[Wavytone]

From personal tests many many years ago when seeing up an 8" for solar a solar eclipse...
A 4" f/6 will ignite paper easily. In an 8" f/6.7, a filing card explodes into flame with an audible pop.

Never mind a 10" !

Be very careful with large scopes near the sun for several reasons:

The concentrated beam from a primary mirror will inevitably strike internal surfaces such as the secondary mirror cell, vanes, the interior of the tube wall, and the focuser. If you are careless this is quite capable of charring paint, melting plastic and igniting flammable parts - wood, epoxy (carbon fibre tubes) and cardboard (sonotube) will be charred or ignited. Metal parts will survive, but black paint will not. If the vanes of the spider were soldered, its quite likely the solder will melt in the beam.

Attempting to put that amount of energy through eyepieces can damage the coatings permanently. Eyepieces with cemented elements should not be used - the cement may boil, causing the lenses to come apart or worse, split. Secondly the glass will get very hot and expand - make sure they are quite loose in the cells because if tight, differential expansion between the glass and cell may well cause the glass elements to fracture.

For the eclipse I made a big oversize Ramsden eyepiece (two elements airspaced) to project the sun from the 8" onto a screen so many could watch the partial phase of the eclipse safely. The big scope provided a very nice big bright image.