Question : blowing the tran log

alter table tablename
alter column columname varchar(5) null
go

just expanding an attribute from char(2) to varchar(5).  
the table is pretty big, about 492984336 records, and i keep blowing the tran log about an hour or so into the job.  

i didn't want to just keep restarting, so now i've created a table2, and am actively copying the data in there in batches of 50K, so the tran log doesn't blow out on me.  the database is completely unused right now.  nobody is on it but me... but, I need to get this done asap.  

it's been running for near 5 1/2 hours, and i'm not even a quarter of the way there.

the basic alter table construct kept blowing the log, and this route seems to be working, but far too slowly.  i'm still going to need to recreate the indices on this thing, once the data is loaded, and my window to do it in, is just not that large.

this may just be all I've got, but i wanted to see if anybody had any tips or tricks, that may help me out in this regard.

Answer : blowing the tran log

Possibly a bulk export - alter/recreate table - bulk import might be faster in your case