help what is silicone "slacker"?

Post by **Prin** » Mon Jan 30, 2023 9:03 pm

I cannot get a definite answer through research here, or on the web general.

Everything say Slacker "makes it feel more life-like"... or adds "jigglyness"...

What I need is "stretchyness"... for a thin layer face skin...

For a mouth/jaw that can open easily under the power of small servos... eyelids... tongue...?

Is slacker the additive that I am needing?

RevJack · Post by **RevJack** » Tue Jan 31, 2023 12:55 am

You need to spend some time on the smooth-on.com web site. You can even email them and talk to them, they are the most knowledgeable and quite helpful.

Slacker is silicone oil that thins out the silicone mix. It does not improve any of the actual specs of the silicone it is added to. If you need a formula with more elasticity, then select a formula with more elasticity. Thinning down the mix you have may make it Seem more elastic but really just loosens (slackens) the bonds within the silicon formula. Easier to stretch is not the same as elasticity.

If your current silicone formula is not what you want, you need a different formula.
Smooth-on publishes the elongation and elasticity values for all of their products.

Kaori Kusanagi · Post by **Kaori Kusanagi** » Tue Jan 31, 2023 3:19 pm

As RevJack said, it's a "thinner". If you use enough to make harder versions softer, it will leave your casts gummy, and this *never* goes away (until enough debris, dirt, or other stuff has stuck to the surface to block this effect until the surface fractures or tears enough to expose more inner surface), and it prevents the surface from retaining any detail from your molds.

Used in excess, it also weakens the structure, so too much of it will just trash your casts. When they stretch, they will stay that way, and not go back to their original shape. Or if large enough mass with small enough surface area and/or connection to a more solid object or surface, will actually just sag under gravity.

Smooth-On can help you best, but of the ones I have used, Dragonskin is the most "elastic" for thin casts...a little slacker (a few percent of the total volume you are mixing) can help it feel more squishy if needed, kind of like a not-exactly-as-soft-as-earlobe vs the rest of the ear, but it also weakens the structure and it will tear easier.

This is one reason it also comes in small containers...you don't want to use much. I learned the above because when I started using it way back when, I figured learning by doing was better than learning by reading.

Was a lot of expensive mistakes.

The good news is that if you really screw up with it, then depending on time since cure vs how well you need it to bond to the new stuff, you can use it as a core in some larger cast you want more squishiness inside of but not at the surface of, as long as there is still enough of the new cast around it to do whatever it is you need that surface to do. If it's too thin, it could tear with the squishier stuff under it.

Kaori Kusanagi · Post by **Kaori Kusanagi** » Tue Jan 31, 2023 3:32 pm

A thought:

If you use a more "pure" dragonskin for the surface cast, then "fill" the cast's thickness with "fat" made of slacker-thinned dragonskin, it will feel and react more like skin. An inner layer of "muscle" of a harder "pure" version of dragonskin or some other platsil, recently precast to the shape of muscles in the area, can be placed onto that slacker-thinned "fat" before it cures to give even more texture to the skin, and partially reinforce the skin (but it will make it harder to stretch and thicker, depending on the muscle structure design and thickness and platsil chosen).

It will probably take significant experimentation of mixes to get exactly the texture you are after, regardless of method chosen...but start with the info at Smooth-On, including their videos...lots of people have used their stuff for a long time and learned what does and doesn't do certain things, and that info may save you time and money.

Post by **Prin** » Tue Jan 31, 2023 6:18 pm

Thank you kindly for the feedback!

James has experimented with dragonskin, and ecoflex 00-30, but the softest result he could get was like a gummy bear.

I know it can be made softer than that.

There is a smooth-on distributor about 2hour drive away... I guess James will just have to drive down and consult in person.

RevJack · Post by **RevJack** » Tue Jan 31, 2023 7:00 pm

Ecoflex 0030 is pretty firm, and is great for molds. The time I used Dragonskin 20 for a dildo it was more a cudgle. Slacker is not the issue, wrong product is the issue. Be honest with the smooth on guys, they supply the silicone for sex doll companies. They will hook you up with what you need.