Gunk Removal?

I have a used canoe, MR Courier, I just picked up and need to clean off some type of adhesive that the previous owners used to secure some “homemade” seats. It’s on the outer hull. It is a royalex hull.

I have access to a heat gun and am thinking that is the way to go, slowly, very slowly heat the gunk up and scrap it off with a putty knife. Could this be the best way to go about this or are there other ways to get this junk off of the hull.


Try solvents first.

– Last Updated: Jan-09-11 9:54 AM EST –

Start with warm water and soap and work your way up. Rubbing alcohol, denatured alcohol, Goo Gone, mineral spirits, naptha (lighter fluid), hexane (Bestine rubber cement thinner) is the order I'd use of stuff I already have on hand. Clean rags, rubber gloves and a bit of elbow grease. Don't leave anything on there for too long - rinse w/ soapy water. Sometimes a Dobie(TM) scouring pad helps to mechanically remove softened residue. I'd leave the chisel, putty knife, scraper approach as a last resort. You'll probably end up with clean and burnished areas that will make the rest of the hull look dirty and dull at which point you could try the 303-electric buffer technique!

If it's a construction adhesive like Liquid Nails, is thick, and has been on there a long time, mechanical removal may be your only alternative. Gentle heat (hair dryer), a dull putty knife (maybe even one of those hard plastic ones), and careful, slow-going is reccommended.

Nice find and good luck!

Ditto on the solvents

– Last Updated: Jan-09-11 2:18 PM EST –

It's not that I have any experience with solvents, but I already know what happens with a mistake as minor as leaving "trouble light" with a 100-watt bulb a few inches from the hull for a couple of minutes. A heat gun would be about 10-times as devastating, and in the blink of an eye too. Be careful.

Doug, didn’t realize that piece of trash you picked up is royalex. Ignore my email from last night. Daggermat had some good advice here…


I’ve never put lacquer thinner on
ABS, but that might be okay. With any solvent you’re not sure about, it’s good practice to try it in an inconspicuous spot first. In good light and using magnification, put a drop on and watch it for a few seconds, then blot it off with a clean white cloth or paper towel. If color comes off on the cloth, or if the material is softened or otherwise shows evidence of dissolving, stop right there and take it back down a notch or two.

Another thing about heat and closed-cell plastic foams. Heat can cause all those little bubbles to expand and even burst! IME, there is a critical temperature reached at which things happen very quickly and, as you stated, great care must be excersized!

I would try a bull-nose plane or a low
angle chisel. Blade must be sharp. Rather than pushing straight ahead, one should “swipe” so that the blade edge cuts sideways as much as forwards.

Thing about Royalex is, any solvent similar to acetone can soak right through the vinyl and soften the ABS structural layer.

Once the offending substance has been mostly sliced away, light sanding may remove the rest.

I like that idea
I think this is excellent advice. Carefully-controlled cutting/slicing can do wonders. I haven’t done this on a boat so far, but I know it works in other situations.

A good quality chisel is your friend. Note that it’s best to turn a chisel “upside-down” for this kind of work so that the beveled side of the blade faces down, not up. That will give you you the shallowest possible cutting angle and eliminate the chance that the chisel will dig deeper than you want it to. On a flat working surface, if you put the beveled side of the blade up, it is not possible to make the other side of the blade flush and parallel to the working surface (the handle gets in the way), but with the bevel side facing down, you can.

Thanks For the Tips
I tried a hair dryer and that did little to this “gunk” and noticed with just that the hull area heated up pretty good so I nixed the heat gun. I’ve used those before, good tool for some jobs but not this. I tried to Goo Gone or whatever it was called. No go. Then I sharpened my chisel and tried that. Made a little dent but I’m not that gifted with it. In the end I got out, this will make your spine quiver, my belt sander and took that to this crap with a very light touch. I haven’t gone through the paint yet and will end up needing to rough those hull areas for glassing down the road.

I have no idea what was used but as it came off it smelled…toxic! Not a good thing I thought as I had my face right over the areas of sanding and yes I wore a mask. Just kills me to see a fairly nice boat abused like this.

Still have one side to finish sanding and then begin work on new gunwales, thwarts and am purchasing a new seat. With an unheated workshop I’ll have to wait for warmer weather for G Flex and glass. I did ask my SO if I could bring it the house to do that but that made for a response I can’t post here. Sometimes I wished I lived alone! :wink: