- Practical advice
- Attention to the flow angle
- Choice finishes
- Preparation of angles
- Welding of the two frames
- Assembly of the structure
Thanks to its solid metal structure, this table with clean lines can accommodate a large tray in solid beech. Its realization is accessible to all DIYers mastering the technique of arc welding.
Cost: 200 €
Time: 1 weekend
Equipment: angled angle of 45° and 90°, clamp, scriber, tape measure, wire brush, brushes, gloves and face shield, angle grinder Ø 125 mm, welder's hammer, saw and file, metal chain saw, arc welding machine, 10 welding rods Ø 2.5 mm, press-mounted
See the plan of this realization (in pdf): A wooden coffee table and steel angles
The structure of this coffee table consists of two frames (seat and tray support) assembled miter cut (45°) by means of welding seams arc. These frames are joined by four uprights, assembled as for them in straight cut (90°). The beech tray is then simply screwed onto the corners.
Attention to the flow angle
The main difficulty of this realization lies in the precision of the cutting of the angle bars (here 30 x 30 mm, thickness 3 mm). Straight and miter cuts are prepared in advance, referring to dimensioned plans. Arc welding is done by means of a short circuit created between the metal core of an electrode (solder rod) and the workpiece, by means of a clamp connected to the welding machine.. The temperature of the arc, above 3000° C, melts locally and simultaneously the parts, the filler metal and the coating of the electrode. Wearing leather gloves and a welding mask is essential.
Steel angle: avoid lossesThe steel angle is available in large DIY surface, in bar of 30 x 30 mm section, 3 mm thick and 2 m long - which often causes large losses in cutting. Specialized trades offer the angle of all sections and thicknesses. They can make the different cuts on demand, depending on your debit card. In this case, allow a 5 to 10 cm increase in the sides for miter cuts.
Grind the welds (angle grinder) to obtain the flatter surface possible: hold the tool almost flat, parallel to the work surface and exert moderate pressure in light zigzags. Wear gloves and goggles.
Once welds are made, the whole is treated with two layers of special iron paint (Dulux Valentine, Dyrup, Hammerite, V33, Julien...). Using an aerosol spray paint (Sinto type) is faster, provided you work in a well ventilated area. An alternative is to apply a colorless glycerophthalic satin varnish. Teflon or felt pads are glued under the base to protect the floor. As for the plateau, here in solid beech, it is better to have it sold in a DIY store. The surface should be finely sanded and brushed in the direction of the fibers. It must then be protected with an oil or a colorless or tinted wax (Libéron, V33, Les Frères Nordin...) or, as here, apply two coats of clear glossy glycerophthalic varnish.
Preparation of angles
Degrease the corner bar with a cloth soaked in whitespirit or lean solvent. Take care of the cleaning if you work the wood in the same workshop: the grease stains are formidable.
Raise the dimensions very precisely using a metal ruler and a scribe. This step guarantees the stability of the entire structure.
To draw the miter cuts, position the protractor at 45° and at the desired point, draw a line at the scribe. At the ends of the line, "lower" the perpendiculars on the flanks of the angle.
Cut with a hacksaw following the line of cut. A long and tedious job but its quality and accuracy will save you time when welding elements.
You can also use an angle grinder (full-size) equipped with a cutting disc. Your gesture must be precise.
Faster and more precise, the hacksaw (Ø 400 mm disc): set the graduated sector of the jaw movable vice (45° for miter cuts or 90° for straight cuts), then block the piece.
Lower the moving head of the hacksaw on the cutting lines, a little outside to take into account the thickness of the disc (about 2 mm).
Burr the morfil with an angle grinder with a grinding disc. Create a slight chamfer where the weld seam will be lodged.
You can also trim the morfil with a cross cut toothing. Hold your tool firmly, slightly inclined at plus or minus 30°.
Welding of the two frames
Check flatness with a metal square. Brace the brackets on the bench with clamps and place the ground clamp connected to the welding machine.
Adjust the intensity of the welding machine (75 A), rub the tip of the electrode (Ø 2.5 mm) on the junction of the parts, then pull a weld bead.
Cool for 2 to 3 minutes, then remove the slag from the welder's hammer.
Rub the weld seam with a wire brush. If it is irregular, iron a cord over it.
Repeat these operations to form the other three corners of the frame. Do the same to realize the other frame. Then check their squareness and flatness with a square positioned outside the corners.
Finish welding the outside corners by making down seams, perpendicular to the junctions. Remove the slag with the welder's hammer and brush together (wire brush).
After this grinding operation, the surface condition of the welds should be smooth, glossy and perfectly flat with the rest of the frame.
Assembly of the structure
Start mounting the frames: place the first one flat on a fi xed and flat support, then check the plumb and the level. Do the same for the second frame. Hold the 4 uprights with the 2 frames using clamps.
Make sure the squareness of the whole (measure the diagonals), to avoid any warping of the structure. A press bench and adjustable workshop candles are useful.
Weld the posts with an intensity of about 80 A. Bend the welds with an angle grinder (Ø 125 mm), held almost flat. Remove the slag, brush, then apply 2 coats of special iron paint. Then screw the solid beech tray onto the top frame.
• Steel angle with equal wings 30 x 30 mm, ep. 3 mm
• Special paint iron or aerosol spray (here, satin aspect)
• White spirit or acetone