To be clear, when we say "bulkhead", we mean any fitting or accessory that passes through the bottom or sidewall of a brewing vessel. Examples would be the bulkhead you use to drain the contents of the vessel, a sight glass/level indicator, a thermometer penatration, etc.
This article discusses the pros, cons, costs and special considerations that will affect whether you should use weldless or welded in fittings.
It's not always a matter of choice. Welding is a niche skill and good, cheap labor is hard to find.
It is sometimes very difficult to find someone local that has the ability and time to take on your project at a price you'll be willing to pay. If the price seems too good to be true, you may want to ask some questions to be sure they know what they are doing. Welding stainless steel is a skill that a lot of professional welders THINK they have and it's either an ego problem or simply ignorance.
First, ask if they have any experience welding stainless. Ask what kind of TIG machine they have. Ask what they do to prevent sugaring on the back of the weld. If they say "nothing" or seem confused by the question, keep moving along. The only two ways to prevent the back of the weld from looking horrible and being a cleaning mess is to back purge the vessel with argon or use solar flux. With that said, a sugared weld area is not the end of the world on a hot side vessel but you'll be a lot happier if the welder prevents it. If you've gotten quotes from several places, make sure you know if they'll be accounting for the back purging or not. At least you'll be able to compare apples to apples.
In many cases, the highly skilled welders that are aware of the various techniques would consider this "sanitary grade" welding and will have had experience working in pharmaceuticals, chemical processing, dairies, and other food processing plants. Here's the rub. Welders capable of this kind of work are busy doing that kind of work for top dollar. No one with a couple hundred feet of welding work over at Johnson and Johnson wants to put a couple doohickies on your kegs for $20. Some shops will offer to take the job and tell you to come back next week...only to find that some higher priced job took priority while you weren't looking. Worse yet, don't fall for a handshake deal with the welder in the back. You may come back to find that your 90 pounds of kegs and parts were sold to the scrapyard and the boss doesn't know who you are. Get something in writing showing what you dropped off, what work is to be done, when and for how much. This doesn't bode well for the stories of bartered welding labor for a couple six packs of homebrew (unless it's a friend of a friend).
Assuming you have some quotes on welding labor, you can now look at the price difference for parts. Labor excluded, the weldless version of the parts/accessory is going to be more expensive. Let's take a bulkhead for draining the keg for example. Forget the ball valve itself as both versions require a valve. The weld-in parts will be limited to a 1/2" NPT full coupling and a 1/2" NPT close nipple to connect to the valve. That's about $5 in parts. The weldless version is $15-19. Logically, you'll be charged more than $14 in welding labor so the welded version is always more $$$$ with everything considered. For one more example, the WLSL sight kit (weldless) is $27 and the weld-in version is $19. Again, you'll pay more than $8 for welding.
How much better is a welded bulkhead really? Is it worth the premium total cost?
Let's start with some general observations:
1. The larger the hole, the more tricky the seal is going to be.
2. Accessories that require handling regularly may be more prone to leaking over time (such as operating the ball valve on the drain bulkhead). A replacement gasket is all it would take to get it back to new again.
3. Static accessories such as sight glasses and thermometers will likely never leak once installed properly.
4. A well designed (ours) and properly installed weldless fitting is preferable to a hack welding job.
5. A lot of the negative impressions people have with weldless fittings is due to poorly designed products that some homebrew shops sell. It's not really their fault because it looks just like what every other shop sells but with a few hard to notice nuances.
Rather than speak in generalities, let's look at some statistics. BrewHardware.com has been building weldless sight kits as a "hobby" since 2008, later introducing weldless versions of dial thermometers and ball valve/bulkheads in 2010. Without divulging specific sales figures, we've sold a "LOT" of them. We can count on one hand how many leak reports there have been and every one of them was fixed by reiterating or clarifying the install instructions. This doesn't account for any situations that were never reported, but it's hard to imagine there are many of those.
I want to skip all the reading, just tell me what to do.
First choice: If you found a welder that you are sure has TIG experience and will back gas (purge) the vessel, AND they can do it in a time frame you can live with AND if it will cost you $10-20 or less per bulkhead, Go WELDED. Of course, there are a lot of ifs and ands in here.
We are extremely confident in the weldless design of the True Weldless Bulkheads and the LK/LP, TK/TP, and LTSK/LTSP sightglass kits so we see absolutely no reason for paying a premium for welding on sight kits.
If you're looking to get welding quotes, don't limit your search to the word "welding" on google or the local directory. Try words such as fabrication, prototyping, stainless, railings, sanitary, dairy, food processing, etc. My last project was welded by someone who worked days at a custom stairs/railing shop and nights at a custom motorcycle shop. The latter took my job and was open to ideas on back-gassing even though the welder had no recent experience with such requirements. As of 2019, we also started offering TIG welding services at the shop in New Jersey if you're within driving distance. If you're too far to drive, the last resort would be shipping your project both ways (probably too expensive).
Lastly, there is a compromise between weldless and welded and that's silver soldering. For now, we'll consider it out of the scope of this article but it's worth mentioning just to keep you from thinking we don't know about it. If you're a DIY type that already knows how to sweat (that's cool guy jargon for soldering) copper pipe, it may work out for you. You'll want to look for Harris Stayclean liquid flux and Harris Stay Brite #8 silver solder (we sell a kit with a small amount of each). The strongest joints are those where the solder meets between two large surfaces. In many cases, this excludes things like a coupling simply slip-fit in a hole in the vessel. For bulkheads that only require exterior threads such as thermometer and sight glass ports, welding SPUDS are a good solderable option. We sell the spuds, but the soldering parts and technique is on you for now. For an idea of how the process works, check these videos out
If you have access to the inside of the tank/kettle, the better solderable option is using a combination of our Pull Through bulkheads and their associated installation tools. The clever design of these parts allow anyone to make a tight press-fit for a solid soldered joint.