1 - Replacement parts for equipment long out of production are difficult, if not impossible to find. Above, damaged wheel supporting a well used but still functional industrial pump needs to be replaced.

2 - A machine shop would charge over $1,000 to custom machine a replacement wheel. A cheaper, faster alternative is to make a mold of an existing undamaged wheel and then cast a replacement wheel out of a rubber or other material.

3 - A functional wheel is removed from the cart platform and cleaned. Slight imperfections are filled with a two-part epoxy.

4 - Measurements are taken to build a mold box for containing the liquid rubber.

5 - A melamine box is constructed to provide a 1'' (2.54 cm) clearance around the model.

6 - The interior of the box is traced onto a melamine base board.

7 - Hot glue is applied to the hub of the wheel.

8 - The wheel is centered in the traced area on the base board.

9 - Non-sulfur oil-based clay is sliced to a 3/8'' (1 cm) thickness.

10 - The slabs of clay are placed on the base board.

11 - After a suitable depth of clay is achieved, the box is placed over the model.

12 - The clay is smoothed using sculpting tools.

13 - Small 'acorn nuts' are placed around the perimeter and partially imbedded in the clay to make registration keys.

14 - Purpose; the positive and negative keys will register the two halves of the finished rubber mold together for casting.

15 - Lines are drawn on the exterior of the box to indicate proper assembly of the box walls.

16 - Vinyl gloves are worn for the remainder of the moldmaking process.

17 - Mold Max® 25 Part A is measured using a gram scale.

18 - Mold Max® 25 Part B is measured on the scale. The mix ratio is 100A:5B.

19 - Mold Max® 25 is very easy to mix. The material is thoroughly mixed for 3 minutes.

20 - After the initial mixing, the Mold Max® 25 silicone is placed in a new container and mixed again for 3 minutes.

21 - The container is placed in a vacuum chamber and degassed for 2 minutes until the mixture rises, breaks and falls.

22 - The mixed and vacuumed Mold Max® 25 is poured over the model in a thin stream.

23 - The Mold Max® 25 is left to cure for 24 hours.

24 - After curing, the box is disassembled.

25 - The clay divides the mold in half.

26 - The mold is inverted...

27 - ...and the base board is removed.

28 - The clay and acorn nuts (registration keys) are removed.

29 - The second half of the rubber mold will be made over the reverse side of the model now embedded in silicone.

30 - The mold box is reassembled using screws.

31 - Ease Release® 200 is sprayed on all surfaces. Ease Release® 200 will keep the new silicone from sticking to the cured silicone.

32 - A funnel is added to the model using a small piece of clay. This funnel will make it easier to pour resin into the finished mold.

33 - A second batch of Mold Max® 25 is mixed, vacuumed and poured over the model and cured mold half.

34 - The Mold Max® 25 is left to cure for 24 hours.

35 - The plastic funnel is removed.

36 - The mold box screws are removed.

37 - The mold box sides are removed.

38 - The two halves of the mold are easily separated thanks to an earlier application of Ease Release 200 release agent.

39 - The Mold Max 25 captured precise dimensional detail from the original and will yield a perfect duplicate part.

40 - The end of a brass tube is carefully sharpened using a utility knife.

41 - The tube is pressed into the mold rubber at a non-critical part of the mold surface.

42 - This removes a plug of silicone, creating an air vent.

43 - Rubber bands are used to hold the mold halves together.

44 - The mold is securely propped up at a 45 degree angle to aid in de-airing the resin as it fills the mold cavity.

45 - The funnel is replaced in the mold.

46 - TASK® 14 is an impact resistant black urethane resin. The TASK® 14 Part B is premixed.

47 - TASK® 14 Part A is measured out using a gram scale.

48 - The TASK® 14 Part B is measured out. The mix ratio of TASK® 14 is 100A:150B by weight.

49 - The TASK® 14 Part A is poured into a clean mixing bucket.

50 - The TASK® 14 Part B is added.

51 - The material is mixed thoroughly for 90 seconds.

52 - Using the pour vent and funnel, the TASK® 14 is poured slowly in to the mold

53 - Excess resin flows from the air vent and the TASK® 14 is left to cure for 45 minutes.

54 - After the resin cures, the funnel is removed.

55 - The overflow resin is removed.

56 - The rubber bands are removed from the mold.

57 - The mold halves are separated, exposing a perfect casting.

58 - The excess vent and pour spout flashing is removed carefully using a utility knife.

59 - The casting reflects perfect detail.

60 - The Mold Max® 25 mold is immediately ready for use again, making it suitable for production casting.

61 - The new cast wheel is installed, restoring support to the portable industrial pump.