Super Jet Project Dance-floor

[Roseand]

Here is the result. The Weave side turned out about perfect in my opinion. Much less resin it would have been a bit dry, much more a waste.

View attachment 367985

The matting side was a learning experience. It is just a touch dry however I would call it acceptable. When I pre wetted out the foam I did not wet out the backside of the 1708 so most of the resin had to drive down through the weave. I should have wetted out the backside of the 1708 in addition to the surface.

View attachment 367986

I think its usable for my purposes. Additionally the plate weighed out to 13.7 oz. That means 7 oz of resin and 6.7 oz of cloth, seems about right.

Are you not using a squeegee or fiberglass roller? You can use extra resin and get the excess out quite easily.

 

[Req]

Are you not using a squeegee or fiberglass roller? You can use extra resin and get the excess out quite easily.

I have a fiberglass roller and I used it for this. My issue wasnt with the wet out on the surface, it was just the 1708 is really thick and really should be wet out on the backside before its applied as well, since the chop strand takes a lot of resin.

 

[Req]

So I have decided to update the midshaft housing to the newer round nose midshaft housing and drill and tap new inserts for the different bolt pattern. I have a GP760 midshaft and housing in great condition so I am going to knock out two birds with one stone, update the housing and move the engine back one inch. The gp760 midshaft is not only the proper thread for AM couplers, its also one inch shorter.


I will be adding a couple of inches to the rear of motor mounts to accommodate this. First I wanted to flatten the chine area to make it easier to build up the new glass for the motor mounts. I started by cutting increasing width strips from half inch up to 3.5 inches. This should create a reverse pyramid and help to fill in the chine.



With the glass to fill in the chine it will be much easier to build up material to the same plane as the motor mounts. Once built up I will sand down flush with the mounts and epoxy in inserts 1" back from stock. Additionally I will be filling in the voids in the mounts since I will need to epoxy in a insert there as well.


Once this and the motor mount extension are cured and sanded I will then reinforce the entire engine bay encapsulating the motor mounts and glass work.


I should be able to wet this out tomorrow, its a pretty light day at work.

 

[Req]

So I layed the glass up in the chine as well as patched a low spot from a waterbox rubbing and did a bit of fill inside the motor mounts. The blue permanent marker I used makes it look like I used ester resin or something but its epoxy. I plan on sanding it all down around and in the mounts once it cures and resume filling, there is a bit of a low spot still in the chine.

 

[Big Kahuna]

Wait, your moving your motormounts so you can run a gp760 midshaft? Why? Wh ast benefit?

 

[Req]

Well I have it out of a donor and I was on the square setup which is much weaker from what I understand. Maybe moving the motor an inch will improve its handling, im betting on not to be frank.

Pretty much doing it for giggles if Im honest.

 

[Req]

I started by sanding everything down and seeing how much more glass I needed to fill in the v. I then finished laying the glass in the chine, flattening that area for the incoming motor mounts to be built up. once it is cured I will sand it down again truing the surface. I also added some triangle pieces of biax to build up the corner of the starboard side mounts, they sit further in the chine and needed some material added there to support the 1" rear shift in the mount.













I should be able to build the mounts tomorrow.

 

[hornedogg79]

Could've just pressed the SN shaft into your GP housing. Then your running gear would be ready to drop in most aftermarket hulls. I think a B head pipe is kinda close to hood channel on a SN already. Might run into some clearance issues.

 

[Req]

Could've just pressed the SN shaft into your GP housing. Then your running gear would be ready to drop in most aftermarket hulls. I think a B head pipe is kinda close to hood channel on a SN already. Might run into some clearance issues.

I have measured and it all clears. I could have easily pressed the shaft in yes. I sort of wanted to move the engine back for science, Rhaas sells a kit to do it so maybe there is merit. Granted it may be a useless thing to do but I am keeping my old mounts accessible and usable so if it was a waste I press in the SN shaft and move the engine forward, if it was a win, I have something to show for it. I am guessing the hull will handle like it has a cart tank in it instead of a stock tank but I dont really know.

 

[Req]

So I flattened the area again and then it was ready for me to build up the motor mount extensions. I just layed a few layers of glass every couple of hours and kept after it with a roller and it turned out pretty good in my opinion. I have to do some sanding/shaping around the border as I have extra material around the edge. I also need to plane it down to the level of the original mounts. After I have it true and shaped how I want I will cap the entire mount extending out to original hull with S glass before I reinforce the engine bay with 1708. That should encapsulate the mount and provide added security.

 

[Req]

yesterday I ground some more and added some more to get the proper height. The front mounts needed two more layers of 1708 to have enough material to level them. I made the shelves way too big so a flap disk is coming out tomorrow to remove about an inch from the rear of them and shape them up in some spots.

Today I focused on grinding the excess resin that had flown around the starboard side of the mounts, I wanted to get it back down to the bare hull there so when I lay the S-glass over the mounts and up the side of the bay I have the original hull to bond to.

I have some help showing up on Saturday so I need to get the engine bay ready for reinforcing before then. Should be doable, I have a few hours left on the motor mounts before I am done with them and a bit more grinding in the nose. I would also like to have the dash rebuilt but I can reinforce before or after the dash is finished.

 

[Req]

I trimmed the motor mounts back a bit today and did some general shaping of them. This is pretty close to the final shape I am going for. I need to take the orbital and finish sanding them down on plane with the original mounts and finish filling the mounts in with scrap 1708 before I drape S-glass over them.

 

[Big Kahuna]

Wait, what are you using for inserts?

 

[Req]

Im not sure yet. I have a couple of couches I can cut up to get some inserts to epoxy in. Additionally I would imagine mcmastercarr has something that will work. I also got some aluminum plate I could embed into the mount after routering out an area for it. Got a recommendation?

 

[Big Kahuna]

Errrr They needed to be installed before you built up all that glass........

 

[Req]

Errrr They needed to be installed before you built up all that glass........

Ehhh... Not sure how one would true all that up that way. I figured I needed to build the glass up first then sand it true to the old mount height to ensure I did not lose alignment. Then I will router out the inside of the mount down a half an inch and install a 1/2 x 1.25 x 4.25 aluminum plate inside the pocket I router out, epoxy it in and glass over the top encapsulating it. Then I can drill and tap anywhere on the mount.

Edit: Here is a mock-up to demonstrate what I am talking about. I will cut a pocket for a piece of 6061 to sit in so that its flush with the top. I will then epoxy it in and drape a layer of 9oz cloth over it. The frontmost insert can remain as I plan on having mounts for both the SJ midhsaft position as well as the GP midshaft position. I will need to drill and tap 3 locations per plate.

simple version


Better version imo.

 

[Big Kahuna]

Ok, that could work.

 

[Req]

Ok, that could work.

My heart be still.... I was worried for a minute.

 

[Big Kahuna]

I would drill additional holes in them with a taper from top and pour in resin with west systems 404 or 405 powder or something similar to help creating a mechanical bond to the hull. Anybody else have ideas?

 

[Req]

I would drill additional holes in them with a taper from top and pour in resin with west systems 404 or 405 powder or something similar to help creating a mechanical bond to the hull. Anybody else have ideas?

I was thinking about drilling 1/8 holes through much of the plate to assist in getting a good bond, acting as fingers that penetrate the aluminum. Additionally I will rough up the surface of the plate. I have both cabosil and glass beads I can use as thickener.

Do you think the taper is necessary? I figured that between the epoxy squeezing up through the holes from below as well as some flowing down from wetting out the S-glass I would get good penetration.