Will it adhere or not

Discussion in 'Materials' started by mapode168, Oct 2, 2014.

  1. mapode168
    Joined: Sep 2014
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    mapode168 Junior Member

    I have a couple of questions

    1.How well will an epoxy like the West System adhere to a piece of 3/4" treated plywood that had been stored inside for 3-4 yrs.

    2.How well will an epoxy like the West System adhere to above piece of treated plywood being dip treated to saturation in coupinal (phonic spelling) or Woodlife, Copper Coat which contains copper naphthenate

    3. Same question but untreated plywood being brush treated with an preservative (woods,Thompson's) or Woodlife Cooper Coat or coupinal

    4. Is it safe to assume that if fiberglass will bond to a substance, epoxies will bond to the same surface.

    5. What is the boil test of plywood?

    Posted my questions on this site because most replies are in complete sentences and respondents seem to be knowledgeable.

    So thanks in advance
  2. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Welcome to the forum.

    I'll try to complete my sentences.

    1 - Who knows. I'm not being glib, it's just there are variables. Assuming the moisture content is below 15% and you employ proper techniques and the PT is CCA, not the current crop of CA treated products, then yep, it'll stick good. BTW, West System sells a bunch of different epoxy formulations, but we'll assume you mean the 105 series resin and the appropriate hardener.

    2 - Epoxy's ability to stick depends on what it's put on, as you'd expect, but if applying over another coating, you're dependent on how well this other coating is stuck to the substrate, so . . . Some of the typical products work well, while others just make you want to commit suicide.

    3 - The suicide comment above is what you'll want if you try to over coat Thompson's and similar products, which are little more then dissolved wax in a vehicle. Stuff like the Rustoleum sealer, are effective in land based conditions, but not so much in marine. These are usually just copper naphthenate and a solvent, often with a bunch of other poison added.

    4 - No it's not safe to assume this, which is why I separated the CCA and CA PT treatments, as their performance levels are significantly different.

    5 - I'll assume you're referring to the type 1 and 2 WBP tests used to determine if something is waterproof. These help "qualify" a product's waterproofness, though on some products of dubious value, mostly because of the way the test is performed. For example TiteBond III is considered waterproof, because it passes the type I test, but it just barely does this and shouldn't be considered structural in these applications. On the other hand the usual marine epoxy formulation (like West 105) doesn't pass the type I test, but unless you park your boat over active underwater volcanoes, you can easily bet it is waterproof and structural in this application. In plywood, it an effective test, to directly answer your question. The test involves boiling and cooling cycling, to see how the glue and veneers hold up to the rapid moisture content changes.

    It might be simpler to just ask what you're trying to do.
  3. daiquiri
    Joined: May 2004
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    daiquiri Engineering and Design

    Just a small pedantic note, perhaps coming from my misinterpretation of the above phrase. :)
    Fiberglass is a common name give to glass-reinforced plastic, which is, essentially, glass fibers bonded together by a resin (for example, epoxy resin). Glass fibers will not bond to anything without the resin. The resin is the glue which bonds together fibers and also the fiberglass piece to some other structure.
    So, the quoted phrase is true by definition, because if epoxy bonds to some surface, it will do it both with and without the glass fibre part.
  4. SukiSolo
    Joined: Dec 2012
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    SukiSolo Senior Member

    Well said daiquiri, the glass fibres are the drawn thin fibers which until bonded by some adhesive resin have very little 'strength'. The cloth, roving or mat is like a flexible fabric off a roll. However it is also important to note that some particular binders used, especially for thin tissue surface materials may NOT be compatible with some resins. There are some materials only suitable for polyester resin builds. It is important when choosing and selecting the glass fabric type (woven,CSM,roving) to ascertain whether it is compatible with all the usual resins or one specific type. Most are multi resin compatible but do not get caught out.

    1. Stored ply is not necessarily dry enough. You may need a meter to tell you if it is. Age is not the factor, but the humidity level of where it has been stored may be a guide. As in an outside barn in Newfoundland (for example) may well be too damp but in a desert area would be OK.

    2. Personally, I don't like anything on the timber before epoxying. Maybe you could get away with a colour stain (spirit or water) well dried after application. If 'Thompsons' is like in the UK, a transparent silicone waterproofer, then an absolute no no, in my book. Same goes for anyting that will leave a greasy, waxy surface in the pores of the ply.

