Vacuum infusion question please

[Fanie]

If I vacuum inject the same size object, with one layer glas, 2 layers glass, 3 layers glass, 4 layers glass, would the resin take the same time to wet the object out or will more or less layers be faster ?

[Landlubber]

you will be using less resin in vacuum infusion, and the specs need to be designed for such. Not so much the less resin, but the compression of the layers, meaning that if you were relying on 6mm thickness from hand laying, you would end up with only 4mm from infusion, so particularly in foam sandwich construction, the lamination specs really need to be designed on infusion.

[Fanie]

Thanks Landlubber,

Is there some sort of a guideline that would indicate the flow speed or is it a matter of try and see ?

[terhohalme]

Google polyworks

[Landlubber]

Fanie,

When the resin comes through the laminate the flow is controlled by the number of layers of cloth, the more layers the longer the wet out is. If there are only about 5 layers the time is quite rapid, you actually see the resin wall creeping along toward the vacuum ports.

Send me your email in a private message and I will send you a pdf, of the process done by DIAB, it is very interesting.

[Fanie]

Have sent - thanks, if you didn't get it let me know.

[Wynand N]

The answer is in your email. A bit of a big folder but complete.

[Fanie]

Thanks Wynand.


One other question.

Can one pressure pump the resin in, to get it distributing faster ?

Why not.

Instead of sucking it only, some controlled pressure should get the resin distributed much faster.

[KnottyBuoyz]

Originally Posted by Fanie

Can one pressure pump the resin in, to get it distributing faster ?

It's my understanding you can only do this in closed molds. Pumping resin into a layup under a vacuum bag would be problematic with the resin pooling and lifting the laminates possibly ending up with some resin rich and resin starved areas.

Originally Posted by Fanie

Why not.

You would have to pump it in at the same rate that it'll flow through the layup. I think vacuum will pull resin through the layup as fast as it'll naturally flow. If it's not going fast enough then get a thinner resin specially formulated for infusion. The one I use has a 4 hr working time.

Originally Posted by Fanie

Instead of sucking it only, some controlled pressure should get the resin distributed much faster.

It'll likely pool against it's natural resistance to flow through a compressed layup. If you're having problems with resin flowing evenly through a layup then put in more resin feed and vacuum lines and use a flow media in the layup to encourage more/even flow of resin in the layup. Common practice on large layups. You can control the flow in and vacuum out easier with more inlets/outlets.

The other things you can do to get resin into a layup faster is to warm the resin first but beware this can reduce working time possibly causing it to kick too early and it's not unheard of using a squeegee to move resin through a layup where it might be lagging behind.

[Fanie]

Thanks Knotty,

Can I have info on your resin please ?

[KnottyBuoyz]

Originally Posted by Fanie

Thanks Knotty,

Can I have info on your resin please ?

http://cgi.ebay.ca/EPOXY-RESIN-THIN-...742.m153.l1262