Talk Composites - The Forum for Advanced Composites

Inable to make an airtight vacuumsetup.

http://www.talkcomposites.com/Topic31517.aspx

By Laurens - 1/5/2019 3:25:06 PM

Hi,
I'm just starting out with resin infusion and for this I bought the resin infusion starter kit.
The package arrived yesterday and I very enthusiastically, immediately tried the following setup.
Vaccumpump - quick release - 8mm hose - catch pot - 6mm hose - line clamp - plug (double stop at the end)
Just to see if and how well my vacuumpump worked and to get familiar with the vacuumsystem. All connections are taped up and the barb connectors have a hose clamp over the hose.
After the initial few fixed errors I left the system full vacuum overnight, disconnected from the vacuumpump. When I returned in the morning I found the vacuumgauge at -25 instead of the initial -29 lb.
I did a second test run after this without the plug at the end as I thought maybe the line clamp and plug interacted with each other. However after 1.5 hours I found the vacuumgauge at -27.5.
Do you have any tips and or tricks on how to make this setup airtight? Or is this normal?
I suspect the black 6mm connector in the catch pot might be the one leaking but I don't know exactly.

Sincerely,
Laurens


By Dravis - 1/23/2019 9:17:14 PM

One trick that really improves the EC catchpot seal at the "cheap" hose through connnector is to simply slide a short piece of aluminium or other metal or hard plastic tubing INSIDE the 6 mm ID "budget" plastic hose.
Make sure it sits right where the compression "grommet"  inside the black  plastic  screw down hose clamp squeezes the 6 mm clear PVC hose.

The drop you have seen is more than good enough for a normal infusion, but I normally clamp off the bag at both  the vacuum tube and the infusion end after  infusion, often I  add a Y-piece hose connector and an extra vacuum gauge that then measures the vacuum in the bag , without requiring the catch-pot assembly to be completely vacuum tight.

Spend the time making your bags completely vacuum tight.. thats much more important and can be a real challenge

Good luck!