silicon/tyvek lid setup
Posted 21 April 2006 - 07:25 PM
Circle pattern was traced onto Tyvek with using a Coke bottle cap as a template. Cut the circles with scissors.
One FedEx envelope will do a lot of lids.
Clear GE Silicone 2 was used to adhere the Tyvek and seal the injection ports.
Holes are punched in the lid with a 6.35 mm (1/4") nail.
Injection holes are made first using a scrap of pine as a support. The nail is driven through the lid into the wood from the top side until the holes are about 2 mm. This is roughly 2 to 3 times the diameter of the syringe to be used. It makes for an easier target later. The gas exchange (center) hole is made by punching the nail entirely through the lid into a pocket in the wood support. The pocket in the support was prepared before lid production by driving the nail deeply into the wood several times.
After all holes are punched there is a problem with burs. Foaf uses an old Phillips head screw driver to burnish the injection holes then gives the center gas exchange hole a few taps with the hammer, burr side down on the wood support. This folds the large burs over.
A ring of silicone is applied to the lid.
The OD of the ring is about 2 to 3 mm smaller than the Tyvek circle to be used. The Tyvek circle is placed lightly on the silicone ring.
Using your finger, the center of the circle is depressed down onto the hole and with an outwardly spiraling motion the Tyvek is pressed lightly into the ring of silicone. The object is to push the Tyvek into the bead of adhesive but force the silicone away from the hole. Stop when silicone has exuded slightly past the edge of the circle. A 1 mm thick silicone layer sandwiched between the Tyvek and the lid should be the goal. A little practice will ensure that the gas exchange hole is not blocked with silicone. Foaf had success on the first lid.
After both the top and bottom of the lid has the Tyvek filter attached, apply silicone to the top and bottom of each injection hole. This makes an auto sealing injection port.
Now you have a big problem...
Where do you sit a finished lid with wet silicone on both sides?
You put it on a jar! If you were careful not to apply silicone onto the rubber seal of the lid then it won't stick to the jar. Foaf did a DUH on this the first time. He made lids and let the top dry overnight then did the bottom side. Doing both sides and putting them on jars to dry seemed like rocket science at the time.
Be aware that the silicone must cure/dry 24 hours before being put into the PC.
The last picture is a variation of this lid and is to be used on grain jars. It also has Tyvek on both the top and bottom. There is only one injection port and it is very close to the edge of the Tyvek. An additional small bead of silicone was applied to the edge of the Tyvek circle due to the increased PC time of grain.
Foaf likes to call this the Jethro Lid. It's a little simple and you only have to cipher up to five.
I hope you enjoyed this public service announcement! Come back now, ya hear.
Posted 21 April 2006 - 09:52 PM
could even sub polyfil for tyvek or in addition to, in between
Posted 22 April 2006 - 03:07 AM
in the vaults..:)
archive material /
Jars, Lids, Bags, Filters
Posted 22 April 2006 - 11:45 AM
i was thinking about making an self sealing injecktion port ,with traditional
i found it not very easy to peal back tape.
i saw this airport technik a few days ago, in one tread posted by Hippie.
it´s a very nice idea .
Thanks for the great ideas around here.
Posted 29 April 2006 - 01:25 PM
Posted 29 April 2006 - 03:59 PM
Posted 29 April 2006 - 04:51 PM
Posted 29 April 2006 - 06:21 PM
how many times do you think the silicon can be PCED/injected before it starts to falter?
BuckarooBanzai did stress tests of silicone sealed injection ports. The ports seem to survive 200 needle sticks and at least 9 hours of PC @ 15lb. This was the same brand as above.
It's in this thread:
All Hail Hippie3 and BuckarooBanzai !
OH, and Al Gore for inventing the internet :teeth:
Posted 30 April 2006 - 05:43 PM