Repairing Plastics

[cruteg8]

I was thinking about trying to repair some cracks in the plastics of a Lakota Sport i just purchased has anyone ever tried (U.S. Chemical & Plastics USC GarageTM Flexible Glaze USC-77704 it) https://www.ebay.com/itm/364866165725. i was thinking jb weld for plastic then using this as a bondo that can be sanded smooth 

[Gwbarm]

I havent used that or JB weld on platics i have used clear epoxy and added a little color to it to try and match the original color. If the plastics are severly cracked, Harbour Freight sells a platic welder with wire clips that melts in to the plastics to hold it together good and then you can go over it with some epoxy to finish it off and sand it smooth works very well to hold the platic together.Just looking at the Flexible Glaze it might be better to finish up with than epoxxy its polyester based and would be easier sanding. My expierience with epoxy alone if you hit anything ridgid it will pop loose that where the platic welder shines, wire is actually melted into the plastic to give a more ridgid repair. 

[cruteg8]

thanks for the info will have to give that plastic welder a try 

[Mrdoodle]

I have the harbor freight plastic melting soldering iron looking thing. Ugly as all get out. I bought some used plastics off a website and cut them up trying to color match.  The soldering iron likes to put nasty black flakes in the pretty yellow plastic. So I went and got the heat gun looking one. Tried with it too. I just cant get the plastic to flow like metal. I haven't been happy with either's looks. I get decent adhesion with the soldering iron style. So I just did my best. Ugly but functional.

[Gwbarm]

Agreed the platic welder doesnt do the prettiest repair. I usually do it from underneath just to hold the pieces together then on top you just have a crack to deal with . I have even used hot glue to fill the crack, but generally use epoxy to fill the crack them sand it smooth, it generally works very well.

[cruteg8]

ok seems like epoxy is the way to go thanks for the input 

 

[Martin82]

Thanks for good idea with the plastic .

[ski522]

Thanks for the idea as well. 

[smipha]

In the past my grandpa used to stitch them with metal wire and then heat them up with a heat gun. Not the best looking but worked great.

[DexKing]

I just did some repairs to the plastics on my Honda Recon with a plastic welding kit from amazon and some stainless steel mesh. Like other mentioned above, looks terrible when you're done, but if you do the underside, the cracks leave a story from the battles your machine has endured over the years. 

[Callaway]

easy way to repair plastics is from behind.  Get a good two part epoxy and a an old rag.  Cut a strip of the rag so that it is 1" bigger than each side of the crack, like a band aid.  Put your two part epoxy on each side of the crack, lay the piece of rag into the epoxy then epoxy over the rag.  When it dries it will be super strong and you wont see the rag because it is on the under side of the plastics.  

[toe420]

Any tips on using the plastic welders? Im super curious about them

[Gwbarm]

Use it underneath the crack push the crack together and use tape to hold it in place while doing the repair use the tool until it melts into the plastic dont go too far or it will burn through use several of the patches along the crack then cut off the extra metal hanging down now remove the tape not perfect but will hold it in place and keep it from getting worse. II have also used epoxy to fill in the top side where the crack is still visible use paint to color the epoxy to close to the finish color never matches perfectly but you can get it very close with trial and error.

[jen]

HMMM?  I am still working on fender crack   Idid not buy  the plastic welder yet.   I was trying to glue.

[Gwbarm]

Glue will work for a while but will eventually break back loose from all the flexing of the plastic.

[jen]

front fender crack. Crack is Right at mounting bracket.  Mine is small is small.

[Gwbarm]

If its really small and not completely cracked all the way to the edge glue might work oK i have even glued a larger washer on to help support and seal the crack and give it more support.

[jen]

well mine is cracked to the edge but only halfway across fender.  Ifloows along right up against the fender support bracket.

[LCP92]

I use a cheap plastic welder purchased on the jungle website.  I usually use the wavy looking staples and melt them in on the bottom side.  Be careful not to sink them too deep where they are noticeable on top.  They make a good strong repair.

[jen]

My sand rail VW motor air housing had some metal fatigue and multiple holes where the Ignition coil was mounted . Others had remounted creating several holes/

I recently installed an Alternator and removed air housing.  I  used an epoxy patch kit to cover and reinforce the area where coil was mounted.  THe kit worked great. Just exposed the fabric patch to  sunlight to cause curing.  After 24 hours I was able to trim /sand and paint. You can see the fiber glass patch cloth in picture before I painted.  It was very ridged when i pushed on it and did not flex.

[jen]

Oh yes here is patch label....sorry

[Gwbarm]

Nice patchwork and kit, i have only used the real messy stuff polyester resin and fiberglass cloth, 

[jen]

I have had that kit in my 'Stash' for a year or so.  Just keep it out of sunlight.  each patch is maybe an 1/8 in + thick. I sanded area until it  was bare.

[jen]

since it is epoxy one could use fiber glass resin with filler (sold at West Marine) to feather in the edges if needed. BTW I have an epoxy Paddle Board that is slick and faster than my other non epoxy (glass)  boards.  

BUT  i keep the glass board covered in a sleeve when up on the shore or transporting as the sunlight degrades it.