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Flashback Fabrication: Butt Welding Tips That Still Hold Strong

MARCEL VENABLE . August 29, 2025 . How to . MARCEL VENABLE
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Tools and Tricks to Help You Butt Weld Like a Pro

For this installment in our series of welding tips and tricks for beginners we will discuss welding joints. The proper term for aligning two pieces of metal to prep them to be fused together is “joint.” There are many types of joints: square, bevel, V, J and U-joints, and so on; however, the most often used type is the butt joint—it’s the reigning king of metal fabrication.

Although butt joints are the most common type used, most welders wish they had a third hand in order to keep the two pieces of metal aligned while maintaining the proper gap for strength. It’s important to maintain a reasonable gap to ensure complete heat and fill wire penetration, which makes the joint stronger than it would be if it were touching surface to surface.

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Most of the time, welders use clamps to hold metal pieces in place, but what happens if the metal piece is longer than the clamp’s throat, or the style of clamp used makes it difficult to keep a consistent gap? There’s a tool to solve this problem known as a butt weld clamp. They are common tools of the trade and are usually sold in multi packs containing four to six clamps. Butt weld clamps can be ordered in different sizes, depending on the desired gap thickness.

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They are very easy to use; check out a few examples where we used butt weld clamps as we welded a 1967 72 C-10 bed floor from Classic Industries. ST

[01] To fix a rusted out steel bed floor on a ’71 C-10 we had to shorten a long-bed floor panel from Classic Industries so that it would fit on a short bed box.
[02] Say hello to my little friend. You to will fall in love with the Miller model 211 welder. Features like the multi-voltage plug, or MVP, will allow you to use 120- or 230-volt power to weld almost anything.
[03] Before getting started, we checked the thickness of the material we’d be using, or its gauge. Then we consulted the reference chart on the inside cover of the machine for the recommended settings. One great feature of Miller’s 211 model is that it’s equipped with an auto set feature. Simply set the knob to the proper auto set based on material thickness and wire size, and the 211 activates the proper heat and wire speed setting. This allows a newbie to lay down beautiful looking and super strong beads just like the pros.
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[04] Chicago Welding makes these slick butt weld clamps, available from Harbor Freight Tools, that make fusing sheet metal a breeze. The clamps open when you loosen the wing nut on the top that holds tension from the crossbar on the bottom of the clamp.
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[05] Loosen the wing nut until the block can be removed. Insert the tub between the seam, and then slide the tab though the hole on the back of the panel. Snug down the wing nut to hold the two panels in place.
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[06] Safety first is the way we like to roll, because stupid hurts. Be sure to wear a protective jacket, gloves and a welding helmet to prevent any injuries.
[07] Begin tack welding the seam close to the clamps at a slow pace to control the heat and prevent warpage. Once the areas that are next to the clamps are tacked, remove them and continue to weld the remaining parts of the seam using the same discipline as if the clamps were still holding the seam together.
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[08] We welded the seam on the underside of the bed to reduce grinding down the bead of the weld, which will make prep for paint easier. Here’s what the seam looked like after it was welded. Note the alignment of the bed floor ribs, and although it’s difficult to see from the photos, there is no sign of warpage or distortion at the seam. These two panels are just as strong, if not stronger, than a single piece.

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SOURCES

MILLER ELECTRIC
Millerwelds.com

CHICAGO WELDING
(HARBOR FREIGHT TOOLS)
Harborfreight.com

CLASSIC INDUSTRIES
Classicindustries.com

 

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