Sticky resin

Sticky resin from kits cast from silicone mould 

Have you ever bought a resin kit that had uncured resin areas, or the whole resin kit was uncured and felt slightly tacky to the touch, or when you handle the kit you notice that when you moved your hand hold on the kit, you found that you had left finger print impressions in the resin because it was soft. The worse part is when you prime the kit in preparation to paint it, only to find that an oily substance leaches up through the primer. The reason for these problems is because the two part resin mixture wasn't mixed equally before it was poured into the kit mould, so the resin is never fully cured.

How to cure the problem?

When you take your resin kit out of the box and realize the resin feels tacky and uncured.

1. If this is a newly purchased item, notify the kit company to send you a replacement.

2. If this is an old kit in your grey army, before you do anything else to the kit, put the sticky parts in a glass ware in the bathroom sink or bathroom bathtub and fill the glass ware with hot water until the water level is about two inches above the tallest part of the kit.

3. Pour in some hot boiling water from a kettle off the stove. The boiling water increases the thoroughness of the curing process. Now just let the resin parts soak in the water until the water is cold. You may need to do this couple of times.

4. Remove the resin parts from the water and you will notice a white chalky substance on the surface of the resin. This is noticeable if the resin is allowed to dry, but you don't need to wait for it to dry. You can now wash the resin parts with soap and water like you normally do to remove mold release from your model kit.

5. Scrub the kit thoroughly with a soft toothbrush. Once the kit is thoroughly scrubbed and the entire white residue has been removed, just rinsed the kit and let it air dry and then you are ready to do your assembly and other finishing procedures. If you have an ultrasonic cleaner you can clean the parts in the cleaner.

This resin curing process is known as ***SHOCKING THE RESIN***.

6. Please be aware boiling water will deform resin which can also correct warped parts. For small parts, do not use boiling water, clean it with rubbing alcohol and coated the parts with thin cyanoacrylate super glue or leave it out under the sun for couple of days. The heat and UV from the sun may also cure the stcky resin. You can also soak the parts in Super Clean degreaser (do not mix with water) or any kind of liquid degreaser from auto store for about two hours. (wear latex gloves and clean the parts with soap and water)

Sticky resin, toxic resin from 3D printed kits 

Chemical compatibility and material properties (toughness, hardness, etc.) can vary a lot between printing resin brands and formulations from different kit producers manufactures. That's true of casting resins as well, though generally not to the same degree among the casting resins hobbyists are likely to run into. General point is still valid, though: it's a different material so folks shouldn't expect it to behave exactly the same.

1. Do not soak the kit in isopropyl alcohol for more than 15 to 20 minutes. ? Acetone destroys detail. Degreasing products also degrade the parts and cause cracks. Submerging in alcohol for long periods of time ditto.

2. Hot water and heat from the sun are safe but it may warp parts.

3. Digital resin is brittle and requires cleanup of the support attachments. To someone new, never force parts together. It is really easy for a key to snap off. Eye protection is recommended when cleaning up. You would be amazed how far a chunk of digital resin can fly.

4. How can you tell the kits you received have properly cleaned and cured under UV light?

Is 3D printing resin toxic?

Liquid resin 3D printing has odor and toxicity issues because the resin itself is a chemical compound that contains volatile organic compounds (VOCs), monomers, and other substances that can evaporate or leach out during the printing and post-processing stages.

https://3dprintmentor.com/is-3d-printer-resin-toxic/

https://all3dp.com/2/sla-3d-printing-is-3d-printer-resin-toxic/

https://the3dprinterbee.com/is-uv-resin-toxic-cured-liquid-vapors/

3D printed kits are thin, brittle and hollow. How can you tell the kits you received have properly cleaned and cured under UV light?  They look nice on the screen where the manufactures and 3D sculptors have packed every minute detail on their sculpts. But when reduced down to kit size, the detail is often soft or lost and is hard to paint.  I personally would not buy any 3D printed kits unless they are printed in solid resin.

Here is an example of a printed bust where resin was not properly cured.

It looks like there are no vent holes and the uncured resin was trapped and finds its way out.