Fire starter

Fire piston

Made in titanium is my favorite

http://www.jsme.or.jp/tsd/ICBTT/conference02/MasanoriOGATA.html

http://www.oberlin.edu/physics/catalog/demonstrations/thermo/firesyringe.html

http://www.bbc.co.uk/bang/article_firepiston.shtml

Scale it up : multi piston fusion ;-)

https://youtu.be/2m9kC1yRnLQ?t=612

Smouldering - char cloth

low-temperature, flameless form of combustion, sustained by the heat evolved when oxygen directly attacks the surface

Smouldering fuels are generally porous, permeable to flow and formed by aggregates (particulates, grains, fibres or of cellular structure). These aggregates facilitate the surface reaction with oxygen by allowing gas flow through the fuel and providing a large surface area per unit volume. They also act as thermal insulation, reducing heat losses.

http://fire.nist.gov/bfrlpubs/fire95/PDF/f95127.pdf

Parabolic mirror

Mirror size : 8cm diameter

Sun : 300 W/m2 ( November Sweden )

The effect hitting the mirror : 0.04*0.04*π*300 = 1.51 W

Let's say that 70% of the incoming radiation i reflected to the focus dot 0.4 cm diameter, thus resulting in a 0.7*1.51 = 1.056 W at an area of 0.004*0.004*π=0,00005027 m2

Emissivity = 0.9 "wood" ( chaga - tinder fungus )

http://www.engineeringtoolbox.com/emissivity-coefficients-d_447.html

Stefan-Boltzmann Law

T=(1.51/(0,00005027*5.6703E-8*0.9))^0.25 - 273 => 600 °C