RE: [PSUBS-MAILIST] Epoxy cast question

Thanks for the info’s!!

It is indeed small; about 1 “ diametric.

http://picasaweb.google.nl/submachine55/Kreideseesub#5278628917830184690 and

http://picasaweb.google.nl/submachine55/Kreideseesub#5333919163143993442

I made already grooves to have better adhesion. But I consider fine sandblasting.

Frank, Please send the drawing.

Regards, Emile

Van: owner-personal_submersibles@psubs.org [mailto:owner-personal_submersibles@psubs.org] Namens Cliff Redus
Verzonden: zaterdag 9 mei 2009 21:23
Aan: personal_submersibles@psubs.org
Onderwerp: Re: [PSUBS-MAILIST] Epoxy cast question

Emile

For small volumes of epoxy like for an electrical penetrator, just about any two part epoxy system will work as long as the surface roughness is adequate. The problem comes when you want to cast larger volumes. For large volumes, you have two issues of concern. The first is getting the epoxy, which can have a high a viscosity, to flow into all the cavities. The second issue has to do with the exothermic reaction. For large volumes if the reaction rate is fast, the temperature gets very hot and the part can crack. I was concerned with both these issues when I cast the two part epoxy that formed the binding agent for the syntactic foam for my boat. My casting had 270 lbs (123 kg) of catalyzed resin which I cast in one piece. To address these issues, I contacted a company that manufactured epoxy resins and catalyst. Their guidance was to go with an epoxy resin/ catalysis system that had a low viscosity so that it could be easily poured and second go with a catalyst that generated a slow, low exothermic reaction. The resin I used was Huntsman Araldite GY-9667 with the associated catalyst Huntsman Jeffamine D-230 Polyoxypropylenediamine. These were mixed on a weight bases of 100% resin (Part A) to 29.46 % catalyst (part B). The canalized resin had a viscosity of 375 cp at 77 F (part A 500 cp and part B 9 cp at 77 F. The curse time was several days. This system worked fine. Not sure if you can get this epoxy system in Europe but you may be able to find something similiar.

Cliff

From: Emile van Essen <emile@airesearch.nl>
To: personal_submersibles@psubs.org
Sent: Saturday, May 9, 2009 8:56:50 AM
Subject: [PSUBS-MAILIST] Epoxy cast question

Hi,

I am about to cast epoxy in some self made el. Penetrators and a barrier in a thruster

First idea is to use normal aero modelling epoxy but when not okay I have a real problem to get it out the thruster.

Does someone have the knowledge or experience about kind of epoxy, adhesion to metals viscosity etc??

Thanks in advance!

Emile van Essen

Alkmaar, the Netherlands

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