displacement resin infusion

[cristofa]

Just thought I'd share a new (to us, anyway) resin infusion method which we love for its ultra simplicity and effectiveness - is anybody else making parts this way?

[ondarvr]

Yes, it's been around since day 1, just not too many shops use it, it works well on some types of parts though.

[cristofa]

That's interesting - I haven't seen it mentioned in any literature. What's the method generally called, and what kind of parts have people been making with it? ... and when was 'day 1', BTW?

[SeaSpark]

To make a laminate as strong and light as possible it should have as much as possible fibers and as least as posible resin in it. Think this metheod is not used very often becouse traditional hand layup and vacuum bagging are better for achieving this goal.

For parts where weight is not that critical (non boat parts) displacement resin infusion could save time and can give a smooth surface on both sides of the laminate.

[SeaSpark]

The Injection moulding process is widely used for fiber reinforced thermoplastics. Mostly in the car industry but also for plasics used in housekeeping and toys for example. It can make a thermoplastic much more strong but not nearly as strong as traditional glass/poly layup.

Long but interessting article on this process:

http://www.brad.ac.uk/acad/comppro/images/glass.pdf

[cristofa]

SeaSpark - I would be very surprised if you could consistently achieve anything like as high a fibre weight fraction with hand layup as you could by infusing in a calibrated closed mould. So far, we are getting over 55% glass fibre content (by wt) in the hull/crossbeam sockets we are making using this method, but I think we might still be able to improve on that.

[SeaSpark]

55% is a good number,

Do you have to apply much pressure to the mould? I can imagine that when a high pressure is applied you are able to push much of the resin out but this would require a very strong mould. Do you use a steel one? These require a large investment so i hope you are going to sell a lot of boat's.

Just had a look at you website, the the fabrication metheod of your hulls also is very interesting, thanks for sharing!

[cristofa]

We just use screw clamps to squeeze the male and female moulds together down to the shutoff, and this gives us a 2.5mm cavity. Weights would do the same job - seems to work best with a steady squeeze, rather than some massive pressure.

And the mould is just a regular glass/Optimold tooling layup, about 8mm thick, which we made.

[ondarvr]

There is very little "new" in the composite industry, most of the methods have been around since the 50s. The current high tech methods are mostly old methods that have been refined with new equipment and a few new twists. A friend of mine was using that method in the early 60s to make boat parts, it's just kind of been forgotten because it's hard for somebody to patten it, or make money selling supplies to do it.

[cristofa]

Surely the whole 'resin infusion' thing is new, having only become possible with the low viscosity resins recently developed for the purpose? And I don't see how this displacement method would work with normal layup resins, as it depends upon the resin moving freely through the fibres.

[jonsailor]

We are building complete yachts in an "infusion method"
Rather than use another clamping mould, we use a vacumm under a plastic membrane and then pull the resin through the entire job. A 40ft hull takes us 40 minutes to complete from a dry lay-up including all foam cores, reinforcing, and anything that needs to be in the structure

[Tactic]

Hi Christopher,
What resin are you using in this process?
Thanks for sharing the method,I build small r/c yachts and this may work well for me.

[cristofa]

Originally Posted by jonsailor

A 40ft hull takes us 40 minutes to complete from a dry lay-up including all foam cores, reinforcing, and anything that needs to be in the structure

... WOW that's fast, and no mess or smell!! How long before infusion, in one guise or other, is universal?

Clearly the displacement method wouldn't work for a 40ft hull, but what I like about it for small parts is its utter simplicity - no vacuum, or seals, or catch pots etc. etc. ... just a very easily achieved male and female matched mould.

Tactic, we are using sicomin 1710 infusion epoxy.

[jonsailor]

The big advantage is clean, quick and limited waste.
The slight down side is that we are using DIAB core which has a groove pattern for the resin flow path. Where this in itself is absolutely brilliant, it adds a bit more weight to the pure race boat situation. However, the quality and the actual resin to fibre ratio is excellent.
We use Australian FGI infusion resin.
The good thing, is that you can set your vacuum bag up over a day or so to get perfect as nothing is going off untill you are ready to shoot the resin.
my website has a few pictures on our latest infusion job. www.sayerdesign.com

[ondarvr]

Resin Infusion is not new and neither are low viscosity resins, there are more of them around now though and for a variety of good reasons infusion and it's various forms have become more popular in the last few years. There are also companies that have developed products just for infusion, they market these products aggressively with classes, demonstrations and starter kits, so now everybody is a little more familiar with it.