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Discussion Starter #1
OK I have a broken mounting ear on one of my head lights. I have all the pieces. Has anyone glued or epoxied one back together and had success with it? I am thinking JB Weld but thought I would ask first.
 

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I have found that gorilla 2 part epoxy is strong stuff and is easy to find. I believe it is better than JB.
 

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Super Road Rocket Pilot
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PC7, never heard of it but looks like a good product. Beware, on their site it does mention that it does NOT adhere to many plastics but do not list the types it does not work on. Plastic can be a troublesome product to adhere to with many adhesives. I usually find that plastic welding is the best and longest lasting solution.

You need to use the same type of plastic you are working with and get a really hot small iron. I usually use an old soldering iron or a tool I bought at Harbor Freight. To insure that you are using the proper plastic I often take plastic from other areas of the item I am working on that are hidden and not very functional and use pieces of it to reinforce the area I am working on.

Permatex has a good product designed just for plastics -

And Gorilla 2 part epoxy mentions it is good for most plastics as well.

Any pics of how bad it is? Just one tab? If you don't have the tools to mess with it feel free to contact me. I can send some as loaners if you want to pay shipping.



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SSR Technical Resource - Good quick resource for SSR stuff
Electronic Repairs - Speedometer, brake, door latch, fuse box, stereo, etc
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My perspective is the same as that of Dragon2U. Plastic parts that see stresses, e.g, from loads applied from being torqued down by fasteners, are best repaired using plastic welding vice an adhesive. Specialty adhesives do work in limited applications and on certain plastics, but not all. There are adhesives that adhere to the base plastic but really function as a filler between broken parts and rely on their own strength to form the repair bond. Admittedly, plastic welding is a specialty and requires knowledge of the various types of plastics, different repair techniques and attention to heat ranges to accomplish effective repairs but can and does save damaged parts that would othewise be discarded.
 

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The SSR headlight housings are made of PPC (polypropylene copolymer) There are NO commercial adhesives that will provide a structural bond to this polymer! It is also very heat resistant with a melting point above 320 Deg F or higher depending on the formula. Automakers use this polymer for headlight housings because it is tough and heat resistant.

So, DO NOT try to heat weld it because it will just burn holes in the housing. No one makes a heat weld stick for this polymer and Polypropylene sticks will melt way before the base material and not bond to the PPC housing.

Some of the Epoxy Plastic Bonders available work well but not for a structural connection like you need on that tab.

Dickator has the right formula for the best possible bond on this material however, to make it even better you need to prime both surfaces with Permabond POP before applying the CA adhesive mixed with filler.
See the link for instructions. You can get the primer on Amazon and then use any Gel CA adhesive mixed with a structural filler. I have just sheared short fibers of fiberglass from some fiberglass cloth and mixed with the Gel CA adhesive. Don't use the liquid CA, its too runny. Apply the primer and adhesive without filler first to the broken surfaces as directed in the link and then reinforce with the CA Filler mixture. This will provide the best possible bond but still not as good as new. Let it cure a full day and be gentle reassembling it.

The accelerator can be used to but that crystallizes the CA too fast and actually weakens the tensile strength of the joint so be patient and let the CA cure normally or hit it with UV light to speed the cure.
Greg
 

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Super Road Rocket Pilot
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Will have to disagree, there are many commercial glues that will work well on PP and you provided one in your statement. Just like any glue, some will work better than others. As you mentioned CA will work fine, CA is a super glue, Cyanoacrylate, and I am pretty sure that is available in quite a few places commercially. To assist any glue, always a good idea to use some primer, even simple 3M tape sugestes the use of primer. The problem I have with Max 1 is that there is not much documentation for it other than it states if can glue anything to anything. Not a good statement since it is not entirely true. Loctite All-Plastic Super glue should work well too and it is an off the shelf system - https://www.homedepot.com/p/Loctite-Plastics-Bonding-System-2g-Super-Glue-681925/100371829

PP can be heated and welded just fine, soldering irons and plastic welders can be heat controlled. Soldering irons operate around the 600 degree area but can be adjusted up and down, plenty warm enough to work with the PP that needs 575 or so for proper welding.

