Rib to transom repair

[Chris-MA]

New to Rib boats as of yesterday, lifetime boater.

I picked up this banged up 18 year old Zodiac yesterday and it is going to need some repairs. I am not sure what the joint is called between the fiberglass bottom and the tube, but you can see it was repaired VERY poorly with what appears to be Marinetex.

Is there a tutorial on how to repair this joint and make it stable? I am not sure what to search for. I have figured out that my boat is PVC not Hypalon. Here is my plan:

Sand, wirebrush or otherwise remove the hard epoxy. Any pointers?

Buy some Polymarine 2 part PVC adhesive.

Wipe down with MEK.

How do I hold this joint together? I can't figure out how to roll it. Should I glue it with the tubes inflated? Any other pointers so I can get this boat wet?

Thanks,
Chris

[beerbelly]

leave inflated and put a ratchet strap around the tube ends behind the transom will pull the tubes together and should close the gap

[beamishken]

Get it cleaned up then glued then inflate the tubes whilst holding them clear of the prepared glue. Once fully inflated roll the tube into the final contact position. Once the glue has 'grabbed' deflate the tube and roll the glued section through the outer deflated section of tube. once rolled to achieve full bond of the contact adhesive then reinflate & ratchet strap

[Chris-MA]

Thanks guys, the rachet strap pulled it right into place.

Any hints how to remove the dried Marine Tex? I assume gentle sanding?

I know it probably depends on temp and humidity, but how long does it take for the adhesive to "grab." Is it 15 minutes? An hour? I don't want to just have it fall apart.

Thanks,
Chris

[Peter_C]

You can constantly chase repairs on the glued sections of the boat, or you can fix it right and tear the floor off, then the transom and reglue everything.

Leave it as it is and the 18 year old glue can fail while off shore. The transom gets kicked around pretty hard in rougher water.

[beamishken]

Originally Posted by Chris-MA

Thanks guys, the rachet strap pulled it right into place.

Any hints how to remove the dried Marine Tex? I assume gentle sanding?

I know it probably depends on temp and humidity, but how long does it take for the adhesive to "grab." Is it 15 minutes? An hour? I don't want to just have it fall apart.

Thanks,
Chris

Carefull sanding is probably the only way to get built up adhesive off then finish with solvent.
The 2 pack glue is applied to both surfaces & is contact adhesive so initial bond is immediate however rolling the two surfaces together with a hand roller increases the bond strength considerably

[Peter_C]

Originally Posted by beamishken

Carefull sanding is probably the only way to get built up adhesive off then finish with solvent.

Sanding is the worst possible thing to do as it will remove material no matter how careful one is.

The coarse grey scuffy pad with Acetone will take the glue off with some elbow work. Dip the pad into the Acetone and replace the scuffy pad pieces once they clog, which is often. Good gloves and proper PPE along with lots of fresh air are important.

The entire boat glue is in the same shape as shown by the OP's pictures. It will fail. There is no quick repair. Remove the tubes from the transom and any other parts of the boat that are glued on, not thermo-welded, and reglue.

I had good luck with Stabond glue. *shrugs* Temperature and humidity are everything.

[beamishken]

Originally Posted by Peter_C

Sanding is the worst possible thing to do as it will remove material no matter how careful one is.

The coarse grey scuffy pad with Acetone will take the glue off with some elbow work. Dip the pad into the Acetone and replace the scuffy pad pieces once they clog, which is often. Good gloves and proper PPE along with lots of fresh air are important.

The entire boat glue is in the same shape as shown by the OP's pictures. It will fail. There is no quick repair. Remove the tubes from the transom and any other parts of the boat that are glued on, not thermo-welded, and reglue.

I had good luck with Stabond glue. *shrugs* Temperature and humidity are everything.

If you read the origional post its been repaired with epoxy, which is going to be difficult if not impossible to remove without abrasion. If it was original glue then I'd agree however its not normal pvc glue thats been used.

[Peter_C]

Originally Posted by beamishken

If you read the origional post its been repaired with epoxy, which is going to be difficult if not impossible to remove without abrasion. If it was original glue then I'd agree however its not normal pvc glue thats been used.

