Plastic welding

[Wayne Orwig]

The seat catch under the EV seat got damaged this summer. The glues that I tried, aren't good enough. And I'm not sure what kind of plastic it is.
Would one of those plastic welders be a good idea? I've never even seen one used so I have no idea how good they are.

[Huzo]

The seat catch under the EV seat got damaged this summer. The glues that I tried, aren't good enough. And I'm not sure what kind of plastic it is.
Would one of those plastic welders be a good idea? I've never even seen one used so I have no idea how good they are.

I did some alterations to my left pannier on the Norge to clear the high muffler Wayne and had some plastic welding done and it's been perfect for 8 years.

[80CX100]

     I had a crack in one of the lower leg shields on my CalVin,plastic welded by a local guy recommended to me by Geoff From Almonte, for $75? Canadian (1/3-1/4 cost of replacement up here). The shields are described as ABS plastic,,, and "ABS" was actually cast/stamped in one corner of the shield. The welder laid a couple of beads on the back for extra strength, and one single bead on front,,,, I haven't filed/ground the beads down yet and tried to hide the repair,,, but the weld seems strong with decent penetration.

    good luck with it

    Kelly

[Sasquatch Jim]

Plastic welds work best if you have a sample of the exact same plastic to fill with.
 And no flame is used.  A plastic welder uses a hot air stream.

[redrider]

I repaired side cover tabs with super glue and baking soda. Sprinkle the soda on the wet glue on both pieces, then press together. It may break again but not at the repaired spot.

[Wayne Orwig]

I repaired side cover tabs with super glue and baking soda. Sprinkle the soda on the wet glue on both pieces, then press together. It may break again but not at the repaired spot.

Yes, I have repaired side covers with fiberglass, or super glue, and such with good results. I believe they are ABS.
The EV seat pan appears to be nylon, or something similar. It is not touched by solvents like acetone, and glue does not stick. Thus the reason to think I may need to get it welded. But I need to identify the material first somehow.
 

[Rich A]

But I need to identify the material first I somehow.

This should help.

http://boedeker.com/burntest.htm

If it is ABS, I think car repair shops that weld bumpers should be able to help. OTOH, the welders are useful to have around and they're not difficult to use.

Rich A

[Antietam Classic Cycle]

I needed to fill a bunch of holes in the airbox of my ATK 604 (US built dual-sport motorcycle) a few years ago. I bought an "airless plastic welder kit" from Urethane Supply. Sort of just a big electric soldering iron with special "Fiberflex" filler rods and stainless steel mesh to reinforce the repair area. IIRC, it works on both polyethylene and polypropylene plastics. 








Worked very well, easy to use.

Wayne, If you'd like to try it, I'll box it up and send it to you.

[donn]

According to my very superficial understanding, thermoplastic resins can commonly be welded;  thermoset cannot.  But someone who does a lot of welding work might also know how to make a strong adhesive bond on a thermoset type.

[Arizona Wayne]

What about that stuff I've seen on TV that welds/glues plastic glasses frames  together where you squeeze the glue out on the break and then hit it with ultralight for a few seconds and it's solid again ?  It can be used on extension cords, etc. to patch too. $16 for a little bit but can be had in bigger amounts too.

[pressureangle]

No contest. I've never used this on anything it failed to fix. Hard enough to drill new screw holes in mounting posts, etc. Not cheap but second to nothing, unless you have a polyethylene fuel tank in which case you'd use the hot air/filler method pointed out above.

http://www.shopwurthusa.com/wurthstorefront/Chemical-Product/Plastic-Repair/Cosmetic/Replast-Plastic-Repair-7-Oz-Cartridge/p/0893301917

[leroysch]

MCN had favorably reviewed this stuff which I had saved to my amazon wish list. In fact, about to buy some to fix a busted fairing tab on the 916.

https://smile.amazon.com/gp/product/B00CP6FLO2/ref=ox_sc_act_title_1?ie=UTF8&psc=1&smid=A2W7NLC0KWN8S4

[shaggy]

Many times when repairing plastic,glue doesnt seem to hold, so i will glue the parts together and after the cure, i will heat a piece of coat hanger or what ever you have and press the wire 90 degrees to the break.You can add a u shape to the wire also to tie it together if you will.

[lost]

Plastic welding should give good results. If trying to use a solvent you need to match the solvent to the plastic. Somewhere I have a cheat sheet but cannot find it right now. Each type of plastic has a specific smell when heated. If you know the smells you can guess the material.

[lost]

So to glue ABS together use MEK, to glue Nylon use Carbolic acid.

[Wayne Orwig]

I think I have it.
I was thinking I had to have a hot AIR plastic welder. But I remembered, that long ago I got an old school soldering gun, which included a tip for melting plastic.
I had my daughter retrieve that from downstairs for me.
So I put on that broad tip, then started to look for a nylon type plastic to match. Then noticed two wire ties in the box, with the soldering gun. Perfect.

So I just sat here one armed, in my wheelchair, and spent a while slowly melting the nylon wire ties into the broken seat pan plastic. Looks like it will do the job.

BTW: earlier this year, when it got broken, I had used JB Weld. And yes, I had taken a small grinding wheel to the plastic to rough it up. But even JB Weld doesn't like to stick to nylon. Or at least I THINK it is nylon.

So I'll it will take a while before I know if this is a good fix, but it looks good.

I need things to keep me busy right now. Now to finish my WiFi battery monitor to keep a remote eye on things.

[Luap McKeever]

I have had a lot of good luck with hot glue guns, coupled with the new "gorilla" heavy duty glue sticks.  Maybe a cheap try. You can get the gun and a pack of sticks for around $15 from wally world.  If they don't work, it's still good to have them around.  I love them.

