Help creating / bending Coleman 400 Generator

@Blueflame - sooo funny! You guys are all very sharp. No, I hadn't realized it was wrong. I hadn't even thought about it. I was just trying t get a pic to @cottage_hill_bill and took the pieces out of the bag and quickly laid them out. No thought went into it.

 

You know more about it than me apparently. Obviously, its a line of sight thing between item and electrode but I never took that as literally meaning it only affects the surface of the item. You ask good questions I can't answer. But I found it "de-rusted", if you will, the exterior of a pair of pliers but also the "interior" of the spinning axis was freed up. It certainly wasn't visible yet the electrons found it. I would think its the entire piece of metal being acted on and not simply its exterior. But these are just all sloppy assumptions on my part. We'll see what transpires when I do it.

The fact that you guys readily think about unsoldering these large-ish brass parts as no big deal is exactly what I am talking about. I'm simply not in your league.

Yeah, thanks for reminding me abut the graphite packing. I knew it was coming up but I didn't know how to approach it. This whole thing is a back burner issue sitting in my attic for the last 5 years. That's when I bought 3 400 Generators on ebay and got 2 stoves up and running. They weren't plentiful but they were still around then. NOT ANYMORE!!! But I never threw the old generators out. Years ago I did order new graphite valve stem packings but they were too huge and they're gone now. I just ordered some of the 1/4" ribbon. Thanks for including that post. Very informative. Much thanks to both you guys.

These generators don't have a chance. I am going to bring them both back into perfect condition! It just doesn't seem like failure is an option. It seems doable!

 

We really appreciate people like you.

 

Aww! Very kind words. Thanks.

Never leaving well enough alone the class clown in me wants to add:
"Too bad my ex wife wasn't a stove aficionado! ---- Ba da bump! Thank you. Thank you very much!"

 

@Blueflame - EEEEK! The previous pic was wrong on multiple levels. This pic is better!

 

You bring the 'never satisfied view' here with pleasure, not any of the crap some seem to add to it.
Your willingness to look at things from outside the conventional box AND the willingness to listen to the tried and true lessons is very refreshing.
I try to keep my mouth shut, and ignore the (Ok, not gonna say it) other people.
I just want to commend you, whether you succeed or not.

Ken

 

Thank you. I genuinely appreciate that. Especially since its very hard to even venture into this space because everyone seems so ridiculously knowledgeable and smart and I feel hopelessly quite the opposite!

And I am totally on board with your sentiment of whether I succeed or not. I will make a serious attempt to restore a generator. I am not an independent lab or a machine shop. I might try a combination of electrolysis, ultra sonic and carbon chemical bath. I'm hopeful that will solve of perhaps partially mitigate the problem. I may completely fail. And that will be totally OK.

I am now at a point where I know how to wrap my head around this problem. I understand this generator stuff way more than I ever did. So for me this has been a success regardless of the final result.

I understand 7 things now that I never knew before. Now, these Observations/Conclusions may not hold up but the fact that I came up with conclusions is what makes this fun for me.

My 7 Observations/Conclusions/Questions for The Coleman 400-499 aka "Model 400" Stove:
1) The Coleman 400-499 aka "400" Flame Control valve (aka 2nd valve) is on the far end of the generator AFTER THE BURNER! The fuel tank and Shut Off valve (aka 1st valve) are both on the near end of the generator BEFORE THE BURNER just like every other single stove in the world.... assuming they have all those parts.
2) I wonder if the "400" stove (& all its 2-valve variants) is the ONLY GAS STOVE IN THE WORLD to have this unique arrangement??????????? (Not important for it to be unique.)
3) I believe this 2nd valve on the far end of the generator AFTER THE BURNER is responsible for its extremely good simmer performance and high heat output, etc, etc. (Big discussion here!)
4) I wonder about generator tube construction techniques. How do they make the flares? Is this done when the metal is softer? Is the metal heat treated afterwards? (You guys all know this stuff!)
5) Integrating the flame adjustment valve into the generator tube as a single piece complicates maintenance by making spares harder hence more expensive to produce.
6) I assume the Flame Control valve should last as long as the Shut-Off valve. I assume there should be no reason to replace it more than the Shut-Off valve!
7) If the 2nd valve / Flame control valve was made like the 1st valve the "new and improved, revised" generator would be screwed on at both ends. Thus we keep the 2nd valve in its extant location AND make generator replacements much simpler and cheaper to produce! Thus simplifying the generator while keeping the exact design in place as-is!

Even if I can't fix it I feel like I understand it much better than I did!

 

I personally would service this generator as often as I could knowing that replacements are unavailable. I'm experimenting with dry ice cleaning, and I'd like to post my results in the near future. Its really much more simple than it sounds as paintball tanks and sodastream bottles are readily available. This generator was designed to be replaced after fouling, we need a simple and effective way to clean them for repeated, long term use. The difficulty lies in the fact that this generator is not a straight tube, this makes cleaning rods hard to get into the places that they need to be to do the cleaning. Also in the fact that carbon is notoriously insoluble. There are very few things aside from molten iron that can truly dissolve carbon.

