10point Posted February 25, 2012 Report Share Posted February 25, 2012 I have a new fish finder on the way and will be removing the old transducer that will leave two small holes in the bottom of the boat. How can I plug these? Would JB weld work? Link to comment Share on other sites More sharing options...
pikehunters Posted February 25, 2012 Report Share Posted February 25, 2012 I have a new fish finder on the way and will be removing the old transducer that will leave two small holes in the bottom of the boat. How can I plug these? Would JB weld work? Alum. or Fiberglass ?? Mine was fiberglass cleaned the holes really good with alcohol wipes, bought the best silicone i could find filled the hole & the ran the screws back in. Lasted 10yrs sold the boat & I bet there still in there! Link to comment Share on other sites More sharing options...
10point Posted February 25, 2012 Author Report Share Posted February 25, 2012 Alum. or Fiberglass ?? Aluminum Link to comment Share on other sites More sharing options...
Ralph Field Posted February 25, 2012 Report Share Posted February 25, 2012 If you can get at them from the top , then I would suggest using the epoxy that you can buy at a dealer or they used to sell it at Canadian tire. I don't know if you could do it from the underside. Link to comment Share on other sites More sharing options...
Bondar Posted February 25, 2012 Report Share Posted February 25, 2012 Sealed rivets and some epoxy would do it Link to comment Share on other sites More sharing options...
DRIFTER_016 Posted February 25, 2012 Report Share Posted February 25, 2012 3M 5200 Fast Cure Marine Sealant Link to comment Share on other sites More sharing options...
aplumma Posted February 25, 2012 Report Share Posted February 25, 2012 On my aluminum boat I drilled out the hole and put a tank to bowl toilet bolt in. The bolthead is outside then the rubber washer then boat then rubber washer then flat washer and finally the nut with a locking back up nut. No leaking in 12 years plus. Art Link to comment Share on other sites More sharing options...
NANUK Posted February 25, 2012 Report Share Posted February 25, 2012 Clean the area with rubbing alcohol, scuff lightly with some sand paper, fill the holes with 3M 5200 marine adhesive, Install a transducer mounting board using the same adhesive and ss screws, mount new transducer on the board. You will never have to worry about drilling or filling holes on your transom. Link to comment Share on other sites More sharing options...
sneak_e_pete Posted February 25, 2012 Report Share Posted February 25, 2012 Clean the area with rubbing alcohol, scuff lightly with some sand paper, fill the holes with 3M 5200 marine adhesive, Install a transducer mounting board using the same adhesive and ss screws, mount new transducer on the board. You will never have to worry about drilling or filling holes on your transom. X2 have done this and not a drop Link to comment Share on other sites More sharing options...
Jigger Posted February 25, 2012 Report Share Posted February 25, 2012 Two stainless screws coated in caulking will do you just fine. Link to comment Share on other sites More sharing options...
OhioFisherman Posted February 25, 2012 Report Share Posted February 25, 2012 They sell a product, I believe it`s called Boat Life caulk? some of it in the hole and a couple of stainless sheet metal screws will work. Link to comment Share on other sites More sharing options...
RSF Posted February 26, 2012 Report Share Posted February 26, 2012 Seems to me, you may want to stay away from metal screw/bolts that will will react in contact with alluminum. What does this mean for aluminum? Galvanic corrosion is the most common cause of aluminum corrosion due to its inherent resistance to more natural forms of corrosion and a lack of preventative measures taken. INFO LINK (PAGE 4): http://cmiengineer.com/whitepapers/aluminum_corrosion.pdf Link to comment Share on other sites More sharing options...
jedimaster Posted February 26, 2012 Report Share Posted February 26, 2012 Clean the area with rubbing alcohol, scuff lightly with some sand paper, fill the holes with 3M 5200 marine adhesive x3 Link to comment Share on other sites More sharing options...
aplumma Posted February 26, 2012 Report Share Posted February 26, 2012 Seems to me, you may want to stay away from metal screw/bolts that will will react in contact with alluminum. What does this mean for aluminum? Galvanic corrosion is the most common cause of aluminum corrosion due to its inherent resistance to more natural forms of corrosion and a lack of preventative measures taken. INFO LINK (PAGE 4): http://cmiengineer.com/whitepapers/aluminum_corrosion.pdf You are correct however the part of the formula missing is a median for the metals electrons to migrate is for the most part missing. You need a fluid to allow the electrolysis to occur. The boat in question likely lives on a trailer and since aluminum oxidizes rapidly it has the desired ability to seal itself. The use of Zinc and or Magnesium are used extensively to stop electrolysis in boats that are left in the water. I have a 28ft aluminum boat with stainless steel and brass shafts and screws that lives in brackish water and with the use of a galvanic isolator and zinc's it has survived since 1985 till today with no damage. Art Link to comment Share on other sites More sharing options...
