Breather fabric question...

[rileytoolworks]

Hopefully, I'm gonna be doing my first glue up under vacuum at the weekend.
Do I need to cover the glue up with breather fabric, or is it O.K to just use a strip from the bag connector to the top of the glue up?
By the way, the glue up is a curved door, made of two pieces of 8mm bendy ply faced both sides with veneer, over a male former.
Thanks for your help.
Adam.

 

[oddsocks]

Adam,
In the test pieces I have done (all flat pieces) I just used breather fabric from and around the vacuum point to the wood, I didn't need to cover the actual item in it. It wouldn't do any harm to do so but would presumably make it harder to confirm nothing had slipped.

Try a dry run first.

Dave

 

[JonnyD]

I usually just put breather fabric upto the former and sometimes around it. You need to check that the bag doesnt get tucked under the ply and the former when the air is extracted. I usually manually stretch the bag while the air is being extracted which also helps to remove air pockets from the curved surface.

It also helps to place the former on a baseboard with MDF grooves in it to help extract the air from around the former and place the breather fabric over the grooves.

I would reccomend doing a dry run with just the ply and former to see what happens and get the technique of stretching the bag sortred.

Jon

 

[rileytoolworks]

Thanks for that.
Jonny, I have a platen on which the former will be placed, and the former itself has grooves routed into the ends of it to aid air evacuation.
Only problem I think I might have now is the Vacuum bag is VERY thin.
It's the stuff used to vacuum form fibreglass and resin infusion.
Not too confident it's going to be up to the task.
Especially with the monster pump I got from Neilyweely...
Still looking for a 300 micron bag. (Noticed tonight that Axi do a 3.6m X 2.1m for £115. Not sure of thickness though.)

Oddsocks, how's your setup doing?
Did you laminate those parts for the bed?
I might have missed the thread (if you made one).

Cheers.
Adam.

 

[rileytoolworks]

JonnyD, shouldn't your name be JonnyU, given your avatar?

 

[JonnyD]

JonnyD, shouldn't your name be JonnyU, given your avatar?

Yeah I suppose it should.

If your bag is quite thin i would recomend rounding all the sharp eges of the baseboard and former over quite severly but you probably know this anyway.

Jon

 

[oddsocks]

Thanks for that.
Oddsocks, how's your setup doing?
Did you laminate those parts for the bed?
I might have missed the thread (if you made one).

Cheers.
Adam.

Adam, you haven't missed it, I haven't yet done that project - unexpected redundancy and various booked holidays /planned family events have taken precedence. I have at least finished the bed design, bought the maple for the legs and lipping and made the component templates but that is as far is it has got. Hopefully I'll progress it during August (tomorrow is the big family party with a 'Hollywood' theme so I have been turning 'oscars' for that and need to BBQ fro 40 + guests tomorrow!)

As far as the vacuum setup goes, I have used it a few times, most recently to laminate iroko together to form 20mm thick slats for a bench (out of necessity as I needed 16 slats and could only get 15 from the wood so resawed each of the 15 and made the 16th). The homemade bags have worked very well