Hi I recently just obtained a double entry tourist visa from Penang, Malaysia. I'm now currently using my first entry and will have to leave the country in 2 weeks. I will be leaving Thailand again within 30 days. Is it possible for me not to use my 2nd entry tourist visa and just obtained a 30days visa in the airport and only use my 2nd entry later after i come back in?

Thanks.

No, you have to use the visa. Immigration now insists on that.

You could get a re-entry permit to keep yur permisison to stay alive. But it won't stop the clock, the days you are outside of Thailand the 60 days will continue to run. Note that you can get a 30 day extension on every entry with a tourist visa.

As Mario2008 said, obtain a re-entry permit,(1.000 baht)from immigration, which would allow you to re-entry with your original 'allowed to stay' stamp, which would have been 60 days from your first entry, then obtain a 30day extension (1.900 baht) again from immigration, when that stamp nears its end,do a border run to use your 2nd entry of the 2 entry tourist visa, and again a 30 days extension if required giving you a 6 month stay in Thailand.

have a good trip