NANUK Posted February 26, 2012 Report Share Posted February 26, 2012 Seems to me, you may want to stay away from metal screw/bolts that will will react in contact with alluminum. What does this mean for aluminum? Galvanic corrosion is the most common cause of aluminum corrosion due to its inherent resistance to more natural forms of corrosion and a lack of preventative measures taken. INFO LINK (PAGE 4): http://cmiengineer.com/whitepapers/aluminum_corrosion.pdf That’s why you should use marine grade adhesive with your ss hardware. Almost every aluminum boat I have seen with a transom mounted transducer has some sort of metal (mostly stainless) fasteners. There are over a dozen stainless screws and bolts in the transom of my boat including four 1/2" mounting bolts for the outboard, I see no sign of corrosion what so ever. Not to mention everything else inside the boat, downriggers, electronics, trolling motor and various accessories are all mounted with ss fasteners. Corrosion is more of a concern in salt water OR if there is a “voltage leak” to the metal hull. An aluminum hull is usually grounded through the motor but it is not used as a ground back to the battery. A boat hull should never be used to run ground to the battery, doing so is a recipe for corrosion regardless of salt or fresh water. Another important thing is to always make sure the sacrificial anodes on your engine are in good clean condition. Clean or replace as necessary. Link to comment Share on other sites More sharing options...
NANUK Posted February 26, 2012 Report Share Posted February 26, 2012 I guess we were typing at the same time Art Link to comment Share on other sites More sharing options...
krixxer Posted February 26, 2012 Report Share Posted February 26, 2012 Two stainless screws coated in caulking will do you just fine. Dissimilar metals should not be used as it promotes corrosion. Link to comment Share on other sites More sharing options...
Sinker Posted February 26, 2012 Report Share Posted February 26, 2012 I just srcrewed a couple aluminum self tapping screws into the old holes. Doesn't leak a drop, and they've been in there for years now. No caulking or any type of sealant so far. S. Link to comment Share on other sites More sharing options...
DRIFTER_016 Posted February 26, 2012 Report Share Posted February 26, 2012 I just srcrewed a couple aluminum self tapping screws into the old holes. Doesn't leak a drop, and they've been in there for years now. No caulking or any type of sealant so far. S. They are leaking you just can't see it. You may want to use a little cauking as the water being soaked up by your transom core is slowly rotting it away. Link to comment Share on other sites More sharing options...
Sinker Posted February 27, 2012 Report Share Posted February 27, 2012 There is no wood where these screws are, just thick aluminum. They don't leak, and never have all this time. I'm not going to touch anything. S. Link to comment Share on other sites More sharing options...
RSF Posted February 27, 2012 Report Share Posted February 27, 2012 Why not play it safe. If you decide to use ss bolts and washers, you might consider insulating the contact points with rubber, rubber tubing or perhaps first marine--epoxy insulate around the holes, both sides and inside, then drill through the eg epoxy as not to make contact with the alluminum. Run two ss bolts, washers and rubber washer so the rubber-only, is making contact with the hole area of hull. (Bolt side thread top: SS Washer--Rubber. Nut side: Rubber--SS Washer--SS Lock Nut.) Then it's a tough, water tight and no mis-matched metals would be making contact. Link to comment Share on other sites More sharing options...
10point Posted February 28, 2012 Author Report Share Posted February 28, 2012 (edited) You guys using 5200, are you using it on aluminum. The package does not mention aluminum. Saw some at home depot. Also, saw some jb water weld. Maybe I should try that. Edited February 28, 2012 by 10point Link to comment Share on other sites More sharing options...
irishfield Posted February 28, 2012 Report Share Posted February 28, 2012 You guys using 5200, are you using it on aluminum. The package does not mention aluminum. Saw some at home depot. Also, saw some jb water weld. Maybe I should try that. Leave the JB in the store! 3M5200 or Sikaflex 1A Link to comment Share on other sites More sharing options...
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