School me on infusion with "Envelope Bagging"

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#1

So i’m trying to cut cost on my consumables so im looking into “envelope bagging” which I just discovered. However, through my search on this forum, and google, I came up empty handed…

right now im attempting it with 20ga clear vinyl from joanns fabric… i just pulled vacuum and the nylon cracked at the inlet connector that sits over the spiral wrap… I’m having a hard time believing the Vinyl stretches 400% unless there is a drastic difference in the vinyl im using…

I’m about to try out othe nylon bag tubes from acp
https://www.acpsales.com/Nylon-Vacuum-Bag-Tubes.html
Is this reusable?

Can someone help explain this process to me?
are you still using spiral wrap?
what kind of connectors are you using for inlet/outlet?
Should i switch to a flat (washer like connectors to avoid breaking the bag?)and a manifold of 2-3 layers of resin flo instead of the spiral wrap?

any help would be really greatly appraciated. Pictures would be GREAT (im very visual). Thanks in advanced

#2

Hi Mui!

Check the pics below. These parts are infused in a bag. Hope it helps.

Vacuum fromt he outside spiral, resin from the middle.

Placed inside the bag.

Pulldown and infusion goes just fine.

When using a vacuum bag for infusion, it’s really no different than using a bag taped to the flanges. Just make sure that the backside of your mold won’t poke holes in your vacuum bag. Also, run your lines out through the tape. You’ll have much fewer issues this way.

#3

thanks advblane! Is there another way where you reuse a bag? I’m looking to cut down on material cost so i thought a reusable envelope would be the right direction…

#4

As far as I know the only reusable bags are the silicone ones that you make specific for your mould.

Look at this site: http://www.smooth-on.com/Vacuum-Bagging/c1334/index.html
A supply shop near me will hire out the equipment or they can make the bag for you.

#5

never used it but it says can be used multiple times.

http://aircraftproducts.wicksaircraft.com/item/vacuum-bagging/bagging-film-d250/d250

#6

For compaction cycles, yes, you might be able to reuse.

For infusion: forget it. Cut cost in other ways. Not on your bags. Penny wise, pound foolish.

#7

Ok so I’ve had success using the clear vinyl i got from joanns fabric!

my mold is very simple. a flat piece with a 90* bend (only pic i have of my mold- this was using the traditional method)

i glued 3 sides to make the envelop bag. i then slide the piece in and tape the 4th side, now im using ~4’ of tape per infusion instead of ~15’ I also eliminated the spiral wrap, and made my own inlet/outlet adapters. (metal tubing welded on a flat piece of metal- the tube is poked through the bag and it is sealed from the flat part, this keeps my bag completely flat. i also double layered vinyl over these spots for reinforcement. so far its worked perfect. my material cost has gone down, the quality is much better now that its more consistant (finding leaks in one side versus hunting them down on all 4 sides. also because i made the flanges so small its much easier that i just throw the mold into the bag vs sealing it on the VERY edge of the mold (my fault, it was my first mold)

I dont know how long the bag i will last but I really like how much labor it saves me. i also have some of ACP tube bag and quick lock seals on order. this will eliminate the need for sealant tape and help dummy proof my process (i HATEEEE finding leaks)

on a side not this is all done with infusion!