Help casting flowers

Dear Instrumentmaker,

I am trying to cast tiny flower with alumilite water clear for a detail part on a piece I'm working on.

After some trial and error the process I'm not on is as follows

1- flowers dried with silica gel sand

A: I am thinking perhaps it is not completely taking out the moisture in the flowers...it would appear you are still over the 5%.

2- flowers are sprayed with acrylic resin spray

A: These are polyurethane resin they are extremely moisture sensitive in their liquid state. Producing bubbling or foaming if it comes in contact with moisture, anything water based, or even humidity out of the air.

3- measure out water clear A and B in separate containers
A: The water clear measurement is by weight not volume, is this how you are measuring is on a scale?

4- pre-heat rubber mould in shop oven to around 150-200 degree

A: 120-130 F is the best temperature range to stay in. You don't want it to warm, it will keep it pliable/soft.

5- vacuum chamber parts A and B under 25gh until they stop bubbling

A: It will not stop bubbling, you only need to vacuum (at the full 29 gh) for a couple of minutes with A and B side mixed together, then let it settle down for 30 seconds and pour. The clear needs to have a full 29 gh to degas, this can be done under pressure as well at 50 PSI.

6- remove from vacuum and mix two parts together

A: With the water clear you have a long enough open time to degas after you put the A and B together, you are probably introducing air in the mixing process.

7 -fasten flowers where I want them with a tiny dab of super glue

A: Make sure Super Glue is good an hard/cured. Another thing you could use would be the Mod Podge glue, it dries clear and leaves no moisture residue.

8- pour aluminate over flower in mould

A: Carefully from corner of box, at a even, steady pace so as not to introduce bubbles.

9- because the casting is only about 1/8" thick I then put mould onto tray and leave in oven at 200 for an hour and a half

A: A post cure is good in that thin of cross section, but not at 200F. Right around 120F works for the post cure process.

Each step in this process was arrived at after a previous failure. First it was tons of bubbles. Then it was the flowers turning green. Then it was the casting remaining sort of rubbery.

So, after following the aforementioned process today, I took the mold out and low and behold, it had tons of bubbles, the casting had turned a bit yellow, and it was still pretty rubbery (although, that was mostly just because I hadn't let it cure all the way.... no doubt, tomorrow it will be hard-er)

I'm getting pretty frustrated. I dont feel as if what I'm trying to do here is all that complicated. I'm not inexperienced with two part epoxy resins... I use them for my work all the time. Although, this is a first for me in terms of trying to cast something for a decorative art which is meant to be crystal clear. All my epoxy experience is with structural applications.

Can anyone see in my process something I'm doing very wrong? Any help would be very appreciated.

Instrumentmaker, I was going to suggest looking at our Amazing Clear Cast, epoxy for this application.

The bubbles are moisture from somewhere or not degassed with the 29" to completely evacuate the bubbles. The flowers turning green... perhaps the stem or leaves (if there were any) had dyed out into the resin if they weren't completely dry. Being soft, yes it was in the oven at to high of temperature it was keeping it pliable. It will more than likely harden just fine. If the resin reaches over 150F sitting in very hot sun or very hot environment it can become pliable. None of the resin are 100% UV stable, over time and in certain conditions they may yellow.

Please feel free to give us a call we would be more than happy to discuss this with you or help you in anyway we can.

Have a wonderful day!

Regards,

Carol

800-447-9344