Transom Replacement- Nida-Bond Pourable compound

[sfc2113]

Am getting the options togther for my 86, 204c transom rebuild this winter. I am planning to do this over the winter and finish up by Jun 2011. I am planning on using wood (marine plywood) and fiberglass to recore.

But, I am also looking into pourable compounds. The price of sea cast is not worth it from my point of view also it would be adding weight to the transom. Would cost around $1,100 in material and I still have to do all the work of removing the wood core. I have came across a company called nida-bond and they make a ceramic based pourable transom compound that is 1/2 the price of seacast and have ordered a free 1 gal sample to test with.

Only thing the engineers tell me is the transom would be lighter than if I rebuild wood and resin. Not sure if this is an issue but, will conult with gw on the weights later.

Has anyone ever used this stuff or seacast to do your transom? If so please add your comments.


I plan on trying to dig out the wood without removing the skins first. chissel, saw ,ect. If I can get the all the wood out and prepair the inside surface for bonding with the pourable core would this option work?.

I will probably start out by trying but I am sure it will get frustrating and I will cut the outer skin off and go with the initial plans of using wood /glass and resin (west sytems).


Here is a link to the nida-bond site:

http://www.nida-core.com/english/nordpr ... ransom.htm

 

[ElyseM]

somebody on THT did a rebuild with a lot of pics. do a search, probably "nida" would be a good tag. ron

 

[NOTHING ELSE MATTERS]

I never used nida, a friend of mine did his transom with sea cast and he is NOT happy with it. Maybe was his fault or the sea cast is not as good as they say it is. First of all you have to remove ALL the plywood and i mean ALL the plywood between 2" of space and more than 3 feet down, it will take for ever and you will not be able to remove all the plywood(some people use chain saws for that). The easiest, cheapest way is plywood(i thing is stronger than anything else) but doing it from the inside, just cut out the inside skin, set you circular saw at 1/4" less than the PLYWOOD thickness, not the transom thickness, make cuts across, then cut up and down creating little squares, then take a chisel or a large screwdriver and remove the plywood. The rest 1/4" plywood you can remove it VERY CAREFULLY with an air chisel( best tool for the job) or a regular chisel.
BTW, by doing it from the inside you have to cut your stringers about a foot of the transom, this is the right time to check for rotted stringers too.

Make sure you use marine plywood, not just exterior fir.

 

[richie rich]

http://forums.bateau2.com/viewtopic.php?f=10&t=19949

Verowing did his Seafarer transom.....check out his post as well.....new ply or Coosa board is the way to go

 

[VeroWing]

I considered using a "nida core/seacast" type of product to rebuild my transom. Some of the problems I found while doing considerable research on them are these. First, it is impossible to entirely remove all of the bad wood sandwiched between exterior and interior fiberglass. You will never be able to clean and prep interior faces of fiberglass skins enough to be sure that "pour type" transom mix securely attaches to them. Second, if you do a "Google" search you will find some stories of people that stated they used these types of transom repairs and experienced cracking of "pourtype" material after a while, if they bumped docks, etc. Othe rstories stated that while curing, that extreme heat caused problems with existing fiberglass, and others spoke of air pockets created when product was poured into glass skins. I have no firsthand experience with these products, but I do know that this is a lot of work, irregardless of which method you choose to use for repair. To me, I wanted to be 200% confident that my repair/rebuild would be better and stronger than new, so I could jump in boat and run offshore with without worrying about my transom falling off. To me, a traditional marine type plywood completely encapsulated with epoxy coated fiberglass was the best, longest lasting method. Check link posted by Richie to see my transom rebuild, and if I can offer you any advice, feel free to ask. Mike

 

[sfc2113]

I agree with you on using the wood, currently that is my direction. But, am still going try to see how much wood I can get out without cutting out any fiberglass off. I really do have nothing else to do over the winter but chip away at it. Again, I am only in the fact finding phase of this and thank you very much for the input keep em comming. I saw the posts on the cracking of the seacast and the only thing seacast could tell me was if used and set properly this would not happen to there product. They also investigated some of the claims I read and found the installation was done incorrectly. There product has allot of air that must be removed during the pour. I would imagine that a material that has air pockets in it would be brittle right? Not very freindly person either I spoke to.

