Hi guys,
I’m new to resin infusion, I finally made a sealed mould and did a drop test before infusing.
I did a 3h drop test in which it held vacuum pressure.
The ambient temp was between 25-30 degrees Celsius.

The resin was de gassed
I started infusion by slowly loosening the hose clamp on the resin side while the pump was running.
Once I got full wetout, I clamped the vacuum side, and about 30s later I clamped the resin side.

everything looked fine for 2 minutes, then I started noticing the bubbles within the flow media, these bubbles started forming in different areas of the part.

Then I noticed some areas of the bag were very loose, e.g the area where the vac hose connects to the bag.

I’m not sure what’s causing this but it’s the second time it’s happened to me!

Would appreciate some help

Thanks

Another thing to try, if not doing so already, is to place a small 'doughnut' of bagging tape around the top of the silicone connectors prior to bagging-up

As you're working around the perimeter, just place the bag over the doughnut on top of the connector and lightly stick down so that there's a little slack between it and the perimeter edge. I say this as, assuming that your envelope bagging was done carefully (and on such a small part is should have been easy enough to ensure a good seal all the way around), it might just be the areas around one or both of the connectors that have caused leaks? This might have been more likely on your initial part, in particular, given the small-ish size and the apparent strain on the bag

The doughnut of tape won't seal things on it's own and you'd still need to apply tape above the bag and around the inlet/outlet pipe as usual, but it does help to reduce the likelihood of the bag being excessively wrinkled when you insert the pipes, especially if you place a finger and thumb over the connector when inserting them though the hole in the bag. Cut the pipes at an angle also, to make inserting them easier. 

I have found that doing this has proved a very reliable way of discounting this element of the bagging process from probable leak sources. I also double back the tape on itself when creating pleats, rather than just fold over a little bit of tape at the top and this also gives a touch more certainty that the tape is thick enough to press down well and create a good seal at the base of each pleat.  

I still encounter the issue you've highlighted from time to time and in most instances it's really difficult to find a logical reason for it happening after the part has infused. As Warren said, be mindful to keep things as clean and tidy as possible when bagging and look out for stray fibres. Create bags with plenty of slack to pull down without straining too much, as a tight bag with little to spare will always be more prone to leaking from the edges and, sometimes, make them more prone to puncture by the edges of the flow media (although I think that this is quite rare in most cases). I tend to wipe around the perimeter with a cloth and a little mould cleaner prior to applying the tape and this helps to ensure that you've got a clean surface to stick to without traces of release agent. Only wipe where the tape will be stuck down, though. 

Be aware of temperature as well, as colder conditions can make the bagging tape less sticky and more likely to leak unexpectedly so definitely worth going around the perimeter several times to ensure that nothings come a little unstuck.