I agree with Zhillauditor's posts fully, but I'll elaborate on a couple of points.
First, I tell my clients all the time that there is no such thing as "lawsuit proof." All that is required to be sued is for someone to have a piece of paper, a means of priniting on it, and the filing fee.
That said, the particular portions of Zhillauditor's post about being a "merchant" under the Uniform Commercial Code (that the UCC thing he mentioned
) is all true. If you fall under the definition of a merchant, then you will indeed be providing an IMPLIED (unless specifically disclaimed) warranty that the product is suitable for its intended purpose. The suggestions earlier about of bill of sale which disclaims such warranties will help in your defense if you are sued.
The other thing I'll point out is good old negligence. Those who practice on the Plaintiff's side of the bar (and yes, I dabble over there from time to time) love negligence. Reason? It's fairly easy to get by the legal hurdles to get the issue to the jury. Then, the fate is decided by "12 people who aren't smart enough to get out of jury duty."
Negligence requires "some proof" (in order to get the jury) of (1) a duty owed, (2) a breach of that duty (3) which is cause of harm and/or damages. Now, under the scenario that you sold a BP pistol to someone and it blew up in their hand, there are several defenses which are readily available. First, the seller didn't owe a duty at all. Second, if he did owe a duty, he didn't breach it. (These are the areas where the bill of sale will likely help as well). It wasn't something that the seller did or failed to do that caused the harm (i.e. the buyer overloaded the pistol).
Not trying to teach everyone Law 101 here, but I thought it worth the electrons to point out that (1) everyone can be sued, (2) getting sued isn't fun (or cheap) and (3) taking some precautions should you be sued certaintly won't hurt your defense should that event arise.
Did anybody else see the video of the woman in the mall, walking along texting, and falling into the fountain? She's not suing over the fall, she's suing because some security camera guy let the video out and she's embarrassed.
....but I digress....