Gary -

I see no compelling reason to apply a thread locker or a thread sealer to the leaking areas you described above. In one instance, you forgot to include the copper washer during assembly (I and others have done that on many occasions) - it happens. Maybe there is an issue with getting the valve in the proper orientation and the connection tight enough to effect a seal with the copper washer?

The steam/hot water wands should have been sealed with the teflon gasket you produced. I know of no instance where a sealer is applied to threads holding the wand to the valve body. The teflon gasket needs to be of such thickness to effect a seal but still allow the wand to rotate ever so slightly. This should be noticeable as you tighten that nut.

Some side notes:

A threadlocker will also act, secondarily, as a thread sealer and a thread sealer will also act, in part, as a threadlocker. I believe you need to differentiate between "food handling" equipment and products that carry NSF approval for potable water use. One US manufacturer of espresso machines (which do have NSF approval) uses Loctite 262 threadlocker and Permatex 24240 threadlocker in their assembly depending upon the specific machine area. No teflon tape is used on any part.

edit - to directly answer one of your questions - Loctite 567 threadsealer will also act as a threadlocker.

Does the copper crush washer sit down flush into that groove? In theory when you tighten the 2 halves of the valve together the copper crush washer will bind them together as well as sealing the gap.

How easy is it to turn the steam knob? If it is too hard then you do risk the 2 halves unscrewing and I would go with Loctite 243. If it is not too hard then I would go for a nice new crush washer and try the Loxeal 18/10, it may not be threadlocker but it does provide a decent bond. If it is

I've probably tried most of the Loctite food range and have found the Loxeal 18/10 to be the business. I never had any luck with 518 which some coffee people use.

Incidently a few Synesso service vids show that they use 262 threadlocker for thread sealing which is not rated for food.

drgary wrote:Thanks, Ray. I'll try the PTFE tape first. That seems the simplest solution. But if it doesn't work there is some Loctite that withstands espresso machine steam temperature.

Hi Gary,

Can you maybe post a video showing these connectors in a little more detail? I'm a little unclear exactly what you are attempting to seal in some of these different areas.

As Eric points out above, if these are joints which are supposed to effect pressure tight seals via surface contact (e.g. via the use of Teflon or copper gaskets), then normally that is how the seal is accomplished. Teflon tape generally is only called for when the sealing is effected strictly by thread to thread contact (such as with air compressor hose fittings, etc.)

Also, in move cases, when using Teflon tape to help seal threads, the threads themselves should be pipe threads. As you probably know, pipe threads are cut on a mild taper, which causes the threads to expand into each other as you tighten the fitting further. In those situations, Teflon tape is enhancing the thread to thread surface contact, in order to produce a pressure tight seal.

In cases where you do not have pipe fittings (which include a taper in the threads), Teflon tape usually isn't as effective and/or shouldn't be employed.

Take my La Pavoni for example:

On the pressure gauge, the gauge itself has a pipe thread (1/8 NPT as I recall). This threads down into the brass fitting I made (which threads into the top of the La Pavoni sight glass). So between the fitting and the gauge, they are using pipe threads, which expand and seal - using Teflon tape here increases the effectiveness of this already existing system of threads sealing due to the taper.

However, when the adapter threads into the top of the La Pavoni's sight glass boss, it's a different situation. La Pavoni cuts M11 or M12 threads, which have a pitch of 1.00 mm as I remember. These are not tapered pipe threads, but rather machine threads, just like a nut or bolt would have. Their purpose isn't to produce a seal via a gradually expanding taper, but rather to produce clamping force by virtue of loading the surfaces of the two fittings against one another.

In this case, you generally need to use some sort of sealing gasket, because the flatness of the surfaces of the fittings typically isn't enough to produce a pressure tight seal. This is when you introduce something such as a copper gasket or an O-ring, etc.

In the case of machine threads (i.e. threads which are perfectly parallel to each other, as opposed to pipe threads which taper against each other), it would be incorrect to attempt to seal at the threads. The purpose of the threads is to apply force, not to produce a seal. Example of this would be compression fittings, such as steam wands or water joints, where you have a nut that pushes two surfaces into each other. In those cases, you do not use Teflon tape [on the threads] to compensate for a lack of sealing at the fitting.

Again, I'm not sure exactly what is leaking or what type of fittings you are using or gaskets are involved. If you can post some clear photos (or a video) for each specific fitting involved, then maybe we can provide further information.

Just remember, Teflon tape is basically used with pipe threads and not much else. If they aren't pipe threads, then your sealing is probably going to come from some location outside of the thread surfaces.

Also, are you familiar with the concept of lapping surfaces together? This is where you take two surfaces (such as surfaces which are meant to seal against each other) and you introduce a mild abrasive compound. You then move the surfaces against one another, which laps them. This can help improve sealing in some situations. I usually use a cleaning product called Bon Ami (available at most stores) or sometimes Barkeeper's friend. Add a few drops of water and it makes a nice lapping paste, which can be used with most metals.

Ray

Thanks, guys. I've solved the leaks at this point, and it's probably for the reasons you described (added a crush washer or missing gasket). I've two issues to solve and will get at that today: 1) clearing the internals of the steam tap so it steams (!) because I probably gunked it up with Loxeal and clearing any excess Loxeal out of the water tap; and 2) figuring out a way to hold the taps in place without swiveling.

