Did I goof? Transom lamination

Indymike

Petty Officer 1st Class
Joined
Aug 17, 2004
Messages
364
Built new transom. Two layers of 3/4 ply. I wet out both faces real good with epoxy and then mixed the batch for the adhesive coat (between the the two layers of ply). Well stupid me didn't use any filler to thicken the adhesive batch. So "A" face to "A" face laminated with out filler. Do I pitch it and start over or will it be OK since it's not uneven surfaces. The good news it's not officially a transom yet. Was doing the lamination of the two sheets before installing in boat. It will support a 115hp OB. on a 16' tri-hull.<br /><br />Thanks,<br />Mike
 

gutshot grouper

Petty Officer 2nd Class
Joined
Aug 29, 2004
Messages
110
Re: Did I goof? Transom lamination

I would say that if the sheets were flat, face to face, you probably have as good a bond as you need. I have done same and used lot of drywall or wood screws to pull sheets together,, if you are really worried, add another layer, no bigger than the boat is, the extra weight would not be a problem,, Gutshot in Raleigh
 

18rabbit

Captain
Joined
Nov 14, 2003
Messages
3,202
Re: Did I goof? Transom lamination

I think you are ok. But for piece of mind you can call the fine folks at U.S. Composites (ask for Mark) and get verification. 1 (561) 588-1001.<br /><br />Here’s why I think you are ok: the adhesive is the epoxy, not the filler and certainly not the wood. Fillers either increase or decrease the density of the epoxy. Fibers fillers can add strength and increase flexibility by integrating a flexible, linear medium into the rigid adhesive (cured epoxy). All fillers detract from the adhesive property of epoxy. The flatter your bonding surfaces, the less you need/want fillers.<br /><br />If you were planning to use West Systems 403 micro fibers, it is teeny-tiny (cotton?) fibers. There would be some strength in the random orientation of those fibers but like you pointed out, you don’t have voids to fill. What you did is a trade-off. You gave up replacing adhesive with fibers, and in exchange you got more adhesive and (insignificantly) less flexibility.<br /><br />If you were planning on adding West Systems 406 colloidal silica (a.k.a. cab-o-sil) it is adding density to the epoxy and makes a more durable finish by imbedding a material that is harder than the cured epoxy. Silica is also used to make the epoxy thicker so it clings to vertical surfaces and the ceiling, should you fling it up there, without dripping/running. Your epoxy is between flat sheets of wood so you have nothing to gain from adding silica.<br /><br />Lastly, the less fillers you have, the greater the opportunity for the adhesive to penetrate the bonding surface. I can see a possible problem if your epoxy was thin and the wood was thirsty. Fillers would prevent epoxy from being almost totally soaked up by the wood. You mentioned wetting the wood before mixing a second batch of the adhesive so that shouldn’t be a problem.<br /><br />Anyways, that’s what I’m thinking… If you call US Composites, please post back here and let us know what they say.
 

JasonJ

Rear Admiral
Joined
Aug 20, 2001
Messages
4,163
Re: Did I goof? Transom lamination

Your fine. The layers will also be clamped by the outboard (or outdrive if an I/O) and the tow eyes. You can always run a bunch of stainless screws throughout to give additional holding power. I did that with my transom, a screw every six inches throughout in addition to resin bonding. The screws need to not come out the other side obviously. Overkill, yes. Peace of mind, definately.
 

G DANE

Commander
Joined
Nov 24, 2001
Messages
2,476
Re: Did I goof? Transom lamination

I would not recommed putting more screws in than nessecary. Try to put just 2 screws thru a stripe of ply and bend it to it breks. Where did it break ? In a line at screws !
 

Indymike

Petty Officer 1st Class
Joined
Aug 17, 2004
Messages
364
Re: Did I goof? Transom lamination

Thanks guys... pretty much what I figured but a little reasurance from you veterns helps.<br /><br />Thanks,<br />Mike
 
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