Updated: Jun 28, 2022
In this (2nd of 3) experiments blog post, I'm sharing my experience (rookie errors included), using 3 brand new silicone moulds, and 3 different resins (or combos of) for each of these moulds. I say rookie errors lightly, since I've been using other types of epoxy resins steady for well over 5 years now, but it was my first time I have used these 3" deep larger moulds, and worked with such large floral castings, using these types of epoxy. I started all 3 moulds on the same day, and journaled my experiment process with photos, for those it might be helpful to.
In the smallest mould (6x6x3"), I used iCoat CE4100 HV (1:1 ratio) casting epoxy, 6 layers, and this mould resin combo are covered in a different blog post (part 1 of 3) link.
In the middle size mould (8x8x3"), I used iCoat CE4100 HV (1:1) ratio casting epoxy, for the base layer to set the florals first, then I used the iCoat TP21 (2:1 ratio) casting resin in the following 3 layers. This middle size mould is covered in this blog post (below).
In the largest mould (10x10x3"), I used iCoat CE4100 HV for base layer to set the florals first, then I used the iCoat Depth (2:1 ratio) deep pour casting resin in the following 2 layers. This mould resin combo are covered in a different blog post (Part 3 of 3) link.
***Important Note: If you are new to floral preservation casting using epoxy resin, this is NOT a beginner level project. It is important to learn more about, and experience some of the basics with resins, as well as with florals before attempting to cast one of these large floral blocks. Creating with florals in epoxy, has a few different challenges, then just using colourants in epoxy. Please click this blog link called, "Floral Preservation Casting (& Silica Gel tips) for Beginners", and plan to practice on some smaller items first.
8x8x3” square block mould. This size mould holds roughly 106oz / 3.14 litres of epoxy. Amount & thickness of florals organics may effect the volume slightly (so you may want to have back up moulds ready to use for any extra epoxy).
This 10x10x3 floral preservation casting was completed using 4 layers:
1st layer HV
2nd layer TP21
3rd layer TP21
4th layer TP21
To see information about using the various iCoat casting epoxies for floral art, click this blog link called, "Floral Preservation Art Tips using various iCoat Epoxy Resins", and scroll down to section about the version of iCoat resin you will be using.
iCoat TP21 Hard Cast Epoxy, is a 2:1 ratio, and low viscosity epoxy resin. TP21 epoxy does NOT require heating bottles to 82F prior to mixing to achieve crystal clear bubble free castings. However ideally, the epoxy should not be cold (cold would be in 60F/15c range or lower), so if it's cold in the bottles, you can warm the bottles in a bucket of hot water. TP21 has a higher shore hardness rating of D78 at 14 the day cure mark. The TP21 epoxy does take longer than HV to cure, about 2 days to demould, (mass & volume dependent). Minimum pour depth is about 1/4" up to max of about 2"d, (temp volume, mass & mould dependent). When using with organics (florals) however, and you're newer with this type of resin & floral casting, it is safest to only pour roughly 3/4" per layer on 8x8" block style mould, or 7/8" on a 12x12" block style mould. The TP21 Casting Epoxy, cures in about 2 days, roughly 48 hours (as with any epoxy, lower depths will take longer, deeper depths with more mass will cure quicker).
IMPORTANT NOTE: With this epoxy resin, use Infrared thermometer gun, to check previous layer of epoxy in mould. If it has returned to room temperature, you can add next layer.
Middle size of the 3 moulds, 10"h x 10"w x 3"d
Day 1, Layer 1, 1st layer HV
photo above taken Sunday 1:21pm
Side view of 1st layer to set florals.
Day 1, Sunday, 6:49pm, temperature shows ready to add layer 2
Day 1, layer 2, Sunday 7:24pm
For this 2nd layer, I used different Epoxy then 1st layer. This layer is iCoat TP21 (2:1 ratio) casting resin. I was thinking 35oz (3/4” is 27oz, it’s so viscous, & piece not too full of florals, so my thinking was 1” depth pour roughly, may be ok).
Sunday, 8:01pm, side view after 2nd layer added.
Day 1, still showing 2nd layer, Sunday, 8:01pm
Day 2, Monday, 7:29am. Temp not down to room temperature yet, so will check later in day.
Day 2, 3rd layer Monday, 7:06pm.
This layer TP21 About 900ml (600 ml part a, 300 ml part b)
Day 3, Tuesday, 8:05AM, 3rd layer still curing.
Day 3, Tuesday 8:26am, still curing 3rd layer
Day 4, Wednesday 11:05am, infrared thermometer shows 81.7, so I went ahead and added 4th layer.
Day 5, Thursday 1:58pm, 4th layer still curing
Day 6, Friday 9:32am, demoulded this 10x10x3 floral block
Day 6, Friday 9:33am, short video clip of piece.
On this floral block, I ended up needing to topcoat (floodcoat) it due to a scratch I made, and a hair I had to sand out. I demoulded this piece first (versus topcoating in the mould). I trimmed the edges using the deburring tool, then taped up the sides of the block (to prevent unwanted drips on the sides), right up to the top edge. Be sure there is no tape lip above the edge for a nice finish. Also I placed the tape to hang past the bottom, so no resin drips go on to the bottom flat edge, rather they just drip from the tape. I set the piece up on cups for support and to allow any drips to hang from the tape. Some people brush Elmer's Glue All adhesive on to the sides and bottom, and let that dry, instead of using tape. Once resin is dry, they say the drips peel off when you peel of the Elmers Glue All. I have not tried this yet, but it's similar to using Liquid Latex (which is also an option, if there are no latex allergies where the piece is going). After the sides and bottom are protected from potential drips, I then did a flood coat using the iCoat Medium Viscosity Countertop Epoxy resin. I poured it in the middle of the top, then carefully nudged it out & up to the edges, trying to keep it all on the top. The floodcoat on the top, turned out really nice, and gave the piece a bit of a domed like finish with a slightly smoother rounded edge on that front side. The reason I demoulded it first, is a topcoating resin will have bubbles, and I did not want to torch it while in the mould. So once I had it out of the mould, I was able to torch away, and ensure there were no bubbles. The topcoat hid the previous flaws I had, and turned out amazing.
For information on top-coating floral block pieces, please see the blog post Top-Coating /Flood-Coating Floral Pieces with iCoat.
Initially, I wasn't going to post my rookie errors (in this series of 3 blogs), but I decided to go ahead, as they become a learning opportunity for others who may not have experienced these issues yet either. And it might be months before I have the time to put together another blog post showing process photos and information. Here's hoping the next one goes without errors. ;)