Dave at Allann told me about issue 2 awhile ago and there was an online discussion about whether to use something as aggressive as JB Weld to hold those steady. I chose not to do so and will try Teflon tape for that purpose. (Added April 5, 2013: After getting the machine restored and running the taps kept wanting to turn and I was faced with disassembling the entire boiler to tighten the water tap because with its dipper tube it can't be tightened down from outside a sealed boiler. I chose to use a small dab of JB Weld on one surface of each tap. That should be enough to steady the tap while also allowing it to be serviced by grinding out that bit of JB Weld with a rotary tool.)

@ Ray, the seals in the tap assemblies are not pipe fittings.

@ Paul, as a beginner it's easy to go lock step with a "food-safe" rating and confuse whether it's necessary. I think you're saying the latter if the thread locker doesn't come in contact with the water or steam passing through a fitting. With Dan's (HB) help I was able to post about 2046 to the old thread of food-safe Loctite.

I'll post more in awhile, including any more photos/videos that either show I've solved these issues or to help you advise.

Well, I was overthinking things there aka "planning ahead." Getting the taps to stop turning was easy. I just needed to add enough PTFE tape to the threads. I also easily unclogged the steam tip by clearing the holes with a pin. So at this point the steam and water taps work, the machine comes up to pressure without leaks, and now it's a matter of fine-tuning the PSTAT setting and tightening up bolts that loosen under heat cycling.

But there's much better news. I just pulled a shot of home roasted Guatemalan Royal water processed decaf, an 88 point coffee. Even though I didn't have the pull perfectly dialed in, the Prestina revealed layers of flavor I didn't know were there. And I discovered something even better. The Prestina's lever can be hand assisted, just as my Lady Duchessa spring lever can. This means I can pressure profile by pushing the lever back. The feel is really good. There's no easy tipping of this machine. With those flavors and that versatility I may have just restored one of the ultimate levers. Added: The flavor layering is no accident. I just pulled a shot of Klatch's Cafe Feminino Rwanda, a home roasted 93 point coffee. The layers of soft and subtle flavoring unfolded for several minutes and remained for 15 minutes. Unbelievable! For others who can't find a Prestina, Conti still makes machines with this group and you come across them from time to time in local online offerings.

Film clips below show the working steam and water taps and the pull. For some people this is like watching the grass grow but for me it's a feeling of accomplishment. My next big task is the drip tray grate. The one you'll see in the clips is an "upgrade" that Jano will enjoy.

The don't call it JB weld for nothing. It's not very good for some plastics, but on metal, it's pretty serious stuff. I've used it to repair cylinder heads, etc.

I wouldn't suggest using it on anything which you ever want to take apart again.

The machine looks great!

Ray

If I could actually weld the pieces of the drip grate together I would. So being able to do that with JB Weld is a good application. I just picked up a Bosch jigsaw with metal cutting blades today and was advised by the Bosch rep at Home Depot. I've created a notch where I want the first cut in the drip tray using a metal file. Also at a local real, old fashioned electronics store was able to source quick connect terminations for the wires without plastic on them so I can solder and followed your suggestion to get a pump to remove extra solder. They also sold me a very nice terminating strip. I bought a butane mini torch/soldering iron at Home Depot. So, the wiring and drip tray grate are being addressed soon. Ironically this afternoon I went to Back Yard Coffee in Redwood City and saw that their Synesso machine has the same shaped drip grate I'm about to cut in half. I went there to pick up a pound of Stumptown Hairbender seven days post roast to see what that tastes like in this phenomenal machine.

And I discovered something even better.

I've read of this from our previous Prestina owners, and it should be a bonus. Glad to hear the machine is exceeding your expectations. I'm not surprised - we've heard great things about the Conti levers before. You may find you need to move the Pavoni to one side to make a little counter space....

Cheers
PC

Stumptown Hairbender

I had some a few shots of Hairbender when I was in Seattle a year ago - one with Hal P of lever forum fame. It was the best espresso I had of several I tried when I was there. The only one, in fact, that was close to as good as what I make at home. It had a flavor profile similar to the Italian Musetti blue espresso blend.

Enjoy that Conti!

peacecup wrote:I've read of this from our previous Prestina owners, and it should be a bonus. Glad to hear the machine is exceeding your expectations. I'm not surprised - we've heard great things about the Conti levers before. You may find you need to move the Pavoni to one side to make a little counter space....

Thanks, Jack. I enjoyed reading the Conti Rebuild thread started by Bill Jackson. The Sirai PSTAT placement on Bill's machine is interesting and I like the professional look of his wiring. Food for thought. Can't figure out the extra electrical device to the right, past the power switch. I'm guessing that's a fuse. His thread has this quote by Richard Penney:

"She is a wonderful machine I would put her against any made anywhere, at any time for quality of espresso. The only reason I gave mine up was that I had a Cremina and could better use the counter space."

My wife and I were visiting with new friends tonight, and after I showed them the Prestina they asked where it would go. She said it would go on the counter and I would sell one of my machines. She was looking at the Isomac Amica, which has a footprint almost as large as the Prestina. Which of my children do I give up for adoption? That's a hard one.

My Millennium Pavoni with group thermometer is now pulling consistent Cremina quality shots, at least compared to others I've had from a Cremina. But the Prestina is showing me I haven't been capturing all of the flavor notes in my coffees, so I may try dialing in my Pavoni shots for more clarity. The bar is now higher.