I could easily be wrong on this so check with experts. I seem to recall that radiator holes/cracks are often repaired using something called "silver soldering". I do not know what silver soldering is but perhaps you could look into it. Any kind of solder would be unaffected by the temperatures seen in a radiator.
I urge caution. No offense to Bryron but he is a new member with no track record. He has not posted any information about himself or his bike and his posts are curiously short and infrequent. These are all suspicous activities. I hope that I am wrong. I strongly recommend that you ONLY use some form of payment that offers guaranteed satisfaction. I think but am not sure that standard Paypal offers this but the fee free version - Paypal, Friends and Family does NOT.
You can buy from members on here safely if you simply use a payment method which offers a guarantee of satisfaction. I believe that standard Paypal and NOT Paypal - Friends and Family is an example of this. It is also safer to deal with members who are not new and have a reasonable number of posts to indicate they are not scammers. Scammers would not spend years of time posting and waiting to pounce on a victim.