Hi Ibrahim,
I do not recommend to purchase the Elektor reflow oven.
There was a thorough experience report in the (German Elektor) forum telling about blisters in soldered connections and missed soldered pins for the fan driver transistor on the controller board and almost shorts between the MCU pins.
The Elektor oven is manufactured in China based on Elektor's plans and is quite expensive (€1500) + €50 for shipping.
The preheat phase is much too short and the baking temperature exceeds 290deg/C. Temperature distribution is a desaster with the temperature probe "miles away" from the object.
First test result was a crispy PCB which had to go directly to the waste.
Here is a more promising reflow oven manufactured by Madell (I guess it's a French company).
Check out
Madell Technology Corporation for info about their reflow oven and other useful SMT-machines.
The only way to achieve equal temperatures all over the oven is a double wall device with holes in the inner wall distributed all over the chamber and a hot air fan with ambient air cooling for the fan motor which I saw at work at Motorola. This reflow oven kept the objects in an atmosphere of Argon to prevent oxidation during the reflow process.
With a hot air fan the cooling phase can be controlled precisely by opening a Y-air-valve to have ambient air expedite or slow down cooling - no matter how long the heating element stays hot.
The Elektor oven omits the controlled cooling phase which might lead to material tensions and early breakage of the board.
I also saw a "cheap" reflow station at work using a "tunnel" for soldering. Small parts like 0805 type resistors erected themselves like "grave stones" and had to be resoldered manually.
Regards
Hans