Sand Autoloader Blast Gate

[kinghong1970]

Looking to see if i can DIY a blast gate...
anyone got one that they can upload some closeups of the gate?

all the images i've found are of the entire setup... got setup, need gate.

thanks.

[dholdgreve]

We made ours based on a knife valve concept, instead of a flapper. A flapper tends to throw sand all over when it closes. A knife valve simply slices through the sand and shuts off the flow. We used 1-1/2"schedule 40 dispensing tube, then slit it half way through with a thin bladed saw, or one with no set to the teeth to keep the cut narrow. Cut a small section of the pipe from scrap 1/4 to 1/2" long, and trace the inside diameter on to a piece of metal duct, or any type of sheet metal 20 to 26 gauge. the bottom half of the circle needs to fit pretty tight, then flair the upper part out and up and wrap the edge around a piece of hardwood (Oak or maple) pine one end, and use the other end as the lever to open and close the gate valve. We ended up putting a spring on it, and connecting it to linkage from an arrow release to allow a supervisor to release the valve from the loading lever to avoid having them add additional sand.

Do keep in mind that this contraption can and will amputate fingers if put too close to the end of the distribution tube. Make absolutely sure that the knife valve is located at least 6" from the end of the tube so and not to be responsible for missing digits!

[kinghong1970]

hmm... thanks for that bit of info.
tried an adaptation of woodworking Dust Collector blast gate...

the HDPE gate was a poor choice of material as the sands get caught in the sliding track and gate was useful for only 1 try.

maybe i should try a version with steel...

will give it another go

[dholdgreve]

PM me you email, and I'll send you some pics of ours.