I am upgrading my fish finder and have to drill new holes in the transom of an aluminum boat for the transducer. Is marine caulk sufficient for filling the old screw holes or is there some kind of aluminum patch that is needed? Holes are less than a half inch in diameter.

For the mechanically challenged, can you give more information about where to get it, etc.

From looking at their prices, they sure don't give the stuff away.

Mike

A few other cheap and easy option (especially for the mechanically challenged) would be:

1) An aluminum epoxy stick (Boaters World $10)

2) 3M 4000 or 4200, not 5200 (Boaters World $5)

3) JB Weld (any auto parts store $5)

I have never done this myself but I have heard of it being done and sounds like a fairly good idea...

get a piece of teak and cut a square larger than the old fishfinder mount... fasten it to the boat using the old holes and marine sealant. Screw the new transducer to the teak.

Just plug the holes with screws coated with 5200, Then drill the new one's for the new trans.

If I had an Al boat, I would get all superfluous holes backed, filled, and faired with Al by a skilled welder. Seriously. It is not hard for a skilled welder to do, it gives you a real fix, you can drill a new hole in it and put in a new screw if you want, and it will look fantastic.

Assuming that you are not covering the old holes with the new 'ducer, make sure you put back the old screw or thru-bolts into the holes along with 3M 5200 or whatever your favorite sealant is.

5200 is recommended for fiberglass and wood not metals. 4000 and 4200 are recommended for metals.

Get a piece of UHMW (cutting board material) about 3/4 inch thick or more and about a foot wide and bolt that to your transom where you want to put your transducer. Use marine silicone to seal up the job. Then you can mount your tranducer, speedometer, next transducer after you break off this one, the real nice one you are going to get after you win the lottery, etc. to the UHMW with SS woodscrews without every putting another hole in your boat. Works slick

Duct tape!! Oh ya baby.

Steelheaddude is right except dont use screws. Use a nut and bolt with 5200. I had a tiny bracket welded on so I didn't have to cut holes below the waterline.

Follow spawnout's advice, any of the major catalogs sell precut boards if you can't find a cutting board.

Use a marine sealant on the back of the board, fill the old holes and coat the threads of the new stainless steel sheet metal mounting screws or bolts. I used rtv marine sealant.

Have it tig welded. Then it is a done deal. no leaky, no worry, peace of mind, end of story.

Spawnouts suggestion is the best idea, simple, ez, and economical. I have that set-up on both my aluminum andl fiberglass boats.

But if you don't want to do that and want a fast, economical, permanent fix, use JB weld, great stuff. tough, sandable. can be shined drilled. ground, etc.

Put 2 pieces of alluminum together with it an try to get them apart!

JMO



herm