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Welding/manganese jaw plate


how do I keep my plate from warping when I am building up the surface? Do I need to pre heat the plate or try to keep it cool?

Any time you are layering build-up material over a large area you will cause massive heat distortion.
Preheating above 650 degF will help a bit, but physical restraint of the part is also recommended.

Pick a piece of heavy plate and tack weld it on the back of the plate as a strengthening rib or "Strongback".
When the part is cooled down, grind off your tacks with a cutoff wheel on a right-angle grinder and break off the strongback.

650 degrees F is really easy to spot because it is the flash-point of motor oil.
Just heat the steel with a rosebud torch tip until a drop of oil flashes off.

Slow cooling is the final step to reduce warpage.
Bury the piece in an insulating material such as ash, powdered lime, vermiculite, or dry sand.
Or you can wrap it in fiberglass insulation batting.

Depending on size you may need multiple strongbacks going both directions.
Just remember to make sure you can easily remove them when done.


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Ernie Leimkuhler


Questions about Oxy-Acetylene welding/cutting, MIG, TIG, Flux-core, Stick welding, brazing and soldering, bike frames, air frames, motorcycle frames, structural welding. Also questions about Welding Certifications and Inspections. All questions about fabrication of metals (stainless steel, steel , aluminum, brass, bronze, copper). Basic questions about underwater welding. TIG is my strongest subject.


Extensive background in most welding fields. 18 years fabrication of metal theatre scenery, 16 years structural steel, 2 years pipe welding, 9 years as a Welding Instructor at South Seattle Community College, and 5.5 years as a Welding Instructor at the Divers Institute of Technology. 16 years Industrial Welding Consultant for fabrication shops in the greater Seattle Area. 11 years Architectural Metal Fabrication. 8 years in Film/TV; SPFX/construction/set-deco/props/. 33 years Blacksmithing and Knifemaking. Currently a Field Welding Inspector for Otto Rosenau and Associates.

American Welding Society - Certified Welding Inspector Washington Assoc of Building Officials (WABO) - Special Inspector - Structural and Reinforcing Steel.

Do a search on google groups for "Ernie Leimkuhler" in the rec.crafts.metalworking and sci.engr.joining.welding groups. Blacksmith's Gazzette - Anvil Making

BA Theatre Technology - Purdue University.

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