1971 20 SF Transom project

[Yamtt125]

Unfortionately, I woke up to rain this mornin so I will have to finish chisseling the old cabosil mixture on Monday b/c i'm going to vermont for the weekend.

So far, this is what the entire transome looks like right now. The wood looks dark b/c it is wet from the rain, but there isn't that much left to take off.



Adios
-andrew

[Yamtt125]

Have today and tomorrow off from work, so I went to the lumber yard and picked up 2 sheets of marine ply. They charged me 92.00 per sheet. Other yards around had similar prices so i figured it wasn't too steep. Also, got all my fiberglass supplys from LBI in groton CT. I have to say, there website is very easy to understand if your a novice in buying fiberglass.

I just have a couple last minute questions before I start to lay it up....I plan on building up the outer skin with a couple layers of glass, and I would to know whether or not I have to wait for each layer to cure completely, or can I just wait an hour or so to lay the next on?
Here is my plan for the transom...

outerskin
1.5 oz mat
1708
1708
wood
1.5 oz mat
wood
1.5 oz mat
24 oz woven
1708
6oz cloth

Am I going overboard with all the layers of glass, or should I have more?....all opinions welcome. Thanks

[Greene]

I'd use 2 layers of 1.5 oz mat for laminating the two pieces of plywood. Make sure they are both wet.

I'd also use some more mat over the 1708 before the final 6 oz cloth layer. If not you'll end up with print-thru of the 1708 pattern.

[Yamtt125]

Would it make any difference if the last four layers were as follows:
1.5
1708
24 oz
6 oz
Thanks for the reply

[WillyC]

Are you using epoxy or polyester based resins?

[Greene]

You wrote outside skin in your post...you meant inside skin, right?

I would use more 1708 on the inner skin. But any combo you use (like the one you suggested) is going to be very strong.

[Yamtt125]

I am using polyester laminating resins.

I mean inside skin of the transom...sorry about the confusion. Thanks

Greene, are you the same Greene some the cm site?
If so, I used your transom job as sort of a template because raybo had alot of input in it.
If you remember, How much resin did you use?
Hows your transom holding up anyways???
Do you have any advice on what NOT to do? Thanks
-Andrew

[Yamtt125]

Forgot one more thing...
Greene, did you end up using a poly resin?
If so, what was the ratio u used. I'm a little confused on it.

[Greene]

I ended using vinylester resin. First I rounded all the corners/angles where the transom meets the bilge/hullsides with thickened resin. After I put a layer of 1708 and 1.5 oz mat on the transom skin to beef it up. I installed the new core and then I used 3 layers of 1708 and 1 layer of 1.5 oz mat to form inside transom skin. I then tabbed three overlapping layers of 1708 at the angle where the transom meets the hullsides. It feels plenty strong, especially after installing the stringer knees, but I haven't hung the motor yet as the project still continues.

Do's and do nots....
-I wish I made the transom opening smaller, but instead I just made cutout from the old transom.
-Get grinding disks from an autobody shop.
-AND round the top edges of the transom core with a roundover bit on the router before installation. This will allow the glass to over top edge of it much easier, ie glass doesn't conform well to 90 degree corners