Bagpress Vacuum System

[Kev]

Was wondering if anyone has one or has used one of these - bagpress

Bought one of these a few years ago but for one reason or another never really got used. Now have a use for it. When you place items in the bag and turn it on the only way you can keep the vacuum pressure is to keep the pump running continuously. Is this correct? Guess I assumed you would turn the system on to get the vacuum pressure up then turn the pump off.

Anyone have any experience of this? Is it okay to keep it running?

Thanks

 

[Myfordman]

There ought be a non return valve somewhere in the system to enable you to turn it off but if there are any leaks then you will have to turn it back on. It is easy enough to make vacuum operated switch and use that to control the vacuum pump.

 

[Yojevol]

It's normal practice to just keep it running, even overnight if necessary. In my experience you only need an hour or two for the glue to hold. If in doubt have a word with Bagpress, they're a good company.
Brian

 

[Keith 66]

The school where i work bought one, very expensive for what they are though works well. Buy a Vac pump of ebay for a lot less. If the bag gets a leak you will never find it & end up running the pump continuously. Out of interest the sealing profile is simply standard electrical conduit with rigid plastic pipe sized to snap into it. Conduit is cheaper than chips You could probably use layflat polythene tube which is also cheap , Worth a pop if you want to save some dosh

 

[Sgian Dubh]

Anyone have any experience of this? Is it okay to keep it running?
Thanks

I use a bagpress pretty often, and have done for, er, I've forgotten just how many years now, but maybe a couple or three decades or more.
Keep the pump running until you need to take out the item you're forming or veneering. I quite frequently leave the pump running overnight if the last pressing goes in just before knocking off time. No harm's ever occurred to the pump or the bag through continuous running in my experience. Slainte.

 

[Kev]

Thanks all,

Sounds like it is okay to keep the pump running until the glue takes.

Also, was not aware of layflat polythene. This seems like a great idea for vacuum pressing (comes in widths up to 1200mm) assuming it is strong enough to hold a vacuum.

Kev

 

[worn thumbs]

Just about any reasonably tough polythene will suffice for a bag.I have one made from damp proof membrane that has seen quite a bit of use.Some years ago I was working with a cabinet maker whose only previous experience of vacuum bagging was with those hinged metal frames with a stretchy silicone membrane.He commented that what we had was nearly as good as a "proper" vacuum bag.I dug out a bit of technical literature showing large composite mouldings and bags the size of a tennis court to expand his knowledge a bit.....

The topic of leaving the pump running overnight shouldn't be a cause for concern if all goes well.If you have enough use for a vacuum system it might be worth building a tank and buying a couple of limit switches so that the whole system functions like a compressor in reverse.When the highest necessary vacuum is achieved the pump stops and then when the lower level is reached it comes back on.It is a big commitment and unless that sort of thing is justified it can be simpler just to use one of those time switched sockets that lots of people use to switch a light or two on when they go away from home.

 

[Steve Maskery]

I recently pressed some wardrobe doors and I used greenhouse polythene. 6m x 2m, IIRC. Only 0.25mm thick, compared to 0.5mm for my proper bag, but it worked fine.

 

[Droogs]

if you are doing only small parts, ie < or = 250mm then you might want to consider getting the food vacuum sealer and the bag roll that they sell now and again in Lidl's aisle of dreams. Works very well for the small stuff