How do i epoxy this plastic to abrasive paper?

[Syphonics]

This plastic tube is smooth in surface. but i did a sand down with a grit 24 sand paper. I even cut groove on the tube for better epoxy holding strength.
Abrasive flaps are epoxy to this tube. Somehow the epoxy did not hold it well enough and the flaps came off.
Is there any way to make the epoxy stronger or doing something about the plastic tube.

[ger21]

Epoxy won't stick to a lot of plastics. Here's some in fo from West System.


Plastic-Adhesion varies. If a plastic is impervious to solvents such as acetone, epoxy generally will not bond to it. Soft, flexible plastics such as polyethylene, polypropylene, nylon, Plexiglas and polycarbonate fall into this category.

Hard, rigid plastics such as PVC, ABS and styrene provide better adhesion with good surface preparation and adequate bonding area. After sanding, flame oxidizing (by quickly passing propane torch over the surface without melting the plastic) can improve bonding in some plastics. It's a good idea to conduct an adhesion test on a plastic that you are uncertain about.

[One of Many]

Some of the defining classes of plastics can be seperated into groups of Thermal form and Thermal set. The ones in the Thermal set group are typically also called Engineered plastics. Certain mixtures that create a solid plastic very impervious to chemicals and cannot be recycled.

By the surface texture of the tube. Is that a glass filled engineered material of nylon or acetal. Some of these types can be acid etched, but that is about it, as far as preparation for adhesive bonding. No guess on how strong the bond would be in use generating heat and on the max rpm of the flapwheel.

I did find this adhesive and a few more interesting sites doing a search for "Flap wheel" + Adhesives.

Flapwheel adhesives


What is the reason you desire to make flap wheels when there are so many on the market. Is yours a custom version?

DC

[Syphonics]

Originally Posted by One of Many What is the reason you desire to make flap wheels when there are so many on the market. Is yours a custom version? DC

Its my job scope thats required me to do so. Was tasked to research on the epoxy and it properties.
So far i did tried with epoxy mixed with aluminuim oxide grains, but i guess my proportion of harderner is too much to the extend the epoxy is not as tough.

[Chuck Reamer]

At work we epoxy plastics and fiberglass to wood all the time, its hold strong enough to machine the plastic while holding on to the wood.

We do a lot of glass moly teflons, and fiberglass the only one we have trouble with is the teflon. The only way I know how to do it is to etch the teflon first, I am not sure what they use to etch with. There are a ton of different glues they use, im not exactally sure I just machine the finished product.

What kind of plastic is it? If you could let me know I could find out the best thing to use for you.

[Syphonics]

Originally Posted by Chuck Reamer At work we epoxy plastics and fiberglass to wood all the time, its hold strong enough to machine the plastic while holding on to the wood. We do a lot of glass moly teflons, and fiberglass the only one we have trouble with is the teflon. The only way I know how to do it is to etch the teflon first, I am not sure what they use to etch with. There are a ton of different glues they use, im not exactally sure I just machine the finished product. What kind of plastic is it? If you could let me know I could find out the best thing to use for you.

i am not really into plastics knowledge. but this plastic tube is real smooth on the surface. it is not easily absorb by glue.

[Chuck Reamer]

Originally Posted by Syphonics i am not really into plastics knowledge. but this plastic tube is real smooth on the surface. it is not easily absorb by glue.

Alright, what type of epoxy are you using?

You need to rough it up alot, so its really nasty looking.

[pced]

Chuck Reamer is correct. The best way to bond plastics is by etching the surface first. Etching is required for materials like Teflon, UHMW and all the other materials in the polyethylene family. All of these materials have something in common, they are very chemically inert to most solvents. This characteristic will retard most attempts at boding. Norton Chemplast makes etching kits, available through MSC and probably McMaster Carr. For big nasty etching jobs, Porter Chemical will etch just about anything and they do an excellent job. That tubing you have is probably polyethylene. You can determine this by cutting off a little piece and burning it, if it drips and smells like a candle it's polyethylene.

For more info on plastics go to www.cncplastics.com

[Syphonics]

the tubing i used might be nylon material

[pced]

If it is Nylon then you can rough the surface up like Chuck Reamer said and go to the loctite website. There, you can tell the site that you are trying to glue Nylon to steel or some other substrate. It will tell you which loctite adhesive to use for that application.

[One of Many]

Just be very aware the anarobic acrylate type glues can craze some plastics which turns it very brittle. For static non-structural uses, they may be fine. But with centrifigal and variable contact loads that create further stress in the substrate. It could fly apart.

DC

[thkoutsidthebox]

My tub of Gorilla Glue says it can bond plastic, along with other non-absorbant materials. Dont know how strong it'd be, but it is 'Gorilla Glue'!!
Try it.