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Tech Notes

Glass Properties

All Chemglass brand glassware meets ASTM specification E438, Type 1, Class A, and is made from Boroslicate 33 Expansion glass. Specifications for this glass is as follows:

Maximum Short time use temperature

500°C

Annealing Point

560°C

Softening Point

815°C

Working Temperature

1270°C

Linear Coefficient of Expansion

32.5 x 10-7 / °C

Refractive Index

1.473

 

Round Bottom Flask Diameters

Capacity mL

Diameter mm

Capacity mL

Diameter mm

5

25

500

102

10

31

1000

130

15

35

2000

161

20

38

3000

185

25

42

5000

221

50

48

6000

236

100

60

10000

279

125

65

12000

295

200

76

22000

350

250

83

50000

457

300

87

72000

520

 

Standard Dimensions for Full-Length Interchangeable Taper-Ground Joints

Joint size Number

Approximate Diameter at small end mm

Approximate Length of Ground Zone mm

Diameter at large End of Ground Zone mm

7/25

5

25

7.5

10/30

7

30

10.0

12/30

9.5

30

12.5

14/35

11

35

14.5

19/38

15

38

18.8

24/40

20

40

24.0

29/42

25

42

29.2

34/45

30

45

34.5

40/50

35

50

40.0

45/50

40

50

45.0

50/50

45

50

50.0

55/50

50

50

55.0

60/50

55

50

60.0

71/60

65

60

71.0

103/60

97

60

103.0

 

Standard Dimensions for Medium-Length Interchangeable Taper-Ground Joints

Joint size Number

Approximate Diameter at small end mm

Approximate Length of Ground Zone mm

Diameter at large End of Ground Zone mm

5/12

3.8

12

5.0

7/15

6.0

15

7.5

10/18

8.2

18

10.0

12/18

10.7

18

12.5

14/20

12.5

20

14.5

19/22

16.6

22

18.8

24/25

21.5

25

24.0

29/26

26.6

26

29.2

34/28

31.7

28

34.5

40/35

36.5

35

40.0

 

Standard Dimensions for Short-Length Interchangeable Taper-Ground Joints

Joint size Number

Approximate Diameter at small end mm

Approximate Length of Ground Zone mm

Diameter at large End of Ground Zone mm

7/10

6.3

10

7.0

10/10

9.0

10

10.0

14/10

13.5

10

14.5

24/12

22.8

12

24.0

29/12

28.0

12

29.2

34/12

33.3

12

34.5

40/12

38.8

12

40.0

45/12

43.8

12

45.0

50/12

48.8

12

50.0

55/12

53.8

12

55.0

60/12

58.8

12

60.0

71/15

69.5

15

71.0