Dumont Tweezers - Grade and Material
Grade (Tip Finish)
Biology (Medical) has the finest tips. The straight pointed tweezers are finer than curved.
High precision (Watch-making) is most commonly used in EM work.
Electronic are not as fine as high precision; they are available in Inox only. For large tweezers, a more robust tip is no disadvantage and electronic grade is good value.
Dumoxel is non-magnetic and strongly anti-corrosive. It is softer than Inox.
Inox is quality stainless steel. It is magnetic which can be a problem when handling nickel grids. Inox is less acid resistant than Dumoxel or Dumostar. Unless the special properties of Dumoxel or Dumostar are required, Inox tweezers are excellent and most Dumont tweezers sold are made from Inox steel.
Inox 02 is standard stainless steel.
Inox 08 is medical grade stainless steel and can be autoclaved at 180°C.
Dumostar is a cobalt rich stainless steel alloy with outstanding characteristics and unmatched durability. It is non-magnetic. The steel is resistant to fatigue; the tips never lose their elasticity. The modulus of elasticity is 210'000 MPA. The hardness is 720 Vickers/ 61 Rockwell. The hardness of the tips is progressive and peaks in the employment zone. Dumostar's resistance is quite superior to the best of stainless steels. It has very good resistance to corrosion in: sea water, HCl, H3PO4, HNO3, H2SO4 and neutral and alkaline environments.
Carbon steel is an extremely hard alloy (>59 HRC) composed of C, Mn and Si. While carbon ensures strong tips, it will nevertheless rust easily. This alloy is magnetic and cannot be sterilised.
Titanium is an alloy composed of C, Fe, O, H, N and Ti. It is totally resistant to corrosion from nitric acid, chloride, sea water and similar. This alloy is not as hard as Inox 08 but is 40% lighter and more flexible. Titanium is 100% antimagnetic and can handle temperatures up to 430°C.
Antimagnetic steel is composed of C, Cr, Ni, and Mo. It is a common steel with good corrosion resistance due to its high molybdenum content. This steel is 80% antimagnetic (less than Dumoxel) and softer than stainless steel. It can resist temperatures as high as 400°C (DIN 50 914) and can be sterilised up to 270°C.
|Carbon Steel||> 59 HRC Hardest Alloy||No||No||No||No||C, Mn,Si|
|Dumostar||210'000 MPA||100%||Excellent||Yes||400°C||500°C||C, Cr, Ni, Mo, Mn, Co, Ni, Si|
|Inox 02 (Standard Stainless Steel)||No||Good||400°C||No||C, Mn,Cr,Si|
|Inox 08 (medical stainless steel)||169 Vickers / 85 Rockwell B||No||Excellent||Yes||400°C||180°C||C, Mn, Cr, Mo,V|
|Dumoxel||95%||Excellent||Yes||400°C||270°C||C, Cr, Ni, Mo, Cu|
|Antimagnetic Steel||80%||Good||Yes||400°C||270°C||C, Ni, Mo, Cr|
|Titanium||Least Hard||Yes||100%||Excellent||Yes||High||430°C||C, Fe, O, H, N and Ti|
Epoxy-coated Except for the tips, some tweezers are covered with a durable blue epoxy coating, giving extra thermal and electric insulation. The epoxy can be used up to 120 degrees C. The intact coating is 220V safe and exceptionally resistant to solvents, acids and saline solutions, but not to strong caustics.
AC are anti-capillary tip tweezers; they are only available in "Biology" grade. Though easily damaged, these tweezers defy capillary action and they are favoured by some users for "staining" operations.
N denotes self-closing.
Medical grade tweezers usually have grooved finger grips and a particularly fine surface finish. Some types are mirror-polished, but most types are supplied with a fine matt finish. The medical finish is available in just a few styles.