[PSUBS-MAILIST] Printed Kort Nozzle

Sat Nov 9 08:46:10 EST 2013

Alan et al,

I've used a disposable syringe to inject resin into spaces where pouring was impractical or there was a risk of air voids.  The thickening agent (when needed) was very short strand or powdered fiberglass.  Going a little light on the catalyst cuts down on the heat generated and gives you more working time.  The other thing I've used is two-part, expansive foam injection.  It was very good for supporting a load, but I don't know what it would have been like under pressure at depth.

Since you're taking about injecting a thermosetting resin into a thermoplastic item that's going to help trap the heat, I'm a little leery that you could get some softening and distortion.

Jim

-----Original Message-----
From: Alan James <alanlindsayjames at yahoo.com>
To: Personal Submersibles General Discussion <personal_submersibles at psubs.org>
Sent: Fri, Nov 8, 2013 11:07 pm
Subject: Re: [PSUBS-MAILIST] Printed Kort Nozzle

Hi Alec,
It would be a matter of putting as much fiber in with the resin that the 
form would enable. With the kort nozzle, the nozzle shape would allow
for a thick mix, but the struts might not.
A bit of experimentation would be required.
If you back lit the printed shell you may be able to see the resin as it fills it,
& be aware of any air voids. Again with the thicker mixes you could ram rod
them down with a flexible piece of plastic rod. 
One concern is that epoxy shrinks when setting, (but not as bad polyester)
& so the shell might need to be filled in a coupe of pours to stop it damaging the outer shell. 
Alan

   From: Private <alecsmyth at gmail.com>
 To: Personal Submersibles General Discussion <personal_submersibles at psubs.org> 
 Sent: Saturday, November 9, 2013 10:23 AM
 Subject: Re: [PSUBS-MAILIST] Printed Kort Nozzle

Sorry, the ones I was referring to are LONG fibers mixed with the resin.

On Nov 8, 2013, at 4:21 PM, "Smyth, Alec" <Alec.Smyth at covisint.com> wrote:

That's stuff is exactly what I meant by "structural fiberglass". You can't pour it. However, if you made the nozzle in two halves like doughnut-shaped dog bowls, you could fill them both up, put them together, and wipe off the excess.

On Nov 8, 2013, at 4:17 PM, "Alan James" <alanlindsayjames at yahoo.com> wrote:

Alec / Joe,
these products "milled glass fibers" or "chopped strand glass fibers"
 may be OK, in combination with epoxy resin.
http://www.fiberglasssupply.com/Product_Catalog/Fillers/fillers.html

The more you can add, the stronger the product, but also it becomes thicker
& harder to pour in to small voids. I would be careful of using polyester resin as it
would probably melt the printed shell.
You may be able to use a thin flexible plastic rod to stuff courser mixtures down in to
the shell.
Alan

From: Alan <alanlindsayjames at yahoo.com>
To: Personal Submersibles General Discussion <personal_submersibles at psubs.org>
Sent: Saturday, November 9, 2013 8:10 AM
Subject: Re: [PSUBS-MAILIST] Printed Kort Nozzle

Alec / Joe,
I will contact a friend who is in the 3d printing business, and try & find out a bit more
about this application & casting materials.
You would need to incorporate risers (tubes) in the design to vent air for the resin 
pouring process, & maybe " keys" on the inside of the mould to give the resin more
grip to the printed shell.
Cheers Alan

Sent from my iPad

On 9/11/2013, at 12:24 AM, Alec Smyth <alecsmyth at gmail.com> wrote:

Hi Alan,

I like this idea! I have a printer I built myself so am a little familiar with them. One of the parameters you provide the printers on each job controls the "filling" of the piece. Normally, to save material that is a sort of cross-hatch, and the parameters control things like the direction and density of that cross-hatch. But the problem with that, for an underwater application, is that the resulting piece is full of air voids. I'd always assumed I would print something like this solid. However, if you print it hollow and fill it with structural fiberglass, the end result is going to be a lot stronger than if it's solid plastic. In addition, if we printed by parts but filled it up once those parts are assembled, the resin itself could be the "glue" that holds those parts together.

Thanks,

Alec 

On Thu, Nov 7, 2013 at 10:01 PM, Alan James<alanlindsayjames at yahoo.com> wrote:

Joe,

I was re thinking your idea of a printed Kort nozzle.
There are printer kits for $900- that would do the job.
http://www.3dstuffmaker.com/

The ABS printer cable I've seen selling for about $1- an ounce.
The $899- version in the above link could possibly be big enough to print
the nozzle in one shot. If not then print it in sections & glue together.
My idea is to print the nozzle hollow with an egg shell wall thickness & fill it with
a fiber reinforced epoxy resin. The resin may need a few pours to allow for contractions
in the resin while setting.
Maybe under $30- in materials.
I am not at the point where I need this & neither are you, but I think this idea still
holds a lot of promise.
Regards Alan

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