I just bought this blue hole prowler. It is pretty scraped up, and I’ve been reading a bunch of advice on here, I just don’t know what im looking at. is this the core? I assume its royalex from what I ve read on here. Best advice for someone with zero idea what they’re looking at?
No, not down to the core, simply have the vinyl worn off, fixable with krylon fusion rattle can paint. The green layer is over the foam core and is susceptible to UV, so paint is a real good idea. If you go down to the foam, you can repair that either with g-flex and glass, the WEST system, or use apply a thin layer of gorilla glue on the foam, let set overnight, sand it down to a thin barrier coat, then apply a slurry of abs (abs weld wire cut into 1-2" lengths is best) and acetone. Acetone will eat the core, hence the barrier coat. You’re not there yet, so paint should do.
Pete may offer advice worth following as well.
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Mat, If you blow that photo up I think you can see one area in which the abrasion has started to expose the core. There are a bunch of little holes visible either side of the midline at the position at which the hull bottom would be expected to receive maximum abrasion.
Regardless, with the amount of red vinyl that has been abraded off and the area over which the ABS has been denuded, I would be very surprised not to find that the outer layer of solid ABS has bee significantly thinned out.
I have tried the ABS slurry technique using both acetone and MEK as a solvent and I have never had much luck with getting a durable repair. I know that you and Jim Michaud have had good results with it. Perhaps I was doing it wrong.
To the OP: yes the canoe is Royalex. The red coating is a layer of vinyl which is bonded to the structural layers of the hull which are ABS. The off-white area is the outer layer of ABS where the vinyl has been completely abraded off. If the canoe has been stored upside-down outside, this area of ABS may have suffered from significant UV degradation in addition to the abrasion damage.
If it were my boat, I would apply a sizable patch of fiberglass, preferably S fiberglass for its greater strength and abrasion resistance, over that whole area of exposed ABS using unthickened G Flex epoxy, then paint the repair after the epoxy has cured. I think that will maximize the remaining life of the boat.
There is another thread running right now on repairing Royalex canoes. Check it out.
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Hi Pete. Yeah, now at home I see the 2 abraded areas…to StaticCircus, glass is good as Pete mentioned, but with thoughts of the cell phone image dancing in my morning slumber, I started thinking the abs slurry approach would be more permanent than the paint. You’d just need a little glue in the abraded area, as mentioned, let it dry, sand down to a barrier, gorilla glue is hilarious in the way it expands while drying. The ABS slurry takes a few days to create, and if you went this method, cheap paint brush, brush QUICKLY as this will dry in a matter of seconds.I kept a bottle of slurry handy when I was running ww 200 days a year, airtight container kept it viscous. This is a close replacement to your missing parent material, though mixing Fiberglass resin (g-flex or epoxy) and mat has no issue reacting with Royalex. Either method is good.
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@pblanc and @daggermat
Thanks for the help.
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I ordered S glass and 32oz g flex.
This is the process as I understand it:
Sand off loose stuff, and any wax.
Wipe with acetone
Fill voids with g flex,
When its flush with the canoe, sand gently, and apply s glass patch
Do you reccomend skid plates? I read (I think from a post you commented on,pete) not to do the kevlar.
If you can miss the rocks, I’d skip the skid plates. Looking at your boats prior history, it looks more like abrasion than collision to me. My main ww boat got the bow nearly torn off one day, high speed edfy into a highway sign which ripped a large gash into the hull, foam hanging out. A gorilla glue base followed by g-flex and 2 concentric fiberglass patches allowed me to run the bejesus out of that boat several more years, at which time I sold it for $50 to a yakker who actually wanted to learn skills, and ran cl. 4 every weekend in it. Those Blue Holes are good solid boats, so between abs slurry, g-flex, glass and glue you can keep her running, and krylon if you want to keep 'er purty.
Thicken the g-flex up with glass beads for the long minor scratches as g-flex takes its time wetting out, and likes to run. Those areas are where I especially like the abs slurry as the fix takes literally 2 minutes.
Yes, that first photo clearly shows some exposed core. Here is what I would try to do.
First, go around the entire area that is missing red vinyl and push in firmly with your thumb. Royalex normally does flex and have some give, but in areas where the outer layer of solid ABS has been severely thinned, the material will feel spongy. I would try to cover any such areas with an S Glass patch that extends onto and overlaps sound hull by about 2" in all directions.
First clean the area well using warm water with some Dreft which should help remove oil and grease. Use a bristle scrub brush and go over the area of exposed core. Then rinse very well. You will get some water down in the exposed core. To get it out, use some denatured alcohol. Alcohol and water are miscible liquids so as the alcohol evaporates it will take the water with it.
