Science Buddies: "Ask an Expert"

Middle school team at an impasse building the Gripper from online toolkit...

The Polaroid pumps we ordered take a larger diameter tubing than will fit into the central air hole in the mini- gripper that we have finished curing ...after two times of 4. Hours each!
We have inserted the smaller diameter tubing but cannot connect it to bulb.

We need expert advice before our Belmont Library presentation called "STEAM POWER."...specifically, Mrs. Nic's SoRo Station. A special guest from either Wyss Institute, Harvard, or Soft Robotics, Inc. will be there.
Should we print molds for the larger size Gripper and use only those?

Mega thanks, in advance for your trouble shooting powers.

Cheers,
Christina Nicolson
[Administrator note: Contact information removed. Contact information is not allowed in the Ask an Expert forums.]

I can think of two possible solutions for your problem. One is a common 'air tubing reducer' which you can find in all sorts of places on the internet. It will accept two different diameters of tubing, one at each end to let you connect a smaller to a larger. You didn't say what the ID and OD of your tubing was so I can't point to a specific one. Fire up Google - you want somthing that looks like http://www.usplastic.com/catalog/images ... 60900p.jpg or http://i.ebayimg.com/00/s/MjcxWDI5Mw==/ ... ~60_35.JPG . I'd even look in a pet store in the aquarium section.

A second option is duct tape. Well, maybe not duct tape specifically, but something to wrap around the tubing when you put the unmatched tubes end to end. Tape may work if it's close, aquarium sealant might work to 'glue' them together if you glob enough around the joint, or some moldable plastic like http://www.radioshack.com/radioshack-u- ... 70162.html .

You need a device that accepts two different sizes of tubing and offers an airtight connection between them. If you can't find one, just make you own.

Howard

Thanks for the rich details about options, Howard. Since I am new with sciencebuddies forum, I did not find your post until Amy Cowen let me know today that I had a reply.
In the meanwhile, my student and I solved it by inserting the smaller tubing into the larger near the gripper body. When we squeezed the bulb , it inflated, with no escape of air at the junction. we're we ever pleased with ourselves!
Your options will be kept on tap!

Cheers, Christina and David