Help with project

[millerman58]

Hey guys,
A friend's son asked me to help with his science fair project. He wants to do something with welding, do any of you have any ideas. Thanks!

Bryce
BB Farm Supply

[triggerman]

There are pages and pages of ideas and info on Miller's site. A few things that come to mind are welding pieces together and show cutaways after each pass. Then do some basic destructive testing. Such as:

Two pieces of 3/8" X 3" layed side by side.

Cut a piece off each for pre-weld display.

Tack them up and whack off a sample.

Weld one pass and cut two pieces, one for cross section and another to clamp in a vise and beat on until it breaks. Take pics of the destructo test and record how many whacks with what size hammer to break.

Weld another pass and repeat.

Weld a third pass and repeat.

Lots of smaller pics, a few larger ones, static samples, comparison data and conclusions about strength after each additional pass. VOILA!

BOL

[harcosparky]

I recall seeing something about a " strength of brazing " demonstration.

The brazed two steel coupons together and used some sort of hydraulic machine to pull the coupons apart. The pieces seperated outside the brazed joint in the base metal. I think it took like 3,000 pounds to pull it apart.

I may have read it in a " Welders Handbook " I purchased from Lowes for $15.95 if ya need a reference.

[JonnyTIG]

If you are going to cut the weldments apart during each successive weld pass, try polishing the cut ends with sand paper or a sanding disk, and etching them with nitric acid. The acid will show the difference between the base metal and the weld deposit, or the layers of each weld bead. The etching process will show the level of penetration of each weld layer, and define the depth of penetration and profile of each weld pass.

I don't know where you can get nitric acid in your area, but I do know it is readily available from supply stores. This etching process is really neat to try, and it works very well. You may have to experiment with the time you leave the acid on the metal, but I found five to ten minutes worked well for my applications.