Corrodive cracks from flux residuals after brazing of thin leaves at an artistic desk lamp

Abstract

Making of an artistic piece usually includes a number of different technologies. It implies that for understanding of eventually present irregularities one should knows a lot of technical details. Brazing tehnology is one of them, inspection of integrity, also. Brazing technology generally has evolved on empirical manner, mainly by trial and error(s). The basic difficulty in this technology is that the real situation is highly complex due to the presence of large number of variables, some of them may not be easy to recognize. The great problem is the appearance of crack(s) in postcleaning periode, i.e after brazing is finished, it means over years or decades. A good braze joint must be both physically and chemically bounded. One of the available method for investigation is radiographic testing, when the thickness of testing components commonly does not represents a problem. Here provided radiographic testing has revealed the existence of some indications only at leaves. The indications usualy mean discontinuity in material homogenity. Penetrant testing is a next step for investigation of surface. Registration of indications and their locations are necessary steps in any further approach for removing such discontinuities. Choosing the repair method always is particular problem, however in entire technique, especially on sensitive artistic component(s). Every action in repairing or restauration may led to more or less visible traces. Unadequate actions may permanently change the appearance or usage of treated artefact. Here is shown one irregularity (crack) at one brazed leaf from an artistic desk lamp.

Choosing the procedure for repair of damaged arm at an unicate desk lamp

“…The subject of repair here is one unicate table lamp which is accidentaly damaged, exactly after one arm is broken. As the same lamp earlier was analysed [1] including the X-ray exmination, at the damaging place there were no found any irregularities which could responsible for such breaking.…”

Corrosion characteristics of laser-cleaned surfaces on iron artefact

“…Different factors can affect corrosion of iron artefacts. Surface treatments and protective coatings can significantly influence the corrosion process rate [1][2][3][4].…”