 

The challenge with these generators is the efficiency of the product. The needle at the burner end is both cleaner and flow control. In order to do both it has to be connected to the control lever at the other end of the generator, and it needs a tight fit at the delivery end. Eliminate the 2-for-1 deal, and it's a lot simpler.

The Chinese stoves seem to often use a cable cleaner system similar to MSR, along with a basic valve for flow. I know it destroys the pleasing simplicity, but would something like that be an option? There are factories currently producing these units so getting supplies should be as simple as placing an order for x units to y design.

And there are stoves that look like Coleman stoves, so possibly the generators are interchangeable? Or at least work the same way, meaning orders can be placed for compatible parts with minor build tweaks.

 

@Boron40 not sure if this would help but I have a 508 stove that uses that same generator. The one that was given to me was broken as the flame adjustment knob spun free and would not actuate the cleaning needle. I ended up going the easy way and finding a donor 400 peak 1 for 5 bucks and taking the generator off it to bring the other stove to life.
The broken generator sits in a bag of junk parts unused but was clean as the owner never used anything but Coleman fuel.
In your photos you show yours apart so if I read it correctly your parts are good but the generator tube is clogged with carbon?
If you like I can send you mine and maybe from the two you can get parts from mine and yours to work?
Mine has a good clean tube... Hardware.. Etc... But the part with the black knob that changes the flame level broke off right behind the nut. If you got that out with the graphite then you would have a good clean tube (I know it's clean because I ran it and it did burn fine but could not adjust the flame level)
I'd be willing to mail it to you so you can experiment with it...or cut it up to see how it works... Looks like you're in the US so no need for payment... Just junk parts that maybe help you out as your parts look complete. Lemme know!

 

@Boron40 my post on the junk generator...
508 regulator/generator is hard to find?

 

My 400A stove had a clogged generator. I have bought with the hope to clean the generator. Unfortunately the mechanism also was missing. Only the generator+ the jet and a screw to close the flame adjuster valve's orifice. Therefore I needed to find appropirate components for the jet cleaner. I have done everything and during these operations I have found that what was clogging the generator was the rust coming from the fountain. I have filled with fresh fuel the tank then I have sucked it from the bottom. The clean fuel was full of dirt, debris and rust. I have repeated the process until there is no debris in the fuel. The fuel tube's bottom orifice was also clogged. Therefore I kindly suggest to screw it out to check whether this small orifice is open. If that stove had a filter that would be great.

 

@okerol Good job discovering the problem. If you unscrewed the Fuel Tube (F/A Tube) then you are accomplished. Not many people in the real world could do that, but probably every single CCS member can!!! While you had it out it would have been great to replace the schrader valve since the "rubber" (NBR back then) does degrade and leak after these many years. I have many 400, 400A, 400B, 508, 576, 505 etc stoves. I've only gotten a few stoves with a rusty fount but I get rid of them promptly because even though you can clean the rust out, the tank inner coating has been compromised. Then I do a complete cleaning to all parts including the generator, replace the schrader valve and then rebuild it. I love these stoves!

 

@Boron40 When I've looked inside of my tank with a battery torch, I've not seen any rusty part in the tank. I assume that the previous owner has used dirty fuel many times and this rust has accumulated at the bottom over time.
My schrader valve is functional. It shuts off correctly. I always depressurize my stove after use, when it's cooled down enough. However I have taken note. The next time I'll need to reopen it, I'll replace the valve.

 

@Boron40 — encountered a bad gen on my 400 (cracked flared end) and thought the same thing about fabricating a replacement. Did you ever try your idea?

 

Exactly. I have fabricated many replacement generators for my 400A stove. The last one (but not tested on this stove yet) consists of a copper tube for the outer case and a bicycle brake outer cable steel casing (after burning off all the plastic stuff) for the inner path. Lastly I have inserted a bicycle brake cable inside for the purpose of cleaning the tube occasionally. Do not forget to leave 1cm of cable past the flared end in order to grab it. My BRS12A stove had a similar generator that was working good anyway.

 

The most dificult part of fabricating a new generator is bending the tube without crashing it. Bicycle outer brake cable prevents that. Otherwise you will need special tools for bending this tube.

 

I would be very interested to see how the copper outer tube performs when the stove is fired. At high temperatures copper will oxidise and form a black scale.

Cheers

Tony

 

Coleman 533 generators are readily and easily available. If you are comfortable brazing, you can cut down the 533 gen, de-braze the tube from the 400 gen, and braze the 533 gen on.

 

Is the 400 gen brazed at the base of the main gen tube where it meets the rectangular pricker body? I’ll look on mine when I’m home.
so then would you keep the insides of the 533 generator (incl the wire?)