filling hole from thru-transom fitting

svdk

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Jul 29, 2005
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I will be removing a thru-transom fitting (located below the water line) that is no longer needed and is currently letting water seep into the transom core. The hole is about 3/4" in diameter. The transom is typical fiberglass and plywood construction. I would like to just fill the hole and be done with it. <br /><br />I'm not too concerned about final appearance, but I want a long term solution that will hold up over time.<br /><br />I'm thinking about doing the following:<br /><br />1) revome fitting and any caulking<br />2) rough up the exposed wood<br />3) bevel gelcoat on outside surface of transom <br />4) bevel inside fiberglass<br />5) fill hole with marine grade epoxy<br />6) sand the epoxy flush to both exterior and interior surfaces<br /><br />Will this work? Is there any thing else I should be concerned about?<br /><br /><br />thanks,<br />svdk
 

Wimperdink

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Re: filling hole from thru-transom fitting

Sorry I cant be of any help but i'm curious... how do you intend to fill it With epoxy on a vertical surface? Seems like a challenge to me.. If it was me I would use a holesaw in another piece of thick plywood for filler then fiberglass that in place.
 

svdk

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Jul 29, 2005
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Re: filling hole from thru-transom fitting

Thanks, I'll clearify what I mean by epoxy. I'm talking about the quickset, two-part stick/dough type epoxy similiar in consistency to jbweld. <br /><br />I thought about just taking a section of 3/4 dowel and plugging the hole and fiberglassing. I just don't want to mess with fiberglass and resin for such a small hole, but maybe that would be the better method.<br /><br /><br />Any additional thoughts?
 

epresutti

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465
Re: filling hole from thru-transom fitting

svdk,<br /><br />I had to fill similar holes. I used sawdust and epoxy, made a very stiff paste, was a 8itch to sand!<br /><br />Peace.<br /><br />Ed.
 

crab bait

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Feb 5, 2002
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Re: filling hole from thru-transom fitting

plug with a dowel .. epoxy up real good.. an the hole also.. push in the hole.. remove an do it again.. an twist.. sounds kinky :) ,, but you want it glued good..<br /><br />push in dowel so it's a SHADE recessed.. 1/6 inch.. <br /><br />let to set up.. clean up with vinegar an rag.. nothing works better..<br /><br />then fill recess with marine-tex epoxy putty ..available at any boat store..
 

djzyla1980

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640
Re: filling hole from thru-transom fitting

Go buy a small can of bondos fiber fill.... 2 part mix... hardner and epoxy/fiberglass strands... Mix it up and shove it in the hole.. It's thick and will sit in there fine... as it sets indent the outsides and fill with JB weld level...used this approach on a couple spots on my transom... and it's holdin up great.<br /><br />Doin some body work on my truck and didn't really want to buy the fiber fill.. but it said it was 10 times stronger then reg bondo... turns out I love the stuff now.. put it right up there with JB weld.Oh yeah... <br /><br /> I should add have a piece of packaging tape ready... when you put the JB weld in the indentions... put a piece of that tape over it til it sets... keeps it from running... and makes it pretty much level with the surface.
 

solidwaste75

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Aug 1, 2005
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Re: filling hole from thru-transom fitting

I had the same problem except it was in the side of the boat for a live well 3/4inch hole with metal tubing..Soo I was pacthing hull with Marine tex on day and said why not I put a big glob in the hole..Next day I sanded it down and took a hammer taped on it then really wacked the crap out of it hammer just bounced off..I check it every time I go out not a drip of water..I swear by that marine tex stuff it really is great..Now I left the metal fiting in and sanded down so it not that attractive but I didnt care..
 

svdk

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Jul 29, 2005
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Re: filling hole from thru-transom fitting

Thanks for the good ideas. Good to here that these simple solutions will hold up. Now I just need to sit down a figure out how I want to proceed.<br /><br />I may give the bondo fiber fill a try--I have little left over from another project.<br /><br />Thanks again.
 

Mark42

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Oct 8, 2003
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9,334
Re: filling hole from thru-transom fitting

FYI, I filled motor mount holes in the transom like Crab Bait said. Dowel about 1/4" shorter than transom with epoxy sealing ends. Its holding up well.
 

imported_Curmudgeon

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Re: filling hole from thru-transom fitting

Last I heard, BONDO was hydroscopic (absorbs water). If true, I don't believe it would be the optimum product for patching a sub-waterline hole ... :confused:
 

svdk

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Jul 29, 2005
Messages
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Re: filling hole from thru-transom fitting

Old Curmudgeon, Bdirect--<br /><br />Thanks for the replies. Good info. Fortunantly, I haven't filled the hole yet. I guess I'll go the dowel and epoxy route.<br /><br />Thanks.
 

Wimperdink

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Re: filling hole from thru-transom fitting

Originally posted by Old Curmudgeon:<br /> Last I heard, BONDO was hydroscopic (absorbs water). If true, I don't believe it would be the optimum product for patching a sub-waterline hole ... :confused:
I believe he was talking about bondo brand fiberglass filler... its a differant consistancy than normal bondo. Its a two part putty that is full of fiberglass strands and dries smooth and very strong. not as porous as normal bondo<br /><br />Still I would at least resin the inside of the hole to seal it before using something like this.<br /><br />In contrast to what I"ve done, I'd suggest epoxy instead of resin for an area outside the hull and below the waterline.
 

djzyla1980

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Re: filling hole from thru-transom fitting

Actually the fiber fill has none of the Normal Bondo materials... cept the cream hardner. It is an epoxy/resin based product with fiberglass strands. It is not your run of the mill pink/grey bondo fill. It is specifically used to fill larger holes in both fiberglass and metals, Auto's and Marine. I believe mine can states in great big bold letter...Great for Repairing Cracks and holes in Boats, autos and more... Go figure it even has a boat on the can. :D <br />
764NEW2.JPG
 

crab bait

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Re: filling hole from thru-transom fitting

can't be 'epoxy/resin base' ..epoxy an resin don't mix.. it's like water & oil..
 

djzyla1980

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Re: filling hole from thru-transom fitting

epoxy/resin = epoxy or resin... get the 2 confused between the 2
 

Mark42

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Re: filling hole from thru-transom fitting

Originally posted by crab bait:<br /> can't be 'epoxy/resin base' ..epoxy an resin don't mix.. it's like water & oil..
Crabby, you obviously don't have a epoxy/resin homogenizer. You know, the same thing that turns oil and water into margarine. LOL!<br /><br />Now the question is when epoxy and resin are homogenized, the epoxy will stick to the resin, but will the resin stick to the epoxy? :D
 

record hunter

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Apr 22, 2003
Messages
99
Re: filling hole from thru-transom fitting

clean out the hole. Drill one size larger. use west system epoxy slow going type mix with aresol to thicken.. put into hole with syringe ish outside of glass and glass on new small piece of fiberglass cloth with the west system sand . fill any inperfections with thickener. can use west system and microballons and microcell mix sand and gel coat over spray to match
 
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