what will these be made out of? how long will the tubes be? Does the design allow for ring clamps, clips, flanges, etc? will they carry any pressure, fluid, vacuum, etc?

Lots of ways to approach, but all depend on the application and design constraints.

The rings are only a portion of the actual design, details about the distal ends (ends that don’t meet) are not there.

The rings are made out of plastic, pretty rigid, but because they are only a millimeter or two thick, if you sqeezed them toward the center, they would bend and eventually break.

The tube length combined would be 2", so an inch a piece. The tubes are only the proximal ends of a larger structure.

This isn’t the actual design, but will give you somewhat what I’m talking about. Imagine two of these being joined together at the cylinders. I would ideally want something that wouldn’t effect the outside much if at all. Ideally, if one side was smaller and it was able to screw into the other side, it would be perfect, which a manufacturer could do, but I’m looking for something to be able to do at home for proof of concept to show how it can be taken apart and put back together and hold together.

Jason

I agree with Raf. A lot more information would be helpful.
Based on what you’ve said I would suggest Duct Tape. I know it’s cliche’ but your description is almost precisely what Duct Tape was designed for.

whoops, simultaneous post. The extra info helps. Do you have a lathe? You could thin the O.D. of one and the I.D. of the other roughly half for about 1/2 inch. With a good lathe 1-2 mm should be workable.

I don’t know it this would interfere with the use of the tubes but could you epoxy magnets on the inside of the half’s so they could be magnetically stuck together?

Lots of good solutions here. I’ll try to post some images of some snap together solutions, pressure clamps, etc.

You could try an approach like this. Note the ring (bump) that goes around the inner hub (flange) of the yellow pipe. There would be a corresponding indentation on the inner surface of the green fitting. So when you push them together they snap into a locked joint.

Raf, great idea…I waish I had your skills for doing gfx, would make it a heck of alot better than my mspaint attempts.

That’s actually a cool way of doing it. I got two methods to work. One I took a piece of cardboard the size of the outside diameter of the openings and then made an inner “wall” (sorry my technical terminology is lacking). this allowed the halves to rest on the circular piece, and let the inner wall (basically a smaller cylinder just smaller than the inside diameter of the two ends). It works, but not ideally.

I’ve got to get myself “in the know” of doing graphical drawings like that. It would make my project look tons better.

Thanks Again.

Jason

Jason if it is just a simple prototype I would suggest using Velcro on the inside of the cylinders. Both strips of Velcro would have to have adhesive on them so you could mount them to the inside of the cylinders. I would put the fuzzy Velcro part flush or better yet slightly below the edge of one of cylinders, say 1/8 of an inch. The fuzzy strip could be around 1/2 inch wide. The smoother Velcro would have to be a one inch wide. It has to be wider because you will need to fold part of it over on to itself say 1/4 inch. The smoother Velcro part would mounted to the inside wall of the other cylinder and extend beyond the edge of the other cylinder, let say 3/16 of an inch or so. You might need to build out the smooth Velcro from the internal cylinder wall by a 1/16th or so that it would just slide over the fuzzy Velcro. If you could find some thin, double sided, foam, mounting tape this would work to build it out. You probably wouldn’t want the two parts of the Velcro to overlap by much. They just basically in firm contact with each other. Too much and you won’t be able to get them a part. Velcro is meant to be pulled apart but not in a shearing direction. If this is a problem you could try using strips of fuzzy Velcro spaced apart rather that one continuous strip to weaken the bond between the cylinders. What ever you do it will take some experimentation to get what you want. I don’t know how strong this has to be and how many times you want to take this apart. This approach might not work for your application.

Jason if you did need the connection to be stronger I would think about using a bushing. I would look at ducting materials at the hardware store. I’m sure you could find a collar stove pipe out of galvanized sheet metal around 7" diameter or better yet larger. You would need some tin snips to cut a strip about 1.5 inches wide. The strip is already formed into a circle but you would need to overlap the ends so you could joint the strip into a ring or bushing. The overlapping strip ends could be connected together with a couple of rivets to form your bushing. The bushing would have to fit very tight. So that you would have to force it down into the cylinder. Jason if you wanted to lock it in place you could use your tin snips to cut two small cuts into the inside edge of the cylinder about 1/8 inch wide by 1/16 deep . You wouldn’t need a lot of these maybe 6 to 8 or so spaced evenly around the bushing. With a needle nose pliers I would bend these 1/8 inch notches outward slightly. The idea is to have them dig into the inside of the plastic cylinder wall and lock in place. So when you pull the cylinders apart one side stays connected to one cylinder.

