Have a solo Royalex canoe, I installed D ring patches using Vyna Bond years ago inside the hull in several places. I need to replace some of them.
Any tips on removing the existing patches? Also any advice prepping site for direct replacements? Plan to use the same standard vinyl patches NRS sells for rafts.
As an alternative if necessary, the existing patches are still very tightly adhered, so could I possibly just plaster new one over the existing one? Needs to take a fair amount of torque.
The material is Royalex “light” so the inside layer is quite thin; i.e. grinding has proven a poor technique (from experience).
I have not removed any vinyl patches bonded to R-84 canoes but have removed probably a hundred or so from Royalex canoes. Try warming the patch with a hair dryer or heat gun. Be careful not to overheat the patch as it can transmit enough heat to the hull material to crimple up the foam core, so keep checking how hot the patch is getting by touch.
Once the patch is good and warm, use a thin-bladed putty knife or paint scraper to lift up whatever edge of the patch seems loosest. Once you get one edge to start to come up, grab it with a pliers and gently lift as you continue to warm the remainder of the patch.
I have been able to reuse most of the vinyl patches I have removed in this way. Some very thin vinyl patches may become too deformed to reuse. If you plan to reuse the patch, I would clean the back of it up with acetone. Acetone can also be used sparingly to clean the hull where the patch was. Be careful, as any prolonged exposure to acetone can melt ABS, but with brief application with an acetone rag, the solvent flashes off so quickly it does no damage.
Sometimes grit and sand will work its way beneath a vinyl patch and get into the adhesive remaining on the hull after removal of the patch. In this case, you may need to wet sand the hull with fine paper (like 180-220 grit) to clean it up. There usually will be some persistent discoloration of the hull where the patch was no matter what you do.
pblanc very adequately described the process for safely removing vinyl patches from Royalex canoes.
I believe it is quite possible that acetone will more quickly have a negative affect on R-84 than it will Royalex.
Speaking for myself; I wouldn’t even consider putting a new vinyl patch over an old one.
Might work fine, but not for me.
I have re-outfitted two whitewater boats with a lot of D-rings that needed to be relocated. In the first, the vinyl was so well attached that that I decided to leave the vinyl patch in place and simply cut off the nylon webbing with a razor blade. I was able re-glue new D-rings over the old patches - it worked fine. You can see some of the old gray patches under the new yellow ones here.
