Strut backing plate/ shaft log repair

[mapleleaf]

After a meeting with a rock last fall I've finally gotten around to putting my boat back together. All the bent up drive line stuff is out being repaired and pending its return I'm trying to have everything else ready. So I've bought all my fiberglassing supplies except the additive for the epoxy resin to thicken it for bedding ( I went with west system stuff, easy to buy off the shelf near home).
I'm clear on the grinding and clean up required to remove the shaft log and the old strut backing plate. What I'd love some advice on is how to rebed the strut backing plate in, when I removed the old one tonight it looked like originally it was bed in with silicone or the like and I'm thinking I'd like to use epoxy...thoughts?
I also plan coating the new backing plate with resin before install to get it sealed, if I plan on reglassing the plate in this weekend what kind of drying time am I looking at just for the resin on the backing plate( i.e.if I coat it fri night will it be ready to be glassed in sat aft???)

[sybrmike]

I'd use a thickened epoxy mixture to bed in the shaft log and strut backing plate. Personally, I like milled or chopped fibers - but cabosil, microballoons, etc. would be fine. Just like bedding stringers, you want the consistancy thick enough to hold shape, but thin enough to squish down without any voids. The goal is a thin layer (it adds no strength to speak of) that insures full contact. Like stringers, radius the top edges and build a fillet along the bottom edges to help the glass lay down.

By strut backing plate, I assume you're talking about the plywood section above the strut & & below the aluminum plate? A coat of resin would be good, but CPES may be better? With a properly mixed epoxy ratio & coated in a warm environment, you could glass it in after a few hours. Lightly sand the epoxy coating prior to glassing it in.

[Okie Boarder]

Most of the work I did with wood I would CPES one coat per side per evening, doing multiple pieces at once. A lot of my coating was done in cooler weather though. I bet you could put two coats of CPES on both sides in one day and bed it / glass it in the next day or later that same day.

I used cabosil and glass bubbles as thickeners. Cabosil when I wasn't going to need to shape or sand it (basic bedding) and glass bubbles for shaped / sanded areas (fillets).

[Ptownkid]

how do you make sure that this type of repair is going to provide a nice level surface to mount the strut to after all is said and done?

[Okie Boarder]

If placed in the same location and same orientation it should be the same. If not the strut can be shimmed when it is bolted up and would be the starting point for performing the alignment process.

[Ptownkid]

Fair enough...next question, would my backing plate in a 1992 saltare with composite stringers still be wood embedded in the glass?

[Tim405]

The materials wouldn't matter ( wood/ Alum) as long as the original strength of the repaired area is greater than or equal too the original structure - just clean clean clean... trichloroethane works really well and leaves no residue... when in doubt - add another layer of glass - 7780 glass weave @ 3 or 4 layers oriented 45 degrees from each other will give good strength - check out fibreglast.com - the have some great stuff. also west systems resin and fast hardener work real well... they sell microballoons also... if it'll work at 550 knots on a Learjet -then you oughta be okay. you want to spread the load across the hull as much as possible by blending the new layers into/over the existing glasswork.

[mapleleaf]

how do you make sure that this type of repair is going to provide a nice level surface to mount the strut to after all is said and done?

the strut is on the under side of the hull, so the backing plate is there , I believe, for strength and to tie off the steering cable, it's alignment not so crucial in comparison to the shaft log, which I won't do until I have the strut and shaft in place.....

Will West Marine have Cabosil or these Glass bubbles??? Newbie questions....

[Ptownkid]

I have a great supplier for alot of that stuff...great service and very knowledgeable.

www.rayplex.com they also do prop repair.

[WakeSurfCanada]

Hey Maple,

Check out Canada Composites! I have been dealing with them for all the products on my resto. Great guys and also very knowledgeable.

Located 410/Matheson in Mississauga

http://www.compositescanada.com/

[Okie Boarder]

You might check out US Composites also. Not sure if there are issues with them shipping to Canada, but their prices were the best I found.

