Sometimes vintage Kerosene lamps were copied and copied badly. The basic design was so distorted, the lamps simply couldn't operate as originally designed.
Sometimes they just didn't get it right. The original design was flawed and the burners never operated correctly.
I have two mods where I have corrected both problems.
Step 1: India Copy of a British Duplex Burner
This little all Brass lamp caught my eye. So I bought it and fired it up. I quickly saw why it was never used. It simply didn't burn right. Sensitive to the slightest breeze, smoked if you turned it up, and very little light.
I experimented with the air dome, bleed holes, wick tower and various wick thicknesses. Nothing helped this poorly made copy of a fine British duplex. This was the perfect candidate for a burner swap.
Step 2: Replacing the Burner Collar
The main problem with replacing the Indian copy of the British Duplex is the thread collar is of a size we don't have here on this side of the "Pond". So, the easiest way to install an American burner on a British lamp is to solder on a new collar.
I choose a #2 American collar that would sit over the existing British style collar from oillampparts.com. Use acid flux to clean both parts. "Tin" both parts and then "melt" the two together, keeping the collar straight.
Step 3: Choosing the American Replacement Burner
My extensive experience with American flat wick burners said I should choose a Plume & Atwood #3 Eagle burner with a single 1-1/2" wick because the base utilized both #2 & #3 threads. This single 1-1/2" wick burner, I knew, would out perform the poorly constructed twin 1-1/8" wick burner.
Step 4: Performance Evaluation
The first image is of the P&A Eagle 3 operating on Kleen Heat with a 0.092" Hattersley wick and 3 x 8-1/2" chimney. Compare that to the output of the poorly designed Indian British copy with twin 1-1/8" wicks and a 2-5/8 x 10" slab side Duplex chimney. The original vintage output specifications stated the British Duplex should output more light than the P&A Duplex. However this poorly executed copy certainly doesn't even come close. The Eagle 3 output is 20cp.
So now I have a useful and now, well designed, lamp.
Step 5: Mod #2. the P&A Acorn Replacement
For years I have had this little Brass plated lamp with a Plume & Atwood Acorn burner on it. The Acorn's were never designed correctly. The wick must be raised above the level of the Air Dome to get the burner to output correctly. That is NOT how a flame is to be developed in a Kerosene lamp. A properly designed burner develops it flame below the Air Dome. See the 3rd figure. First a "pre-mixed" Blue flame is developed at the base of the wick. Then, with a properly designed Air Dome and with the correct Wick Tube height, extra fresh air is mixed with the flame creating a "Diffusion Flame", disrupting the Blue Flame into a Yellow Flame.
A more technical explanation is available here.
Step 6: The Replacement Burner
I picked up this little burner at an antique show. Didn't know exactly what it was but I could tell the Air Dome was designed correctly and it looked like a P&A #0, only smaller. So it should fit in place of the #00 P&A Acorn burner on my Brass plated lamp.
It took a few emails to experts in the EU to determine I had a pre-war Camerco. It had a 5/16" wick. Very unusual size 'till I realized this German burner used a 7mm metric wick. I sent to England for a package of 3 Hattersley 7mm / 5/16" wicks.
Step 7: OOPS!
Comparing the P&A Acorn threads on the left with the Camerco on the right, they look the same size but, OOPS! The Camerco is Metric threads. Crap! Time for a re-think of this project.
Step 8: Project Re-Think
I decided to use a glass Fount with a #00 American collar. Next was to rummage around in my burner parts box to find a "donor" burner with a #00 thread base.
Step 9: Cut the Thread Base Off the "Donor" Burner
Using a Dremel and a cut off wheel, you can carefully separate the threads from the upper part of the "Donor" burner which was broken beyond repair.
Step 10: Test Fit the American Threads to the German Metric Thread Base
Test fit your "Donor" threads onto the Camerco burner.
Step 11: Soldering on the American #0 Threads
"Tin" both sides. Put the two together and "melt" together with heat making sure the threads are straight so the burner sits straight.
Step 12: Performance Testing
1st image is the Camerco. As you can see, the burn is perfectly formed below the Air Dome unlike the P&A Acorn in the 2nd image.
The 3rd image is a direct comparison of the two. Both burners have Hattersley wicks, operating on Kleen Heat and both have the same 1-5/8" x 4-3/4" chimney. The only difference is the Camerco, on the left is operating on a tiny 7mm / 5/16" wick vs the larger 3/8" wick of the P&A Acorn. A properly designed burner makes all the difference. Output is a whopping 3-1/2cp!