Possible Alternative to Hysol E-90


#1

Hi Everyone,

I'm in Melbourne Australia and am assembling a V2.5 ROV and I'm very excited!

I have some experience with 2 part resins and casting of small parts but have been struggling to find Hysol E-90 here in Australia (no surprises there) but have been able to locate one or 2 possible alternatives in the epoxy area of resins etc. One possibility would be West System r105 Resin with the H206 Slow hardener, it is a marine epoxy with low viscosity and it is quite widely available around Australia. I have not tested this yet but plan to do so over the upcoming month or so.

http://www.atlcomposites.com.au/files2/products.epoxy.west_system__brand.resin___hardeners/west_system_r105_eng_data.pdf

In my investigations I have spoken to various manufacturers and chemical bonding suppliers and most have said the same thing: in their opinion the Epoxy bonding will NOT form a proper 'chemical' bond with the acrylic layer material. This is probably ok initially but with each use there will be some flex in the end caps and wiring and this may eventually result in the plug/potting having a hairline crack from the endcap and small water leaks.

I am intending to do some tests with an acrylic casting resin (usually for jewellery and craft), which should form a firm chemical bond with the acrylic of the end cap and solve this issue.

http://www.dalchem.com.au/index.php?option=com_content&task=view&id=383

There will not be as much flex in the final material but I think a stiffener may be able to be added to the wire loom to prevent work hardening of the cores. This material is often used to pour around delicate objects like insects, and should be ideal for getting in and around the wiring harness. It also sets water clear allowing some inspection of the loom if required. It should also expand and contract at the same rate with temperature changes as the rest of the endcap assembly.

If anyone has any tips or suggestions or thoughts on the above regarding the choice of casting materials I would be keen to hear, I will of course let know know how my testing goes with the different alternatives.

Sorry for the long post.

Cheers

Rob


#2

I'm in Melbourne too! Looking forward to seeing what you come up with. I see that Araldite 2011 is mentioned somewhere as being a good alternative but it's super expensive


#3

Hi Jarrod,

None of the parts I have found so far are what could be called 'cheap' but I will add some of the 2011 into the testing mix as well.

Thanks for the tip.

Cheers

Rob


#4

Hi Rob,

I've just finished building my v2.5. I ended up using standard super strength 24hr Araldite from Bunnings, all works fine so far.

I am having some issues getting it balanced and not having the vertical thruster flip the rov back, but all in all it's working great.


#5

Hi Rob and Jarrod, I'm also in Melbourne and have decided to build one of these. West Systems Epoxy is very expensive but it just so happens I have a heap of it in my garage. Happy to share some, doubt you need much! Did you guys buy the kit or get it cut? If you got it cut could you let me know where? There are heaps of suppliers and laser cutters I've found locally but it would be good to find one you've had a good experience with. Cheers, Matt.


#6

And also I agree that epoxy won't form a chemical bond with the acrylic. It will make a very strong mechanical bond if you rough the surface though. It works great in combination with plywood for boat building because it soaks into the ply, the ply effectively becomes plastic.


#7

Hi Matt,

You don't need very much epoxy. I used about 80% of one of the small tubes of Araldite. Yes, a good idea to rough up the surface of the acrylic where you can.

I purchased all of the bits separately. I got the laser cutting done by these guys, http://onlinelasercutting.com.au/ they turned the orders around very quick however they don't have Polyprop material.

For Polyprop I am going to use a company in China, pretty cheap but takes longer than the Aussie company above due to shipping time, will let you know how that goes.