HCC Paddling Forum

Re: "the layer of contact cement. Is there a way to remove that, without damaging the vinyl layer on the inside of the boat?"

Mineral spirits or acetone.  Apply lightly with a sponge, and let it soak in.  That will soften the glue so it can be removed.  Scrape it off with a plastic squeegee, or something that will be gentle on your boat's plastic.

       - John Rich

https://goofoffproducts.com/product/pro-strength-remover-6-oz/

or

https://googone.com/pro-power-8oz

  Well folks, I have repaired the Royalex boat, using Partite 731 (Recommended by Old Town), and a layer of fiberglass cloth and more Partite. I think that one of the Old Town or Carlisle Royalex patch kits would have worked fine, as well as West Systems G-Flex with fiberglass form the auto parts store. 

  Now I might need to remove the canoe's closed-cell foam seat pedestals and knee pads, since the boat's owner and I are no as flexible in the knees as we used to be. I can apply a saw and use sandpaper to get down to the layer of contact cement. Is there a way to remove that, without damaging the vinyl layer on the inside of the boat? 

I use denatured anyway which I get in cans at hardware store, Wal Mart, Home Depot, Loews etc. I buy the gallon size which is around $15 because I use in camping alcohol stoves. Also available in quart cans.

I have done all right with 2 part epoxy attaching Kelver grunge plates to Royalex. I put them on my canoe in 2000 and they are still there although there has been some wear on them in the meantime. I got the grunge plates because Jack Richardson had bought some kits to attach them to polyethlene canoes from Old Town. The special stuff that Old Town put in the kit was only enough to saturate one pad so the other pad had to be attached with the stuff from the other kit so I was given the left over two pads. I put them on the Royalex canoe using 105/205 2 part  West Systems epoxy. My guess is the Old Town special stuff was just relabeled 2 part epoxy. Polyethlene has to be torched to get anything to stick to it. 

I repair my fiberglass boats with the newer West Systems Gflex and use fiberglass cloth. I do it outside on a good day or leave the garage door open for ventilation. I use disposible  gloves so I have no skin contact with the epoxy. West Systems has web, print and video help about doing fiberglass work. Follow the instructions about getting the mixing portions right. Fiberglass materials are available at your local boat store West etc. or on the web. They have special Gflex for Plastic, Aluminum and Fiberglass boats.

By the way, 99% isopropyl alcohol is available at medical supply stores, such as Complete Medical Supply on 18th and Jester. It isn't cheap, though - $8/pint. Cheaper than screwing up your boat repair, though! ("Denatured" alcohol can have all sorts of stuff in it.)

Thanks, everyone, but no more, please. I've got lots of good advice. Now I just have to go do it. 

I read that completely denatured alcohol is better than isopropyl alcohol (if you can get it), since completely denatured alcohol does not leave an oily film to reduce adhesion.

I recommend the commercial Royalex repair kit, even though it's pricey ($75), and contains only enough material for one medium sized patch.

I tried everything else to save money, and nothing else worked properly.  This included auto body products from the auto parts store, like fiberglass repair kits, and Bondo.  None of those adhere properly to Royalex.  And since the bottom of the boat will flex a little as it bumps into things, the patch needs to flex with it.  A rigid patch on a flexible surface will just come loose.

You can't let that foam core soak up water, or it can start to delaminate the other layers, and it will add weight.

I had an old beat-up boat anyway, so I didn't mind experimenting on it.

It's an established metal-working trick to drill holes at the ends of cracks, in order to keep them from continuing to grow in length.  Not sure I like that idea in a boat, where you're intentionally compromising the hull integrity.  If one of those plugs comes out on day 2 of a week-long expedition trip, what then?  

Follow the instructions.  Roughen the surfaces with sandpaper.  Clean with isopropyl alcohol that will evaporate.  Run a torch over it very briefly to burn off any oils.  Layer several patches on top of each other, staggering the size of the patches.

If you don't trust your boat, don't go anywhere in it where you don't want to be stuck.

If all else fails, buy a new boat.

  Does anyone have experience repairing Royalex? A friend just bought a Royalex boat with some small cracks/scrapes on the bottom, through to the core layer. I've seen protocols involving anything from G-flex epoxy, to commercial Royalex repair kits, two-part liquid epoxy + PC-7 + "Goop" + ABS sheets + drilling lots of holes and plugging them with dowels. Yikes! Advice gladly accepted.