looking for some VERY strong epoxy/glue

Best Plastic to Plastic Glue?

I'm doing a project soon where I need to glue a Radio Shack battery holder into one of those clear Otterbox cases that BatteryStation sells. I want the holder glued in there really securely, so whacks and drops won't dislodge it. But I've had bad luck glueing (sp.?) plastic to plastic, especially using the soft polyethylene (the "garbage bag" plastic) they make those battery holders out of.

What's my best bet for making a really GOOD bond between these parts? /ubbthreads/images/graemlins/confused.gif

Re: Best Plastic to Plastic Glue?

I am NOT an expert, but when I want to glue something forever, I use a two-part epoxy.

This stuff will seal an engine block crack. Waterproof, etc.

Re: Best Plastic to Plastic Glue?

There are different kinds of plastic and they need different kinds of glue. I think not much will stick to polyurethane, and the adhesives for it actually contain a solvent that partly dissolves the plastic, so that when it hardens again, the result is more like a weld than a glue bond.

For the battery holder to the otter box, your best bet is probably screws rather than glue, with RTV sealant or something similar around the screws to keep the holes sealed.

Re: Best Plastic to Plastic Glue?

Epoxy should work. I use hot glue in some situations.

Re: Best Plastic to Plastic Glue?

[ QUOTE ]
JohnK said:
I am NOT an expert, but when I want to glue something forever, I use a two-part epoxy.


[/ QUOTE ]

Yup epoxy should work best. In your case with the battery holder, epoxy made for plastics or the durable/flexible type epoxy should work best.

Local Walmart has the epoxy made for plastic called "Plastic Welder" and the durable epoxy is called "Super Poxy".

Re: Best Plastic to Plastic Glue?

Weld it in with Hot Glue. The hi temp yellowish kind made for wood from Home Depot, Sears etc.. Scrape good to remove left-over mold release. Work glue into parts with tip of gun.

Second best-- Generously score both parts with tip of knife held at flat angle and use GOOP (use contact cement method).

Re: Best Plastic to Plastic Glue?

Whiskey, I like that GOOP also.

It's worked on a myriad of projects Fairly long cure time though.

Re: Best Plastic to Plastic Glue?

3M makes some hot melts for olefins that can't be beat.
You would never get them apart again, but its not something that you can come by every day.
If you have a gun that can accept 5/8" sticks, I can point them out to you.

Re: Best Plastic to Plastic Glue?

You might want to try this . I use it a lot to repair speaker cones and never had any of the fail or separate after using this thing. It is a two part glue an activator and the bonding agent, you first use the activator to prepare the surface and then apply the bonding agent. It's kind of like superglue but the two pieces of plastic will never come apart. I bye it at a local supermarket for like $4.00 .

P.S. Just notice you are from NJ if you have a Stop & Shop around you can find it there.

Re: Best Plastic to Plastic Glue?

Scott- If the pieces are the same type of plastic, a superior glue can be made by dissolving the same type of plastic in a coffee can with some Xylene. It will take a while to melt though. Thinned to the consistency of molasses and applied, it will actually weld the pieces together. The only drawback its the time invoved in waiting for the mix to dissolve, and then re-cure after application. You won't *ever* have to worry about the assembly coming apart though. /ubbthreads/images/graemlins/smile.gif

Peter

Re: Best Plastic to Plastic Glue?

[ QUOTE ]
bdl666 said:
You might want to try this . I use it a lot to repair speaker cones and never had any of the fail or separate after using this thing. It is a two part glue an activator and the bonding agent, you first use the activator to prepare the surface and then apply the bonding agent. It's kind of like superglue but the two pieces of plastic will never come apart. I bye it at a local supermarket for like $4.00 .

P.S. Just notice you are from NJ if you have a Stop & Shop around you can find it there.

[/ QUOTE ]

Thanks! /ubbthreads/images/graemlins/smile.gif Turns out I bought some of that stuff a couple weeks ago at the local hardware store. I used it once to bond a plastic part to a metal part, and it failed. But more recently I glued plastic to plastic, and so far the bond seems to have worked fine!

Haven't tried it with polyethylene yet, though. /ubbthreads/images/graemlins/thinking.gif

Yes, I'll give it a try.

Re: Best Plastic to Plastic Glue?

Finally something is my realm of expertise.

You guys want the llllong explaination and low down on plastics? or the uick cheat sheet of what works for most plastics we play with????

OH good the long version


Ok There are two types of "Glueing" the first is called adhesion. Which is what it sounds like taking two similar or dissimilar materials and bonding them together.

The second type of bonding is called cohesion. That's where you take two similar materials and fuse them together. Usually using a solvent...I.E. xylene, acetone, and methylene chloride.

Typically done correctly cohesion is a stronger bond them adhesion-typically.

Anyway back to the science of glueing.

Polyolefins hate absolutely hate pretty much all chemicals....that's why we use them for gas cans and such. So trying to use xylene to melt ethylene or propylene won't work. So using two parts and other glues doen't work out so well. but there are some tricks to help with it.

