I got a double TV in Vientiane for 60 days and when it expired I then got a 30 day extension. When it expires can I just go to Myanmar and come back and the second of the entries will come into play? Also has anyone the experience of doing that at Mae Sot? Can you tell me what is required?

You must make the second entry while the visa is still valid (check the use/expiration date on the visa itself).

Yes go to any neighboring country and return the visa is activated the day that you return. You do not need copies of anything. You may need a visa for visiting neghboring countries, or they may stamp you out and in at the same time. I have not done this at Mae Sot. Nong Khai only.

Point of note for TVF readers. Entering Thailand at Nong Khai there are three immigration booths.

The far left for Laotians, the centre and right booths for everyone else.

Posted on the second booth above eye level are the date a 14 day land border entry will expire, the date a 30 day visa entry will expire, and the date that a double entry will expire. So have a look at that and make sure that the proper date corresponds to the one the immigration officer is going to put in your passport. These dates are changed daily, obviously. This may help avoid some confusion.

Entry by land is 15 days for most visa exempt countries. Day of entry is day one of that 15 day count. A double entry can not have an expiration date until you make the second entry so suspect you mean a tourist visa entry of 60 days?

Mae Sot is easy. Get stamped out of Thailand, either walk across the bridge or take the songtau. ay 500 baht for Burmese visa get stamped in then out, back across the border and get stamped in at Thai Immigration, free.

The biggest problem is getting there, either bus or van from Tak then tuk tuk from the bus station to the border. If you are driving, there's parking under the bridge, decent market and restaurants.

you can't just wait for the 30 day extension to expire ,

chances are you will have to go earlier than that - look at the enter before date written on the visa that's your last day to goto burma.

mae sot or mai sai much the same 500 baht to enter burma for the day or just 5 mins . you can get a flight upto chiang rai and a 40 min transfer to the mai sai border maybe ?

sometimes burma accepts 10 $ instead of 500 baht if your lucky but they have to be new notes.