Spark Test

[Bob]

Spark testing was mentioned on another thread. I thought I would attempt to photograph some sparks.

The first is "weldable steel" you might buy at OSH or Home Depot.

[Bob]

Next was an old bed frame. (Seem to have lots of these around as scrap).

[Bob]

Next the handle of a large monkey wrench.

Not much color difference, but you can make out a few splits in the spark tracks.

[Bob]

Last (for now) Craftsman chorme tool steel.

More splitting sooner in this one.

Humm. It did look like more difference between the spark patterns while I was making them. I may have to work at this form of photography. Hoping some others may be able to capture the differences better than I have.

Bob

[Guest]

Originally posted by Bob
Next was an old bed frame. (Seem to have lots of these around as scrap).

A note of caution on welding bed rails. They are hardened and don't weld very good. The ones we had in the Army were impossible to weld.

[Bob]

Rocky D,

Thank you for your input.

The bed frame rails do seem an odd lot. A bit harder, yet not the red sparks of cast iron. They saw and drill OK, but seem slightly harder material.

Anyway I am (for right or wrong) building a motorbike caboose for my neighbor's motorhome (receiver hitch). Mostly using old bedframe rails. I am planning lots of crossbracking, tension straps, and weld backing plates into the mix.

Bedframe metal does seem to melt and mingle with weld metal. While that is a good sign, the expert metalurgist may be having fits.

Bob

[Roger]

What kind or comera are you using to photograph the spark trails? If it is digital you might be able to shift the contrast or darken it a bit to bring out detail as some of the trails seem a bit too light which would be over exposed. Also shifting picture to right and down a little to show end of fan of sparks might help.

With a still film camera I would have to make my best exposure guess using light meter. I would then bracket the exposure high and low to get best results recording exposure settings for each frame. Would also have to try different exposure times to see which shutter speed gave best spark tracks. I know it can be done having seen nice color pictures or spark trails. As to color of spark trails you can make them any color your heart desires with a computer program or while printing a photograph.

The saying that pictures don't lie is a lie.

[Bob]

Camera is an Aiptek "pen cam" ($100 list, $70 on the web) so there are almost no controls. I was making the sparks and taking the pix all at once and can probably do better with a helper.

Ah but it is Monday morning and I must return to my day job.
Bob