I can't reach out and touch the glue, so is it hard or soft? Looks to me more like 3M 5200. https://www.boatingmag.com/marine-so...removing-5200/

Epoxy should be super easy to remove. Just bend the fabric back and forth on a cold day, and it should release as the epoxy would be stiff.

[Chris-MA]

Hey guys, my poly marine showed up today. I cleaned up the boat today with some bleach and it looks good. I am on the hunt for some MEK, does Acetone do a good enough job softening the PVC before gluing?

Good point on the 5200, you guys are probably right. I was able to clean up one of the pork chops with 120 grit paper on a stationary belt sander. I may also try to clean up the rest of the adhesive with MEK if I can find it.

How important is the rolling? What tool should use for that? I am starting to think I should glue the pork chops first and then once they are cured, glue the tubes back to the transom?

Thanks,
Chris

[Peter_C]

Originally Posted by Chris-MA

Hey guys, my poly marine showed up today. I cleaned up the boat today with some bleach and it looks good.

It will be a fun little boat

Originally Posted by Chris-MA

I am on the hunt for some MEK, does Acetone do a good enough job softening the PVC before gluing?

Per Poly Marine, they want you to buy their chemical prep wipe, which is made up of mostly MEK (BUTANONE) with some TETRAHYDROFURAN which is a softener. MEK is a good way to get proper chemical penetration. I do not know if MEK is banned in your state like it is in California. Here they offer a "fake" alternative MEK, and it won't work, so read the label carefully. Auto part stores should carry it if it is not banned.

SDS sheet for Poly Marine 2903. https://s3-ap-southeast-2.amazonaws....LVENT-2903.pdf

Originally Posted by Chris-MA

Good point on the 5200, you guys are probably right. I was able to clean up one of the pork chops with 120 grit paper on a stationary belt sander. I may also try to clean up the rest of the adhesive with MEK if I can find it.

The goal is pretty much no material removal. Acetone is a better cleaner in that it won't soften the PVC. Is the 5200 coming off easy enough?

The hull will need to be scuffed up for better adhesion after removing all the old glue. This could be done with 60 grit by hand, then cleaned thoroughly after. Right before the prep wipe you will need to scuff the PVC material. Some 60 grit could get it done, but a tool like this is cleaner. https://www.amazon.com/Roller-Rasp-V...1856003&sr=8-1

Originally Posted by Chris-MA

How important is the rolling? What tool should use for that?

Rolling is how the air bubbles get removed, and the glue gets proper adhesion. Roll, roll, roll, at least three passes. You will hear bubbles coming out. If you have ever done window tint, stickers, etc, it is the same process just using a roller. The rollers can be found under "sound deadening roller" "wall paper roller" and probably a few other names that include "roller". Something like this set. (Good for drysuit seal repairs too!) https://www.amazon.com/Vehicle-Deade...856047&sr=8-10

Originally Posted by Chris-MA

I am starting to think I should glue the pork chops first and then once they are cured, glue the tubes back to the transom?

Reverse order of how you take it apart. It is done in layers. Take pictures. https://www.polymarine.com/advice/ho...flatable-boat/

Have you tried pulling on other areas of the glued on sections to see if they are failing also?

[Chris-MA]

Ok, today is glue up day! I used some 80 grit sanding discs in my drill to remove all the 3M 5200. I think it cleaned up pretty well. I have a few more questions before I mix up the glue.

1. Alignment - it seems like the fore/aft alignment is off a 1/4" or so. How do I fix this? Do I need some support under the tubes pushing them up?
2. Order of operations - I have to glue the tubes to the transom before I glue to pork chops to the tubes. Therefore I cannot deflate and rub the surfaces together. Is rubbing the seams against the hard tube enough?
3. Do I do this all at once? Seems like I need to glue everything in one fell swoop.
4. How do I minimize the creases in the transom to tube seam? As you can see it does not lay down very flat.
5. DO you think my cleanup job was sufficient?
6. I do not have a bench seat, does that keep the tubes more ridgid? Should I buy another seat before I drop it in the water again?

Thanks for all your help!

[Peter_C]

All the brown glue needs to be removed. Scuffy pad and Acetone.

The pictures clearly show the remainder of the glue is failing. The entire boat needs to be taken apart and reglued, A heat gun gets used to remove the remainder of the PVC.