[mapleleaf]

So it looks like the factory strut backing plate had only 1 layer of glass over it. Is this sufficient or would a couple be better? And if so then would the strut backing bracket being a little taller in the bilge cause any issue with regard to the steering cable being attached to it? I'm under impression that the steering cable is flexible and could stand to be a 1/4" or so higher....
Going in this eve to grind out the bilge and clean, tomorrow I hope to be glassing the new one in.....
Pic's to follow......

[Ptownkid]

Let me know if you actually get this done this weekend...if not, I am home next weekend and would love to come see/help/meet you.

[mapleleaf]

Will do, it's looking more and more like I'll have all the prep done, but possibly not the glass work (I've got to be realistic). I also smucked my coupler good enough yesterday that it'll finally be getting replaced, picked up a new one today and that job'll take precedence tonight. It had some damage from the PO and I've put the final nail in that coffin... I also haven't got my drive line stuff abck yet to reglass the shaft log in..... I'll keep you posted.....

[sybrmike]

I'd go back with more than one layer for sure. As for the extra height - as long as it's not too excessive, the clamp block and sleeved hinge bracket on the tail of the shaft should handle accommodate it (1/4" with no problem).

[mapleleaf]

Ground everything down tonight, but forgot to take pics ( exhaustion I think) The PO or some giant tool obviously tried to repair a leaky shaft log before me by pouring a load of thickened epoxy in the bilge, what a PITA> Anyway I got all suited up SAFETY GLASSES and all and it went pretty well, I know this isn't the fun part of owning a boat, but I enjoyed it, knowing what the end result will be. More pics this week as I begin fiberglassing my evening's away.....

[Okie Boarder]

I would agree with more than one layer. I would do at least two, maybe 3 depending on what type of cloth you are using.

[mapleleaf]

Got the new strut backing plate bedded in tonight, I have to say now having work with the thicken epoxy that fillet stringers must be an animal of a job!
Anyhow it went in without to much trouble and oozed out the sides a little which I then put a radius on>
The shaft log on the other hand is diff. story. I thought a previous repair was a really heavy bed of epoxy. Turns out it's epoxy on a bed of automotive body filler ( these 2 layers are just about an 1"thick) So I'm positive now how it failed. Got too late to grind in front of my house so I snapped a couple shots and will hopefully finish grinding tomorrow. The shaft log as it sits now is quite high off the hull, I'm hoping to resolve that issue once the drive shaft comes back and I can check for alignment....

[mapleleaf]

a couple more....and one of my helper..

[Ptownkid]

Good work dude!

[sybrmike]

Great work - looks like a pro. Yeah, I found the factory used bondo to bed my stringers in & still had 6" gaps in places with no contact.:confused:

[Ptownkid]

What kind of grinding disk are you using?

[Okie Boarder]

maple...looking really good. I found some similar materials used on mine. You definitely want to do more work on your fillets. Do another pass and radius them a little more. The cloth will lay down so much smoother when you do that.

It is a lot of work on the stringers but well worth it when it comes time to lay the cloth. Try taking a piece of shim material from the home store or a large paint stir stick. Grind or sand it into a radius and use that as your tool to shape and smooth the wet thickened epoxy to the radius you want.

[mapleleaf]

P 36 and 80 grit flapper's on my 4 1/2 grinder....they're awesome...
Okie, I didn't take any pics, but heeded your advice and now have a fillet around that plate that would stop a bus, tomorrow I glass it in, in hopes that I can mount the strut once and align the shaft with the shaft log this weekend ( hoping I can tie the glass in from the backing plate to the shaft log)

[Ptownkid]

Hmmmm, that sounds like a good idea...I was just going to use a thin masonry disk, but flapper seems safer.

[sybrmike]

2nd on the heavy grit flapper discs - messy as hell, but make quick work of grinding out old glass.

Maple, good luck this weekend.

[Okie Boarder]

I just used the thin resin sanding disks and they worked good too. I tried the flappers and they seemed to work fine, also, but seemed like they wore out almost as fast as the cheapy flat ones.

[mapleleaf]

I just used the thin resin sanding disks and they worked good too. I tried the flappers and they seemed to work fine, also, but seemed like they wore out almost as fast as the cheapy flat ones.

