Herman thanks thats interesting about how friable the product is without post cure.
What are your broken foils from dingy or cat?
broken foils where from a capricorn F18 cat.
Aluminium AC Heated Rudder & Foil Moulds, very successful good quality every time up to 4ft. x 2ft. in size.
Bladerunner Boats
more pics. of Alum. moulds plus Expancel loading for 32mm Tube.
Looks good. So you make hollow foils, with the Expancel removed, or do you keep it in?
I keep it in when the tooling is closed as shown in pic. the Expancel adds structural strength if it has not started to shrink due to its over temp./ time reaction!.
Bladerunner, I hope you dont mind me asking but in what sort price region would metal tooling for a small item like your aluminium rudder & foil moulds run to.
Aprox. $600 Aud. for the cnc machining plus the Alum. and about $60 for the elements, I use the same Thermo controls for all my Alum. Moulds
Very nice! What is the plastic around the expancel?What expancel are you using? Did it take you long to work out expansion rates, etc?
I have a few samples in my cupboard still awaiting some trials 
Here is the product selector for DU type (dry, unexpanded).
For my application - DU820 - it has a lower exp.activation temp. it is contained in a sausage to suit your tooling!, made from Stretchalon 200 bag joined with high temp Flashbreaker Tape, this does the trick filled with Expancel DU820 to aprox. 1/2 the volume of the void in your tooling after stacking it with your choice of laminate.
Does the Expancel when expanded during the heating process bond together into a stable solid form like a foam core and could a density value be given to it? I am thinking the Expancel would be quiet friable. But would love to be wrong.
Edit Is Expancel dissolvable at all?
I have tried most solvents, Acetone seems to be the only one that “slowly” dissolves the DU820 that I use, otherwise I physically remove the foam if I am trying to get the lightest outcome!.
I would compare the density of the foam in my 32mm OD Tube to say 88-100kg. Div-cel. it is very hard to remove from the Pre-Preg laminate even though it is still in the bag, I have an old wood bit welded to a 1/4 universal and a meter long SS rod that I use to bore out both the curved & Straight sections, I hope this explains my outcome?.
John
I would like to try this prdduct too. I plan on making a nissan pulsar single peice propshaft in the near future
Following the activation temperature of the expancel, say its 80 deg C for sake of argument; if you cure you’re composite at this temperature and then following full-cure, increase the heat to say 100 deg C, would this ‘soften’ (i.e. with hardened foams this would be the foaming temperature) the expancel sufficiently to make removal that bit easier?
The DU820 I use is subject to a max. temp of say 100-110deg.C max. for a maximum time 2 1/2 hrs. when I turn off my AC heating, I leave the moulds to cool and usually strip the next day before re-stacking for the next production cycle.
The above time frame gives me a solid DU820 “Core” say equiv. to 80-100kg./cu.mtr. Div.Cel or similar, I drill this out for a lighter tube outcome, if I leave the heater on for longer than say 3hrs. which I did for my first few that I made, the DU820 Shrinks back from the laminate to say 1/2 - 2/3 of the ID., I prefer to have the DU820 solid and intact knowing that it is still exerting pressure against the laminate-tooling!.
So to answer your question, after your expansion cycle for your Expancel?, I suppose you could ramp up/down etc. your temp for post curing of your particular resin system, if you exceed the Expancel Max. temp. you will “Kill” it, resulting in shrink back!, this describes the reaction of the DU820 I use!.
This is how I use the 32mm OD Tube for the Outriggers on competition canoes, they are lighter and stronger than the equiv. Aluminium tube
Hey Bladerunner. So good that you are sharing your experience with this.
I have made only a few experiments with the expancell 820 (very old sample pack) and these have worked ok. Recently I have enquired about getting this product again and the only option seems to be expancell [COLOR=black]031DU40 . It sounds the same? do you know of this one and if it is suitable?[/COLOR]
They have been messing somewhat with the products and product numbers, and also keep in mind that if you want smaller quantities, you are stuck with what is available for larger customers.
I used to buy WE version by the pallet.
They have been messing somewhat with the products and product numbers, and also keep in mind that if you want smaller quantities, you are stuck with what is available for larger customers.
I used to buy WE version by the pallet.
Just some more images of Pre-Preg Tailoring and other projects in progress!.