JBC T245 Handle disassembly

[nukie]

I was surfing our Chinese cousin's electronics forum and was surprised to see Kibi's & Dave's JBC review photos posted there so I wanted to share some of the Chinese's photos. Unfortunately they haven't got much but anyway this is a little interest to the owners out there like me who's itching tear apart the handle 

[amyk]

I wonder what plastic that is for the socket... it'd have to be pretty heat-resistant to be used there.

[nukie]

I'll measure the temperature at the socket when I get sometime.

[digsys]

Even on our biggest mass tip, I can grab it by the terminals (~rear 1/3) and it's not even warm. Beats me how they do it.

[amyk]

Looking at the anatomy here: http://bbs.38hot.net/thread-28591-1-1.html there appears to be a few air gaps inside.

[nukie]

I don't have the largest tip so I don't know the size but I think the T245 series is a low thermal mass high power iron, compared to other irons with big tips and heavy mass, Ie big copper tips. So the heat is localised at the tip area instead of spreading, I don't know that's my theory. Need a thermal imager for a quick analysis.

Even on our biggest mass tip, I can grab it by the terminals (~rear 1/3) and it's not even warm. Beats me how they do it.

[digsys]

I don't have the largest tip so I don't know the size but I think the T245 series is a low thermal mass high power iron, compared to other irons with big tips and heavy mass, Ie big copper tips. So the heat is localised at the tip area instead of spreading, I don't know that's my theory. 

What I meant to say is - on ALL series of Irons (210, 245, 470 etc) , and ALL tip types (and I have many), the connector end never gets warm.
I can take the largest 470 tip out and immediately grab it by the connection end, and it's cool. Must be one heck of an air gap, if that's how
they do it. I often have more than 3 tips in the holder, so I'm always moving them around. I don't recall any other brand tips that you can do that with.

[Smokey]

Even on our biggest mass tip, I can grab it by the terminals (~rear 1/3) and it's not even warm. Beats me how they do it.

Metcals are the same way.  You can pull them out and as long as it's upside down you can grab it all you want. 

[Rufus]

I can take the largest 470 tip out and immediately grab it by the connection end, and it's cool. Must be one heck of an air gap, if that's how they do it. I often have more than 3 tips in the holder, so I'm always moving them around. I don't recall any other brand tips that you can do that with.

The cartridges have thin wall stainless shafts. Stainless has about 1/23rd the thermal conductivity of copper for example. 

The end of the cartridge is also heatsinked to the aluminium of the hand piece. The hand piece and the end of the cartridge does get warm after a while.

[nukie]

I measured the C245-036 cartridge with the tip temperature set at 300°C. I used a simple welded ball tip K-Type thermocouple. Ambient temp, 16.7°C as reported by the Fluke. The tip temperature is around 285°C, I added a little bit of solder at the end to help with the heat transfer. The temperature of the cartridge body at the arrow/line near the metal sleeve on the T245 handle is around 80°C. I am not surprise to find the connectors at the end of the cartridge to be at least low 40s°C which is perfectly fine for most plastic.

Like Rufus said the cartridge is built out of thin wall stainless, which explains why, not only it heats up quickly but also sheds heat fast. I have a massive tip C245-407 which I planned to use it on heavy copper such as PC motherboards, I doubt it sheds heat as fast as the smaller tips.