Fiberglass Questions

[MR nova @#25]

1. My new transom is in, My plan is to use a layer of heavy matt and a layer of heavy Woven to cover the transom. Will that be enough?
2.Its looks like the engine compartment is a separate section of gelcoted fiberglass that was bonded/glued to the bottom of the boat. Its a little harder than Bondo I'm sure it 5200 or something close to it. Between the bottom of the boat and the engine compartment this stuff was about 1/3in thick. It took a couple hrs. to grind it all out( glade I did found some bad spots under all the goop):listening_headphone.
My question is: Do I need to do anything to compensate for this missing glue, Or should I just add a extra layer glass and drive on!?

 

[jbcurt00]

Re: Fiberglass Questions

I/O have a specific dimension thru the keyhole that must be maintained, 2-2.25"

Several alternating layers of CSM & 1708, would be better, rather then 2 thick layers, using heavier weave woven & mat You want the plywood lamination to be BONDED to the transom & the inner layers of glass well bonded to the plywood, not just achieve the correct thickness (build-up) of glass.

I'm sorry, from your description & the very small pix, I'm not sure what your referring to about the engine compartment's seperate construction & thick resin layer..

If you can load the pix larger, so they can be more easily viewed, enlarging the current pix causes them to pixelate & become too fuzzy, perhaps it'll make more sense to me.

 

[Woodonglass]

Re: Fiberglass Questions

Yep, Better pics are required. What Boat is this?? Dual engines?? Do you know the required Transom Thickness? I'd prolly recommend CSM and 1908 Biaxial Cloth Since you're running Dual's. Have you checked the motor mounts and stringers too? We're gunna need more details.

 

[MR nova @#25]

Re: Fiberglass Questions

I'm aware of the thickness for the outdrives. I have plenty of 1708 on hand, I just thought that heavier Might be better when it comes to the Transom. Thanks you I just avoided a Headache

 

[MR nova @#25]

Re: Fiberglass Questions

Sorry about that Sir. For some reason I thought you could go back into my history and track all my post and pictures. I guess that's a Facebook thing
Its a 1976 Wellcraft Nova 250 offshore, with a pair of 302's. Short version, Everything Aft of the cabin, to include the fuel tank and motors are being replaced.

 

[Bondo]

Re: Fiberglass Questions

Sorry about that Sir. For some reason I thought you could go back into my history and track all my post and pictures. I guess that's a Facebook thing
Its a 1976 Wellcraft Nova 250 offshore, with a pair of 302's. Short version, Everything Aft of the cabin, to include the fuel tank and motors are being replaced.

Ayuh,... That requires Alota diggin',...

Which is Why We always ask posters to use the Same thread for All they're rebuildin' threads,....

It saves, Sooooo much confusion,...

 

[Georgesalmon]

Re: Fiberglass Questions

Before the advent of the biaxial fabrics 24oz WR with or without 1,5oz mat attached was the standard for building boats. The new (I guess new was a while ago now) biaxial's were developed to get the same strength with less weight and thickness. It took awhile for boat builders to make the change because the biaxials were more expensive and it took more oz's per sq yard to get the same stiffness because it was thinner than a comparable WR fabric. And resin was cheap. As we all know the important number in calculating flexural modulus (stiffness) is in the thickness of the sample. There is nothing wrong with using WR as can be attested to by all the 40+ year boats still in service or being restored, the glass is still good just the wood got rotten. It is important to keep the thickness correct where the outdrives are attached. I would not worry about strength being a factor as long as the transoms original thickness is maintained using WR or 1708/1908. 1708 is 17oz/sq yard plus 1oz CSM. 2415 is 24oz WR plus 1.5oz CSM for a comparison, though a 24oz biaxial would be slightly thinner than a 24oz WR and would use less resin to wet out properly.

 

[MR nova @#25]

Re: Fiberglass Questions

Thanks.

 

[MR nova @#25]

Re: Fiberglass Questions

got it

 

[MR nova @#25]

Re: Fiberglass Questions

1. My new transom is in, My plan is to use a layer of heavy matt and a layer of heavy Woven to cover the transom. Will that be enough?
2.Its looks like the engine compartment is a separate section of gelcoted fiberglass that was bonded/glued to the bottom of the boat. Its a little harder than Bondo I'm sure it 5200 or something close to it. Between the bottom of the boat and the engine compartment this stuff was about 1/3in thick. It took a couple hrs. to grind it all out( glade I did found some bad spots under all the goop)View attachment 218597View attachment 218598View attachment 218599:listening_headphone.
My question is: Do I need to do anything to compensate for this missing glue, Or should I just add a extra layer glass and drive on!?

Over time (30yrs) can oil left in the bilge seep thru Fiberglas? I ask because, When I removed the center motor mount box( that what it was) form the boat. The woven roven in the center was darker than all the other glass in the boat, and it literally (the oil ) was under the woven roven. I had to grid it all out. strangest fiberglass encounter I've had to date

 

[MR nova @#25]

Re: Fiberglass Questions

sorry about the pixs..there from my phone.

 

[Woodonglass]

Re: Fiberglass Questions

Yeah, sorry but the pics really aren't big enuf to help us see much. Get the PhotBucket Mobile app and you can load your pics from it.

 

[jbcurt00]

Re: Fiberglass Questions

Fiberglass is porous.

So yes, after 30yrs it is possible that oil made it's way into & thru some of the fiberglass in the bilge. More likely there were minor imperfections in the layup that aided in allowing the oil in.

 

[Grub54891]

Re: Fiberglass Questions

Mine was the same way. Also,someone had applied black patint to the inner transom! Talk about a dark hole to work in! It'll be a nece white when I'm done with it.
Grub

 

[ondarvr]

Re: Fiberglass Questions

It's not likely oil would migrate through a good laminate in any quantity that you could easily detect by eye, but like already mentioned, it's very likely that slight defects (which are very common) could allow plenty of oil to pass through.

 

[MR nova @#25]

Re: Fiberglass Questions


The center motor support actually rested on the pink stuff( that was 3/8in thick) It never made contact with the bottom of the hull. My question/concern is, when I fabricate a new center support, I don't think a few layers of 1708 will support a pair of v8s? Like I mention earlier this pink stuff was Sold! Im sure it was some kind of bonding material that also added to the strength of the glass.
what do I need to do

 

[jbcurt00]

Re: Fiberglass Questions

 

[Woodonglass]

Re: Fiberglass Questions

I agree with the above drawing. I might use double thickness of 3/4" Plywood to construct the center Mount, and instead of using 1708 I would prolly use 2 layers of 24oz Woven Roving for added bulk/strength and then a layer or two of 1708 to finish up with. It would be a tank then. Gunna take a lot of resin to make this happen.

 

[MR nova @#25]

Re: Fiberglass Questions

That's code for Money LOL

 

[Woodonglass]

Re: Fiberglass Questions

I'd say to do the layup on the Motor Mounts as drawn and using the 24 oz WR and 1708 would take about 3 yds of WR and 3 YDs of 1708 Give or Take.
Based on that You'd need approx 3 gallons of Resin so for cloth and resin and wood I'd Guess-Ti-Mate you could fabricate the mounts for around $200 bucks.