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2020 Canvas Mildewcide options *in the US

Discussion in 'Wood and Canvas' started by floydvoid, Jun 16, 2020.

  1. floydvoid

    floydvoid Curious about Wooden Canoes

    I have done a lot of searching on the forum. I have untreated canvas to use and though I store my boats well, I would like to protect my canvas better so I can be a little less careful. I already put copper naphthenate in my filler. I'm trying to figure out some option still available in 2020 for treating the inside of the canvas:

    -Copper naphthenate: Still available in the US, turns wood green. Would not impact the filler is my assumption if painted on the inside of canvas and dried. If I treat my canvas with this would it turn my feet green if my boat gets wet?

    -MX3 mildewcide (Carbamic acid, butyl-, 3-iodo-2-propynyl ester)
    or ADD-2(2-(4-Thiazolyl)Benzimidazole ):
    It mixes with oil or water base paint, I was thinking mix it with thinner and paint it on the inside of the canvas. Would this last? Would it poison me if my boat gets wet? I assume something like this is applied to the mildew treated canvas available from boat suppliers; perhaps when this is made at the factory they have some other carrying agent that keeps the chemical where it should stay?

    -Experimental idea: Thin down pine tar, apply to inside of canvas, apply a non-organic dust like diatomaceous earth (DE) or something like that to keep the pine tar from being sticky. Pine tar is a natural anti microbial, correct? Easily available, but would I have spontaneous combustion issues? filler sticking issues? smell too bad?

    -Other ideas?
  2. Dan Miller

    Dan Miller cranky canoeist Staff Member

    mmmalmberg likes this.
  3. mccloud

    mccloud "Tiger Rag" back on the tidal Potomac

    All three of the fungicides you list are licensed, and have low toxicity. Some have even been used as food additives and in cosmetics. I have used MX3 and ADD2, either by adding to filler, or spraying onto the canvas after it has been stretched over the hull, or both. Since I've not removed the canvas from any canoes done this way I do not know how effective the preservatives have been. The water solubility of copper naphthalenate is so low your feet are unlikely to turn green, and it might serve as an athletes foot prophylactic. My unbased opinion is that pine tar/ turpentine will be miscible into filler and oil-based paint. Therefore adhesion should not be a problem. But will the dark pine tar slowly migrate outward and into your paint?? Maybe. I'd like to know. You might make a mock-up before painting the entire canoe, something like an artists canvas, putting tar on one side, filler, followed by a light colored paint on the opposite., and set it in the NC sun. TM...
  4. 1905Gerrish

    1905Gerrish LOVES Wooden Canoes

    Been putting "Stay clean" mildewcide in my filler for years. Cheap insurance.
    Last edited: Jun 16, 2020
  5. David Satter

    David Satter LOVES Wooden Canoes

  6. Greg Nolan

    Greg Nolan enthusiast

    I would pass on having one of my canoes be the guinea pig for this stuff.

    The MSDS for Concrobium Mold Control indicates that the components of this product are trisodium phosphate (between 1% and 5% by weight) and sodium carbonate (less than 1% by weight).

    Sodium carbonate is used, inter alia, as a wetting agent, ph regulator, and foaming agent. It is soluble in water.

    Trisodium phosphate is a common water-soluble cleaning agent, a/k/a TSP.

    Since the component parts are soluble in water, I imagine it would leach away sooner or later – depending on how often you got the canvas of your canoe wet. (Read the negative reviews at Lowes -- very informative as to its preventative capabilities.)

    I don’t even think I’d use this stuff to clean mold off something – if I wanted trisodium phosphate, I’d just get an ordinary box of TSP. A 4 ½ pound box is $10.48 at Lowes, and the instructions call for mixing ½ cup with 2 gallons of water. I don’t know how many ½ cups are in 4 ½ pounds of TSP, but I imagine that it is several. The Concrobium stuff sells for $34.99 a gallon at Lowes.

    ‘Nuff said.
    Last edited: Jun 17, 2020
  7. Rich BWCA

    Rich BWCA 1977 Seliga

    My Seliga canoe from the early 1970s has been in my basement for perhaps 15-20 years. Over the past few weeks I've noticed several times that the exterior surface of the hull (Petit Pine Green, as Joe had recommended) was developing the whitish appearance of mildew. I wondered if that paint was even still available. So onto Google I went and discovered there is a WCHA, and then I found the wonderful write up (the "Joe Seliga" thread) of a warm, unpretentious, and engaging man who with his wife invited my friend and I into their home and shop for some wonderful conversations. I'm pleased to be here with those who know the wonderful feel of canvas gliding through the water! Sorry for the diversion, but it's great to know there is a group of WC enthusiasts!!

