The Art of Lead Burning / A practical treatise explaining the apparatus and processes.

by C. H. Fay

Horizontal Lap Seams.

This seam is prepared precisely as described for flat lap seams. The strips can be fastened to a board with a few tacks. The strips can then be supported in the position shown in Fig. 28. The burning is commenced, as before, at the side nearest the operator. The flame must be made as short as is consistent with the weight of the stock. It will be found to the beginner's advantage to have fusion take place slowly. The point of the inner flame is brought to bear on the outer edge of the lapped sheet and at an angle of 45 degrees. Both sheets should begin to brighten at about the same time. The melted drop must be driven against the back sheet by the force of the jet of flame, and if the sheets are clean fusion will take place quickly.

Fig. 28.—Burning a Horizontal Lap Seam.

The drops or beads of lead will appear very small on this form of seam, owing to that great obstacle, gravity, which causes the drop when melted to flow downward and so swell the seam. The drops, in common with other forms of lap seams, should be made short, letting each drop overlap the previous drop as much as possible. Great care must be taken not to weaken the seam, as shown at a. The beginner should strive to get the seams so that when cut into small sections each section will resemble the result shown at b.

Upright Lap Seams.

Prepare the sheets as for flat lap seams, fastening the sheets securely to a board, as previously described. The burning should be begun at the lowest point of the seam. After regulating the flame, the point of the inner flame is applied to the edge of the outer sheet slightly above the point decided upon as the starting point, and at an angle of about 30 degrees, as shown at a in Fig. 29. As the drop begins to melt it will have a tendency to flow downward. By a quick turn of the wrist the flame must then be directed against the back sheet and slightly under the melting drop.

The under sheet should brighten at once, and the force of the flame, being partially directed against the melted drop, tends to force it against the bright spot on the back sheet, with which it instantly unites. The flame must then be withdrawn for an instant, to give the fused drop time to set. The operation must be repeated until the seam is finished. Using ordinary language, it may be said that the drop is cut from the upper sheet, carried slightly downward and then stuck against the back sheet by the force of the flame.

Fig. 29.—Burning an Upright Lap Seam.