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Internet # 308472914

Model # 50139

Store SKU # 1004067038

0.85 oz. PlasticBonder Black Adhesive Epoxy

  • Black drying 2-part body panel adhesive and gap filler
  • Sets in 15 minutes and cures in 30 minutes
  • No mess, no waste cap - no accidental mixing and it won't dry out
  • View More Details
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Product Details

About This Product

J-B Weld Plastic Bonder Black Syringe is a quick-setting, 2-part, urethane adhesive system that provides strong and lasting repairs and works on thermoset, carbon fiber composites, thermoplastics, coated metals, concrete and more. Plastic Bonder has a 1:1 mixing ratio, sets in 15 minutes and can be sanded after 30 minutes. With a tensile strength of 3770 PSI, Plastic Bonder sets to a black color and cures to a hard, permanent bond.


  • Black drying 2-part body panel adhesive and gap filler sets in 15 minutes and cures in 30 minutes
  • Great for filling gaps, plastic to metal and plastic to plastic bonding
  • Tensile strength of 3770 PSI for a strong, permanent bond
  • No mess, no waste cap screws on one way to eliminate accidental mixing and ensure it won't dry out
  • Dries Black
  • 1:1 mixing ratio
  • Can be sanded once cured
  • Hard, permanent bond
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Product Information

Internet # 308472914

Model # 50139

Store SKU # 1004067038

Additional Resources

Shop All J-B Weld
From the Manufacturer


Dimensions: H 8.63 in, W 4.38 in, D 1.25 in


Product Depth (in.)

1.25 in

Product Height (in.)

8.63 in

Product Size (oz.)


Product Width (in.)

4.38 in


Adhesion level


Curing time (hours)


Dry Color


Epoxy Accessory Type



No Additional Features


2 Part

Glue/Epoxy Type

Plastic Epoxy



Package Quantity


Product Form


Product Weight (oz.)

0.1 oz

Recommended Surfaces




Set Time (Min.)


Usage Location


Warranty / Certifications

Manufacturer Warranty


Questions & Answers

Q:I need to bond new bolt ears/tabs on a metal detector search coil. Both parts are plastic (unknown composition) and have about 1.5 x 2 in flat surfaces that mate together when glued. It will be used under water sometimes. Which product is best?
by|Jan 5, 2024
1 Answer
Answer This Question

A:  Plastic Bonder 50139

by|Jan 7, 2024
    Q:My Xmas tree stand has a very tiny leak along the bottom of the tank where it meets the flat base. Enameled metal. If I wipe, it stays dry for a few seconds. Can I use this product to seal along the bottom of the tank while there’s water in it?
    by|Dec 4, 2023
    1 Answer
    Answer This Question

    A:  Best to use engine repair black RTV silicone like our 32329 or any other found at auto parts stores for this

    by|Dec 4, 2023
      Q:Will this fill a misdrilled hole in a phenolic resin router insert plate and can it be drilled when cured? Thanks.
      by|Nov 11, 2023
      1 Answer
      Answer This Question

      A:  Yes. Be sure to let it cure a good 24 hours before drilling

      by|Nov 12, 2023
        Q:I broke a plastic bolt eye off my tractor side case. The plastic is black and about 3/8 thick. I stuck it back on and held it in place as I bolted in on and it stays in place. Does that sound like something this would work on?
        by|Nov 3, 2023
        1 Answer
        Answer This Question

        A:  It is the best choice we have for this. Be sure to clean well with acetone

        by|Dec 19, 2023
          1 found this answer helpful
          Showing 1-4 of 21

