CS23 - Dad's dream

[peter-curacao]

Is station F a permanent part of the boat, or is it a temporary mold? If it's temporary, I'd use the cheapest stuff I could find and save that expensive ply for where it's needed.

Probably station F (in the 23 version) is the bulkhead before the transom

However, on a boat that size, I usually don't expect to find a clamping board. I expect to find a full sized transom that is a minimum of 38mm core thickness and 51mm total thickness.

It is, transom is 3 x 13 mm clamp board 2 x 13mm (assuming it's the same as in the 25 version)

[TRC886]

[quote="TRC886]
When making glue, you are using something to thicken the epoxy to a peanut butter consistency I believe that you used cotton flocks on you canoe?

A small thing, but I believe the food related texture for epoxy glue is catsup, not peanut butter. The peanut butter consistency is used for making fillets. Yum! [/quote][/quote][/quote][/quote]
That's probably why I had so much trouble gluing my clamping board together

Thank you for making the clarification. I've just reviewed the "how to" mix glue again, and it should be between ketchup and mayonnaise. I will edit my previous post.

Again, thank you for helping to keep me straight

[antoniekruger]

Hi,

Thanks for the advice
The transom is 3x12mm sheets and the clamping board another 2x12mm, so your estimate is spot-on. I used a epoxy thickener for the transom glue(apparently similar stuff is used as a food thickener as well - go figure) on both sides. Now in hindsight I should have primed the transom parts with a 5% diluted epoxy before I did the glue....next time.

I'll cut and glue the clamping board tomorrow evening using this method.

Oh, yes, Station F is the back-end bulkhead of the motorwell. So yes, its permanent.
Antonie

[peter-curacao]

Now in hindsight I should have primed the transom parts with a 5% diluted epoxy before I did the glue....next time.
Antonie

If I understood you correctly you really should check the transom lamination's, rolling in the laminated parts with unthickened epoxy (don't know where you get the diluted part from )before laminating them with thickened epoxy is essential for a good bond, if you skip that step there is a good chance the wood will starve the glue, resulting in a bad bond.

[antoniekruger]

Hi Peter,
Thats what I did, but I used normal mix epoxy as a primer and then the glue mix between those whilst all wet.

(don't know where you get the diluted part from )

I stumbled across a discussion about epoxy penetration from around 2003(if memory serves) on this site where it was suggested that wood should be sealed with a 5% diluted epoxy mix. I'll see if I can find it again with a link.
Thanks for keeping an eye.
Antonie

[tech_support]

I stumbled across a discussion about epoxy penetration from around 2003(if memory serves) on this site where it was suggested that wood should be sealed with a 5% diluted epoxy mix. I'll see if I can find it again with a link.

Please let me know if you find it here and I will delete it.

DO NO THIN THE EPOXY Hope that is clear enough.

Studies have proven it does not do much good (if any), but it can make the bonding of subsequent layers of epoxy weak.

[antoniekruger]

Hi, OK here's the quote:

by jacquesmm » Mon Sep 29, 2003 7:40 pm

I dilute the first coat, the primer coat, with max. 5% of lacquer thinner.
BUT this is not my final coat.

If I am fiberglassing that part, I always pre-coat: wet the part again with undiluted resin then apply the glass plus more resin if needed etc.
If the part is not fiberglassed, I will pass another coat of undiluted resin over it as a final coat.

The purpose of the primer coat is to penetrate or saturate the wood. It doesn't take much to saturate, the resin never goes very deep but with the thinned primer coat, it will go a little deeper (I hope so) and not waste resin.
I find the 3 coats specified by System Three excessive especially since I know that first time builders use 3 times more resin per coat than I do!
BTW, I also disagree with the flow coating system described in the Gougeon book.
I have done it a few times but it was because I was too lazy to do a good sanding job.

With my system, you will have a better lamination, with less resin and more fiber (the plywood is made of cellulose fibers).
On parts that are not fiberglassed, you will have one primer coat plus one undiluted coat plus a paint primer plus paint. That's more than enough.

I learned the priming coat system many years ago from a boat upholstery shop. His problem was the moisture trapped in the foam, rot was spreading fast.
He coated all the plywood with several coats of resin but the pieces that were pre-coated with thinned resin resisted better than those with thick resin.Jacques Mertens - Designer
http://bateau.com

I'm not getting into a debate about this. NO thinning it would be-yes dad. Thanks for clearing that up. I'm on my way to cut and glue my clamping boards. Just picked up more wood and epoxy for the long weekend ahead.
I'll post some more pics by the weekend.BTW my BOQ states a 400g biax tape. I can only get a 450(same width). I do not foresee an issue with this except for a higher epoxy use. Any comments welcome.
Thanks Guys for all your input.

[tech_support]

thanks Im glad to see that 10 year old thread s still useful.

I will add a line to the bottom of that thread explaining why we do not think thinning is a good idea.

[antoniekruger]

Oh my word, this transom is heavy - I'll have to devise a holding mechanism over the beams in my carport to help hold it whilst I mount it on the strong back or I'm going to bend my chassis trying to hold and mount.

Shine, what do you mean old - it is only 2003 in South-Africa now

Another question about resin and glass : When I mix epoxy for 1m^2 wood coating - first coat, it should be 400g(argument sake for 400g biax), correct? How much should I mix extra to ensure the wood is soaked out as well or is it better to prime the wood before you start the layups.

[WobblyLegs]

Another question about resin and glass : When I mix epoxy for 1m^2 wood coating - first coat, it should be 400g(argument sake for 400g biax), correct? How much should I mix extra to ensure the wood is soaked out as well or is it better to prime the wood before you start the layups.

Antonie,

Going by memory I used approximately 8 pumps of epoxy per sq. metre - rough estimate! My pumps are 30g a time (25g epoxy, 5g hardener) - so around 250g or so per metre.

Don't worry too much - you get a feel for it very quickly - but you won't be doing biax yet for a while...

Oh, and I'm satisfied with my results of laying dry cloth over dry wood and using a squeegee or foam roller to press the goo in. Just don't do it in direct sunlight or rising temperatures - you WILL get bubbles as air expands in the wood and out-gasses through the epoxy. Use slow hardener - it makes life easier.

Regards,

Tim.