I'm havin trouble with my first infusion where iv got a tiny air leak sumwhere and I can't find it.

An ultra sonic detector is the best option.. Vac innovation do a good one. Dont get the ones they sell for car mechanics as it is not sensitive enough. BUT it can still be impossible to find some leaks.. The air tracks along creases or you just cannot find it.. But it is still worth having one if you lose a bag once in a while it happens but it gives you the best chance of fixing a leak. 

Hello Im an apprentice aircraft structures technician and i work mainly with composites my company has started building carbon parts and i am running into difficulties with losing vacuum while resin infusing it seems that either my vacuum bag is blowing out or the vacuum is being cut of by the resin flow. Any pointers or helpful tips and tricks to avoid these issues would be much appreciated.

If you are having leak issues it may be better for you to envelope bag the part,make sure you have no sharp elements to the reverse side of the mould as this may puncture the bag and you can cover the reverse side in breather fabric. 

What's the easiest way to envelope it 

Cut out a two sheets of bag-film quite a bit larger than the whole mold..   put one on the table top, prepped mold with all things in (CF, peel-ply, mesh, silicone hose holders and infusion spreaders)

Gum around entire edge ,CAREFULLY    !

Take the protection tape of the gum strip as you go along putting the top sheet of bagging film down, to avoit getting creases (those are in my experience the sinner in 99 % of all bagging leaks)

If youre worried about sharp points on the outside of your mold, then put it down on af layer of breather cloth...

That's it ... really...

"Sapere Aude"... Dare to KNOW!

The written word is the only truly efficient vehicle for transmitting a complex concept from mind to mind...

103% of all people do not understand statistics...

Do not adjust our mind, theres a fault in reality :-)

Create a bag using your bagging film/ tape and and insert the mould into the bag.

Thanks everyone il give it all a go tomorrow 

In my experience the cause of the leak was ALWAYS the same! It was the infusion mesh flow media!
Any where you have a cut edge in the bag of the flow media is sharp. If you picture it as the sharp edge of a chain link fence you can imagine how easily it will puncture the bag. To solve this problem I simple cut strips of peel ply ( just 2 inches wide) and place them over EVERY single cut line of the flow media! I have NEVER had a leak since and I do a lot of infusion. Before I did this technic I NEVER had a perfectly sealed bag, and I thought it was impossible to have one.
Try it and you will become a believer.
Hope this helps.
Fred