Thanks Bob. I was thinking about looking at plumbing supplies too.

A tools-around-the-house method would be to:
1. Cut about a 1 inch wide ring of the material.
2. Out of that piece cut three two inch long strips.
3. Place one piece against the inside diameter of one of the cylinders extending roughly 1/2 inch above the edge. It won’t match exactly but should be close.
4. Either glue in place or affix with two screws.
5. Repeat for all three pieces 120 degrees apart.
6. The other cylinder should fit snugly over this and can be attached with three screws, one in each piece.

I hope this helps.

More important than skills in CAD would be your skills in finding parts from existing devices. Looks like you’re well on the right track for that. Next brush up on your ability to create prototypes the old fashioned way, out of clay and then apply silicon rubber & plastic molding techniques. Funny thing happens when you combine these two skills; your ability to create great prototypes increases exponentially.

For the CAD part. I usually use Alibre Design (free). The free version lets me export to SL rapid prototypers. But to creat really quick and dirty parts like those above, I go back to this old 3D program called Asymetrix. No longer available, but it is to fast and intuitive, it makes life really easy.

Rafael – Tell me more about the silicon rubber and plastic mold stuff. You said that the plastic is a 2 part concoction, right?

What is the name of it and where can I get it?

Well, unless you have a good vaccuum chamber, which I do not have, you’ve only got a couple of choices for the ruber mold. Oomoo or Rebound 25 silicon rubber. These are both high density which reduces the tendancy to bubble. I’m trying to dig some old pictures out of mothballs to show on another thread, Shoestring Budget – Raffy’s Flower Machine. I think I’ll have to take new photos. Anyway making the mold is fairly simple. Spray object with release agent. Mix 50% part A with 50% part B. Pour into a container to submerge the object to be copied. Let it set overnight. Remove object.

Once you have a good mold, you then get two part plastic. You have a lot of choices. For generic prototyping work, I like EasyFlo 60. It’s not bubble proof, but its pretty dense, so you only get very small bubbles, which you can fill in with plastic puttty, plumbers putty, even wood filler, etc.

You have to be willing to play around and go through about $50 to $100 worth before you get good enough to eliminate bubbles entirely. But you can do it if you’re careful.

Keep in touch. Once my pics are up you can see how to do it without wasting your own money making mistakes.

Rafael have you tried making a simple vibrating table to try and get some of the bubbles out. When I used to do lost wax casting I would use a vibrating table and pull a vacuum at the same time. This is done to get the bubbles out of the liquid investment before it hardens. Vibration by itself probably won’t get all the bubbles out but it might get most of them out.

I haven’t tried vibrating. Sounds worth a try. So how do you make a simple vibrating table?

Rafael,
I haven’t built one but I would start with a pager-motor. You can find them on Ebay or try sciplus.com .

what about using a palm sander and rigging it to a stand/table…those suckers vibrate like heck.

Palm sander and a couple of c-clamps…

Palm sander? Maybe. Sounds a little violent. But I’ll give it a try the next time I need to put out a few parts. thanks!

Rafael sorry I couldn’t get back to you right away. I don’t know how large a table you want to build so I’ll use an 8" X 8" by 1/4" thick as an example. You will need a bottom base board and a top floater board. Plywood 1/4" thick would work fine for both. You will need to pick up four bolts 1/4" by 3" long and 8ea. nuts and four 1/4" washers. Drill four 1/4" clearance holes, one at each corner, on the bottom board. Put the four bolts through the clearance holes and secure in place with a 1/4" nut. It should look like a mini table with four legs. The top table or floater plate would have to have the four 5/16" corner holes drilled which are sightly larger than the bottom holes. The best and easiest way to accomplish this if you aren’t into perfection would be to clamp the two boards together. Drill four 1/4" holes through both boards and mark the edges of both boards somewhere with a witness mark so you can reassemble the boards so the bolt holes will line up. Un clamp the two boards and take one board which is going to be your floater table top and drill out the 1/4 hole to 5/16".

