Well, you just don't want anything poisonous in there...
TIG brazing is something I haven't heard of, all brazing I've seen has been done with a acetylene torch, but I guess it's possible to TIG it, the seam should be a lot tidier.

I sent the boiler of my Olympia Club out to be replated with an FDA-grade nickel process. The company's URL is found at the link below; they may be able to recommend companies that do potable-safe TIG-welding or a repair that could be made safe after replating.

http://tinyurl.com/3uczkc

Regards
T

peacecup

The boiler on my PVE appears to be quite well made. Fortunately it appears to be made from a drawn cylinder, has a minimum number of flanges and penetrations etc and the brazing looks very good. Also it appears to be nickel plated. I have no data so cannot comment the toxicity of materials used, but by all appearances as a pressure vessel it should work safely and well and last a long time.

I have only little experience so others hopefully can comment on the pressure stat, thermal switches and other issues raised here. However, the pressure relief valve - the brass one on the top of the boiler - looks well made. I test mine occasionally because I invert the boiler to dump the water after each use and although unlikely, it is not impossible that scale could enter the valve and block it. I always test at low boiler pressure by I turning off the switch and reducing the pressure to about half by opening then closing the frothing valve. With a gloved hand and using a pair of long parellel jointed pliers I quickly lift and release the valve stem. A shot burst of steam is emitted then stops. I then turn the machine back on, allow it to reach operating pressure to ensure that the valve has reseated correctly.

I have not dismantled the valve but I think it can be left attached to the boiler and disassembled in situ by unscrewing the top knurled nut. Again others with more experience and knowledge should comment. However, it is important to note that over the long term the elastomeric seal(s?) in the pressure relief valve and everywhere else for that matter can degrade. This typically either creates a leak condition or a less common but dangerous failure mode where the valve is literally glued shut. Yet, another good reason to test the valve occasionally, and to replaced this seal along with others during routine maintenance.

I agree, all this makes does make one really appreciate the simplicity or the Caravel - maybe one day!

Geoffrey

It would be nice to know if that boiler is an obtainable part at a resonable cost, although I thing a good TIG guy could put it back together...or even braze the seam....but you will likely change the dimension of the boiler slighly since the two halves would be ground flat to fit, or even reseamed by stretching one half to fit inside the other half for a good seam for brazing. Since the steam and water controls are on the ends this would not be a problem and the rest is rebending copper supply lines. I think the general feeling is that a new boiler would be either impossible to get or frighteningly expensive, so therefore the thoughts on repairing the original boiler come to fore.

But think about it, most metal guys would approach this job like this......you go in with your boiler and explain the whole thing and your concerns with this or that alloy and the pressurized nature of the boiler and the food safe issues and all of these concerns, which are valid.....and the guy is going to, when you are gone, look it over, grind the two halves to fit nicely, and do a very good job brazing or soldering with whatever materials he chooses because they work well for him, and then he will plug up all the ports and apply a little air to one port and test the seam under water for bubbles. No bubbles and you pick up the boiler and pay him and go your merry way with a fixed boiler with whatever chemicals or alloys, just as you do not know what chemicals or alloys are in your factory new boiler which may or may not hold up under pressure any better than the one you just had fixed. the new boiler is in a sense a false feeling of security, if you know what I mean, an implied sense of safety versus the repaired one.

One must also realize, that if a professional welder has gone to tech school, that in the final exam they are given an aluminum beer can cut in half and they have to weld the can back together so it holds water. think about how hard that is. Go to a competent welder and they will have your boiler back in service. Trust a pro, some of these guys can do anything with heat and metal.

Doug - I completely agree with you. I've spoken with Joe at GCC and dropped him an email in which I asked if he might have any old boilers kicking around, just to get a sense of price if so. On the homefront, I've dropped emails to a few welding shops around Toronto to try and track down someone who's up for the task. Unfortunately with the holiday season where it is, no one's in any rush to get back to me, so I likely won't make any progress on the boiler repair/replacement until the new year.
As for the toxicity of whatever is used, all I can do is explain what I need and hope for the best. Whenever I get the boiler back I'll surely be doing a pretty extensive scrub down before ever consuming anything out of it.
My strategy for dealing the shape requirements of the boiler is to take in the frame with it. That way, the welder will have a solid reference regarding the amount it can be stretched or shrunk. So long as the bolts on the bottom of the boiler fit through their corresponding holes on the frame, I should be alright.
Sorry for the lack of updates lately, until I hear back from Joe regarding new parts and a welder regarding the boiler, I'm stuck in a holding pattern...
Thanks again to everyone for all the input, I'll post any news as I get it.
Happy holidays from beneath the snow of Toronto.

Snow? In Toronto? Cold air seems to be Canada's leading export to the states and we are getting a lot of it lately, at leat in the West. I always reflect that no one seems in much of a hurry to do some business.....wish we had a boiler to dangle in front of your eyes, visions of sugarplums and all....we really like to answer questions or queries right away, kindof amazes people. True, not much hurry in the greater scheme of things, but every person is not the same on the hurry up and wait scale. Seems that in a down economy that a guy in Toronto with a crack in his boiler would be seen as money in the bank, but then again, we do like to see things progress apace, whatever the season. Happy boxing day up there y'all.

Happy New Year to all

garthbreaks

You may find more people willing to do your job with an oxy acetylene torch than with other more sophisticated methods. Oxy acetylene brazing is most common and although not high tech when it is done by a competent craftsman who understands all the necessary criteria is certainly a viable option. With this method probably the most critical thing is flame chemistry which effects the metallurgy of both the joint and parent metals. The following company seems have a good understanding and good explanation of this in their Brazing Guide.

The company:

Induction atmospheres:

http://www.inductionatmospheres.com/index.html

Click on their Brazing guide the 5th item in the top list.

Also this company might also be worth looking into for your job

Good luck
Geoffrey

Just a chime in. There are folks that quite commonly weld copper and it is no big thing. A TIG torch is no more trouble than an oxyacetylene torch to one that knows how. There are pure copper welding fill rods available. There are Cadmium and phosphorous free silver braze rod and strips if the boiler is brass or copper. They may also do a wrapped and brazed band over the seam if they are concerned about pressure. So, the trick is to find someone who knows how.
many happy Pulls to you!
-Richard

You might want to ask brazing questions at overclocking fora. The people who build their own 3 stage phase change cascades also deal with brazing and pressures.

They look a bit like espresso machines. Only the other way around. Minus instead of plus.