If you know someone who regularly orders from them, you can ask to have them order for you on their shipping dime and offer some homebrew in trade. My job has an account with them, but i have yet to need anything just yet.While McMaster probably has everything you'd need, they will be the most expensive option, without question. Better options are Lowes/HD for coolers, copper, and basic plumbing parts.
Murray Equipment (.com) has the best prices on stainless fittings that I've been able to find. And Bargain Fittings (.com) has great prices on stainless conversion kits and parts for coolers, kettles, etc. Do a little searching before you go with Mcmaster because you will severely overpay if you go with them.
Half the fun of building your own rig is finding the parts you want. I'm willing to bet that almost no two systems are alike. Each brewer has their own configurations that are tailor made to fit their process. I say roll up those sleeves and do the dirty work. That way you can have EXACTLY what you want![]()