On Mon, Oct 8, 2018 at 9:27 PM '.' eruttan@yahoo.com [harryproa] <harryproa@yahoogroups.com.au> wrote:

 

I can see about getting you and me samples. Or perhaps we can find a local pipe insulation maker to you.

Found one who produces the stuff.  Samples, prices and specs are on their way.

| Tried melting plastic into fibreglass. Nowhere near the resin fibre ratios (or the pressure) of vac bagged epoxy, but the bond is excellent and tougher than epoxy.

Neat. Can we get more details of what you were thinking to do and what this helped or fixed?

I am playing around with building shipping boxes for the cargo ferry using plastic garbage from the ocean and landfill.  First samples worked well, but broke under a 3 kg hammer dropped from 5 metres, so I was looking at ways to toughen it up.   A couple of layers of glass were an obvious starting point.

| Also tried heating the surface of foam to make a tough outer layer. Worked well, but the exchange is over 10:1 bubbles to solid, so probably not viable for much more than furniture. Probably better ways to achieve it.

Did the epoxy stick well to the debubbled plastic surface?

Did not use epoxy, just softened the surface to make a panel from polystyrene solid/polystyrene foam/polystyrene.  

What foam did you debubble?

Extruded polystyrene

Did you mean Furniture in the boat? Is that a highest load/impact area where delamination is most likely?

No, low loads, low impact areas such as shelves, etc.  

| > They also have a laminate version that has less course bubbles, and slightly less compressive strength.
| >
| > Which made me wonder if the Divinycell has large bubbles or small fine bubbles like the 700kpa XPS. Rob you have seen both, please advise when you get a chance.

| H 80 is much bigger bubbles than the Foamular 400. H100 about in the middle. Bubble sizes differ a lot between sheets of the 'same' weight....

Do you think bubble size matters? Should not finer bubbles mean less epoxy?

It is all about resin binding area.  The limit is probably when the bubbles are too small for the epoxy to enter/air escape.  No idea what this is.  

I assume the Foamular 1000 is even finer still.

I would imagine so.    

I know there has been discussions about large bubbles being better for adhesion, but I am not sure that matters, as foam should not/is not loaded like that, epoxy sucks in that role as it is weak when it is thick, and we carve channels for flow anyway.

The epoxy should not be thick enough to be a problem.  The adhesion only has to be as good as that of the foam to itself, but this is higher than say, epoxy onto smooth pvc.  Interestingly, I have been using various plastics as mould surfaces.  After several uses, the epoxy sticks like the proverbial to a blanket, presumably as something in the epoxy reacts with or damages something in the plastic.