Help!! Please!!! The last few times I have made modeling chocolate, it hasn't held its shape, it becomes very crumbly and dry. I've tried kneading in more corn syrup and/ or some shortening. The shortening helps a little, but the chocolate still cracks.
Any suggestions, or a reliable recipe would be greatly appreciated.

What recipe are you using?
I use a 14 oz package of candy melts and 1/3 cup of corn syrup... I have never had a problem with mine. Are you letting it harden overnight?

I have let it cool overnight before with the same results. However, I have never used chocolate melts, I have always used chocolate chips, or bulk chocolate ( the kind you buy at a candy making supply store). I will try the chocolate melts. Thanks!!

You must be very careful not to scorch the chocolate. Scorching can cause all sorts of problems.

I have had trouble using chocolate chips before. I use only the candy melts now. Their composition is different than chocolate chips and they are made to be melted. I didn't have cracking problems when I used chocolate chips but, after I sculpted my figure the chocolate bloomed as it dried and it looked messy.

i use plain on basic nestle chocolate chip in my modelling chocolate and really never have issues.

how much corn syrup to chocolate are you using?

are you kneading until it just becomes shiny before attempting to use? (over kneading will cause it not to hold shape and can cause textural problems and underkneading makes it hard to work with and can cause cracking).

if you know your chocolate was old, that can also cause dry MC prone to cracking.

agree with cutthecake, scorching could be an issue too. i melt mine in a dble boiler because microwaving can easily cause scorching.

the candy melts are tempered so will work when the chips will not.

that's true. but modelling chocolate doesn't need tempering.

I use candy melts and/or almond bark when making my modeling chocolate. I knead it until the greasy cocoa butter drips out of it. I knead it until no more greasy goop seeps out of it. Then I wrap it and allow it to finish cooling. Works great. No little bumps of hard waxy stuff later. If it's dry and crumbly just keep working it until it warms up enough to work again. Even left overs I think are beyond use- if you knead long enough can be rejuvinated and used.
Note: I knead the modeling clay over a tray made out of alumunium foil so I can just toss it when I'm done.

One time I used chocolate chips and it worked ok but gets extremely hard when setting and takes a lot of effort to warm up again (trouble it getting it too warm when using the microwave) by kneading.

I made alot of modeling chocolate over the weekend after having horrible results with RKT. I used 10 oz merkens chocolate melts to 1/3 cup light corn syrup. Put it in a shallow cookie sheet lined with plastic wrap. Refrigerate for half hour. Worked like a charm