Transom strength on 1981 lund mr pike 16ft. Motor setback

Its ok just when dealling with some one that a one timer best to keep everything simple as possible . It why i bought up the temprature a humidity . Just dont want to see the guy coming back saying he has problems .
Its like a blind person eating rice with one long and one short chop stick posting on here sometimes !! its why i like to see pictures ! makes the chop sticks even lengths at least !

 

Tunnels, Thanks for the the info on the temp and humidity. That was going to be one of my questions since I know chemical reactions like certain conditions. I learned about that when I refoamed the boat with a b foam. Given the dimensions 65"x 20" x 1" 7/8 of the transom how much epoxy should I get? I am thinking I will need 3 sheets of ply to get the thickness I need so I have to account for the epoxy in between the sheets as well. I live in Ohio and I am performing the work in my garage with a turbo heater to keep the temp up and I do not think humidity should be an issue this time of year.


Par I am going to read over the guide from west marine to get a better understanding of the expoy and how to use it.

I appreciate all of the feedback from you guys!! I know a few people in the boating community and they all said that you guys are the experts on here

 

Also I'm working on pulling the transom wood today so I'll post some pics of what the box looks like.

 

All resins need warmth to go hard and more warmth for a longer period of time to cure Note i say warmth not heat!! once the resin goes hard it is best to try and cure it with you warmth for agood period of time 8 hours or longer . Curing finishes off the hardening process . Direct heat can undo all you hard work In your case a slow hardener could be just the thing . allows the plywood to let the epoxy to get into the wood !! but remember it only goes the deepth of the outside veneer and stops at the glue line so the less veneers the thicker they will be so the more possible penetration with the thicker veneers !! good thinking ?? When you laminate the plywood can use steel pan head screws and when its all hard and solid back the screws out and put them back in the box!. once you done a dry fit and used the grinder to round a few patchs Id put it up some place and paint a couple of coats of epoxy resin around all the end grain !! This is where the water gets into all transoms through the end grain of the ply !! and travels in all directions . Sounds like a lot of work but its not that much at all !!
WE ARE ALWAYS HERE TO HELP ANY TIME

 

Thanks for the info on the resin. I'm thinking that I will build it in the garage with heater running to bring ambient temp up and then take it inside the house to keep it above 60 degrees F. and let it stay in there for a good 24 hours. Thanks for the pan screws idea! I had planned on doing the edges after it was all done to make sure it's good and sealed before it goes in for the final instal.

Any idea on how much resin I'm going to need with the dimensions I listed above? qt? gal?

Attached are some photos of it with everything removed from the transom top. Tomorrow I'm pulling the wood out...should be interesting lol.

 

Turbo Heater ?? not familiar with that term but if it is what we Canuks call a Salamander you need to be very aware of the humidity as these heater units( Kerosean or propane generate alot of humidity as a by product of combustion. My choice would be a 220V electric box construction heater. If you do not have a 220v outlet in the garage simply rig up an extention cord to reach your electric clothes dryer outlet. Your other option of course would be to run a de humidifier. Because you are attempting to bond to aluminium it would be good to get the working enviorment within specs. From past experience having built an aluminium motorsailer and fairing with epoxy filler I can tell you it does bond well to aluminium once the surface has been sanded.

A yacht is not defined by the vessel but by the care and love of her owner----

 

During your read of the West system epoxy subjetc did you come across rubber toughened epoxy ??
Rubber toughened sticks really well to Aluminium and because it has a little elastisity its wont let go so easy and absorbs vibration much much better .
We used this type of epoxy to stick the decks down on Racing yachts !! just has a flange join 60 mm wide and is stuck with no fastening of any sort any where along the whole deck join .

As a sample we stuck some glass to glass and it just ripped the glass layers to bits !! the join could not be got apart even with a chisel just couldnt get it apart at all .the chisel just bounced no mater how hard you hit it !!
I have absolutly no doubt as to its sticking . id hang my life on it !!

 

Certainly would compensate for any differences in expansion/contraction rates plus absorb the high freq. transom vibration that the epoxy/alum bond would be subject to. Interesting this is a new product mix I wasn't aware of. This will be my: "learn something new every day" --Tnx.

 

Are you talking about G/Flex? I did see that and I was thinking of maybe using that on the outside between the wood and aluminum. Between the sheets of ply I'm thinking I'll just epoxy with a high density filler, like 404 from west system.

 

Rubber reinforced epoxy is pretty much as the name suggests. Neoprene is a common material employed, but other materials are also used, such as polyurethane and even the super low elongation stuff like kevlar and spectra. For you application, you don't need any of these formulations, which just adds to cost anyway. 404, with a little 406 (silica) mixed in to control viscosity (so it doesn't run) will work, though again, I'd still toss in some milled fibers (403 or milled 'glass).

 

Yip Milled fibres should be added to anything that more than 5 mm in thickness . its cut down on cracking and the fibres reinforce the glue that by its self can be brittle .
The rubber toughened adhesive sticks man oh man does it stick !! its the stick to the aluminium that would be my greatest concern , adhesion to the woods not a problem !!

 

I've done aluminum transoms before and I just stuck a flap wheel on a drill extension and scuffed it up good, before applying goo.

 

AFTER sitting in the nice warm sun for a while thinking (dont get to do this very ofter ) the inside aliminium panel , how is it held in place ?? welded ? ??rivited ??? what ?? If its rivited surely it would be easyer to remove it to do all this work done and get a thicker tramsom !! From one of the pictures it looks like a neat fit and coule be just spot welded with a adhesive maybe . The center Knee bracket will tell you where its attached to the hull 1!

 

It looks riveted.

 

The panel is held in place by rivets. The problem with making it bigger is I would have to cut out the splash, which is one solid about 4 ft wide, well and I'm not wanting to break those rivets. Also you can see from the pics that the area on the gunnels are butted right up to panels from the sides of the boat. I measured the piece and it's going to be 1" 3/4 thick. As you can see from the pic the wood was overdue on being replaced. I'm glad that I only ran 1 summer on the thing after seeing it outside the transom.

On a side note I got my stuff today for the wood. I've got 406 and 404 along with the resin and hardner. I am going to pick up the marine plywood next week and prob. work on building it this following weekend. What consistency am I looking for when I mix the fillers in? mayonnaise consistency?