Camp fire sparks, an odd question.

[GadgetBoy]

I'm considering using an aluminum mesh to catch sparks from a camp fire so that they can't hit a tarp and melt holes in it. Do you think they have a positive enough potential to be attracted to a grounded mesh?

[IanB]

I'm considering using an aluminum mesh to catch sparks from a camp fire so that they can't hit a tarp and melt holes in it. Do you think they have a positive enough potential to be attracted to a grounded mesh?

Why would you think electrostatics comes into it? And if a mesh is grounded, why positive and not negative? Both would be attracted equally. Charge is charge.

Short answer: electricity doesn't come into it. If the sparks (burning embers) are bigger than the holes in the mesh they will be stopped by it. If they are smaller then some may get through.

[SparkyFX]

I think they move mostly based on convection and inertia (water vaporizing, wood gas exploding).

The best way to avoid this is to only burn dry wood, or dry it before burning... and keep a safe distance from anything inflammable.

[T3sl4co1l]

1. Note, a huge bonfire may be so hot that the aluminum screen would have to be quite high up, and quite large, to avoid melting it.  A stainless steel screen may be more practical.  A modest sized campfire for cooking and warmth should be okay though.  (You didn't specify, so, making that clear.)

2. There's probably little charge coming off the fire itself, of either polarity.  Charcoal is conductive, and flames contain ions (especially the readily ionized sodium, not even so much by quantity as by sheer optical output) thus making the fire somewhat conductive and keeping charge equalized.

3. You can still do it, by alternating charged screens.  You need multiple screens of course, insulated from each other, and charged with high voltage.  Screens are okay for the charging grids, but the precipitators should be flat vanes to reduce the air velocity and turbulence flowing over the stuck particles.

It's probably more practical to spray the tarp with water, or spread dirt on it, or just not keep it so close to the fire.  Or not place it downwind of the fire, but, there's the old campfire superstition about saying/doing things to make the smoke go away from ones' position that always seems to work never but sorta...  Basically, the wind is always changing at ground level, so not much help there.

Tim

[Dundarave]

How about simply applying some tin foil to the exposed areas of the tarp within spark distance?

[Jwillis]

There are screens made for camp fires.Unfortunately they seem unrealistically expensive.But you could build one easy enough just make sure you use steel mesh,Aluminum will most certainly melt as T3sl4co1l mentioned.