Removing welded aluminum box

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I have a boat that is made of .125" 5086 Marine Aluminum. It had a dry box welded in it that i roughly cut out. The beads runs along the side wall and down to the floor. I used a saw zaw to cut out the box. Well I would like to remove the weld and remainder of the box (pictured in yellow) and have the side of the hull flush and smooth like it would have originally looked like before a dry box was welded in. My question is what is the best way to tackle this? I have roughly 8 feet of bead to remove with most being straight lines and fairly easy to get to. Ive tried doing research and searching forums but the terms used "aluminum weld removal" bring back mostly how to weld topics. I tried a rotozip and a flush cut metal blade http://www.homedepot.com/h_d1/N-5yc1...1#.UHyZ5G_YEwo. I didnt use any wax so im not sure how much that makes a difference. Does that help with speed of cut or only extending the life of the blade?  It worked well with getting it flush but I think it would take a year to do the whole boat.. Thanks for any response. Attached ImagesLast edited by jasonphoto01; 10-15-2012 at 07:25 PM.
Reply:Plasma cutter will make quick work of it.Is there a danger with creating sparks near the area?JasonLincoln Idealarc 250 stick/tigThermal Dynamics Cutmaster 52Miller Bobcat 250Torchmate CNC tableThermal Arc Hefty 2Ironworkers Local 720
Reply:There is no issue with sparks. Would I have to worry about it burning through the side of the boat?
Reply:Originally Posted by jasonphoto01There is no issue with sparks. Would I have to worry about it burning through the side of the boat?
Reply:Well I dont have access to a plama cutter so other equally effective alternatives might be better.
Reply:I'd make a template and use a router. If space is tight you might be able to get it with a trim router. It doesn't take much to cut 1/8". I cut circles all the time with my trim router. I'd recommend a down ward spiral bit as it pushes the chips away from you. I use the 1/4" bits from home depot... just don't tell the sales guy your cutting aluminum or they will tell you how it won't work.  Carbide is ideal but high speed steel will also work fine. I normally cut dry with carbide. You may want some coolant/lubricant/wax with hss. The router will leave you with a very nice finish.
Reply:Yikes! When I first looked at the photo I was thinking this was a double hull... but it looks like a single. I think I'd take a different approach.Use a die grinder with a carbide burr on it. Mount the die grinder onto a plate that you can run on the hull surface. Set the depth of the burr to almost flush with the hull. Bring the burr into the weld from the top and carefully cut it down. By mounting the die grinder you minimize the risk of cutting into the surface. Once the weld has been cut down then carefully blend the weld into the surface with a small sander.
Reply:How about a SawzAll with a nice long  flexible metal cutting blade on it?  Let it flex against the side of the boat and it shouldn't gouge.  Will get almost all of the sides of the box down to the wall of the boat.Miller Syncrowave 350Millermatic 252/ 30A spoolgunMiller Bobcat 225g w/ 3545 spoolgunLincoln PowerArc4000Lincoln 175 Mig  Lincoln 135 Mig Everlast 250EX TigCentury ac/dc 230 amp stickVictor O/AHypertherm 1000 plasma
Reply:Originally Posted by DougAustinTXHow about a SawzAll with a nice long  flexible metal cutting blade on it?  Let it flex against the side of the boat and it shouldn't gouge.  Will get almost all of the sides of the box down to the wall of the boat.
Reply:Originally Posted by DougAustinTXHow about a SawzAll with a nice long  flexible metal cutting blade on it?  Let it flex against the side of the boat and it shouldn't gouge.  Will get almost all of the sides of the box down to the wall of the boat.
Reply:Originally Posted by forhireYikes! When I first looked at the photo I was thinking this was a double hull... but it looks like a single. I think I'd take a different approach.Use a die grinder with a carbide burr on it. Mount the die grinder onto a plate that you can run on the hull surface. Set the depth of the burr to almost flush with the hull. Bring the burr into the weld from the top and carefully cut it down. By mounting the die grinder you minimize the risk of cutting into the surface. Once the weld has been cut down then carefully blend the weld into the surface with a small sander.
Reply:You can "mill" it off the surface using a skill saw and a non-ferrous cutting carbide blade with as many teeth as you can get on it.     The majority can be cut our by setting the saw on a short piece of 2x4 and set the depth of cut to around 1.25 inches. Make cuts while riding on the wood until there is only 1/4 inch sitting proud then you gently drag the spinning blade sideways across the welds and shave it down the last amount.   Definitely practice on some scrap until your saw skills are good.  try to make too big a cut and the blade will grab.  Vacuum up the cuttings afterward.   Face shield. ear protection as well as gloves are recomended.  The shavings are hot.
Reply:After you cut out the majority of the walls of the box, you can get the rest of the metal down (including the aluminum welds) using a flap wheel on a 4 1/2" grinder.  I'd use about a 30 grit flap wheel initially, then a 60 or 80 grit as you get down to the level to blend the residual raised area with the wall of the boat.  Flap wheels are great for this sort of thing.Miller Syncrowave 350Millermatic 252/ 30A spoolgunMiller Bobcat 225g w/ 3545 spoolgunLincoln PowerArc4000Lincoln 175 Mig  Lincoln 135 Mig Everlast 250EX TigCentury ac/dc 230 amp stickVictor O/AHypertherm 1000 plasma
Reply:https://www.partsmaster.us/SitePages...px?Code=010110http://weldingweb.com/attachment.php...1&d=1350442791       i seen the video  on hear a some time back. Attached Images
Reply:Originally Posted by lotechmanYou can "mill" it off the surface using a skill saw and a non-ferrous cutting carbide blade with as many teeth as you can get on it.     The majority can be cut our by setting the saw on a short piece of 2x4 and set the depth of cut to around 1.25 inches. Make cuts while riding on the wood until there is only 1/4 inch sitting proud then you gently drag the spinning blade sideways across the welds and shave it down the last amount.   Definitely practice on some scrap until your saw skills are good.  try to make too big a cut and the blade will grab.  Vacuum up the cuttings afterward.   Face shield. ear protection as well as gloves are recomended.  The shavings are hot.
Reply:Used the sawzal to cut most of it down then went back over everything with a 40 grit flap wheel and wax then a palm sander with 150 grit. The flap wheel worked perfectly and everything came out great. Thanks for all the useful information!There are a few problem areas though where the sawzal got away from me and gouged some of the aluminum. Could I fill this with JB weld or something similar then sand it down smooth to restore a more even flush look?