Epoxy use advice

[george]

Hello
I am hoping for some experienced people`s advice with using epoxy. To explain, I would like to use a 50/50 epoxy mix to encapsulate an item to make it water proof/shock proof.
I have heard, not sure from whom, that putting kitchen baking parchment paper on your work surface, epoxy will not stick to it and use kids Play Doh to form the mold cavity, the epoxy will not stick to it also.
Is that true?

Now I know there are MORE tried methods: Rubber mold and Release spray. Those are costly here in my area and mail order. They are also used more for repetitive use whereas I am thinking more of a one or two of shot.

Please let me know IF anyone has worked with those "cheaper" materials and the results.

Thanks for your time and replies.

George

[redboat219]

[Bob Gato]

George I can't attest to the virtues of Play-Doh, but...

Parchment paper is the best thing since sliced bread I use it all the time.. I make my fiberglass sheets between two pieces of parchment paper and two pieces of MDF squeegeed out flat with a credit card.. I also use parchment paper as a peel -ply to make a factory like smooth surface on the interiors of my hulls... Also works with polyester.

[CC Clarke]

In 2M (micro-miniature repair) school, for mixing small batches of two-part epoxy we used glass slabs and a Dremel tool with a reversed bit, (straight shaft) to mix the two parts at slow speed without inducing bubbles. (Instant failure if detected and we weren't allowed to use a vacuum pump.)

For through-board patch repairs to fiberglass PCBs, we used plastic non-stick coffee can lids cut to fit and taped in place as a backing with Kapton. The fiberglass PCB edges were undercut for better epoxy bonding. The plastic backing lifted off easily, leaving a pretty smooth surface that was eventually water-sanded until the instructors couldn't feel the seam when dragging their fingernails over the surface. (Another instant fail criterion.)

Since then, I've always had a glass slab in my toolbox. Once the epoxy is mixed and applied, they're easy to clean off with IPA. And KimWipes, lots of KimWipes!

For the really deep stuff, we made and applied syntactic foam.

Another good waterproofing method for electronics is to use clear Eurathane and build it up as required. It can be easily removed with a proper-sized electronics heat gun and dental tools if needed.

Speaking of which: --Another tip: Always ask for any old dental tools when you're at the dentist. They have to toss many of them for minor wear and tear while they're still very useful for modeling purposes. The double-ended, angled micro-chisels and explorers are always useful, especially when scribing. Bone saws are excellent for reducing high spots of epoxy before sanding.

[george]

Thank You ALL for your replies. Helpful / Educational.

[Bob Gato]

Your welcome George...One last thing I use accelerated RTV for my small molding jobs-I use corn starch as accelerator and pure 100% silicone from Home Depot ($5-$8 US) It cures in less then an hour -the captions under the pictures tells you exactly what type of RTV and how to do it without a mess-BG

https://www.rcgroups.com/forums/showpost.php?p=41224199&postcount=251

[george]

Hello Bob

Just went through both those links above. Thank You. More Education - is a Good thing.