Infusion Q&A

Can you mix it in a flexible container with no air (like a bag)? Or some sealed, filled to the top container with a mixer shaft that goes into it.
Then the air doesn't get in in the first place.

 

Damn!

 

flow simulation software http://www.polyworx.com/apz/

 

Very slick! Have you tried or purchased this, Rick?

 

No. Don't think I will. I've been tinkering trying to figure out all the in's & out's of infusion on my own. I don't think I'll be infusing an entire hull at this point. If I ever did a tool like that would probably be well worth the investment to minimize the risk of a large infusion disaster such as a large hull.

 

We just started small and worked our way up to hulls & decks. For our 26' boat we use 1/2" feed lines. We usually try to plumb them at waterlines. every 2 to 3 feet or so. Filling from the bottom and working our way to the top.

Really though, start with the small bits. This gives you a good "feel" for how it works and by the time your doing hulls & decks, plumbing will probably no longer be an issue for you.

-jim lee

 

Degassing resin

jonr, I mix up to 5kg batches in 9L buckets and I dont like the idea of transferring this to another mixing container. The best container mixing system I could think of is like the paint pressure pot with the built in mixer. Put the resin bucket into the pot, evacuate the air and mix under vacuum. Dont know how long the seal around the mixer shaft would last and still hold full vacuum.
Another alternative is to use a magnetic mixing puck in the bucket and an electric motor with a magnetic bar externally driving the puck.

I think the ideal system would be inline metering and mixing, thats why the question to see if anyone has built such a system.
I imagine there would be commercial systems available but have not searched the net as I assume I could not afford it.

How many of you are bothering to degass your resin? if so what do you do?

 

Degassing can be an important step to reduce voids in the future laminate. Not only during mixing you introduce a lot of air, but already during production air is introduced into the resin. It is this air that needs to get out as well.

For degassing I have a large pan with transparent lid. A bucket with resin is placed in the pan, the lid is put on, and a deep vacuum pump (2 stage rotary vane pump) degasses the resin.

To help the resin get rid of the excess air, throw a scotchbrite in the resin (and make sure it sinks to the bottom). Another solution is to introduce air in the mixture (which sounds stupid) but the airbubbles will also pull the dissolved air out. (some friends did a subsidised project researching this). For simplicity, I would still opt for the scotchbrite option.

There are mixing machines available, mostly air operated pumps, which draw the resin from their barrels, at a fixed ratio (by volume!!!), mixes it through a static mixer, and optionally degasses it (somewhat). It can also apply pressure to the outlet, to fill (semi) rigid moulds.
www.composite-integration.co.uk can be checked for these machines. Ranging from 10.000 euro upwards. I have one, but it is set up for polyester now.

 

Degasing resin

Thanks Herman, I am using a two stage pump and a chamber with a transparent lid.
I have also read the mentioned article using air or scotchbrite to speed up the removal of dissolved gases. I have not tried the scotchbrite yet only compared the time it takes to degas a mix with a small amount of mixed in air and one with lots.
The one with lots of air takes longer but as the mentioned article suggest does a better job in pulling out the dissolved gas.
At this stage I think I will be happy just to pull out the mixed in air as long as I can do it fast enough. Thus the thinking that a metering and static mixing system would help in this regard.
I do not require a high output system, at the moment I will look into the inexpensive manual piston and gear pumps. As well as trying the under vacuum mixing options I mentioned above.

Cheers
Andrew

 

These is a company "resix" which you should look up on the internet. They have nifty dosing machines as well, and have a static mixer option as well (although a bit steep in price to my liking)

 

EnkaFusion Anyone? This looked like an alternate to flo lines. Anybody ever play around with this. http://www.colbond-usa.com

 

I've got a sample from there a yr or so ago. Couldn't find a Cdn supplier. IIRC it was pretty expensive. I've pretty much given up experimenting and settled down with AirTech products. I have their green flow media and it's ok. I did get some red mesh from a guy a couple of years ago. Much larger mesh and worked great but haven't been able to find a source for that either. I'm sorta in infusion hell here trying to find decently priced consumables. Apparently Lowes has some shade cloth that works but I haven't been able to find any of that nearby either! *sigh*

 

Tried it, didn't like it. We found that it ends up being a resin blob that gets really hot on the back surface of the part. The heat caused print through. We could see on the gelcoat side where the EnkaFuse was laying on the back side of the part.

-jim lee

 

Infusion Resins. At the ACMA show, everyone we asked said the same thing, Reichhold Hydrex. It has low exotherm, flows fast and non foaming. I don't recall the part number though. Anyone had any experiance with this product?

 

13AL, I had a quick look at the Reichold site, Hydrex 100HF is for infusion. It has a nice low viscosity of 175cps at 77'F, but the listed mechanical properties are for a post cure of 2hrs at 150'F + 2 hrs at 250'F.
When selecting a resin first establish what mechanical properties you require, if you are going to post cure then what temperature can you achieve. Make sure you get mechanical data for this temperature, if not post curing then for long term ambient cure. I would look for a viscosity <200cps at 77'F (mPas at 25'C) and a gel time of 45 - 60minutes. Also look for a resin with the highest elongation.
A friend of mine uses Huntsman AME600, I have only infused with epoxy resin.