Volunteering

[nkz]

Hello,

I plan to volunteer in the States. If I understood well I should apply for B1 visa.
1.I got in contact with a non-profit that deals with ocean preservation. Is it okay if they send me an invitation letter for volunteering for a year (probably once a week)? Or is that too long?
2.I know that I will probably get a 6 month permit at the border if I get the visa but can I go back in after 6 months?
3.Is it often that people ask for this kind of visa for the sole purpose of volunteering?
4.Can I get a B1/B2 visa if I say that I will also be traveling during my volunteering period?

Thank you!

[jnk]

Please provide some more information about your situation like do you currently work, married etc.

1. They can send invitation letter. But you need to voluntary work only once a week. What are gonna to for the rest of the duration. 1 year is too long.
2. How will you survive in US for 1yr without any pay by doing only voluntary.
3. It's not very common.
4. Again visa officer will ask the same question how will you survive without getting paid?