Thanks for providing the info that the material is PP. Now eeryone knows what they are working with and I agree that the glues I mentioned in my previous post will NOT work well and I will go back and correct it so people are not confused. There are quite a few alternatives that should do fine. Just read the label and insure that whatever you use is compatible with a polypropylene.
 

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Discussion Starter #11
Ok follow up on what I have to deal with here. I got a pair of tail lights and one arrived broken and was wondering if it can be repaired with epoxy or not. If not, no biggie. I got one good one and one that was thrown in with the deal. So if it is beyond repair I am not out anything on it. The head light I got as a back up set and the one tab was broken in shipping. The tab broke in 3 pieces. While I was looking at the pieces and the head light, I am thinking I may be better off to make an aluminum bracket to slip into the hole under where the tab was and screw the aluminum bracket in place and use some silicone to help absorb of the shock load on it. After reading the reply on the type plastic and available glues out there the aluminum bracket maybe the better option. What are the thoughts of others?
In the last picture I drew a yellow line around where I think I could slip the aluminum bracket in and then the
571090
571091
571092
571093
red circles are where I think I could run screws through and thread into the aluminum bracket
 

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Super Road Rocket Pilot
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Dang, those parts are cracked pretty bad. I would try some industrial super glue as Dick and I pointed out for the rear light and other stuff but for the headlight I think an aluminum bracket would be a great DIY option if you have the room to get one in there. As you said, it is just a spare anyway, so no biggie how it is attached, as long as it stays put and nobody can see the boo boo.
 

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Will have to disagree, there are many commercial glues that will work well on PP and you provided one in your statement. Just like any glue, some will work better than others. As you mentioned CA will work fine, CA is a super glue, Cyanoacrylate, and I am pretty sure that is available in quite a few places commercially. To assist any glue, always a good idea to use some primer, even simple 3M tape sugestes the use of primer. The problem I have with Max 1 is that there is not much documentation for it other than it states if can glue anything to anything. Not a good statement since it is not entirely true. Loctite All-Plastic Super glue should work well too and it is an off the shelf system - https://www.homedepot.com/p/Loctite-Plastics-Bonding-System-2g-Super-Glue-681925/100371829

PP can be heated and welded just fine, soldering irons and plastic welders can be heat controlled. Soldering irons operate around the 600 degree area but can be adjusted up and down, plenty warm enough to work with the PP that needs 575 or so for proper welding.

Thanks for providing the info that the material is PP. Now eeryone knows what they are working with and I agree that the glues I mentioned in my previous post will NOT work well and I will go back and correct it so people are not confused. There are quite a few alternatives that should do fine. Just read the label and insure that whatever you use is compatible with a polypropylene.
Mike, don't let the name of the material distract you. It's Not PolyPropylene it is Polypropylene CoPolymer which is a whole different compound than PP and it will NOT heat Weld and definitely not with PP rod! It is a completely different copoymer. It is a copolymer of carbon dioxide and propylene oxide were as PP is polymerized Propylene. PPC main uses are in the food industry, fuel tanks, and many automotive applications.

The use of a primer and CA with a reinforcing overlay is about the only way to repair it to have any structural integrity.

I worked with BASF in LA who was one of the few manufacturers of this polymer in the US. (I'm not sure they even produce it there anymore) Our plant supplied the oxygen to the PO unit which was used for the manufacture of the PPC. Most of the PPC comes from Asia under dozens of brand names. I learned a lot about the chemistry of various copolymers working with these customers so we could properly provide added value to their processes.
Greg
 

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Ok follow up on what I have to deal with here. I got a pair of tail lights and one arrived broken and was wondering if it can be repaired with epoxy or not. If not, no biggie. I got one good one and one that was thrown in with the deal. So if it is beyond repair I am not out anything on it. The head light I got as a back up set and the one tab was broken in shipping. The tab broke in 3 pieces. While I was looking at the pieces and the head light, I am thinking I may be better off to make an aluminum bracket to slip into the hole under where the tab was and screw the aluminum bracket in place and use some silicone to help absorb of the shock load on it. After reading the reply on the type plastic and available glues out there the aluminum bracket maybe the better option. What are the thoughts of others?
In the last picture I drew a yellow line around where I think I could slip the aluminum bracket in and then the View attachment 571090 View attachment 571091 View attachment 571092 View attachment 571093 red circles are where I think I could run screws through and thread into the aluminum bracket
The taillight housings may be a different material than the headlights. I don't have a taillight to look at.
Look on the back of the housing and the brackets and see if you can find the material designation molded in like PPC, PPE, ABS, PC, TPR etc. All plastic parts by law have a designation on them for recycling. If you can ID the material I can tell you what adhesive or solvent will work or the best way to repair it.
Greg
 

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Discussion Starter #15
The tail light has on the back lens PMMA and housing ABS-PC. Both of the tail lights look like someone has glued the lens back on because it has a pretty messy black that looks like it is over a gray around the outer edge. They also look like the inside silver is not in the best of shape.
 

