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Old 05 November 2009, 05:28   #11
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That'd look excellent, but a smooth gel coat inner transom isn't the best surface to laminate knees to.
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Old 05 November 2009, 05:49   #12
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Originally Posted by Dirk Diggler View Post
That'd look excellent, but a smooth gel coat inner transom isn't the best surface to laminate knees to.
The smooth gel coat surface goes on the outside of the boat. If you use peelply between last layer of CSM and the bubble wrap that will give you a good surface for bonding you knees to. Any resin supplier can supply peelply. The bubble wrap spreads the vacuuum over the whole panel.
regards
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Old 05 November 2009, 06:24   #13
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That's an unusually thick transom for a little boat, 2 x 18 mm is the norm. any thicker and you may run into problems with steering clearance/motor fit
You reckon? That's 54mm Mine's about that thickness, and only rated for a 110Kg 60. (granted no bracing) Plenty of room for the clamps to fit - and my Aux won't go over the back of a 90Hp rated Ribcraft transom - I think it was a 5.8, so not too far off the size of a 5.4.......)

36mm transom wouldn't fill me with much confidence to hold a 90 up!
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Old 05 November 2009, 06:33   #14
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The smooth gel coat surface goes on the outside of the boat. If you use peelply between last layer of CSM and the bubble wrap that will give you a good surface for bonding you knees to. Any resin supplier can supply peelply. The bubble wrap spreads the vacuuum over the whole panel.
regards
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I wasn't aware that he was removing the whole transom, I assumed he was leaving the main lay up, and just replacing the Wood and overlaminates.

As for vacuuming, I expect that's a bit too technical for an Avon, and not that easy to source the materials and equipment!
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Old 05 November 2009, 06:38   #15
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36mm transom wouldn't fill me with much confidence to hold a 90 up!
I'm not suggesting that the transom should be a total of 36mm, just the wood that's in it. Assuming the outer laminates are being used (see above post) then a couple of csm's to bed the first 18mm ply on, then a couple more csm's, followed by another 18mm ply, then overlaminated with more csm's, woven and csm, (or combi), then the knee's, and more over laminating will result in a transom well in excess of 50mm, which is the recognised std for a transom!!!

FWIW, a sterndrive transom cannot be more than 50mm, or you can't fit the transom assembly.
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Old 05 November 2009, 06:44   #16
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You could release wax a smooth flat surface, gelcoat it let it set, add some layers of CSM,add a layer of plywood , add a layer of CSM , add the next layer of ply wood, then some more CSM , then a layer of bubble wrap, then stick a layer of plasic over the whole lot,and use wide plastic sticky tape to seal it. Apply vacuum to it to clamp it all together.
Make sure you wet out the plywood before you lay it on the CSM or you will get a dry joint.

To locate the plywood you could use some wooden dowels (so they don't slide around ).

You will end up with a smooth gelcoat surface .from the smooth table

If you use epoxy resin you will have to use it every where, as polyester resin dosen't
stick to epoxy resin. Epoxy sticks to polyester well.

The picture is the trasom I built for the RIB I am building.
Hope this helps.
regards
RPM

Well that is a very fine job you are doing on that transom, shame I don’t have a vacuum pump… no I would get shot if I was to have the dyson in the garage. I have still got the outer layer of glassfibre as I really felt it would be handy to have some thing to use as a starting point. So once I have the ply wood bonded together I was looking to bond it to what is left of the transom and then build in the knees and stringers etc.
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Old 05 November 2009, 07:03   #17
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Follow Dirk's advice. 2 x 18mm plus all the laminating. Make sure the old surfaces you are laminating to are rough and clean and have a big area. There will be no chemical bonding to your old hull surface so your resin has got to grab hold to anything it can for adhesion.
Take the knees right down to the hull and also laminate the deck to them.

Your transom will be angled so, if you want a good fit, the new transom edges (particularly the bottom edge) will need to be angled to fit against the hull and each 18mm piece will need to be offset so the angled edges align. If the top is to be the usual right angle, then the18mm transom ply panels will not be the same size.

Good luck.
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Old 05 November 2009, 07:44   #18
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Follow Dirk's advice. 2 x 18mm plus all the laminating. Make sure the old surfaces you are laminating to are rough and clean and have a big area. There will be no chemical bonding to your old hull surface so your resin has got to grab hold to anything it can for adhesion.
Take the knees right down to the hull and also laminate the deck to them.
The idea behind not just the knees but the stringers too was to do all we can to increase the amount of the old hull we could glass too. And to try and triangulate the whole lot.... Grinder at the ready to rough up the hull


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Your transom will be angled so, if you want a good fit, the new transom edges (particularly the bottom edge) will need to be angled to fit against the hull and each 18mm piece will need to be offset so the angled edges align. If the top is to be the usual right angle, then the18mm transom ply panels will not be the same size.
Aye, I had worked out that there was to be a need to cut each section slightly differently to get the required steps to fit the hull floor as other wise the angle of the transom would create quite a gap once the full 36 or 54mm width had been stuck in place.

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Good luck.
should this not be may the rib gods smile on you? Thanks
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Old 05 November 2009, 08:35   #19
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Sorry I thought you were removing the entire transom.
Unless you can sand the transom perfectly flat.You could mix some filler with resin when bonding the first layer of plywood to the existing transom laminate,that should fill up any voids between the two. If you use straight resin it will just drain out the bottom of the join.
regards
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Old 05 November 2009, 08:42   #20
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Follow Dirk's advice.
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