The following modifications should help reduce particles of powder from bouncing out of the powder collection pan and eliminate the problem with powder falling down the vent holes and clogging or disabling the weighing mechanism. If the latter happens, it is a factory authorized repair not covered by warranty.
Simply wedge a piece of corrugated cardboard across the back support posts and in front of the vent holes. About 90mm high should be fine. Leave room for air flow. If air flow is impeded, the balance will not stabilize. The following picture shows this from the back of the scale.
The above picture shows the placement of the piece of cardboard from the inside. There is no gap which would let a grain of powder slip through.
The Erlenmeyer flask is polypropylene. The capacity is 100 ml. This as a E-Bay item that is about $2 if ordered from a seller based in China! It is 110 mm tall. A glass flask is too heavy for the scale. Eighty or 90mm is too short. That powder bounces!
The plastic straw has been replaced with a brass tube 8mm in diameter that was ordered online. The brand was K&S. The item number and specs show in the next picture. A piece of painters tape was used to wedge it into the AutoThrow so it doesn’t slip out and the top was internally chamfered.
The next picture shows the bend that was put in the brass tube with a small tubing bender. Go slow. It took me 3 pieces of tubing to get it correct without pinching the tube. The ruler will give an idea of what was needed for the tube to reach the Erlenmeyer flask and the amount of bend I used. If the plastic top plate that came with the throw is used, the top plate mounting ridge has to be filed flush with the plate so I could use the 409 AutoThrow base. If the original mount is used, this modification is not necessary but the length of the brass tube will need correction for the different mount.
The last picture shows the complete assembly from the front. It is easy to see where the top plate was modified in this picture. Note the placement of the trickler tube and brass powder throw tube. The brass tube comes just below the flask lip. The trickler tube is far enough away so that emerging powder doesn’t bounce off the brass tube or side of the flask and 1/8” above the lip.
Simply wedge a piece of corrugated cardboard across the back support posts and in front of the vent holes. About 90mm high should be fine. Leave room for air flow. If air flow is impeded, the balance will not stabilize. The following picture shows this from the back of the scale.
The above picture shows the placement of the piece of cardboard from the inside. There is no gap which would let a grain of powder slip through.
The Erlenmeyer flask is polypropylene. The capacity is 100 ml. This as a E-Bay item that is about $2 if ordered from a seller based in China! It is 110 mm tall. A glass flask is too heavy for the scale. Eighty or 90mm is too short. That powder bounces!
The plastic straw has been replaced with a brass tube 8mm in diameter that was ordered online. The brand was K&S. The item number and specs show in the next picture. A piece of painters tape was used to wedge it into the AutoThrow so it doesn’t slip out and the top was internally chamfered.
The next picture shows the bend that was put in the brass tube with a small tubing bender. Go slow. It took me 3 pieces of tubing to get it correct without pinching the tube. The ruler will give an idea of what was needed for the tube to reach the Erlenmeyer flask and the amount of bend I used. If the plastic top plate that came with the throw is used, the top plate mounting ridge has to be filed flush with the plate so I could use the 409 AutoThrow base. If the original mount is used, this modification is not necessary but the length of the brass tube will need correction for the different mount.
The last picture shows the complete assembly from the front. It is easy to see where the top plate was modified in this picture. Note the placement of the trickler tube and brass powder throw tube. The brass tube comes just below the flask lip. The trickler tube is far enough away so that emerging powder doesn’t bounce off the brass tube or side of the flask and 1/8” above the lip.
