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mrbungle · Posted: Wed Apr 15, 2009 1:33 pm Post subject: MB's first vactable. wip

here is the vactable i have been working on. it ain't perfect but i hope it will work.

i have to finish the heating side. i going to cover the sides with duraroc and i am going to lay tin foil in the inside and on the bottom of the lid to help hold heat. i am installing a thermostat so i don't overheat the plastic.

here is the plumbing. shut off valves for the platen and tank. gauge to see how much pull you are getting. i have plumbed it up to use the vacpump,tank and a shopvac as a back up and last pull on the form. i still have to put the filter on the pump on the air intake.

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yes, my name is mrbungle like the band...............

TK 109 · Guru Joined: 11 May 2007 Posts: 712 Location: Galena, Ohio

Well, COOL!! Very Happy

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-Alex

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jegner · Posted: Wed Apr 15, 2009 2:37 pm Post subject:

Looking good! The heater concerns me some, those edges and corners are going to be cooler than the center. Any thoughts on how to rectify that?

semajarab · Newbie Joined: 07 Apr 2009 Posts: 5 Location: Atlanta, GA

looks great to me.

+1 on the edges. Have you thought about spacing them out evenly and perhaps building a convex top to allow heat to pool more evenly at the edges? (one with a dip in the middle, but taller outside areas for more heat retention)
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mrbungle · Posted: Wed Apr 15, 2009 9:51 pm Post subject:

ANH trooper · Master Joined: 20 Oct 2005 Posts: 305 Location: UK

I looked into using these kind of elements before I built my oven using nichrome wire. I came up with four 12" x 12" elements spaced out equally so that the whole of the oven bed was covered. You need to have a heat source which larger or the same size as the sheet of plastic you are using. Anything less will result in cool corners, which is no good for making an air tight seal.

Good luck!

mrbungle · Posted: Thu Apr 16, 2009 8:57 am Post subject:

that is what i am finding out. so back to drawing board. i am going to order some more strips to place on the sides of the main heating element.

they are pretty cheap and should do the job.
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yes, my name is mrbungle like the band...............

mrbungle · Posted: Tue Apr 21, 2009 10:22 am Post subject:

i am getting a 24x24 heating element made. do you guys think this will work?
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yes, my name is mrbungle like the band...............

jegner · Posted: Tue Apr 21, 2009 2:01 pm Post subject:

Well, the ovens I've worked with had a large base and a tapered side walls to facilitate good corner heating. Example, the sheet of plastic is 24x24 inches, same size as my holding frame, same size as my oven TOP, but the base of the oven is actually 28x28. This taper causes some convection and does a simple yet good job getting the edges of the plastic hot.

FWIW

Jim

mrbungle · Posted: Wed Apr 22, 2009 6:53 am Post subject:

the tapered walls i have. talked to the heating element guy today and i am getting 2 24x11.5 elements made. i plan to but these in the 27x27 box i have. if i spread them out a little these should work, right??
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yes, my name is mrbungle like the band...............

mrbungle · Posted: Sat Apr 25, 2009 10:41 am Post subject:

small up date. got the tank and pump and platen all hooked up.

pump is locked up. f**k!!! g*****n ebay!!!

called the old man , asked him what he thought and he said the pump had been sitting up and to take the front cover off and turn the pistons and put it back together.

the old man was right!! once again. i love my dad.

i did a little test on it.
i put a roll of duct tape on the platen and cover the platen with a garbage bag. it pulled great to the point it ripped a hole in the bag in the middle of the tape roll.

i am only getting -15 pulls so i have a small airleak somewhere. i should be getting -27
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yes, my name is mrbungle like the band...............

Stomper · Posted: Sun Apr 26, 2009 10:57 am Post subject:

Looks pretty cool so far... just wondering why the brass check valve?
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Tony Krewson
FEAR... is not my god!!

spektr · Master Joined: 07 Jan 2008 Posts: 425

The brass check valve keeps the oil in the pump. If you have it plumbed open into the tanks, and you have vacuum in the tanks with the pump not running, you can suck the oil out of the pump back into the tanks. This check valve is MANDATORY if you are ever going to have the pump off while holding any vacuum.....

Scott.

Stomper · Posted: Sun Apr 26, 2009 3:11 pm Post subject:

Ahh... got it. I never really considered a check valve in the setup before as I have the same Vac-pump pictured (mines a 10-CFM) and it has a black-handled isolation handle on the side... still a pretty cool thing to have so its fully automatic... I'll have to remember that when I get around to building my rig.
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Tony Krewson
FEAR... is not my god!!

mrbungle · Posted: Tue May 19, 2009 9:16 am Post subject:

my first pulls!!!! some success.

the problem i am having is my vacuum pulling holes through the tiny platen holes and losing suction. and the the edges are not pulling flush in some places.

this is done out of .125 hips. i am going with .090 to get sharper pulls.

thanks to everyone on this board for the help. i could not of got my table off the ground with your help.

here are some pics.

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yes, my name is mrbungle like the band...............