Short Answer
While it is unclear whether or not your intended use of Mickey Mouse falls under the Fair Use doctrine, you are unlikely to get into any trouble over it.
Long Answer
First things first: just about any prediction of how a particular copyright case will turn out is at best and educated guess because copyright law is still largely untested within the courts. There are safer and riskier bets, of course, and there a few settled areas. In general, however, it is a vast legal unknown. Groups like the RIAA use copyright law as a big stick to intimidate people into settling out of court, but many experts consider their claims to go beyond the actual law.
In any case, whether or not something is for sale is only one factor in determining whether or not it falls under the Fair Use doctrine. There are commercial uses where the use of copyrighted material is allowed, and non-commercial uses where it is prohibited. The four factors taken into consideration are:
1. the purpose and character of the use, including whether such use is of a commercial nature or is for nonprofit educational purposes;
2. the nature of the copyrighted work;
3. the amount and substantiality of the portion used in relation to the copyrighted work as a whole; and
4. the effect of the use upon the potential market for or value of the copyrighted work.
That your use of Mickey Mouse is non-commercial is a point in its favor, though personal use is not quite as favorable as educational use would be. It is also likely that your use will not affect the potential market for Mickey Mouse products. Any moderately clever lawyer would argue that you might have gone out and purchased a Disney product had you not made a copy of Mickey for yourself, but that would only be plausible if Disney sells a comparable product to the craft you are making.
The other issue here is trademarks, which are not the same as copyrights. Intellectual property holders tend to be quite concerned with two things: keeping their trademarks intact, and not losing revenue due to infringement. The second is covered above. The first, however, is a major driver of intellectual property lawsuits. If Disney turns a blind eye to someone’s use of Mickey Mouse, they could wind up losing their trademark for failure to enforce it. This gives them a reason to care about the infringement even if they otherwise would not.
Not just any usage of Mickey Mouse is a threat to their trademark, though. The usage has to be reasonably public (otherwise they cannot be expected to know about it), and the violations must be either multiple or ongoing. Moreover, trademarks have to do with trade. UPS has a trademark on Pullman brown, but that trademark is only enforceable against other delivery companies or against non-delivery companies attempting to take advantage of UPS brand’s reputation. Your craft is no threat to the trademark.
In short, your use of Mickey Mouse—even if you take a photograph of it and put it on Facebook—is unlikely to get you into trouble. Could it open you up to prosecution? Yes. Then again, just about anything can. I’m a terrible artist. If I draw a picture of Jerry and it just so happens to look like Mickey due to my incompetence, I could be opening myself to prosecution by Disney despite the fact that Jerry is property of MGM!
The case is unlikely to be successful, however, and thus probably wouldn’t be filed in the first place. The same goes for your Mickey Mouse craft. The likelihood of a lawsuit being worthwhile is incredibly low both because it’s not clear that Disney would win, and it’s unlikely to be worth Disney’s time. Assuming your Facebook picture is not easily accessible to all the world, then, you would probably be in the clear. So just make sure to check your privacy settings!
Standard disclaimer: I am not a lawyer. The above is based on seminars I’ve taken on copyright law and discussions with colleagues who have studied and/or practiced copyright law. The information may be out of date or based on a misunderstanding. It is always advisable to speak to a practicing lawyer.