I was following this thread late last year, because I wanted to investigate getting a new Interstate tank. After having some non-responses from ebay sellers in India, or their local reps (whoever they might be!?) I emailed Singh Precisions direct as follows
" I have a \'73 Norton Commando and I am thinking about an \"Interstate\" tank. I have followed the saga of your health on the AccessNorton forums and I hope that you are fully recovered. The principal issue with tanks from the sub-continent is fit, and IMO a good look at the bottom of a tank gives a pretty good idea of the quality of the construction generally. Can you post or send me a pic of the bottom of an Interstate tank? Also, have you considered making 850 Mk111 side panels? Also very hard to find. Cheers!"
Two weeks later I received the following reply.
"Thanks for getting in touch. Sorry i could not reply to you any sooner. Our Server was down, msgs didn't get thru until today.
I am doing much better now. On medication for 6 months. Thanks for asking , appreciate it.
Attached is a pic of the Interstate tank's underside.
The welds are all TIG. The outer sides are often double passed and the inner holding the under tunnel are single pass.
Once I finish the welding and pressure test the tank, I pressure test it with 5+ PSI of pressure. That’s a lot more than whats needed for leak testing. Just to give you an idea, at 9 PSI, the tank splits open like a pack of chips.
The reason why 5 PSI is my preference is because such high pressure not only reveals any leaks, but it also tests the welds on the entire tank. Many a times, any weak weld or non penetrative weld pops right up the second pressure hits 5 PSI.
Usually, any tank would have 5-6 microscopic leaks after I am done with the welding. Strong welds are not necessarily leak proof. So to seal the leaks, the leaking section needs a small pass( Few cms) again - NOT spot welding.
The particular spot where the leak is fixed may look Botched, but since i don't grind the welds for cosmetic purposes, they withstand the vibrations of the Bike (specially early commandos) far better than the sanded welds.
But however, i can sand the welds and make them look cosmetically pleasing the client orders for it.
I understand your concern about the quality of the Tank, so let me know if you need more pics or info on the tanks or welds."
The photo of the top of the tank looks fine, but would need to be measured and eyeballed to ensure it would paint up well, but what are your opinions about the bottom weld fest. It seems to me that if anyone was fair-dinkum about making these tanks it would not be beyond them to fabricate a basic die to push out one piece formed tank bottoms to avoid the potential problems of a fully welded unit. It would, I assume be much easier and less time consuming to fabricate too. One ebay seller on Ebay/au has a red interstate tank pictured with the original pressed steel tank bottom, but I's bet dollars to doniuts that's not what you'd get if you laid down your hard earned! Some resellers (Burton?) advertise tanks that look a bit like this-does anyone know if the bottoms are welded up, or presssed??
Opinions/experiences please.