Sending files other than html via Actionmailer

I’ve been trying to set up to send already generated PDF’s via the
ActionMailer class however it dosn’t seem to send the full file. So when
I try to load the file after being sent it via email it dosn’t because
it is corrupt. When I choose to send HTML instead it sends fine but it
dosn’t work with Word Documents either

Do I need to do anything special for other file types?