Stuff like acrylic(Plexiglass), polycarbonate, and styrene based plastics love absolutely love solvent bonding. But you do have to what for whitening and stress cracking.

So we come back to polyethylene. How do we bond it???

Hot glue is a good choice (Most of the hot gule is either nylon or olefin based.) Dbl sided tape also works, using a soldering iron to actually weld the plastic can be done...if you know how to do it. and finally mechanically fastening it.



There are some things you can do to get better adhesion on polyolefins.

The first and someone already said it. Rough it up with sandpaper. The more nook and crannys the you have for the glue to get into the better. The second is called flame treatment. >>>>THIS IS ONLY FOR POLYOLEFINS<<<< But you can take a propane torch and set it on low flame them pass the flame over the surface of the plastic. You know you hit gold when you see tiny little bubbles from on the surface, the texture of the surface will get slightly bumpy.

But you have to watch it because too much and you have a meltdown.

Ok that's a shortened version of the long version. If you want more info just PM me or email me I can give you the rundown

Re: Best Plastic to Plastic Glue?

Scott I had the exact same problem when I was prototyping kitelights. Nothing would work permantly.

When I contacted a plastics suppier, they told me that it had to be welded with a plastic welder. I not only sanded the surface, but took a Dremel to it with a coarse wheel. I drilled some holes that I got glue to ooze through.

The problem is further complicated by the fact that the holders flex when you put batteries in and take them out.

Cliker seems to be in the know. I guess I screwed up in reverse because I tried the flame treatment (I was trying ANYTHING) but it always messed up the holder. If it didn't warp it too badly, then it still made it very ridgid and not flexible enough to hold the batteries securely.

Hot glue did the best job (I was VERY surprised at that), but still it would eventually fail. I PMd Floating Spots for info on the 3M product that he referred to. I ended up using a velcro strap in addition to the glue.

I would suggest using screws or rivets if you really want it to hold up.

Re: Best Plastic to Plastic Glue?

I'm going to reply in this thread because more than one person asked. It will also allow more knowledgeable people to correct my (presented) deficiencies.

The one I ended up using was 3M's 3748 hot melt.
This one is a good bonder and ends up off white.
It's specifically says "A high performance hot melt adhesive for bonding many plastics including polyethylene and polypropylene."
Now, I didn't select it for this property specifically.
I selected it because it is also non corrosive to copper (which is good when tacking PCBs /ubbthreads/images/graemlins/smile.gif ). However, I played with it some and it didn't exhibit a lot of adhesive failure. I saw more substrate failure and cohesive failure. (I'm an electrical engineer. Why do I know this? /ubbthreads/images/graemlins/grin.gif)

Looking around, 3M have one I have never tried. Its their 3796, which looks to be their high end plastic bonder.
It's listed with the description of "High performance adhesive for bonding many metals, plastics, leather, and other non-porous substrates. It has good heat and oil resistance with a long bonding range."

3M's website is one of the worst I have ever worked with.
The info is scarce and hard to find.
The search utility brings back sheets from all countries, even though one must first specify where they are starting...
A few links are provided:
Hot Melt Selection Guide
3748
3748 PDF
3796
3796 PDF

Re: Best Plastic to Plastic Glue?

Wow. This is getting better and better, guys. I appreciate the info! /ubbthreads/images/graemlins/grin.gif

Not sure this is the right spot but, here goes anyway. I have a pair of binoculars which have rubber lens barrel protector guards (not sure this is the technical terminology!) onto which plastic lens caps are attached. My difficulty is with the rubber guards which should be more firmly attached to the plastic lens barrels. I almost lost one the other week when I took the lens caps off and the rubber protector fell into high grass on a hike. Now the question--I have tried Shoe Goo (traditionally used for running shoe and sole repairs) and Devcon rubber adhesive to try to more firmly attach the rubber guards to the plastic lens barrels, both without much success. Any ideas of what may be more useful so I don't end up trying to replace a part which is non-descript and possibly unobtainable?


Karl

Re: Adhesive Question

try superglue first... amazing range of what it will successfully hold together.
for instance superglue works great for holding foam washers on ARC's.

used for shoe repairs, comes in large bottle in gel form. my bottle purchased from shoe repair shop dried up before I could use it all. great stuff!

3M plastics and emblem adhesive would be another candidate.

Re: Adhesive Question

Thanks CY! Jeez, you've got all the answers today haven't you?:wave:


Karl

Re: Adhesive Question

Some plastics are just notoriously hard to glue. If the cyanoacrylate (Super Glue) fails, I'd try a silicone glue (Elmer's Stix-All) or polyurethane (Gorilla Glue) next.

The 3M Plastic and Emblem Adhesive is a solvent-based flexible glue similar to Shoe Goo/Goop or Devcon Rubber Adhesive.

Re: Adhesive Question

Also marine silicone "Sikaflex" will stick alot of things and remain flexible.