I was thinking about attending a hack-a-thon event to get help creating a prototype. I am a non technical founder and was told this route may be a good option. However, I just found out that you give up some ownership by doing this. So my question is; how does this typically work, and how much ownership do you usually give up?
I get asked that question often with regards to participation in Startup Weekends. In general, it all depends on 2 factors:
Having gone to a startup weekend and seen how things have worked, one big takeaway is that teams often disintegrate after the weekend is over. Of the three I paid attention to, all were reduced to the original idea-holder plus 1-2 people. Given that this is the case, I strongly support the concept of vesting. A weekend's worth of work can be quite a lot, especially given the intensity from the time constraint.
Don't approach it as "sweet, free work!" At typical rates, each developer is probably putting in a couple thousand dollars worth of time to the idea. As long as they continue to be involved with the company, that should count as dues, IMHO.
Make sure you hammer out the details the first night, it's not good to have contributors with hurt feelings.
Ideally, you would be able to trust your team enough to figure out a fair solution that everyone agrees with. Put yourself in the shoes of your team mates - look at their skills and the years they spent to achieve that.. what do you think would be fair?