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prkaye

Well Known Member
I need to attach two plastic pieces together (two different GPS mounting parts). There's no room for a mechanical fastener. I tried LePage Extreme Repair, but it wasn't strong enough (after two days of curing I was able to pull the piece off with a little bit of leverage). I'm wondering what the strongest glue would be for this purpose?
I was thinking I would use West Systems Epoxy with 406 Adhessive filler, becuase I've found this to be pretty strong in the past, but is there a better choice that you guys would recommend?
 
It depends,

What type of plastic is it? I have found that chemical or mechanical melting most plastics together creats the strongest bond. Some plastics do not lend themselves to that or you may not want to do that for some other reason. In that case you will likely need an adhesive. Here's an excellent primer on the use of adhesives on plastics: http://machinedesign.com/article/guidelines-for-bonding-plastics: http://machinedesign.com/article/guidelines-for-bonding-plastics-0615
Whichever method you chose, careful preparation is the key.
 
I'm not sure how to identify what "type" of plastic it is... but it's the hard black plastic that GPS mounts are made of.

I don't want to melt the plastic because one of the pieces to be boded has electrical connections encased inside it.

The bond should be strong enough to hold a Garmin GPS and for the normal strength required to swivel the GPS on the mount, so it doesn't need to be strong enough to hold an elephant.

I'll read that primer, thanks!
 
glue skool?

Yes, always tough to glue unkown materials.
In the past, I've usually elected to add an aluminum 'patch' or gusset along the side of the break, and as much 40-grit mechanical roughening of the surface as possible.
don't ignore the automotive store, they have a lot of cyan0-acrylate based krazy-glues for ABS and urethane bumpers that are thickened, and may just do the trick. Model airplane guys are also glue experts.

Repairing a split golf club head shaft once, I mixed up a batch of WEst epoxy and wrapped a zillion strands of fibreglas around the break.....got the idea from Rutan's landing gear axle on the Catbird or Grizzly; to make the right angle attachment, just did the same on a grand scale!
 
Phil

Assuming that you have enough mass at the contact points, let me suggest a 1mm layer of premium clear silicone. Some two-sided tapes may work,
but due to higher cockpit temps in the summer, there may be some movement there.
Regards.
 
What about west systems 406 structural adhesive filler? I have lots left over - is it not as strong as i believe it to be?
 
Adhesive fro plastic

I had two parts to bond together on the inside of a battery operated dtill. They were very small and need to be held rigidly. I used ast curing JB Weld and it worked great. I had to put a little on the exterior of the joint but it is still holding up after a year.
Woodman
 
JB-Weld... now there's an interesting option. I've never used that stuff.
Based on my reading of their website material, it appears to be an epoxy, so in the same family as West Systems I guess. Maybe a better bet than the 406 with epoxy resin?
 
One of my favorites...

JB weld.

Sand the surface and then a thin layer of JB weld.

Kent
 
Can you contact the manufactures and see what they recommend???

At least see if you can get the kind of material, then go to various glue/adhesive companies and ask for something to bond the stuff.
 
Find out the types of plastic

and check out www.theengineerguy.com in Atlanta Ga. I just received my Weld-On 45 for my windows. I am not using 10 as it is too thin/messy. Best prices I could find and quick service.

You can also try your local auto body/paint store. I found several different high quality plastic adhesives by 3M and SEM but none were "structural". It sounds like you do not need structural adhesive like I did.

West Systems is really made for wood or fiberglass. It does not have great bond strength with plastics or aluminum. Tested that already. If you need to bond to aluminum it should be sanded, phosphoric acid etched, and a chromic acid conversion coating applied first like on our RV-10 top fwd fuse skin- winshield bond.
 
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Plastic GPS mounts are probably some type of ABS/PVC "alloy" blend. I think that's what the Airgizmos GPS docks are made out of.

