Vacuum chamber ideas

[ ... my post snipped ... ]
O.K.
:-)
I think that the centers of some of the bumpers are support columns distributed over the top, so I'm not sure what this proves without knowing precisely where the weight was applied, and where the support columns were relative to that.
That is somewhat more meaningful.
We don't know what other support members may be present hidden from view.
O.K. They will certainly err on the conservative side.
Hmm ... I don't know the ID of your "6?" (which I presume to be 6 inch) pipe, so calculating from the OD, I come up with 28.27 square inches, or 145.6 pounds total force.
Again -- I don't trust the bonded principle. There are a lot of things which can go wrong in the bonding. And -- if you are going to try solvent bonding over a large area -- expect the solvent to be trapped in the center areas, weakening them.
And -- add to that the fact that acryllic tends to form cracks from exposure to oil (from the machine tool which fabricated the parts, unless you worked with totally clean new tools dipped in acetone to wash off the oil before cutting. Also -- all clamping surfaces will similarly need to be cleaned of oil totally.
Until I see evidence to the contrary, I am reluctant to consider two layers of Plexiglas bonded together to be any stronger than the thicker of the two individual layers.
This looks a lot smaller than what you originally wanted in volume.
Maybe -- but consider that the walls are undergong lateral force which could weaken them. Consider a pipe 20' tall supporting a load something like 80% of the calculated safe load. Then apply 20% of that force sideways to the center of the pipe. What would happen?
This -- I don't trust. Especially with the surface area being solvent glued together. How long would it take the solvent to dry in the center of the glued surface?
Well ... I tend to be rather conservative when it comes to vacuum containers.
And for the tempered glass -- what happens with that if a scratch is applied to the surface -- especially on the center of the inside, so it becomes a stress riser.
I would feel more comfortable with Lexan. It is not as brittle as Plexiglas. (Have you ever used the scribe and bend method of cutting Plexiglas?)
You're welcome.
Best of luck, DoN.
Reply to
DoN. Nichols
Loading thread data ...
Not here! You must have created your ASCII graphics in a proportional pitch font -- which gets drastically distorted when viewed with a fixed pitch font. (The width of different characters, including spaces) is different in a proportional pitch font. If you had used a fixed pitch font, like (courier), you would have produced an easier to read image.
Just as an example, I will do a simple ASCII graphics square with multiples of various width characters in it, and you can see how well the right margin lines up on your system. Then switch to Courier (or some other fixed pitch font) and see what it looks like.
+----------------------------------------+ | | | ___________________________________ | | MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM | | ''''''''''''''''''''''''''''''''''' | | nnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn | | 11111111111111111111111111111111111 | | | | QQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQ | | | | jjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjj | | | | ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, | | | | ----------------------------------- | | | | !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! | +----------------------------------------+
Now -- since I can't switch to a proportional spaced font in my newsreader, and since proportional space fonts vary somewhat even with the supposedly same font on different machines, I'll just wait.
I wish that I had an easy way to show you what it looks like on my system. :-)
At least, you didn't use tabs, which adds yet another problem, as different systems have different tab settings. :-)
Good Luck, DoN.
Reply to
DoN. Nichols
Just build a reinforced metal top with a small window or two in it. You do not need to see what is happening except for grins. Could grind a lens on the end of a plastic slug to see all over the cavity.
[ ... my post snipped ... ]
O.K.
:-)
I think that the centers of some of the bumpers are support columns distributed over the top, so I'm not sure what this proves without knowing precisely where the weight was applied, and where the support columns were relative to that.
That is somewhat more meaningful.
We don't know what other support members may be present hidden from view.
O.K. They will certainly err on the conservative side.
Hmm ... I don't know the ID of your "6?" (which I presume to be 6 inch) pipe, so calculating from the OD, I come up with 28.27 square inches, or 145.6 pounds total force.
Again -- I don't trust the bonded principle. There are a lot of things which can go wrong in the bonding. And -- if you are going to try solvent bonding over a large area -- expect the solvent to be trapped in the center areas, weakening them.
And -- add to that the fact that acryllic tends to form cracks from exposure to oil (from the machine tool which fabricated the parts, unless you worked with totally clean new tools dipped in acetone to wash off the oil before cutting. Also -- all clamping surfaces will similarly need to be cleaned of oil totally.
Until I see evidence to the contrary, I am reluctant to consider two layers of Plexiglas bonded together to be any stronger than the thicker of the two individual layers.
This looks a lot smaller than what you originally wanted in volume.
Maybe -- but consider that the walls are undergong lateral force which could weaken them. Consider a pipe 20' tall supporting a load something like 80% of the calculated safe load. Then apply 20% of that force sideways to the center of the pipe. What would happen?
This -- I don't trust. Especially with the surface area being solvent glued together. How long would it take the solvent to dry in the center of the glued surface?
Well ... I tend to be rather conservative when it comes to vacuum containers.
And for the tempered glass -- what happens with that if a scratch is applied to the surface -- especially on the center of the inside, so it becomes a stress riser.
I would feel more comfortable with Lexan. It is not as brittle as Plexiglas. (Have you ever used the scribe and bend method of cutting Plexiglas?)
You're welcome.
Best of luck, DoN.
Reply to
Califbill
Im still wondering how the OP is going to close the bags of food when the vacuum has been achieved if he cant reach inside.
I am the Sword of my Family and the Shield of my Nation. If sent, I will crush everything you have built, burn everything you love, and kill every one of you. (Hebrew quote)
Reply to
Gunner Asch
Gunner Asch on Sat, 23 Oct 2010 01:59:35 -0700 typed in rec.crafts.metalworking the following:
You know about the little man who turns off the light in the refrigerator? He has a cousin who owns a vacuum suit and is looking for work ...
pyotr
Reply to
pyotr filipivich
Gunner Asch on Sat, 23 Oct 2010 01:59:35 -0700 typed in rec.crafts.metalworking the following:
You know about the little man who turns off the light in the refrigerator? He has a cousin who owns a vacuum suit and is looking for work ...
pyotr
Actually is easy. Just like a Tillia Food Saver. And every vacuum chamber one I have seen. You put the bag end on top of the sealer bar and neoprene / flexible gasket comes down against the bag and bar. the pressure is light and the air can be sucked out. Then when the heating bar is energized the gasket gives enough pressure to ensure a seal when the plastic is melted. And the little guy who controls the refrigerator light enjoys a moment of warmth from the heating bar.
Reply to
Califbill
So they already have this nifty closing device ready to put in their various tubing and tanks?
Gunner
I am the Sword of my Family and the Shield of my Nation. If sent, I will crush everything you have built, burn everything you love, and kill every one of you. (Hebrew quote)
Reply to
Gunner Asch
So they already have this nifty closing device ready to put in their various tubing and tanks?
Gunner
Just get an old Food saver or build a gasket holder over the heater bar.
formatting link
Picture. Notice a silicon gasket at the top.
Reply to
Califbill
The instructions say to freeze or partially freeze juicy foods before sealing. Over night does it.
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Reply to
Winston_Smith

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