Marks pager motor sounds like a great idea. I was thinking of an $5.00 Oral-B toothbrush from WalMart. Marks would probably be easier to mount than the tooth brush. If you use the toothbrush you will have to remove the brush head and expose the vibrating rod. Next you can mount the vibrator to the bottom to the floater board or the opposite side of what is going to be your table top. I was going to suggest cable ties to secure the vibrator. You could mount the vibrator close to one edge. That way when your cable ties stick through the board they won’t be in the way on the table top surface. You could try to hot glue it to the bottom floater board but it might vibrate loose. The easiest thing would be to just hold the vibrating tooth brush rod against the floater board and forget about mounting it.

Next you will need to locate four compression springs about 2" to 2.5" long with an ID at least 3/8 or larger. They should have enough tension to support the board and the average weight of whatever you put on the table. The idea is to have the springs give a little when you place your average load one the table and at the same time support the load. To finish place the springs over the four bolts then line up the floater board with the witness mark and secure lightly in place with a 1/4" washer and nut. The objective is to have the top, floater board loose and able to move easily so don’t tighten down the top nuts at all. Kevin’s idea might work great, just by holding the pad of the orbital sander against the floater board.

The next step would be to find a used vacuum pump and turn your table into vibrating, vacuum table. You will need a bulkhead fitting, rubber pad, a heave wall glass bowl etc.

Wow Tom! That sounds like a great design. Now I can’t wait to build it and give it a try. I think by late August I’ll have enough free time to build and try it out. While I’m building, I’ll try to take some pics so we can post it here for other inventors. Thanks!

Rafael, I could post some drawings on the forum but I don’t know how to do that.

hey fellow inventors. I have another invention I’m currently working on. I’m in the need of some sort of fabric, or material that is elastic and when pulled, recoils quickly (think of a rubber band). I originally thought of using women’s nylon stockings, but although its stretchy, it doesn’t have the right “return” or rebound. Ideally it would be soft, and flexible.

I made a trip to the dollar store and looked around. The only things I saw that were close were the nylons, and these stretchy “wall crawler” things that you throw at the wall and it crawls down.

I was thinking about latex, like latex gloves. The problem is, I need more than a glove has. Also, I want to be able to make a “pocket” or bag out of it where it is open on one side and has a deep pocket.

Not sure if anyone has any ideas, but if you do, I’d appreciate the info.

How about spandex(think bicycle shorts) or Neoprene(think wet suit)

I have used this stuff called ShapeLock for some of my prototyping.

http://shapelock.com/

I went for a trip to walmart and got an idea. I picked p some of those elastic things that girls use to put their hair up. They’re sort of like rings of elastic cord. I think if I can interlock them into a net, this would work like I need it to.

Jason,
Go to your local fabric store. Or go to one online. There are many fabrics like that. They should be able to help you find what you need. Lycra, spandex, elastic fabrics, etc.

Good luck!

Jason, back to your original question about the tubes, I have always found that plastic stretches nicely when heated up. Depending on how daring you are, boiling water or a kiss with a blow torch works good. Then you can fit one over the other and let them cool. If your using fire, you may want to put some flux on them so they don’t fuse together during the cooling process. After the peices are fitting together as you like, reheat the outer piece and indent a locking channel in it. Reheat the inner peice and dimple it. When attaching the two tubes, the dimple fits into the channel, and a right twist locks them together.
You should practice on scraps first so you can get the heat and force right.

Ok folks…I’ve got a question and wondering if anyone knows the answer.

I’ve got an idea for a new invention…let’s call it a beverage container. An added benefit to this product could be made if I can find a clear substance, with the viscosity of water, that won’t freeze. If the liquid could be non-toxic and also help to cool the beverage, it would even be better.

I was thinking about a water solution with maybe salt added so it wouldn’t freeze?

I want something I can stick in the freezer, pull it out hours later and have it have the same properties of water.

Jason

What about a type of alcohol, rubbing alcohol may be a good fit, I do not know if it would keep anything super cold but it wouldn’t freeze, hope it helps good luck.