patching holes below water line

[boatman37]

Going to be installing a new depth finder and transducer but need to fill the holes from the old one. Stopping at West Marine Friday. What is the best product for this? I used Spectrum gel paste for other holes but it came loose when I was pressure washing it so I either didn't clean it good enough or it isn't the best choice? Only have 4 holes to fill so only need a little bit.

Best product to seal the new screws? 4200? Something better?

Thanks!

 

[Scott Danforth]

5200 for the old holes and the new.

 

[alldodge]

Agree 5200, but you might want to drill the holes out a tad bigger to se if the wood is wet, also so you can get clean wood for adhesion

 

[kcon]

Alternatively to the 5200, you probably don't want to buy a quart of epoxy resin just to use a small amount of it considering the cost, I hear the product MarineTex works quite well for that, I have some but have yet to use it personally.

 

[boatman37]

Sounds good. Will use 5200. Will I have issues if I need to remove the new transducer with the 5200? Will drill it slightly oversize too just to be safe.

Saw Marine Tek at the local dealer. Heard it's good too.

 

[Grub54891]

I personally am a firm believer in drilling any mounting holes oversized fill with epoxy cabosil mix then drilling them out to the proper size screw you use. Still use sealer, but less chance of any leaks getting to the wood.

 

[alldodge]

The 5200 is to seal the old holes, I wouldn't use it and then put the new screws in. New screws should be installed as Grub mentioned (oversize, fill, then new screws) and would do it has he suggested or fill with 5200, Marine-Tex, Other two part epoxy.

Could also fill new screw holes with 4200 and then install screws when still wet. This is how Formula install trim tabs

 

[Grub54891]

Well yes no need to install screws in the old holes. What I meant was to do up the new holes as I said, it would not hurt to fill the old holes with the epoxy to seal them up, but then you would put a dab of gelcoat over that to make them totally sealed, and unseen to the rest of the world.

 

[Woodonglass]

I personally am a firm believer in drilling any mounting holes oversized fill with epoxy cabosil mix then drilling them out to the proper size screw you use. Still use sealer, but less chance of any leaks getting to the wood.

+2 on this method. 1/2" hole filled with PB and redrilled and filled with a bit of 4200 ensures everything will stay dry!!
Do NOT over drill all the way thru the transom. Just about 1" deep should be plenty deep. Screws shouldn't be much longer than 3/4 inch.

 

[boatman37]

1/2" hole?

So on the old holes just fill with 5200 or use the same 'PB' mentioned for the new holes? I still have some spectrum gel coat paste so could 'level' off the holes before drilling to be less noticeable.

 

[boatman37]

Well that was scary! Drilling into the back of my boat! Ran the wire for the new depth finder and took the old screws out from the old one. Drilled those to about 5/16 for 1) see how the wood looked 2) be easier to fill the holes with Marine Tex. Also drilled new 7/16" holes for the new transducer, all 1" deep. Drilled another 5/16" hole 1/2" deep for the cable 'clamp' to attach the cable to the transom. Beveled the holes slightly too just for better adhesion.

The good news is all wood that was drilled was all light colored and dry. Even took pics of them in case we sell it or whatever then I can show the buyer the pics.

Next question...Not going to apply the Marine Tex yet because of ambient temps but before I do should I use acetone inside of the holes before I apply the Marine Tex? Meaning get the acetone on the wood too? Thinking of using a Q-Tip to get the acetone inside the holes if I need to.

Also, got my impeller done, reinstalled the lower unit, replaced anodes. Making progress! Now if the weather would just cooperate.

 

[Woodonglass]

Not totally necessary but...Won't hurt a thing. Marine Tex sticks to about anything. Just make sure no dust or contaminants (Greasem Fuel etc) are present.

 

[boatman37]

Thanks Wood. Shop-vacced the holes so should have got everything out but will be sure when it comes time to fill 'em

 

[alldodge]

Acetone always a good thing to use to make sure any and all grease/oil/fuel is gone

 

[boatman37]

Acetone always a good thing to use to make sure any and all grease/oil/fuel is gone

Yeah, just wasn't sure if it would hurt getting it on the wood

 

[alldodge]

It will leave no residue behind and does not effect the wood

 

[boatman37]

Sounds good! Thanks all!

 

[boatman37]

Well filled holes today with marine tex. what a mess...lol. cleaned up good but i was covered in it. should be completely cured by this weekend so plan to drill it and attach the transducer