Repairing Tabbing

[smj]

Originally Posted by colemj

If this is just furniture tabbing, then some here are going into overkill on solutions. I couldn't tell, but it didn't sound like a structural bulkhead or even anything structural at all.

smj and I have debated before our differing opinions on epoxy/poly (I freely use both for things). However, my experience with poly secondary bonding to poly is not the nightmare he describes. I think a lot of people spend unnecessary money and expose themselves to unnecessary toxicity because of this epoxy cult. Many, many, many, many, many boats have been structurally repaired with poly in the past when epoxy hadn't even arrived on the scene yet. Probably more boats than have been repaired with epoxy since.

And I can't tell you how many epoxy bonds I have peeled off poly builds before. If not done very carefully, any additional bonding capabilities of epoxy are lost. Poly is much more forgiving in this.

However, if bonding to wood that previously had a poly bond, I would use epoxy.

But only if it is structural. If it is just sticking some furniture together, then cheap and easy is just fine. As long as the wood itself is OK, clean and dry.

Mark

Not necessarily a nightmare but polyester is definitely not the best resin for the job. Let's face it, if the tabbing is losing it's bond with the hull, it's most probably the original polyester secondary bond done at the factory. I will agree that prep is the key whether using epoxy or polyester. I'll also agree if it isn't structural then no harm using polyester.


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[Terra Nova]

Originally Posted by Boatyarddog

...Re glassing with poly... is fine...

Epoxy is... very brittle...

Simply not true.

[minaret]

Originally Posted by colemj

It would have to be a long, wide, thick tab with the good bond side in a difficult to access area before whacking the whole thing off with a grinder and retabbing became less easy than your alternate method.

I'm not arguing your method, just putting the parameters in perspective before people gravitate too soon to that method.

Mark

Nope. I write bids for this stuff all the time. Our shop would have more hours into vessel protecting for dust control on a decent size tab grind than the four or so billable hours in the quick fix I just gave you. You can't just fire up a grinder and start grinding. You have to protect decks, mask for dust control, mask for resin control in the new layup, suit up, grind, clean up, before even beginning a layup.

[UNCIVILIZED]

Assuming that you want to go with Epoxy, there are certain brands & formulations designed not to produce amine blush. Though one has to hunt for them. But the whole issue can be avoided by using peel ply.

Also, do some studying on several formulations & types of epoxy. You'll find that there's a decent range of how flexible one resin is vs. another, & there are even ones, purposely designed to be very flexible. The reason for the various flexibilities of epoxy is so that when building, or doing repairs, you can match the stretch properties of the resin to those of the reinforcements which you're using. Be it; CF, E-glass, S-glass, Kevlar, Basaltic Fiber, various Woods, etc.
So, obviously, all of the various manufacturers have this data (for the asking).

And as already stated, epoxy does a far better job of sticking to wood than to polyester. Plus, it pays to do good prep work for doing secondary bonds with epoxy. Without it, then, yeah, the bond strength will be poor. But with it, then it definitely bonds well to polyester.

[a64pilot]

Cmon guys don't we learn anything here?

Just fill the gap with that green snot stuff

[HappyMdRSailor]

Originally Posted by a64pilot

Cmon guys don't we learn anything here?

Just fill the gap with that green snot stuff

No kidding... Or just pour some Tab in there...

Don't use diet Tab... It isn't sticky enough...

[Cheechako]

Originally Posted by minaret

Nope. I write bids for this stuff all the time. Our shop would have more hours into vessel protecting for dust control on a decent size tab grind than the four or so billable hours in the quick fix I just gave you. You can't just fire up a grinder and start grinding. You have to protect decks, mask for dust control, mask for resin control in the new layup, suit up, grind, clean up, before even beginning a layup.

[Cheechako]

Originally Posted by Boatyarddog

5200 to fix this is short lived and really not the right way.
I think the manufactures would have used it if it was a long lasting.
Just my opinion from having used it for repairs over the years.
This stuff will shrink, glass will not.
Expansion rates of differing substrates usually causes this problem of releasing the bond, or water.


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Boy.... I'm sorry but glasswork does shrink over time ... a lot on some boats... It's not hard to see either... especially on boats where the bulkheads were cut to fit without a gap between them and the hull. As the glasswork shrinks you will see the bulkhead as a linear lump on the outside of the hull.
It amazes me how some will say "I never use 5200 mounting hardware (etc) as it pulls the glass apart trying to remove it" but then on this thread wont use 5200 because it wont work for a simple tabbing creep repair!
Sure ....if it were the main bulkhead and I was willing to tear the boat apart to redo the bulkhead, I'd glass it.

[Boatyarddog]

I will have to concede to smj that epoxy is superior to poly or vinyl ester resins.
I believe if you clean well to remove all surface contaminates, and grind well you'll have a more than adequate bond.

The thing with epoxy is have your ducks in a row to finish the repair in one push, or be prepared to remove the amine blush for the next round.
Extra work is just that an unnecessary step, from the data the differences aren't that dramatic between resins.
Prep well and it will last.

The substrate that you attach to must also be solid.
Plywood is exactly that in plys, so if the resins bond to an degraded layer in the plywood it won't last, be sure to wet out everything, thinned resin may work ok, personally I favor scratching the surfaces very well as a physical bond and wetting out the area,
Be prepared to move with the repair quickly, once the stuff sets up, you won't get any air out.
Cut your glass, have an assistant mix your resins if in tight quarters, so you'll have time to finish.


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[Boatyarddog]

If I saw that someone had used 5200 to retab a bulkhead, I'd be looking a lot closer at the boat.
My opinion.

But I will say that I don't believe the working boat repair yard would recommend this type of repair.
Only the DIYers
No disrespect.
For me the difference is in knowing I've done the best repair I can do.



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[Boatyarddog]

I'd think you bid that job knowing your going to do vessel protection.
Maybe that sells a repair or not.
Won't say it's an adequate repair though.
In our boatyard, it's not bid or repaired that way.
It's a free country to choose your budget repair or the production repair.
I'll take the extra steps.
We've built our reputation on it.


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