[Chuck in Indiana]

I need things to keep me busy right now.

Absolutely. When your world is falling apart the best thing you can do is "normal" things.

[PeteS]

If this was ABS there are many solvent glues that will bond it. I use Tenax 7R available from many hobby shops on small jobs. For larger jobs straight methylene choride works.
I would guess this plastic is delrin. Similar to nylon but stronger and more stable but just as resistant to solvents. Again on small items the soldering iron trick can work but the joint will not be strong as new.
A plastic welder is probably your best bet assuming you can't just replace the part with new.

Pete

[Wayne Orwig]

If this was ABS there are many solvent glues that will bond it. I use Tenax 7R available from many hobby shops on small jobs. For larger jobs straight methylene choride works.
I would guess this plastic is delrin. Similar to nylon but stronger and more stable but just as resistant to solvents. Again on small items the soldering iron trick can work but the joint will not be strong as new.
A plastic welder is probably your best bet assuming you can't just replace the part with new.

None of my normal solvents touched it. It is slick, like nylon or delrin.
The soldering gun I used has a broad flat tip just for this type of job. But you have to manually trigger it constantly to control the temperature. I think I got the melted 'wire tie' to penetrate well. Time will tell.

[Madtownguzzi]

I have used ABS cement with luck before.
http://www.homedepot.com/p/Oatey-4-oz-ABS-Cement-309993/100136815

[Chuck in Indiana]

None of my normal solvents touched it. It is slick, like nylon or delrin.
The soldering gun I used has a broad flat tip just for this type of job. But you have to manually trigger it constantly to control the temperature. I think I got the melted 'wire tie' to penetrate well. Time will tell.

If it's nylon or delrin.. forget about sticking an adhesive to it. Yeah, it'll "sorta" stick.

[Ncdan]

Yes, I have repaired side covers with fiberglass, or super glue, and such with good results. I believe they are ABS.
The EV seat pan appears to be nylon, or something similar. It is not touched by solvents like acetone, and glue does not stick. Thus the reason to think I may need to get it welded. But I need to identify the material first somehow.

Wayne, I have done a considerable amount of plastic welding with very good results. I use a small butane torch for the heat source. This allows you to concentrate the heat to only the area you wish to repair. It's just like metal welding, you simply have to be sure all materials involved are in a molten state. The second rule is, you MUST BE SURE THE WELDIND ROD IS THE SAME MATERIAL AS WHAT YOU ARE REPAIRING!  Practice a little on something you don't mind failing on a little and when you get the procedure down pat, get her done. Good luck with your project

Dan

[Chuck in Indiana]

^^^^^ good advice there.

[averb]

The seat base on my Breva is Polypropelene. Which makes sense as it is tough and cheap as chips and there is no tolerance issues with a seat base. Like Nylon ( and delrin, aka acetal or POM, which is more expensive) it it a low surface energy plastic and will not work well with adhesives. If you have already welded with Nylon filler I guess you will find out if a PP/PA alloy will work - regardless it will be better than any adhesive.
Fingers crossed
Steve

[lost]

If this was ABS there are many solvent glues that will bond it. I use Tenax 7R available from many hobby shops on small jobs. For larger jobs straight methylene choride works.
I would guess this plastic is delrin. Similar to nylon but stronger and more stable but just as resistant to solvents. Again on small items the soldering iron trick can work but the joint will not be strong as new.
A plastic welder is probably your best bet assuming you can't just replace the part with new.

Pete

If the material is Delrin and you heat it over 420 degrees you will have no doubts as to whether it is Delrin or not. This material when over heated will cause your eyes to burn and your lungs will not be happy.

[donn]

The seat base on my Breva is Polypropelene.

Cool. Polypropylene is apparently a weldable thermoplastic, which is good because there's no hope with solvents.  How did you find out it's polypropylene?  Is there a way to tell, like the smoke test someone mentioned above?

[Chuck in Indiana]

If the material is Delrin and you heat it over 420 degrees you will have no doubts as to whether it is Delrin or not. This material when over heated will cause your eyes to burn and your lungs will not be happy.

Yep, it creates  formaldehyde..not a particularly good thing to be breathing.. 

[gearman]

Yes, I have repaired side covers with fiberglass, or super glue, and such with good results. I believe they are ABS.
The EV seat pan appears to be nylon, or something similar. It is not touched by solvents like acetone, and glue does not stick. Thus the reason to think I may need to get it welded. But I need to identify the material first somehow.

I have glued a ton of abs with mek.Evaporates slower so you have more time to dissolve the plastic.Slippery plastics cannot be glued. The solvent has to dissolve the plastic. think uhmw.Some plastic is a mix of abs and a slippery plastic that does not glue well.I glued a whole pacific coast together and you could not see the repairs. Took two weeks. I have a plastic welder blower gun  and never got good results on bumpers .Most plastic panels have a recycling code on them in a triangle outline.

[averb]

Cool. Polypropylene is apparently a weldable thermoplastic, which is good because there's no hope with solvents.  How did you find out it's polypropylene?  Is there a way to tell, like the smoke test someone mentioned above?

There is "PP" moulded into a non-visible surface. You will find this on most plastic parts moulded by a European company. If it was Nylon (like the Breva tank) it has PA, Delrin would have POM, ABS would have ABS etc etc.
I believe all thermoplastics can be welded unless there are fillers that would burn or degrade.
Nylon, Delrin, Polypropelene and Polyethelene are all low surface energy plastics and are crap with all adhesives unless you have a good primer or flame the surface or some other tricky stuff and have a large surface area to adhere.
No there are no solvents for these polymers.
Steve