best filler for Royalex repair?

[MotorCityOC-1]

I'm no longer in love with JB Weld or PC-7. What are my other choices for filler material? These are the ones I know about:

- West System epoxy and little bitty pieces of Kevlar felt
- PC-7, etc
- many coats of ABS slurry???
- 3M two part urethane epoxy (32thirtysomething) --expensive filler!
- Gorrila Glue?

I have a 3" x 8" hole down to the inner layer of ABS/vinyl (foam seems oddly thin here- thicker ABS @ stem and stern?) I had a patch of 1/8 ABS over the area, and I think it didn't hold up because there was a pocket/weak area under it. So what's the beefy-est stuff I can use?

Speaking of beefy, I've been told that patches on the inside of the hull (at the ends) have a tendency to just pop right off in one piece. True?

I worry that no matter what material I use to patch the outer hull, the first good hit will punch the filler material right through the inner layers...

Sincerely,
Flummoxed In Detroit

[ezwater]

I would get several concentric layers of S-glass, largest layer first, on the outside, to make a stiff enough force distributor so that a hard blow doesn't get transferred to your inside repair.

Regarding the filler, if the area to be filled is as wide, long, and deep as you say, I might mix epoxy with microfibers (no special reason to use Kevlar) and microballoons, and build up the repair in stages, to prevent the epoxy getting too hot. You might be able to get the "next" layer of filler in before the amine blush appears on the "last" layer. Another way to fill a big gap might be Spheretex, but that's a material I haven't worked with. Finally, your inside patch should be several layers, largest first down to the smallest, and probably you should be using Kevlar because of the nature of the stresses on the inside patch.

Certainly others will have good ideas on filler.

[philcanoe]

you might consider going 180 degrees in the opposite direction...

instead of creating a hard patch that will transfer the load, to the remaining good layer of hull... i might try creating a soft inner layer of maybe Devcon (or ABS slurry with Cabosil) and cover this with a harder outer layer of maybe just ABS putty (or glass if you must)

a hard outer patch is going to transfer any force to the inside of the hull, everything time it's touched, hit, or flexed... just a guess, but i'd imagine it like fusing bad vertebrae together - where those to either side get overworked and damaged as a result of overuse and inflexabillity...

one drawback of glass is rock's like to grab hold of it, and not slide... this would also help cause a increase (of load or force) in a smaller area... of course you may need the strength of glass if the area is very large

[ezwater]

Mmmmm, Phil, the idea of a soft inner core is great..... But I don't get the part about glass grabbing and refusing to slide. My glass boats are good sliders. My Noah had something other than glass on the outside, and slid a bit less well. My old Phoenix C-1 has no glass in most of the hull, and slides a bit less well.

Maybe this also has to do with something about the total layup, of which glass is only the outer layer?

[boatbuster]

I would go with the ABS slurry to fill the void and then thermoform a piece of ABS over the outside and attach it with Plumber's Goop or Welder contact cement.

Met a guy, might have been at ALF, who used some kevlar cloth and regular Shoe Goo. Not sure how long that will last but it certainly flexed.

The problem with attaching any kind of glass to ABS is always the same. The ABS flexes, the glass doesn't and you end up with a temporary repair.

[sbroam]

I repaired a number of Mohawk Intrepids using Gorilla Glue as the filler and ABS slurry / ABS sheet for the skin. I'll let you know how that holds up after this summer's use...

[Randy Dodson]

One of our most experienced hair runnin, steep creekin open boaters has been using Marine Goop and used dryer sheets for years. He swears by it. He removes all the jagged edges and sands it smooth (this includes damaged areas that go all the way into the foam). He then alternates thin layers of Marine goop and used dryer sheets letting each layer cure before adding the next layer. I believe he uses the goop for the last layer and then lays saran wrap over it so it will be smooth when it dries.

We also have another man here in Arkansas who owns a canoe livery on Big Piney creek (comparable to the Nanty in difficulty) who uses a product called Smooth On. Five years ago, I had an Ovation come off a trailer at 70 mph. The road rash on that boat was extensive. He used Smooth On to repair my canoe and it is still holding well. For the last five years that boat has been on the water between 40 and 60 days a year.

Both of these fixes seem to be durable and flexible.

[Dale Barton]

Actually, I use the Marine Goop to fill in any defects in the ABS or Vinyl layers, sometimes in several thin layers, and then use dryer sheets that have been through the dryer at least once(not necessary to actually dry clothes), to cover the dried Goop layer, and epoxy worked in like you were doing fiberglass. It's cheap and easy. Dale

[mattm]

the abs slurry over gorilla glue has been working quite well on my sons whitesell and my encore for 4 months now, about 25 outings, including a few seal launches. the pirana was pretty spongy so we dug out the rotted foam (about 4" square) and put in the gorilla glue, which needed to be sanded down 'cuz it's effervescent or whatever; it foamed up. we sanded it below the outer skin layer and smeared on some abs. Nice; it flexes like royalex should, much more firm than rotted foam with sliced vinyl . The Encore just needed the abs in a couple spots. Love those tanks; just got Aaron one that looks like new.

geez, you guys got me all motivated .Just went out to the shed to check on my jar of abs slurry. It was a perfect texture. Just painted skid plates on Aarons "new" Encore and Reflection, got about 1/2 the bottom painted on my Encore. Mixed up another jar. Couple days the Dumoines gonna have a black bottom. Poling doesn't gouge the canoes, but a lot of sliding over rocks goes on.

[sbroam]

Dryer sheets?! Neat idea. I can vouch for Marine Goop - I put a layer on our tripper (grunch pad area) years ago ( I really can't remember - 6? 7?) and it is still on there - yellow, but there. I'm only just now thinking of doing doing something different. Maybe I'll use dryer sheets...

[Chris S.]

describe. Now I use seam sealer to fill in the gaps under the ABS layer and then lay up one or two layers of s-glass with Devcon Flexane 80. I repaired a 3 foot rip on the on side of a viper 12 with one layer of glass this way three years ago and only had to go back last year and put another later over an 8" area that was cracking. Flexible and strong. It will also slide well if you don't put too much Flexane 80. I'm thinking to try the ABS flurry thing to see if it works better...but I suspect the Flexane 80 is going to hold up longer. I used West System epoxy on my Viper 11 and it only lasted a season...which these days in Alabama is not many boating days.

WRT the inside patch...none of the inside patches I've done have come off, ever...and they were just with left over scrap glass, kevlar, & carbon fiber with west system epoxy. The inside one by the thigh strap D-ring did crack this year and I just put a little JB weld over the crack and it seems to be holding fine.

Chris