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Super Road Rocket Pilot
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Hmmmmm, you could take them apart, clean up the reflector and seal everything up again. Or maybe use them for a special lens conversion.

PMMA is just acrylic, plesiglass, etc, and easy to work wtih.
The ABS housing is pretty easy to work with and repair as well.
For both, I use "special" glue from the hobby store that works very well and "welds" it for a seamless look on clear plastic.
 

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Hmmmmm, you could take them apart, clean up the reflector and seal everything up again. Or maybe use them for a special lens conversion.

PMMA is just acrylic, plesiglass, etc, and easy to work wtih.
The ABS housing is pretty easy to work with and repair as well.
For both, I use "special" glue from the hobby store that works very well and "welds" it for a seamless look on clear plastic.
Agree Mike both are easy to repair. I use a ABS cement made for abs plumbing pipe. Can get it in most plumbing supply plaves and sometimes Lowes has it to. It's heavy base and adds some reinforcing too.
The acrylic lens can be glued easily but will look ugly.
Greg
 

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The SSR headlight housings are made of PPC (polypropylene copolymer) There are NO commercial adhesives that will provide a structural bond to this polymer! It is also very heat resistant with a melting point above 320 Deg F or higher depending on the formula. Automakers use this polymer for headlight housings because it is tough and heat resistant.

So, DO NOT try to heat weld it because it will just burn holes in the housing. No one makes a heat weld stick for this polymer and Polypropylene sticks will melt way before the base material and not bond to the PPC housing.

Some of the Epoxy Plastic Bonders available work well but not for a structural connection like you need on that tab.

Dickator has the right formula for the best possible bond on this material however, to make it even better you need to prime both surfaces with Permabond POP before applying the CA adhesive mixed with filler.
See the link for instructions. You can get the primer on Amazon and then use any Gel CA adhesive mixed with a structural filler. I have just sheared short fibers of fiberglass from some fiberglass cloth and mixed with the Gel CA adhesive. Don't use the liquid CA, its too runny. Apply the primer and adhesive without filler first to the broken surfaces as directed in the link and then reinforce with the CA Filler mixture. This will provide the best possible bond but still not as good as new. Let it cure a full day and be gentle reassembling it.

The accelerator can be used to but that crystallizes the CA too fast and actually weakens the tensile strength of the joint so be patient and let the CA cure normally or hit it with UV light to speed the cure.
Greg
Correcting my post, PPC is Polypropylene Carbonate. Polypropylene copolymer is a form of PP.
been a while since I dealt with this and they are easily confused and so am I.
Anyway they are totally different materials. PPC is not weldable but the PP copolymer and PP homomonomer are.
Greg
 

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Discussion Starter #19
I decided to mess with the better of the two tail lights and I think they came off a flood truck, because there is a line inside the lens. The silver inside is almost all gone as well. The outer housing is very fragile and the edge broke in a couple of spots. I think I can glue it all back together and make it look better than it was and make it usable when I am done.
 

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I decided to mess with the better of the two tail lights and I think they came off a flood truck, because there is a line inside the lens. The silver inside is almost all gone as well. The outer housing is very fragile and the edge broke in a couple of spots. I think I can glue it all back together and make it look better than it was and make it usable when I am done.
The best way to repair a broken or cracked tail lens if no pieces are missing, is to clean it up real good, hold the crack(s) together as tight as you can and using a fine long pointed brush dipped in acetone, let the acetone flow into the crack just enough to coat the broken surfaces. Wait about 10 min and repeat as needed to seal the crack. The acetone will Weld the acrylic edges together. Wait a day and sand the area with 1000 grit wet paper then polish with plastic polish.
 
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