I just started using this resin for some art projects and have already run into a bit of trouble. I was trying to suspend a figure in some resin through layering and had a weird split where the two layers met.
I suspended the figure in the container and added the first layer. After about 40 minutes it was hardened and I removed the wire holding object in place. I then poured in the second layer of resin on top. After the resin started to cure, there was an obvious splitting where the two layers met. It looks like the top layer started to peel away from the bottom and created a ring of air.
Do I need to wait for the first layer to cure fully over several days before applying a second layer? Or do I need to add the second layer sooner while the first one is still slightly soft to the touch? I've mostly been playing with UV resin so I'm not sure how to go about doing this properly.
I think the top cracked because I tried to remove some air bubbles that snuck out of a crevice, but the resin was already too hard.
Post by carol - Alumilite Corp on May 29, 2018 15:50:51 GMT -5
If the application thicknesses is greater than 3/8" in a single pour the resin may shrink, discolor, pull away from surfaces, and/or warp. Where thicker coatings or thicker pours are needed it is recommended to pour multiple coats of not greater than the 3/8" thickness. When reapplying or adding additional coats/layers this is the schedule that is best to follow. It shouldn't be applied no sooner than 3-4 hours between each addition and no longer than 12 hours for optimum adhesion.
I had something similar to this in my early days of beginning to work with resin. You may have experienced thermal runaway and heat cracked it. Especially if its trying to cure inside a tight space like that. My jar got so hot it burned a hole in the plastic base and i had to submerge it in a cold water bath. Doing a piece like this DEFINITLEY no more than 3/8, like Carol says. and definitely wait at LEAST a day for a full cure before the next layer
Post by carol - Alumilite Corp on Jul 6, 2018 11:45:17 GMT -5
Thanks John and you are right... I tried to make fake wine in a larger wine glass one time. If you are going to try larger pieces like that there will be more exothermic reaction, (getting hotter) it is best to use the Alumilite Clear Slow. The open time is such on the Clear Slow, it is more suitable with the 12 minute open time for larger castings.
I have read that when recoating using Alumilite Amazing Clear Cast Resin you need to recoat after 24 hours but before 48 hours to avoid having to sand your piece. Here it says recoat after 3-4 hours or before 12 hours.... What is the correct time? I am wanting to pour a 2nd coat onto 4"×4" tiles that have a photo on them the 1st coat left a few small voids I wasnt to correct. When can I and another coat or what's the proper way to achieve a 2nd thicker finish? Thanks for any help!
If there are no problems with the surface, then you don't need to sand between re-coats. I've added more ACC to a casting within minutes of pouring a first layer (because the first layer wasn't thick enough) and I've also done it days or weeks after but the thing is - none of those had any surface problems that required sanding.
Small voids (where it made an indentation without trapping a bubble under the surface) don't need sanding so just add the second coat when you can.