How Rotten is Too Rotten?

[techrtr]

I'm curious to know how damaged a rib top has to be before other people who have restored an old canoe would replace it. I'm working on a canoe right now. A few of the rib tops are completely gone but most are just split. Not sure if I should replace them all or just reinforce them with GitRot. I've included a photo to illustrate the condition of most of my ribs. I'm interested to know what other people think.

Bruce

 

[Tariacuri]

This is a great question!!

 

[1905Gerrish]

Those are not to bad. Git Rot and then epoxy if any wood is missing. It mix my epoxy so its firm but flexible. I do this because of the nails and screws that will shatter the rib tips down the road even after pre drilling the holes. Years of trying different things. Might take a few attempts to get the epoxy correct but it works for me. To hard it will shatter, to soft it will tear out. Good luck!

 

[Todd Bradshaw]

I think the first step is always going to be to "define your rottenness", as it were. Truly rotten wood tends to crumble under pressure and has lost nearly all structural integrity and strength. You can saturate it with Git Rot, CPES or other diluted epoxy products and usually make it hard again, but you are not really going to make it strong again. The resulting piece will never have the same sort of strength or physical characteristics that it originally had. Whether or not you can get away with that depends on the spot in question and what sort of in-use stress it will get. If your particular "rot" is more a case of severe weathering, and/or maybe losing some of the original material, but decent structure remains, then you may still have sufficient strength left to live with and can augment it with your repair.

As a general rule of wooden boatbuilding though, it is always better to replace obviously bad wood with new wood whenever possible. If you have stuff in there which crumbles away when prodded, it is really difficult to make a good case for keeping it, and usually pretty foolish to think that the application of some form of modern goo is really going to fix it.

 

[techrtr]

Hey, thanks for the replies everyone. I think I'll error on the side of caution and replace rather than try to repair. Bit more work but I want the results to be good and solid.

 

[H.E. Pennypacker]

From the image shown (granted only a few of many ribs), your rib tops look perfectly fine! If it were me, I'd pull those steel nails, repair the cracks with epoxy, and re-nail using bronze ring nails. Having restored quite a few canoes in many stages of disrepair, to me these rib tops look pretty darn good. You used the word "rotten" but those in the photo look only split, not rotten. Of course those that are "completely gone" need splices or replacement.

 

[techrtr]

Okay, so to repair those cracks, would I use Git Rot or something like GFlex from West Systems? I've been working down the port side which is where most of the damage is. Luckily, I think I only have one or two ribs that need their tops replaced on the starboard side.

 

[Easternrivers]

IMHO....I don't think Git-Rot will be the glue of choice here as it doesn't seem to have much gap filling property.
I've used epoxy or even TBIII thickened with a bit of sawdust. I've also used a 2 part waterproof glue called Unibond (used to be called URAC 185) which can be made thicker with additional powdered catalyst added to the resin. It fills gaps well. I've used this to build traditional bows over the last few years. Great stuff.
My policy is if there's any doubt scarf in new wood...don't take much more time and the end result is better.

 

[Dave Osborn]

Same as Eastern Rivers,....I'm not a big fan of Git Rot or penetrating epoxies on rib tips. It just doesn't look right to me. If it is that bad, scarf in new tips. Stain them dark and no one will ever know.
For split rib tips use a syringe and squirt tite bond III or good epoxy in the splits and clamp them together. It helps to blow out any dust, sand, or debris from the splits prior to gluing, too.
I've found that syringes from Jamestown Distrubutors can be useful in many areas of restoration....

There are plenty of forum posts on how to scarf new wood to existing ribs.....

 

[Paul Miller]

Hi Bruce,

You have heard from a number of people and their personal experiences and preferences. Some I have found to be accurate others not so much. But there is more than one way to fix stuff on a canoe.

Best thing is to try a few and use the one you like; and always be open to some other idea that comes up in the future.

BTW Git Rot and CPES are not glues, and not all "penetrating" Epoxy's are the same.

Always trying to keep an open flow of ideas,

Paul

 

[H.E. Pennypacker]

I failed to say so in my response but I agree with others here - Git Rot isn't the answer. Penetrating epoxies like this are fine to start in order to seal things up particularly where end grain is exposed, but a thickened epoxy will fill and bond those cracks. When I do repairs like this I first apply freshly-prepared (i.e., low-viscosity) epoxy into the damaged area, let that soak in and maybe add more if it soaks in quickly, then thicken the epoxy with cotton microfibers or fine sanding dust and use that to fill the gap and bind the two sides of the cracks to each other. Plane, scrape and/or sand down any runs or lumps once the epoxy is cured, drill holes, and use bronze ring nails to re-attach ribs to inwales.

 

[techrtr]

Lots of good information coming in - thanks everyone. I've gotten pretty quick at removing damaged rib tops and scarfing new pieces in. I'll leave some of the split but otherwise sound rib tops in place because I kind of like the way they look. It gives the canoe a bit of a patina.