    3. WBP is a test to designated standard which you can look up. I've removed and seen so much rotted ply that 'passes' that test, it has become almost meaningless. Massive differences in quality, usually based on the adhesive type used. BS1088 is still good though for marine ply.

    PAR asks the right question, what is it you are looking at doing?
  5. sdowney717
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    sdowney717 Senior Member

    I have had success with epoxy on PT plywood.
    Dont bother with cuprinol or any commercial coatings.

    What you CAN DIY to aid in rot killing ability is to mix boric acid in hot water and paint this on Plywood end grain and all over if you wish. That will soak into the wood and kill and prevent rot. Boric acid dried into wood will have no effect on the wood ability to be glued or coated. If you get to much BA dried onto the wood surface, just brush it off the wood. BA is commonly called roach powder.

    BA dissolves best in hot water, but also dissolves a little in cool water, but you get more saturation in hot water. If the water can soak the wood, then so can the glue, and if BA is in the water then it is also moving into the wood.

    BA dissolves very well in rubbing alcohol which I use to treat active rot areas that I plan to glue later.

    BA dissolved in green antifreeze for cars that is ethylene glycol makes for a long lasting excellent killer of fungus and bugs like termites. But it takes a long time for EG to dry which is good for long term protection, bad if you want to glue, so use rubbing alcohol with BA or water with BA for wood meant to be glued today.

    Especially if you want to treat wood and glue same day, then use BA mixed with rubbing alcohol, paint it on the wood. It will dry fast. If you want it dry and it is not, then use a heat gun to dry the wood. I like to let the BA mix sit on the wood wet for awhile to give it more time to diffuse into the wood.
  6. mapode168
    Joined: Sep 2014
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    mapode168 Junior Member

    will it adhere

    WOW! The wealth of information & advice on this site is amazing & the best part is responders fully explain what they are saying.

    Sdowney717 thanks for your reply, I think I will try your method. One question, as I understand it the boric acid will kill existing dry rot & prevent future dry rot so it's good for for prevention, what about wood that already has dry rot. Guess what I'm asking what is the best way to take care of an area of dry rot. Use boric acid then use something like Get Rot to treat the. Area for strength?

    Have a Skiff Craft, which is a plywood lap strake with Aproxmenitly 1"x1" ribs. Some of the ribs are soft as well of some of the plywood planks. The planks have small areas of soft wood 2 -3 plus deep out of 5 ply. There are some soft spots in the bow stem. This is the Area I'm most concerned with. After your reply my plan is to treat stem with BA then treat with get Rot ( unless there are better options). Ribs same way. Planks treat same way then fill in with thickened West System or fiber glass filler. Planks below water line.
  7. lewisboats
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    lewisboats Obsessed Member

    Git rot or other such treatments can only penetrate and stabilize the rotted area... it can't restore the strength of the original wood. The way to restore the actual strength to the piece is to replace the rotted wood with new. The sloppy way to do it is to stabilize the ribs and then sister them with other pieces to help support. Carve out the rotted plywood and patch in additional pieces (Dutchmen) and depending on how bad the stem is, either patch it or replace it completely... the latter being the recommended option.
  8. mapode168
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    mapode168 Junior Member

    Lewisboats, I agree with you but it's way above my skill level. The stem soft wood is no so critical that it's compromising boat safety, same with the other soft wood. Guess I'm looking to extend the boats life a few years. I got this boat for the price of removing it from a trailer the boat was on & the owner sold trailer & buyer did not want boat.
  9. lewisboats
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    lewisboats Obsessed Member

    Nah... it's just wood. You mess it up... do it again until you get it right, or at least until it works properly even if it ain't pretty. Remember... boats have been hacked out of trees for many thousands of years by every tool from steel adzs to bone ones, by more folks with no training than all the trained boatwrights that have ever been.

  10. mapode168
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    mapode168 Junior Member

    Well thanks for your encouragement. I'm 70 years old and my 90 year old dad just shakes his head every time I try a project that involveds working with wood. He tried to teach, I was very good at not wanting to learn, back then. Now he is no longer able to teach or give advice.
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