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Weld-On 4 Acrylic Adhesive - 4 Oz and Weld-On Applicator Bottle with Needle

4.5 out of 5 stars 196 customer reviews
| 31 answered questions

Price: $15.21 & FREE Shipping on orders over $49. Details
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Specifications for this item
Brand Name Weldon
Import Designation Made in USA
Material Type Acrylic Adhesive
UNSPSC Code 30111601

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Frequently Bought Together

  • Weld-On 4 Acrylic Adhesive - 4 Oz and Weld-On Applicator Bottle with Needle
  • +
  • SCIGRIP 16 10315 Acrylic Cement, Low-VOC, Medium bodied, 5 Ounce Tube, Clear
  • +
  • Applicator Bottle with Stainless Steel Needle - 3 Pack
Total price: $31.20
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Product Features

  • Applicator Bottle with Needle Optional

Product Description

Moderately Fast-Setting Solvent Cement for Bonding Acrylic. WELD-ON 4 is a water-thin, somewhat flammable cement formulated to quickly develop very clear and high strength bonds for many thermoplastic substrates. The bond is achieved by first softening the surfaces to be joined and then fusing them together with the dissipation of the solvent. The initial bond forms within a matter of minutes and is followed by a significant and continual increase in bond strength over the next several hours. WELD-ON 4 may be preferred by some plastic fabricators because it is less likely to leave white marks (commonly called blushing). For similar applications but faster setting cement, WELD-ON 3 is recommended. Weld-On 4 Acrylic Adhesive water thin, somewhat flammable, moderately fast-setting, blush-resistant solvent cement for bonding acrylic. It will also bond with other thermoplastics such as polystyrene, CAB (cellulose acetate butyrate), and polycarbonate to themselves. Does not bond to cross-linked acrylics. SUBSTRATE RECOMMENDATIONS : WELD-ON 4 is formulated as a blush-resistant cement for bonding acrylic (poly-methyl methacrylate) to itself. It will also form strong bonds with other thermoplastics such as polystyrene, CAB (cellulose acetate butyrate), and polycarbonate to themselves. It is not recommended for cross-linked acrylic. SUGGESTED BONDING APPLICATIONS: WELD-ON 4 is used extensively in sign fabrication for cementing acrylic letters to fat acrylic presentation panels and trim-capping of cut out acrylic letters. Strong butt joints are made with fat sheets by using the soak method. WELD-ON 4 is also widely used in many applications e.g. fabrication of display and presentation cases, medical equipment assembly, the bonding of plastic containers and pre-forms, and in the manufacture of numerous solvent welded structures and subassemblies using the capillary method. Color: Clear Contents of

Product Details

  • Shipping Weight: 6.4 ounces (View shipping rates and policies)
  • ASIN: B0096TWKCW
  • Average Customer Review: 4.5 out of 5 stars  See all reviews (196 customer reviews)
  • Amazon Best Sellers Rank: #1,571 in Industrial & Scientific (See Top 100 in Industrial & Scientific)
  • Product Warranty: For warranty information about this product, please click here

Customer Questions & Answers

Customer Reviews

Top Customer Reviews

By B. Johnson on January 31, 2014
Verified Purchase
I bought this for my first attempt at acrylic welding. I had a little difficultly getting the hang of using the plastic bottle, applied too much and made a total mess of the parts. I didn't know I was doing it at the time though, I thought I was doing it right. I recommend using several test pieces to get the hang of it first. My next attempt turned out much better. Not perfect, but unless you give it a close inspection you'd never know. Incredibly strong, the "weld" actually liquifies the acrylic at the joint so that when it hardens there's no seam. It becomes one piece as if it was molded that way. Note that the smoother you can get the cut edge, the stronger your joint will be. I cut my pieces on a table saw then used my router to smooth the edges.
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I use a Replicator 2 which uses PLA instead of ABS plastic. The Weld-On 4 works perfectly on it and acts as a solvent for the PLA so the bond that forms is the dissolved plastic bonding back together again.

Weld-On 4 has the consistency of ether, like car starting fluid, as it will evaporate instantly where its not on a part. So use it in a well ventilated area.
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I used this to add a chamber to my 40 gallon acrylic sump to make a 20 gallon refugium in the larger part of it. It dries ultra clear if you get the sides of the polycarb or lexan ultra smooth and straight. you need to watch carefully and add it slow and even when you inject it into the seam, only use enough till you see the entire seam turn a "wet look of clear". There are many you tube videos on this "how to build a acrylic tank".
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Have used this in the past for my acrylic displays cases. Drys quickly with maximum adhesion. Highly recommended if you are working with acrylics. Great service from vendor I had it before the scheduled delivery time.
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Fixed the flybridge windscreen on the boat that snapped in two.
The only thing I think everyone needs to know:
The liquid is very thin, and runs out of the needle VERY quickly. I would practice on a piece of wood or some other material to get the flow out of the needle under control, then do the actual weld.
Remember, you are not gluing, you are welding, so do not, repeat, do not sandpaper or any other abrasive on the surfaces to be welded, that will reduce the strength of the welded bond. Look online for videos, there are several.
Also, when removing the inner lid on the can, go slowly and carefully, don't dent the top of the can, the screw-on lid will then leak. The needles can be re-used. Store them in an old prescription bottle, nobody gets stuck.
Overall, very happy with the result. But practice first. I will next time.
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Works good... maybe too good :)
I see some say practice first, I did not practice and regretted it later. Practice first and this stuff works great. Bonds or molds it back together. Very thin and comes out fast if you do not practice and you do not want this stuff anywhere but the surfaces you want to put together.
It melts and bonds chemically. So if extra gets on surface it will distort it. I used it on plexiglass and got some on the surface. Bonded great and melted the surface due to my spill/excess application.
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I have never welded acrylic before but used this to create a water tight box that holds about 4 gallons. Read up on how to use it first and first practice on some scrap if you haven't done it before. My box has held water for over a month without a leak so I think this did its job :)
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Worked just as described. Took a little practice on some scrap pieces to become proficient, but worked great just as intended
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