          Customer Reviews

          4.2 out of 5

          • 4.2 out of 56 reviews
          • 84% recommend this product
          Filter by:
          Showing 1-10 of 56 reviews
          Fiberglass headlight case
          Used JB Weld to repair a motorcycle black headlight case. Holding great!
          • Verified Purchase
          • Recommended
          So simple to use
          [This review was collected as part of a promotion.] I am very happy with this plastic bonder. It was so simple to use. After opening the cap and pushing out the desired amount I needed I just stirred the to portions together to activate the bonding. I was able to use it before it started to cure and after it was completely dry it sealed the crack that I repaired.
            I love this stuff!
            For the people saying it never hardens (gummy but sorta-set) or remains sticky (touching it leaves something on your skin), I have only found that to happen when the mix of the two components is not 50/50 enough. Mind how much of each you squeeze out, and be sure to mix it all thoroughly up. In my (pretty extensive...I've truly used this for YEARS now) experience, if it is 'flexibly-wobbly' or tacky forever, but not sticky or slimy, you have a bit too much 'black' in the mix. The 'sticky-or-slimy tacky' variant is when you have too much 'white'. Make note that the syringe plungers can easily 'stick' on one cylinder or the other, and that can lead you to have 'strange mixes'. If you notice a mix coming up an unexpected color, you CAN generally mix in more of the 'missing agent' to correct the mistake if done before the compound gets to cure too much to mix. Just mix in more of the stuff it's hopefully short of, and use as usual. The cure time will be 'odd', but not too much longer than normal if you correct it in time. If you get desperate to be able to have it 'set properly', make a much larger batch of it. Sticky cylinders are less likely to be an issue 'in the long run', and the unevenness evens out. Another option is to get those mixing-tube-nozzles, that does a pretty good job of things too. Squeeze out a 'dead portion' before using the mix from the tube, just to avoid the goopy-problem if you had the cylinders stick or 'warp' a bit. I use this "Plastic Bonder" stuff for a ton of different purposes. I've found it to be amazing for helping to bond the interior plastics in my 1996 Honda Civic. The stuff marked "PP" (assuming Polypropylene?) works great with it. It's not at all sticky or goopy when cured, if mixed correctly and in the proper "50/50" ratio of components. In my use in my Honda PP stuff, it dries solidly but 'sorta-flexibly'? I wouldn't want it to be expected to flex for a plastic joint, but it can flex a bit without breaking. When it does break, it's sorta like 'cement made of plastic' and it rip-deforms to separate along a weaker line of the material. It's really hard to just /stress/ apart, as long as you clean the surface and 'sand the area' a bit to rough the surface up. It grabs WAY better when done that way. Very take note of if you try to bind interior plastics that you have cleaned or waxed in the past...this may or may not manage to grab anyway if you rough the surface up, but the BEST bond is gotten by my making sure it is CLEAN plastic. I get some in the break-area itself, then generally overlay the break with some more plastic bonder. For broken 'usable plastic areas' (again, this is me heavily using it to fix up interior Civic door panels, supports, and structures inside the panels in this 26 year old car) I may add an on-lay of 'a bit of fiberglass cloth' or 'an emptied and cleaned tea bag' to reinforce things, and generally lay the bonder on thicker on the inside. Just put some down for the break and a bit extra, embed the material you want to use to spread the strain of future use, then promptly cover it with more of the same mix-batch. Try not to ever need to, but when I've HAD to add more after curing, I've used 80-120 grain sandpaper to super-rough-up the plastic bonder's surface. It's...alright? It doesn't seem to bond excellently that way, but it works well-enough if you're desperate. Try to avoid it. I'm (hopefully) attaching a photo of one of my Honda PP bonds. Don't mind the ugly bond...it was for my battery-cover under the hood, and it's only ugly because I was lazy and didn't bother to smooth it very well. I never thought anyone would ever need to see it, and now here I am, writing a review...
              • Recommended
              Best Plastic Glue ever - store tubes upright!
              Of all the "Plastic glues" I have tried this is the best. Be AWARE - your mixture MUST be 50/50 Resin (black) and Hardener (white) not 60/40. AIR Bubbles form in the syringe during storage - which leads to uneven dispensing of mixture (not 50-/50) to avoid this: STORE YOUR TUBE IN THE UPRIGHT POSITION SO AIR BUBBLES RISE TO THE TOP (end glue comes out). When you are dispensing - use your eyes to insure you are getting a 50/50 mix to avoid "not hard" cures. Also - rough up your plastic surface for best adhesion.
                • Recommended
                Excellent product for repairing broken plastic
                I've used the black JB Weld Plastic Bonder dozens of times to repair broken plastic pieces, both bonding the broken parts and rebuilding lost portions of plastic. It has never failed to meet my expectations of providing a tough bond and/or filler. It's solid enough that machining with a Dremel takes time and, as long as you are careful, gives excellent results. It's much stronger and harder than the original plastic being repaired.
                Response from jbweld TeamFeb 28, 2024
                Thanks for the kind words. The 50139 is a strong item indeed. jbweld
                  Strong but too slow to harden
                  I’ve used this plastic binder few times, the best way is to mix it well on hard piece of paper then wait about 3 minutes for reaction before applying on broken parts, then leave the parts about 30 minutes to dry hard before use
                    WARNING: DOES NOT DRY HARD
                    This expoxy needs this on the label: DOES NOT DRY HARD. It’s a completely different product than any other epoxy I’ve ever seen! Instead of drying hard, it dries into a gummy, foamy consistency. Sanding is extremely difficult and results are a mess. I’m left with 4 wheels that have weird foamy gummy stuff stuck to them. I’ll have to get a wheel repair place to completely sandblast the stuff off and repaint them at $200 per wheel so this $10 product cost me $800!!!
                    Response from jbweld TeamFeb 1, 2024
                    You got a bad item, and we can send you a fresh replacement by contacting us at jbweld.com. This is a urethane and can be removed with acetone. jbweld
                      product doesnt work
                      Having the same problem other people have had. Mixed the substance thoroughly and have allowed to cure for 24 hours and still mushy
                        Great glue. Worked perfectly on a cracked outside side auto mirror. Cures in 10-15 minutes.
                        • Verified Purchase
                        • Verified Purchase
                        Showing 1-10 of 56 reviews