    My plan has been to wash the canvas exterior with TSP, rinse really well and let it dry thoroughly, then repaint the exterior. The surface looks in really good condition, so I don't think I need to do more than clean and paint. Anyone used Petit paint recently? Is there a preferred alternative?

    After the paint dries, I may revarnish the interior - any recommendations for a varnish formulation?

    I also have one of my cane seats with a small rip, so I'd welcome any thoughts on a source of good quality caning for seats.

    Thanks so much and best wishes!
  8. MGC

    MGC Scrapmaker

    Hello Rich...welcome. How lucky you are to have a Seliga.
    It's a bit worrisome that you are seeing mildew on the canvas. You might want to be sure that the canvas is not dry rotting.
    Your plan to TSP and paint sounds good. You should lightly sand the hull before you paint it. I would TSP, sand and then use a tack cloth to clean up before painting.
    WRT paint, Petit TopSide paints are still available. Pine Green is not. They currently offer Seafoam (it's dreadful), Jade (a dark green) and Kelly (think shamrock). I have had decent luck with Petit but some find it a bit of a challenge to use. I prefer Epifanes bootlack. They offer 8 different shades of greens and perhaps one is a match to Pine Green. Another option is Kirby paint. They will color match and may already have a Pine Green blend. Some folks swear by Interlux paints. Most folks roll the paint on with foam rollers and the tip it with a foam brush. Using that approach you apply several layers of thinned paint.
    For varnish, use a good quality spar varnish. My preference is Epifanes but I have also had good luck with Captains Spar. You should plan to apply two coats to the interior, decks, rails etc. and possibly more if the varnish is failing. I would TSP the interior at the same time as the canvas and then thoroughly rinse and dry before sanding. Tack cloth, good quality varnish brush and off to the races. which do you do first? Paint or varnish?
  9. Rich BWCA

    Rich BWCA 1977 Seliga

    Hi MGC - thanks so much for the welcome and all that great and really useful information! I do feel so fortunate to have my Seliga canoe and to have known Joe. The canoe was a treasured companion in the BWCA, and it so greatly enhanced my experiences amongst all that timelessness and tranquility. When I left MN I debated about whether to take it with me or leave it in its home state to someone who would enjoy it. I decided I couldn't part with it, and my wife and sons and I used it many times before the kids moved on to HS, college, and now careers.

    I do want to follow-up with you if you have time about the dry rot potential. What would I look for as definitive signs and symptoms to make a diagnosis? Is it a sign that the canvas needs to be replaced or, if present, can it be stopped? The mildew looks like it's on the surface, but I understand about mycelium potentially penetrating within the canvas (ugh!). My first thought when I saw it was that it was a surface problem, and that it seemed odd because there have been no major changes in the basement interior and no visible growth problem earlier. Are there air conditions that promote dry rot in canoe canvas?
  10. MGC

    MGC Scrapmaker

    Dry rot tends to show up around the rails and stem tips. The canvas starts shredding. You can very carefully poke around those areas to see if it seems like the cloth is soft and punky. If it is the boat will need a canvas. Damp basement storage can lead to problems as can the classic under the cottage porch storage. I have a canoe that has dry rotted inside rails from sitting in "dry" storage for many years.
    Hopefully there is nothing to worry about and your canvas is good. Someone else may know if Joe used lead in his fillers...leaded fillers can last a very long time with proper care.
  11. 1905Gerrish

    1905Gerrish LOVES Wooden Canoes

    Floydvoid, Wondering what your decision was on the mildewcide option? Find any other useful information out?
  12. OP

    floydvoid Curious about Wooden Canoes

    I am about to treat and put the canvas on the boat after getting distracted with other boats this summer. I'm going to go with diluted "turns wood green" Copper Naphthenate painted on the canvas. I was going to do a test piece of canvas to see if I can just paint it on the outside to see if it will soak through, if it does I'll just apply it to the outside after canvasing the boat. I'll report back in 10 years!
  13. OP

    floydvoid Curious about Wooden Canoes

    Well, I opted to not treat the canvas in favor of skipping an extra step and not making my garage stink like Turns Wood Green.

    This canoe won’t be completely abused so I’m less worried about mildew if I let it dry out during storage time.

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