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JSoup

Best wood for 5o5 transom rebuild

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I am helping my 15 yr old son rehab a neglected 1972 Moore 5o5.  We have no illusions of making this a race ready boat, just a fun toy to screw around on.  The mostly open transom had a wood core that was half dry rot, so we chiseled that out and need to replace the wood.  The original wood was 1" solid fir (? - not plywood).  I was originally thinking we would use 1" marine plywood, but that is hard to come by locally and expensive considering how much we would need to buy versus actually need. Now I'm wondering if there is a better, at least more economical solution. We will encase the new core in epoxy and fiberglass it into place, there will be no exposed wood. Thoughts?  Thank you!

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Access to thinner exterior grade ply? Laminate 2 or 3 pieces of 1/2" or 3/8" ply together with thickened epoxy, seal the edges with epoxy after shaping. Will be stronger and easier to work with than 1". (Also if you only have smaller pieces, you can use several pieces and stagger the joints to be even more economical with the ply. Best to use 3 layers!)

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As I have no idea how many cubic inches need to be filled I cannot give a singular answer.

1. You could mix up a slurry of resin and scissored fiberglass strands and just fill the void. ... Don’t do it all at all At once as it will overheat and burn itself up . 1/2 inch at a time is a good rule 

 

2, if the skins are good and the core isn’t necessary for the structure  you can pack it full of Bondo

3, you can wrap pieces of wood in fiberglass and stuff them in there 

I really don’t want to speculate  further without seeing photos.. 

take a dozen and oust them 

photo hint: cell phone photos on my iPhone are too big for the rules here.

i take a big photo with what I need in the center, open theceditir, crop away 3/4 of the photo to leave only what I want and  they post 

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Thanks to both of your for your responses.  I think laminating  two 1/2" or one 1/2" and 3/4" together is probably the best option.  The skins are generally in good shape.  The wood goes in the vertical sections on about 3" on each side and across the top section.  It appears that the wood core was exposed originally, which is hard to understand, but I will glass it in.  

close detail.JPG

core removed.JPG

transom closer detail.JPG

transom from behind.JPG

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What about Airex PXc, once known as Penske board?  It's a dense urethane foam that's specifically intended as core in applications that need more compression strength/ 

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I like the idea of some plywoid eith exterior glue

i also like the  idea of making your own plywood from thin pieces of fir,  spruce, mahogany, 

the area is pretty small . $20 Worth Of Wood Wouid set you up with all kinds of  choices . 

You can make shaped pieces of home made epoxy glued plywood and clamp them in place 

make a mass... dip each wood chunk in epoxy before gluing your plywood together 

 

just a thought .

stay simple

get done

go sailing 

 

oh yeah... you really need to sand the hell out of thosr  inner surfaces. 

Scraping outbthe composted old Wood  is obvious.

sanding the relatively inaccessible surfaces is a pain.

One handy tool you can use for many years>>>

get sone 3m Green Corps 40 grit air file  strips.  You can buy a little sherbet of three at Walmart for about $5

find a hunk of  three inch wide metal to use as a backing plate . Carry a 12 pack into virtually any metal shop or welder, and ask if he has something flat and stiff that is 3”  wide and 28 inches long 

Or cut your own backing plate from a cutting board. 

 Thattool Wil find all kinds of uses

 

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Any good quality plywood sealed with epoxy will work just fine truthfully.

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Now I've seen pics, laminated thinner ply pieces may be the best way to go as you can fit them in place easily. (Dry-fit them first!)

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