That’s it. Does epoxy bond/stick to plastic?
depends I suppose on the exact epoxy & plastics you’re referring to. In my experience, generally NO.
Dfinitely not to polycarbonate plastic…
Epoxy and polyester resin are basically casting agents.
When you apply them to foam, they soak in a little, and then form a casting mold that includes a small amount of foam.
When you apply them to solids, they do not really bond, they more or less cast themselves to the surface. The rougher the surface, the better the adhesion. So, roughing with a 50 grit sandpaper helps adhesion a lot.
When we make our fin boxes we use a 40% fiberglass filled urethane. We made the exterior surfaces coarse by bead blasting the cavities. But, we also process the material such that we float as much of the glass to the surface as possible and we put perpendicular holes into the walls of the boxes to produce undercuts for the resin to flow into. We don’t have many complaints of resin not adhearing to the boxes, unless the boxes are not acetone wash prior to installing or setting the resin too hot resulting in the resin shrinking away from the box.
Man it’s hard enough to get urethane to bond to urethane for your leash ends. Now, you want a chemical bond between resin and plastic. It really comes down to what you are calling plastic. Polyester and epoxy resins are both plastics by definition. Nylon, Polypropylene and polycarbonate are all very chemically resistant plastics and are not great candidates for epoxy to plastic adhesision. ABS and polyester will bond pretty well to epoxy. But, structurally they are not that tough. So, when you design a part you need to consider what is critical and how you can optimize other characteristics. Polyurethane is one of the toughest, most consistant, resiliant materials available today. Unfortunately, it is also very expensive relative to say polycarbonate/abs blends that are most often used.
So, I guess I’d need more information to answer your question.
Epoxy is a great adhesive for most thermoplastics, however plasma, corona, or flame-treating is usually necessary to modify the surface chemistry for bomb-proof bonds. For do-it-yourselfers, buy a Burnzamatic propane torch and quickly pass the silver tip of the inside flame cone about a quarter of an inch from the plastic. Move it fast and don’t let it heat up much. If the plastic melts, then it won’t bond at all. Pre-test the surface-tension by wetting with water. If it beads up, it won’t bond. If it wets, it usually indicates an adequate bond. Good luck, it works like magic. Love, Delbert Pumpernickel
I was just wondering about stuff like PVC.
A specialty epoxy (like the one Mark refered to) or surface treatment (like holly refered to) would allow you to bond to poly vinyl chloride. But, PVC is about middle of the range of plastics when it comes to chemical resistance.
Which gives rise to the question ‘what are you planning on doing with the PVC?’. Depending on what you are trying to stick the PVC to, there may be a bunch of better approaches. For instance, in the boat biz, we glass in PVC stuff, but we mainly use what would be considered massive laminations in surfboard work, so that it’s more the mechanical strength of the fiberglass/resin composite holding it there than any bond to the PVC that keeps it all solid…
For what it’s worth, there’s a product called ‘vinyl ester’ polyester-based resin that might work for you too - I’d suspect that the chemical similarities resin-PVC might create a chemical bond. The resin itself is stronger than most polyester resins though somewhat weaker than most epoxies.
hope that’s of use
doc…
I was thinking of maybe using small diameter pvc tubing as side fins on a fish, or a 2+1 setup on a longboard. I was curious as to what they would do and seeing what Roy stewart is doing with his tunnel fin I just thought I’d give it a try. Also, there is a new material out that is being used to layer skateboard ramps made out of recycled milk bottles, diapers, etc. This stuff bends amazingly and I thought it might be possible to make a paddleboard or kayak out of the stuff and then epoxy it. I’m just throwing ideas around in my head and thought I’d ask cause I won’t go spending money on something that totally won’t work at all.
Hey Monkstar,
A couple of weeks ago, a buddy and I repaired a cracked oil resevoir (UV damaged - probably polypropylene) on his boat with Greg’s epoxy. Cleaned it with acetone, roughed it with 36, and cleaned with acetone again before applying. Before reinstalling the tank, we gave it a couple of raps with mallet to see if it separated and all flexed together without separating - seemed to be holding like heck.
I also had him put the tank in a secondary containment for when/if it goes again though. He told me he was ordering a new one and just need to get the next couple of fares out - I know him better than that.
Note: previously he tried polyester resin and that pulled right off like butter was under it.
Best,
HerbB
Gents
I generally build kiteboards and there has been loads of discussion recently about rail materials.
Here is what I have learned so far:-
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PVC bonds very well with Epoxy, just a rough sanding needed.
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ABS, needs to be scrubbed with 40 grit then flamed before it will bond.
Epoxy is a thermoset. So, the epoxy will stick to other thermosets such as polyester, vinylester, urethane resin systems. However epoxy doesn’t stick to thermoplastics such as Polyetheylene (PE), polypropolene (PP), Acrylonitrile-butadiene-styrene (ABS), Polyvinyl chloride (PVC), Acrylic, Polycarbonite (PC), Polystryene (PS) etc.
To stick similar materials together such as thermoplastics to thermoplastics the material to use as a solvent for a solvent bond or cohesive bond.
For thermosets an adhesive may be used for an adhesive bond. Most retailers and building supply stores cary a variety of adhesives, both water-thin and thickened to be cured at room temp. (77 degrees F) in 3-5 minutes and up to 3-24 hours if necesary.
Check out Roo Glue made by Roo Products.
Ken
Holly is absolutely on the money. Herb’s method works too. I’ve done repairs on pe gas tanks that were still going strong after 5 years. Another help in bonding is to use a veil mat in your glue line. 2020 or 2040 gives a better bond than 2000.
Roo glue is a melamine glue that is nice for some applications as well. Air must get to it for it to dry though. Epoxy is a thermoset so it’ll dry anywhere.
Holly - Have you tried the RTM stuff yet?