DIY Mash Tun (metal materials question)

Hi all.

I am in the final stages of building my mash tun from a 52 qt. Coleman Xtreme using lustreking's guide (with a few modifications):

http://brewing.lustreking.com/gear/mashtun.html

I like the idea of having some kind of locknut on both the inside and outside but I am having trouble finding anything in the local HD or Lowes. I was watching this video and they are using "Two 1/2" Conduit Locknuts".



The only ones that I was able to find are neither brass, stainless nor plastic. I'm assuming they are some sort of steel.

Wouldn't this be an issue? From everything that I read, the only safe metal materials to touch your wort are copper, stainless and brass (once surface lead is cleaned).

Can someone please enlighten me?

John

Actually, this just sparked a second question. I emailed Stave (lustreking) but figured I would ask here for more opinions.

In his guide, he using a 3/4" zinc coated washer (not stainless). Is that safe?

TIA,

John

OK...Steve answered the question about the 3/4" washer inside the tun. That one is stainless.

Thanks Steve!

John

johnodon said:

OK...Steve answered the question about the 3/4" washer inside the tun. That one is stainless.

Thanks Steve!

John

Click to expand...

Hoping to find some answers here.

I'm doing the same conversion as above and I've run into a problem trying to find a 3/4" stainless steel washer. It seems that anything wider than 1/2" is going to be zinc (since it's cheaper to make, I was told).

So, my first question is, where can I get a stainless steel 3/4" washer. And if I can't without a great deal of effort, what is the next best material to use for the inside of the mash tun? Is nylon ok?

A 3/4" washer seems an odd size for a cooler conversion (someone correct me of I'm wrong). Have you checked bargainfittings.com?

OK ... I looked at lustreking's site. It looks like a stainless 1/2" washer inside, 3/4" zinc outside the cooler. Not sure why you would need a 3/4" outside, except maybe to distribute the force.

dutchoven said:

OK ... I looked at lustreking's site. It looks like a stainless 1/2" washer inside, 3/4" zinc outside the cooler. Not sure why you would need a 3/4" outside, except maybe to distribute the force.

Click to expand...

It's a 3/4" stainless on the inside. It goes around the nipple, same as the rest of the washers involved. The washers sandwich the entire piece in place between the cooler walls.

I realize I could order a stainless washer, but then I'm paying an additionaL $5 in shipping for an item that should only cost half that much at a hardware store. Not that $8 is going to break the bank... but it's the principal, y'know?

So, I figure the SS washer on the inside probably doesn't have to be SS, just so long as it is firm enough to hold its own, and safe for wort contact. Anybody know what other materials are both readily available and safe?

Everyone take a deep breath ;-)

A 3/4" washer is for a 3/4" bolt and is usually oversized just a bit to .8". 1/2" NPT pipe is actually .83" OD give or take. A 3/4" washer often is not quite big enough to slip over. It will make it almost all the way down the tapered threads. You can find these in the specialty hardware drawers at lowes if you have that area in your store. A washer meant for 21mm bolts will fit better but it's not a homecenter item.

There is no stainless pipe locknut at any home center. It's an industrial supply type item. No you can't use the zinc coated steel ones in the electrical section like the guy in the video. I promise that thing rusted out after like the second or third use.

Brass is getting so expensive that it's almost as cheap to order a bulkhead kit in stainless including the shipping rather than use brass parts from Lowes.

OT: OMG, they put that teflon tape on backwards in the video. Poking my pet peeves pretty hard there.

FWIW,

McMaster-Carr has these locknuts:

4429K124 1/2" Locknut, Brass (with groove for o-ring)

Obviously it would not be very cost effective to order just a lock nut or two, but might be an option if you add in some other stuff you may need.

You can substitute a pipe fitting (brass or SS coupling etc) for a back nut. The valve on the outside can also function as a effective nut. The trick is to use brass or stainless washers to take up any slack if the nipple is too long. You can install the shims on either or both sides of the bulkhead. Here's the part number for SS shims from M-C that will fit over the 1/2" pipe: 98126A797 Stainless Steel Shim

IMO, it would probably be best to just buy a bulkhead kit from one of the vendors. It's not worth running all over town trying to locate the correct parts and some of them may not be available locally at all. Time spent and gas burned vs an online kit purchase seems like it would be an easy decision. I did buy the parts from M-C, but I bought enough stuff to build about 10 bulkheads when I only needed one. It was not long before the extras went to friends at cost. I kinda figured that would happen based on a lot of new people in my club. It seems that almost every new home brewer will be looking for the parts. I carry the nipple, shims, silicone 0-ring and back nut assembly in my pocket at our club meetings. When a newbie asks about how to install a weldless bulkhead, I just whip it out. The assembly that is!

Judochop said:

It's a 3/4" stainless on the inside. It goes around the nipple, same as the rest of the washers involved. The washers sandwich the entire piece in place between the cooler walls.

I realize I could order a stainless washer, but then I'm paying an additionaL $5 in shipping for an item that should only cost half that much at a hardware store. Not that $8 is going to break the bank... but it's the principal, y'know?

So, I figure the SS washer on the inside probably doesn't have to be SS, just so long as it is firm enough to hold its own, and safe for wort contact. Anybody know what other materials are both readily available and safe?

Click to expand...

I should've clarified. I'm following the Lustreking design. No zinc inside the cooler for sure! I solved my problem a few minutes ago by using a smaller ID SS washer and boring a bigger hole to where it fits over the nipple threads. Thank goodness for neighbors with big tools. So to speak. I think.