered and painted it with Hammerite. Total investment about $65-70.
Because the tank is DOT rated, it is not required to be retro-fitted with the new external thread fitting on current BBQ tanks, and does not require the anti-overfill (i.e. no more than 80% full) valve. It uses the older-style internal threads. I have never had any problem having it filled.
My recollection is that the rated capacity is about 13 lbs., and that it will take slightly more than 12 lbs. before the overflow valve starts to spit.