Smokie...Your repair job is really easy. Don't use the liquid weld. Here's how to do a pro job on it. Get a peice of aluminum sheet approx 4" x 6". You can get it from any supply house the sells HVAC duct supplies. Look in the yellow pages. Should cost under $5.00. Go to any marine/boating store such as Boat US or West Marine and buy a tube of 3M 5200 Polyurethane Adhesive/Sealant. Click here to see:
http://www.boatus-store.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=20002&1 . For tools you'll need a caulking gun, electric drill, 1/8" drill bit, pop rivet gun, and a pkg of 1/8" short alum. pop rivets.
Center the alum patch over the tear and drill 1/8" holes spaced 1/2" apart through the patch and boat bottom. Make sure the holes are about 3/8" in from the edge of the patch. Remove the patch and coat it with the 5200 sealant. Set the patch back over the tear and pop rivet it in place. From the outside apply the 5200 over the rivets and along the edge of the patch and smooth over with your finger. There you go, good as new and will last forever. If you already have a caulk and pop rivet gun the whole job should cost about $20.00. Hope this helps.
Catman.