New Transom Knees for AE-21

[JUPITER PULSARE]

Now that I've got my AE-21 transom cleaned and prepped for glasswork, it's time to begin building the transom knees. I made a cardboard template yesterday morning by crawling inside the bilge. I cut two new transom knees out of 1.5" thick 24lb density Airex PXC (Penske board). Each knee will receive two layers of 1708 glass before I bond them to the floor/transom/topdeck. I'm going to use West Systems Epoxy for the resin.

[OFFSHORE GINGER]

Hey guy , how are things going ?

[JUPITER PULSARE]

Hey guy , how are things going ?

Just got back from celebrating my 50th in Key West...gotta work the rest of the week before I start on the boat again. I'm going to talk to some glass guys regarding using the 1708 with the epoxy resin..

[brianincc]

I have seen this brought up quite a bit. It is my understanding that the 1708 is fine to use with epoxy as the mat does not contain binders, instead it relies on the stitching to hold it together. That being said the additional mat will not add any significant strength over plain 1700 only help to build thickness. I've used 1708 on the bottoms of several hard use flats boats to add some abrasion resistance and I have never had a problem. I am hesitant to reply to these types of things as I have seen what happens with some of these threads. This is my opinion based on my experience.

[OFFSHORE GINGER]

Hey guy not trying to be rude or tell you what you to use but i have worked at two different boat Co,s that use Epoxy in there build and have seen 1708 fail when used with Epoxy either in high speed applications or cruiser style boat's such as Tiara or S 2 YACHTS as there are often called and i think if you use a fabric with a no chop back you will find that you will be able to keep the cost down in the resin Dept because the chop backed fabric such as 1708 takes a bit morer resin to wet out AND 1700 Bia , S or E glass are great fabrics to use with Epoxy and designed for that type of resin and like i said its your call and i have been using epoxy for over 38 years now and is the only resin that i will ever use for any type of repairs .

[1BadAction]

I have seen this brought up quite a bit. It is my understanding that the 1708 is fine to use with epoxy as the mat does not contain binders, instead it relies on the stitching to hold it together. That being said the additional mat will not add any significant strength over plain 1700 only help to build thickness. I've used 1708 on the bottoms of several hard use flats boats to add some abrasion resistance and I have never had a problem. I am hesitant to reply to these types of things as I have seen what happens with some of these threads. This is my opinion based on my experience.

That is dead on, 1708 is called stitch mat because the mat has no binder in it. If it did, the binder would show after it was layed up, which isn't the case. That said, there are better options for epoxy as long as you have the time to order it.

[JamesGang]

Hey JP hows it goin.
If I were you I would pull some of the floor and tie the knees into the stringers and then put the floor back.

[j90]

Look into Mas Epoxy They have a thiner epoxy that works very well. I am redoing a boat with it and yes the 1708 does take more to wet out. Don't skimp. It is also a non blush epoxy. I have used west and others but like the Mas and they are good to deal with. Check them out on the web.

[JUPITER PULSARE]

Hey JP hows it goin.
If I were you I would pull some of the floor and tie the knees into the stringers and then put the floor back.

Hey JG, the transom knees will rest on the center pod lifting strakes and will be bonded to the strakes and verticle sides of the center pod...you can see the center pod lifting strakes towards the outer edges of the picture below:

[rchevelle71]

Personally, I would go with 1708, and Vinyl Ester, but thats just me.

[Jay R.]

use Cheese cloth and liquid nails, works great everytime!

[JUPITER PULSARE]

I'm getting advice from Polymeric Products in WPB. They are a specialty FibreGlass shop that builds boats, molds, race car fairings, motorcycle fairings, ground effect kits, custom work, surfboards..etc. He's the guy that built the mold for the 41' Apache that is now at the Pantera factory..The owner "Jed" has been working with fibreglass, resins, cores, kevlar, etc for over 45 years. He's kind of like a mad scientist who speaks way over my head...compression ratiios, molecule flex failures, chemical bonding aspects, core shear,...the guys written an entire chapter on the elements of surfboard design, hydrodynamics, lift and foil...etc. As soon as I get some spare time, I'll run by his factory and confirm the dynamics of using 1708 biaxial glass with epoxy resin...

[Jay R.]

that sounds like to much work, take my word for it, cheese cloth and liquid nail, or super glue.....
or anything my 5 year old is playing with...... I don't know how he does it, but everything is sticky and what ever it is, its hard to remove...

[OFFSHORE GINGER]

that sounds like to much work, take my word for it, cheese cloth and liquid nail, or super glue.....
or anything my 5 year old is playing with...... I don't know how he does it, but everything is sticky and what ever it is, its hard to remove...

Good one .

[JamesGang]

OK that sound better than what I thought you were doing by looking at the first picture. I still think I would opt for tying in to the outside of the stringers. The stringers are the backbone of the boat, if the engine tries to flex the transom and the transom is tied with knees to the stringers instead of the transom flexing the bow just goes up. That is what you want your transom tied into via the knees.