I have talked to an engineer at nida-bond and he told me that if I am able to get most of the wood out I should be able to coat the inside transom skins with resin using a small resin roller and would ensure a very good bond to the pourabe material. There poduct does not have a problem with air pockets and its max temp during cure is 160 deg. As far there product being brittle and hitting something or cracking the transom they have had no report of material defects from there consumers. He told me no matter what product I use, wood, honeycomb, seacast, ect if you hit it hard enough, something is gonna give. He did say there product is flexible to a point and a moderate impact will not crack or break there maetrial.
They are sending me a free sample 1 gal and told me to do a mockup of some kind and see what happens to it when I apply stress and impacts to the material. I also got a direct line to the engineer. I like that.

So Seacast is now out of the picture.

 

[Grog]

What I have seen is people do is attack the transom from the inside to get all the wood out then clean the inside skin. When both sides are clean they attach the inside skin and pour the "filling". That way you know there is no wood left to compromise the bond of the pour to the skins. Without opening her up there is no way to get all the rotted wood out. If you're going to hang anything more than a 9.9 off the transom, don't use the chainsaw (or like) method.

 

[richie rich]

Grog and Vero have a very good point....you need to remove the inner skin, not only to remove the wood, but to prep the insides of both skins for bonding of any resin....after you chip out all that wood, which will take forever, you will still be left with chards of wet and rotted material stuck to the old glass...resin does not bond well to that...the biggest failure in bonding with any resin is surface prep...you need a clean and scratched up surface....new boats using the pourable stuff in the chine and strake areas are doing it when the glass/resin is still clean and fresh...maybe even a little tacky....I don't think any resin manufacturer like West or Mas or S3 would recommend doing it without prep with their product.....what you may end up having is a core thats sandwiched between 2 skins, but niether is actually bonded properly to each other.....thats really a risky proposition IMHO....you will be chipping all winter what should only take a weekend if you remove the skin....I couldn't sleep at night....and that stuff aint cheap either...I would do a little more research before buying any materials (either way you decide) to be completely confortable with the game plan on this one. Let us know how it turns out...

 

[BobP]

On the 204C you can get to the inner skin by cutting out the rear part of the liner and the corner caps. A plan needs to be layed out where to make the cuts to create clear access, otherwise it gets crazy trying to reach in there, and you will go crazy. Once it is clear, then it is easy. Not much to the inner skin and tabs. Then have to figure out spice plates or the like to get it back in place later.

The boat also has the battery platforms in either corner seat base, may hace to cutout and then glass back.

Marine plywood is better than original. No issue with weight.

The easiest way is to cut thru the outer skin, by far about 1/3 as much work as doing it inside due to the liner and cap in/out.

If the motor cutout has the alum cap, glass it over instead when going back.

If you work in a heated indoor area, you can work the glass and resin all winter, if not, wait to above 70 deg F to use resin. But all removals and wood fitup can be ready to go when temp rises come spring.

Marine plywood is about 100 bucks per sheet on the 1/2 in, more at 3/4 inch.

 

[sfc2113]

Thanks Bob, I think I will taking off the outside skin to accomplish this. The wood in the stringers is dry and in good shape, If they were not dry I was going to let a shop do it. I have NO exp with fiberglassing, other than filling some holes with thick epoxy here and there. So, if I were to tackle this from the inside , will never get done and it wont be right. I think I can handle glassing in the wood from the outside. I have priced out how much pourabe compound I will need to do this job and with shipping it is $550.00 I figure with wood and resin and glass It will be around $400.00 now I am thinking , Why would I not want to just clean out the old wood, clean up the inside and outside surfaces of the skins, glass the outer skin back on and pour the nida bond into the cavity. :hmm

 

[richie rich]

if your going from the outside, you need to leave enough original glass to bond the new skin to. That outer skin is probably 1/4 inch thick...which is like 5-6 layers of 1810 biax glass...18oz 0/90 plus 10 oz matt....normally you overlap each layer by 2 inches to get the best bond...that would mean 12 inches of surface area which you won't have from the outside unless you wrap around the gunnels and bottom....that means lots of fairing......so if you do a 1 inch overlap with each layer, you will need 6 inches of existing skin to bond to....grind off all the gelcoat and get to solid glass for the repair...you have to repaint anyway and gelcoat on its own is weak..get to the glass.....now that you have a clean inner skin, and replace a new clean outer skin....what to use for the core????hhhmmmmmm

 

[Gotboostedvr6]

How did this end up?