Ziplock Space Bagging

I had kind of a minor breakthrough yesterday vacuum bagging a first part (of 45) for the lander’s top dome. Typically when vacuum bagging, you put the part into the bag and run the vacuum for 6 to 10 hours, depending on temperature.

I have seen the Ziplock Spacebags keeping a quilt vacuumed for what, 6 months? I wondered if it couldn’t be also used to vacuum boat or spaceship parts. Yes, it worked. My concerns that it could not stand my high vacuum pressure, or that the shutoff was tricky, were unfounded. I did create a kind of plastic airlock around the bags shut-off valve so that I could keep my high vacuum longer. I ran the high vacuum pressure 8mm hose through the airlock bag and into the jaws of the shut-off valvve. Next I started the compressor and got my 25 inches of mercury vacuum from my Venturi and compressor. Finally, and in one flash move, I pulled the hose out of the valve jaws and closed them. The next morning it had held the vacuum all night.

My parts are small for this job (2’ on a side) and the bags are also small (3’ x 4’) but with proof of concept, I can start to replicate on bigger parts in the future. Also this means that I can vacuum bag several parts at once as they only need to suck for a couple of minutes.  www.spacebagbrand.com

zipbag1
Bag sucking, showing “airlock” I added.
zipbag2
The bag the next morning.
zipbag3
Bag closed but not yet sucking

2 thoughts on “Ziplock Space Bagging”

  1. Wow, 25in.Hg is 635mmHg, 12.3 psi, 0.835 atmosphere. This is 3 – 4 times the pressure we use for cyl. mold ply/epoxy. Is that a ply/foam sandwich? and what is min vacuum needed? Did you have a gauge on the bag so you could see the final vacuum reading after cure? Please detail your “venturi and compressor”. And Merry Xmas from our southern summer! Cheers, Chris A.

  2. Chris, Hi!

    Been hoping to hear from you. My Outlook went away with your email address from before. Send a progress report and pictures (Chris is building a 20m catamaran of his own design, using a variation on CM, all).
    Venturi pump is from Fiberlay. Oddly enough is not on their website yet. Biggest reason is that it is so quiet compared to shop vac. Don’t want to scare the neighbors. Parts are ply/core/ply and could surely work with shop vac, but my Makita compressor and Venturi pump are so quiet. I have not measured vacuum, but Joe Parker noted that single stage Venturi will have about that pull.

Leave a Reply

Your email address will not be published. Required fields are marked *