J. Phil Thien's Projects

I had to put my build on hold. No time to work on project or get on the site. Hope to get back in the shop this weekend.

I cant tell you what dimensions are right. I am following others designs that have been successful. What I am sure of, don?t use plexiglass, use Lexan (polycarbonate)

I riveted it together tonight. Thanks Ron. It is very satisfying to make a custom round to rectangular transition from a $10 sheet metal piece from Lowes. And I still have a good size piece left over from sheet to make something else.

Yeah, down the road I may remake my trasition. This thread should help me remember my mistakes so I dont repeat them. And hopefully help others that plan to make a similar Top Hat.

The main reason I went with thin is because Phil says its better. It?s his design and he has done so much testing. To me it makes sense that debris can fall past a 1/8 wall easier than a 15/16 wall.

If you decide not to use a thin baffle, Some have added a chamfer around the slot (can side) to kind of achieve the thin baffle benefit.

You can use a heat gun to bend .250 thick plastic I guess, but .125 is plenty thick if you use polycarbonate. You dont need heat to bend it. And you can reposition it. If I build a second one, I will use .094.

Like Ron?s design and mine, the distance to the opening is just a development of the 120? that is symmetrical.

The ?shoot? length. Again, this is a development. The length is determined by how wide your input is. Take a look at Ron?s drawing (middle bottom). His ?shoot length? is a development of the width he chose of 3- 7/8. The length of the sheet metal transition gives the air a chance to be pushed against the outside of separator.

1. You want to have one of the diameters be a snug fit on the can. Like a Tupperware lid. Some designs fit the OD., Some ID, and I think some fit on both.
2. I don?t think you will be able to bend .25? plastic very easily. I have .125 thick and its plenty strong. I think .094 thick would be fine too.
3. No idea
4. Hard to explain in words. There are many pics of the correct orientation. That is one thing that is very important. Everyone I?ve seen has it the same way.
5. Ditto
6. Not sure what you are calling the shoot.
7. Varies, Phil recommends starting out at 1.125.

One thing I think you are missing is a thin baffle. You are planning on having the bottom be the baffle? Others have done this. But it is recommended to use a thin baffle. Like .125 thick  hardboard. Take another look at my design. Like others, I have .125 hard board supported by the bottom. The drop slot is like an inch or more wider than the baffle drop slot.

I have been thinking about this. Over thinking probably. My drawing was for the inside dimensions. While folding, I needed to see the lines. So, the inside became the outside. Does it make sense that the material thickness offset multiplied by all the bends caused the gap?

Anyways.... I plan to cut a sheet metal strip, from the scrap left over, and rivet it in place to close the gap. And Tape the seams with foil tape.

It is recomended that you start out with 1.12. I read somewhere that someone opened his up to 2 inches. Why, I dont remember. But he was happy with it. I know this doesnt help at all.  :-[

I just about gave up on finding Lexan here in Asheville, NC. Nothing was coming up in searches. Then I searched the plain old yellow pages and found multiple places. I guess its because places like that don?t do a lot of business with general public. So, it doesn?t make sense to pay to come up on search engines.

Good idea Phil. I put hose clamps on and it clamped round to the form.

Ron, I still have about .5 inch gap. Tapping the remaining creases out with hammer may close the gap a little more, but not enough to fasten. I cant figure out what went wrong. My plan was for spiral pipe to fit inside the inlet. It has a 5.03 O.D. I think I will be able to forget the spiral pipe and use the crimped end of regular duct.

03-25-2012: Today I made an assembly jig for the round to rectangular intake. It is two .75 thick 5.06 diameter pieces of mdf screwed and doweled together. Two .75 thick pieces of 3.58 x 5.95 pieces of mdf screwed and doweled together. The round and rectangular parts are screwed and doweled to an 8 inch long 2x4. The rectangular end of the sheet metal fits the form fine. But I can?t get the round side to wrap all the way around. I quadruple checked my ?round to rectangular transition drawing?. Ron advised to try not to have your diagonal bends go into the round section. Well, I couldn?t help it, the creases did. I figured I could flatten them out once I got it on the jig. I just can?t get the round part to be round yet. I think a sheet metal shop has a device that has two rollers that clamp the sheet and you push it back and forth to take out the crease. Obviously I don?t have that. Trying to figure out a way. I gave up for tonight and decided to post my status.

Its hard to believe that the creases would take up so much space on the circumferance. But like I said, I am sure my drawing and sheet metal cuts are correct. Any ideas out there?

03-24-2012: Making the transition intake. The first half of the diagonal bends went really well. The second half is giving me trouble. As Ron said, the curve ends up hitting the bottom of the bench.

After a short break, I went back to it. Finished off the diagonal bends. It looks pretty good.

I got my plastic from local mirror place. You can buy it on-line cheap. But UPS wont deliver a package that long and bendable. I went with 1/8 thick polycarbonate.

Quote from: Dougp28704 on March 16, 2012, 06:09:07 AM
I?ll export file to dwg tonight.

Sorry. I thought SW's could export to dwg. It can, but only the 2-d drawings. Can sketchup import other 3-d files? I can export to iges, step, parasolid, acis.