If possible you may want to try to remove the vinyl from the area that needs to be patched. Sometimes this is easy, sometimes not. If you have a fairly sharp wood chisel, you can often get under the vinyl layer and peel it off the ABS like peeling tape off a package. The rationale for doing this is to allow your 'glass to be bonded directly to the ABS eliminating the possibility that the vinyl will delaminate taking your repair off with it. But if you can’t do this without gouging up the ABS forget it. I have found that G Flex bonds to vinyl just fine.
You do need to make sure and remove any loose vinyl material, however, and you should rough up any vinyl and ABS you are bonding to by going over the surface with 100-120 grit sand paper to get a good bond.
Be careful with the acetone. Yes, you can wipe down the solid ABS and vinyl with acetone but stay away from the foam core. The material there is very thin and easily dissolved with acetone. Acetone will “flash off” the solid surface quickly enough it won’t do any damage, but avoid prolonged contact.
West Systems recommends pretreating the surface of ABS before bonding with G Flex by flame oxidation to improve the bond strength but this is somewhat optional. The bond strength data collected by West Systems does show an improvement in distractional bond strength with flame oxidation so it is probably worth doing. But don’t try to flame the foam core. The instructions that come with the G Flex include pretty detailed instructions on how to do this. You need an inexpensive, hand-held propane torch that you can get at any hardware store. You want to do this within 30 minutes of applying the G Flex as the effect is temporary.
I usually thicken G Flex a bit with colloidal silica powder (cab-o-sil) to fill in the exposed foam core but it is not necessary. You will probably need to mix up several small batches and apply epoxy to the core every 30 minutes or so as it will tend to settle into the little interstices. Continue until no spaces remain visible and overfill the area a bit. Let the epoxy cure and then sand that area fair, smooth, and flush with the surrounding hull while maintaining the curvature of the hull cross section. Then wash and rinse everything again, give it a wipe with either denatured alcohol or acetone, and mark out the outlines of your patch. Flame away if you are going to and mask off the area of your patch.
I apply a thin coat of unthinned G flex to the area of repair and then lay the cloth on it carefully. Your mask will help you maintain the shape of the patch as it will want to change shape. Start wetting out the cloth at the center of the patch and work your way toward the edges. Be gentle as you approach the edges to avoid fraying as much as possible. It also takes a little time for the cloth to take up the G Flex. G Flex is more viscous than conventional epoxies and is often about the consistency of thin honey depending on ambient temperature. If the epoxy seems too thick you can thin it a little by gently warming the mixed epoxy with a hair drier or heat gun, but that will decrease the working life. I usually apply the epoxy using a plastic squeege but a disposable foam brush also works well. Make sure that the cloth is fully wetted out. Sometimes you will need to apply a bit more epoxy to accomplish this.
To fully fill the weave of the fabric to get a smooth surface will almost always require a second application of epoxy. If this is done within 24 hours of the initial application you don’t need to do anything special. If for some reason more time has elapsed, you should wash the cured epoxy to remove any amine blush which might interfere with bonding of a second application. If you want a really smooth surface, the cured epoxy can be wet sanded with fine sandpaper after it has fully cured. When the repair is complete, it should be painted to protect it from UV degradation.
I would probably repair the area of damage with a fiberglass patch of whatever size and shape is necessary and then apply a separate abrasion plate over it. You can use S 'glass for that purpose or 5 ounce/square yard Dynel. But if you don’t want to buy additional fabric, S 'glass will work fine. But for going over a curvature at the stem you want to cut that fabric on the bias so that the fibers of the weave and warp are crossing the midline axis of the hull at 45 degree angles. That will allow it to lay down over the curve more easily without pleating and will reduce the tendency of the fabric to fray at the edges somewhat. I like to mix graphite powder in the epoxy when installing abrasion plates but you can paint them instead.
I clean up application tools and mixing pots with white vinegar which is cheap and works pretty well. You are going to need a bunch of incidental materials including but not limited to masking tape, disposable gloves, squeeges and/or disposable foam brushes, denatured alcohol, spray paint, paper towels, scissors to cut your fabric with, and Sharpies to mark out the outlines of your repairs and to mark your fabric prior to cutting.
And yes, I detest Kevlar felt skid plates. They are easy to apply but they are thick, heavy, weak, and cannot be sanded smooth.
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Got it sanded, and a couple layers of epoxy down. My s glass finally came in. The entirety of the hull is scratched up…is putting the s glass over the entire hull overkill?
Yes, it would be overkill. Scratches on Royalex are normal and really don’t result in any significant loss of strength. Those old Blue Hole canoes are heavy enough without putting a full blanket of 'glass on the hull.