I needed to glue up some cracks in the "Royalite" (ABS) plastic instrument panel overlays for my Cherokee, and used ABS plumbers' cement... a solvent-based glue that basically melts the ABS plastic back together chemically. That cement is black in color and it worked very well on my panel overlays. The black color didn't exactly match the panel overlays very well, but a rattle-can of satin-finish Krylon plastic paint solved that problem.
 
Sorry to disappoint the last post - West will almost glue air to water !!!

I have used West to glue wood, metal, glass, plastics of all types, composites etc etc.

The secret is scuff it up well, thoroughly degrease with panel wipe or thinners - add a little flox to give it body and let the epoxy do the rest.

My two best 'bodges' were on a polypropylene wheelbarrow that some horsey female had burned a hole in and my lawn tractor hood - again in a very difficult plastic.

Both were repaired 2 or 3 years ago with West, they have been left outside to sun and elements and still stick like **** to a blanket.......

My favourite trick with left over West is to thicken with a little flox and stick a penny to the sidewalk.

They usually last about a year before someone finally gets them off :D
 
A bit of research has revealed a type of product called "plastic weld" which appears to be a two-part epoxy like JB-Weld, but that also contains some ingredient to chemically etch the plastic. Any pireps here on that stuff?
 
West Systems G-Flex is made for some plastics

but it is still a mechanical bond and not a chemical bond. It really all depends on what kind of strength one is looking for.
 
Plastic GPS mounts are probably some type of ABS/PVC "alloy" blend
Click to expand...
Maybe i should try an ABS cement first. If this works, it would be a chemical bond, right? I would imagine, because of this, i would either get an incredibly strong bond or a very weak one and it would be easy to tell if it worked?
 
i photo of what you are working on would help.

my old stand by is marine tex. a 2 part boat product it hardens like steel. it can be drilled and tapped. in special cases were more strength is needed across a joint i embed some small brads or nails into the stuff to help the area. we never left port without it back in the days of boating. sounds like you need a jury rig. good luck.
 
prkaye said:
A bit of research has revealed a type of product called "plastic weld" which appears to be a two-part epoxy like JB-Weld, but that also contains some ingredient to chemically etch the plastic. Any pireps here on that stuff?
Click to expand...

Yes, I've used it on many plastic parts, including aircraft interior ABS parts and found it to work well.

It can usually be found in the Ace or Home Depot aviation aisles in a "double syringe" form....:)
 
I bought a small amount of 2-part "plastic weld" yesterday evening, but i think the stuff I bought had been sitting on the shelf too long because the second stage (the thicker stuff) was so thick it wouldn't come through the nozzle properly. It also didn't bond as instantly as advertised, so I pulled it apart and cleaned it off.

I then discovered a way that i should be able to rig up a metal strip as a sort of "clamp" and use screws/nuts with it to clamp the pieces together. I think I'm going to use my west systems with 406 and then do this clamping solution on top of that. This is all probably way overkill, but I just don't want my GPS falling off its mount in-flight.

Thanks for all the advice on here!
 
Most adhesives/cements/sealants should be stored

in a cool, dark place.

On a store shelf exposed to flourescent lights or sunlight is probably not the best place for some of those. Sometimes they have date codes that we can comprehend and other times only the mfr knows. I called around when checking on plastic adhesive for my windows. If they said,"We only have one in stock and don't sell too much of it" or "I have never heard of that" I called the someone else. If you find a heavy collection of dust on top of the package in the store then you know that they probably don't sell too many. Good luck with the bonding.
 
ca

Hi Phil, if you have a hobby lobby store around or a rc modeler hobby shop, go there, what you want is the "thick" ca glue. It will hold any plastic the best. CA stands for Cyanoacrylate. It is different then your run of the mill super glue as it is much more refined for the model airplane industry. Also while you are there look for some accelerant, this will keep you from having to hold or clamp parts for a period of time. I always have some thin, medium and thick ca around the shop, it is invaluble when comes to what you are looking to do. I have several large and small r/c aircraft that have been completely assembled with ca and are many years old and still as strong as the day they were built. Hope this helps you.

Bird
 
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