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having trouble with suction

Posted: Fri Nov 27, 2009 4:05 pm
by o2bjedi
My current set-up is a mold with mdf on top. I have a pump and trying to do few tests berfore laminating. My plan is to seal the plastic to the mold with that rubbery bagging tape. I've tried sealing the hose to the plastic and sealing the hose from the side with the tape and putting tape over that. Then I bought a cheap fixture with rubber gaskets on either side with a nut that clamps the piece together from the hole in the plastic. The hose connects on top. I can only pull about 5 inches and I can hear the part leak, yet won't seal with the tape around it. ANy suggestions? Any parts recommended?

Posted: Fri Nov 27, 2009 7:02 pm
by krp8128
MDF is porous, and will not hold a vacuum.


Once you get that fixed, just stick the vacuum hose through the bag and seal it with some of the butyl tape.

Posted: Fri Nov 27, 2009 7:05 pm
by Head Monkey
You would probably be amazed how porous MDF is… you would probably need to seal it very well (many coats of something) in order for it to be a reasonable top surface for a vacuum mold. Most (everyone?) use an aluminum top skin.

This is the source for all things vacuum bagging: https://www.airtechonline.com/. This is what you want for a thru-bag connector: https://www.airtechonline.com/Airtechst ... oductID=17.

Good luck!

Posted: Fri Nov 27, 2009 7:07 pm
by Head Monkey
Oh, and here's that connector in action:

Image

Posted: Fri Nov 27, 2009 7:22 pm
by o2bjedi
thanks for the suggestions. I had a feeling the mdf night be a factor. Does that thin counter-top material (can't remember the name) work pretty well?

Posted: Fri Nov 27, 2009 9:01 pm
by ben_mtl
yes Formica laminate is just perfect for vacuum bagging, easy to apply and non-porous, just make sure you get the smooth ones, there are some with a texture on them.

Posted: Mon Nov 30, 2009 9:22 am
by hafte
Just glass the surface with some leftover fabric. It'll cost all of $20 max.(epoxy and glass) and a bit of elbow greese to make it pretty and flat. Mine are wide enough to do a pair of skis or a snowboard. And its a very easy surface to maintain. See photos here http://www.skibuilders.com/cpg/index.php

Last time I looked formica was very $$$.

Hafte

Thats better than the smart ass answer. I was going to tell you to wet your lips a bit more. Sorry couldn't help myself.