No kidding, 8 bucks a pop up here at the box store.....

[Ptownkid]

Do you know what the dims of your backing plate are? Anyone know if it would be a bad idea to use an aluminum plate?

[mapleleaf]

Tonight I got my first taste of 5200. Holy @#*% that stuff is something I hope to never work with again, under a boat on a trailer!
After a second attempt my strut is def at the right angle (small engine alignment tomorrow) I really understand how you guys who have rebuilt feel, having reglassed and installed my repaired driveline the excitement to hit the water is building.. I should be able to tie up the packing nut, alignment and stereo by friday aft, when we should be on a small bay on Lake Huron. Its late, I'm tired hope this message makes a little sense, I've got that damn 5200 all over the back of my head, guess I'll need a hair cut!

[Ptownkid]

Do you know what the dims of your backing plate are? Anyone know if it would be a bad idea to use an aluminum plate?

Need to know this asap if possible...I'm 200kms from my boat and hoping to do the repair this weekend.

[sybrmike]

Glad to hear you're aligned, Maple. Yeah, 5200 can be a real mess. If you used the original formula, it takes several days to fully cure but you're probably good to go for the weekend. If you want to avoid the haircut - Acetone or MEK work pretty good for clean up even after a day or so. Probably dry the snot out of your hair, so have to heavily condition afterwards to keep your locks silky smooth :). If you used the fast set 5200, definitely set for the weekend - but you may be sporting a new hair style...

Ptown - the strut backing plate on my 89 Salt is 10-1/4" fore/aft x 8-3/4" wide. Looks to be 1/2" ply. I guess aluminum plate could be used, but I'd go 1/4" minimum & be sure to bed it in real good paying extra attention to avoid hard edges. The resin/glass won't bond with the aluminum as good as wood, so I'd go with several layers of heavy cloth and epoxy resin on top to really encapsulate it. The aluminum plate will probably lower the clamp block a tad, but could be shimmed up if the steering linkage won't compensate (which it probably should).

[docdrs]

Tonight I got my first taste of 5200. Holy @#*% that stuff is something I hope to never work with again, under a boat on a trailer!
I've got that damn 5200 all over the back of my head, guess I'll need a hair cut!

LOL Those were almost the exact words my buddy said when he did it. Makes one heck of a mess......should have warned ya

[mapleleaf]

P- My backing plate is the same size as Mike's, I used 1" marine ply, it's freaking beefy!
I've got a couple more pieces of marine ply at the shop if you want'em......( bottom of Blk Creek at St. Clair)
And Mike, I took the Acetone bath last night, I don't think that stuff is very healthy....Used the fast cure, it runs worse than oil paint
Tonight will be fine engine alignment and 2nd amp install, Really crossing my fingers there's no new vibrations when I get her on the water....

[Ptownkid]

That'd be great...but it has to be tomorrow (thursday) night.

[mapleleaf]

That'd be great...but it has to be tomorrow (thursday) night.

No prob, I'll pick'em up and bring'em home (straight down jane street instead to st. Clair). Call me tomorrow.
In a thunderstorm under the cover we rough wired in another amp to the cabin speakers and hooked up my new sub....It sounds great!
Managed to get the drive shaft to within .003 alignment and bolted everything up. I need to move the back of the motor sideways to tighten that tolerance , so I loosened the nuts on the motor mounts for sideways adjustment, but couldn't get it to budge. Anybody got any tricks?
Tomorrow night is prop install and a deep cleaning, I mean deep! This is amazing, weather pending I'll be on the water fri!!!!!!

[Ptownkid]

Word, I'll call late this aft.

[Okie Boarder]

I need to move the back of the motor sideways to tighten that tolerance , so I loosened the nuts on the motor mounts for sideways adjustment, but couldn't get it to budge. Anybody got any tricks?


Something with leverage like a good crowbar and using some type of penetrating oil like PB Blaster. I had issues with mine too...they were pretty much "stuck" until I really convinced them to move.

[sybrmike]

A big pry bar right where the trunion meets the block is working for me.