well I am finally getting things up and running here. Successfully bagged a few parts but I am having a few problems.
First of all, I am having many bag leaks. I have to leave my pump running continuously as the vaccuum will not hold. Leaks are minor but are a real pita! Are there any techniques that arent obvious to help minimize bag leaks? Also, how are people dealing with sealing bag pleats? I am using the yellow sealant tape and econo bagging film.
First off, it is a steep learning curve but once mastered, then it’s a piece of cake.
Where are you getting the bag leaks?
If from the VIP netting, try an extra layer of peel ply of even cheap nylon cloth over the netting.
With the econo bagging, it is thinner…IMO.
Um, you’re supposed to leave the pump running! If you turn it off, the laminate will decompress. Doesn’t mean there are bag leaks.
Ummm…What?!
I thought the point was, once you’ve established sufficient vacuum, you clamp off the vac line, and leave it, and then it’s fine, 'cause you did a decent job of bagging, so there’s no leaks!
Negatory. The vacuum system works just like an air compressor. An air compressor will maintain pressure even when the pump is off. The pressure will only drop when there is a tool actively in use. The same applies for vacuum. Once maximum vacuum is reached, the pump will not be doing any good. There are a few variables such as air pockets trapped in the laminate or ambient air pressure that will affect the amount of vacuum pressure but typically isn’t enough to cause a loss in compression. It is entirely possible to infuse without the pump once full vacuum is reached.
I recon there be more than one person gettin’ learned up in this thread 
Technically that is possible, but I don’t know anyone who produces parts for $ that would feel comfortable shutting off the pump after full vacuum is reached.
I agree. It is always a good idea to leave the pump running during infusion in case there are air pockets and/or small leaks. It also helps evacuate the air pocket that gets trapped between the clamp and resin bucket. I do, however, shut the pump off immediately after the infusion is complete.
Ive been using an ultra sonic leak detector. Its worth every bit of $300. It detected a leak in our air compressor from over 20ft away.
I pull full vacuum and then turn the pump off (or the pressure switch does). The way I see it is that if a leak happens during or after the infusion then the part will be garbage anyway. A lot of our parts are e glass with no surface coat. So ANY air means rejection.
I believe i have been getting leaks from around the edges of the bags and potentially at pleat points. I have been sticking the bag tape to my table which has been well waxed and has no holes in it. I have been seeing a number of leaks, again, primarily at the pleats I believe.
To test a mold (or table) to see if it is leaking, try placing carbon paper in the mold and vacuum bag it. They spray (I think it is) vinager on the under side and you will see the smallest leak on the carbon paper.
Bondline Products told me about that test…and they sell a sealing paint for such problems.