Radius 7 "Special Silent" Cap Fettle

Hello gentlemen!

Here's something a little different that I hope you will find entertaining and perhaps educational as well. First the back story to set the scene.

I found a Radius stove on French eBay that was listed as a Radius 17, a relatively common stove as Radiuses (Radii?) go. But, in closely inspecting the photos, I became convinced that it was instead a much rarer Radius 7 fitted with a "Special Silent" burner that included at least some part of the unique silent cap. You can see pictures of a relative of the stove I was hoping to get in the Stove Reference Gallery. Link It's the one on the right. I won the auction with little competition for a very reasonable price.

Though intended to go via air, the package was redirected to surface (boat) and 32 days after payment, I received my package. Or, rather, what was left of it.



Miraculously, the stove and the pan ring survived this abuse with little damage. The pot supports/legs are a bit bent, but should be easy to restore to their original positions.



However, the "Special Silent" cap was nowhere to be found and probably fell out of the gaping holes in the package aboard the scurvy ship o'transport.

Here's my solution.



I used an old brass bell, a 3/4" nominal copper plumbing pipe cap, and some brass stock to fettle a cap. You can see above that I've drilled a hole in the bell to fit over the 9/16" diameter central spigot on the burner, cut it down to size and also cut down the pipe cap.



Here, I've rather inaccurately marked out some lines for drilling holes in the bell.



And, as the cap I am using to top the burner does not have sloping sides like the original, I thought it might be smart to fashion a center deflector to direct fuel/air downward into the lower part of the cap.

More on Post #2 below.

 

This picture shows how I intend to use the fuel/air diffuser cone in the top of the cap.

Drilling the hole in the brass plate.


The cap after silver brazing it together, shaping the plate round and doing some clean-up/polish.



The bottom part of the cap with two sizes of holes drilled in a somewhat serendipitous pattern. (Hey, I'd never made one before and I was winging it!)


Put it all together and after a false start or two (pictures of which you just don't need to see), it looked like this:

While this burned quite loverly for a good twenty minutes, it stopped working so nice after that. I put it down to a dirty tank and a very clogged burner. Soooooo, I cleaned the burner using my "boil-n-quench" method and scoured the inside of the tank.

A clean burner inside and out.


What came out of the burner. This water was completely clear when I started.


What came out of the tank. Yuck! (Those things that look like fish eggs are BBs I use in the tank to scrub it clean.)


In the last part posted below, I'll show how the burner goes together and performs now. And, I'll present another option for such a burner.

 

First, the bottom part of the burner.


Then a 5/8" OD brass "spigot extender".


Then the top cap, which you've already seen.


I think it looks pretty good, produces a lot of heat for it's size and definitely passes the "tea test".


I still need to work out some details. My plan is to silbraze the extender tube to the lower "bell" part of the burner cap. It turns out that the length of that extender tube is what determines the quality of burn. I'd like to fuss with that a bit more to get it "just right".

The other issue is to provide some centering method so the top cap is not just sitting loosely on top of the bell portion but is locked in in some way. The easiest thing would be just to silbraze it all together.

Lastly, should you find yourself in possession of a Radius "Special Silent" burner and without a cap for it and don't feel up to doing all this fettling, here's what you do. Make a #4 inner cap as shown here: Link

Then, use a Con #4 outer cap from Base-Camp. It'll look like this and run just great.

Actually, this picture shows it with a #4 brass outer, but the Con worked just as well. Full-bore operation.


Simmer.


There you have it. I hope that you enjoyed this epic three-part post. Sometime in the not-too-distant future, I'll add the Radius 7 to the Reference Gallery. I want to straighten those legs and clean it up first.

Best wishes to yo all,
Gary

 

BernieDawg

Sodding brilliant!!

 

Thats one master-fettle, BD, and a beautiful blue flame too!!!


Regards,
Alan

 

Very nice BernieDawg. Great fabrication skills! It's amazing that the stove wasn't damaged worse during shipment when the box looked like it did.
dday

 

Everything has been said! Awesome fettle and creativity!
Best,
Randy

 

you really had your ups and downs with that one! great work and how long did it take to come up with that bell idea? oh and what's a con #4 cap? whats the con stand for, brand or material?

 

That's awsome mate, well done. I wish I was able to do the same.

Si

 

Hi Gary, Absolutely Amazing!!!
I bet you are the first person in over 75 years to make Radius "Special Silent" burner caps.

Wonderful work.

Best Regards,
Kerophile.

 

Hi Nagant, This link will tell you all you need to know about "Con"
https://classiccampstoves.com/threads/86

The No.4 the Gary referred to fits a Primus No.4, stove. If you consult the Reference Gallery, you will see that this stove is a 1.5 pint, classic brass tank, three-legged paraffin stove, fitted with a rather neat silent burner. Stove and burner are of course smaller that a Primus No.5, the more common model.

"Con" manufactured spares and accesories for Primus stoves, with both the Con and Primus names often appearing on the labelling.

Base Camp currently sells some new, old stock Con No.4 outer silent burner caps at a very fair price.

Best Regards,
Kerophile.

 

Hi Gary,

Everyone else has said what needs to be said, just wanted to tip my titfer in your direction.

 

WOW 8) Respect

Nick

 

Great piece of fettling Gary

 

stunning work Gary
my hat is off to you yet again
i love the flame pattern looks gorgeous mate

 

Thank you very much! You are all more than kind with your lovely comments.

Nagant, I see that Kerophile has linked you up with the Con article. I confess I'd forgotten about it. Our UK friends know a huge amount about stoves and their history.

FWIW (For What It's Worth), here's a picture of a 5-hole Primus #4 "Con" cap that I purchased from Base-Camp.



Also, I cannot take credit for the idea of brass bells as items that are useful for stove fettling. I've been collecting bells and egg cups since I saw this post about making 00 roarer burner flame rings. I believe the egg cup variant was mentioned to me by Kerophile.

Link

The local metal scrap yard has a large brass bin near the scale that I poke through when I'm there. Most of it consists of discarded decorative brass items that were foundered in India. The bell I used for this project was one of a pair I got for less than a dollar.

With regard to the flame appearance, I really was in quest of this:



This is the photo of an actual Radius #7 "Special Silent" burner with the original cap posted by Aktopp here: Link

I think it's very beautiful and I've been obsessed with it since I first saw it. It's what I was trying to achieve with this lemons-to-lemonade project.

Thanks again to all! Good luck with your fettling challenges - don't give up!

Cheers,
Gary

 

Inspirational Gary.

 

WOW WHAT A WORK !

CONGRAT MY FRIEND. YOU DESERVE THIS...

 

Very well done Gary
Like you, I find the flame pattern of the special silent burner very beautiful.
And you have managed to make a well working replacement. Awesome

 

That's a fantastic flame Is it truly silent? It's amazing what you can do with a brass bell or candle holder with enough time and patience.Great job Gary

Ernie