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I have a few cracks in a plastic '75 grill I am refinishing and wanted opinions on the best adhesive to repair them. Can I use a standard 2 part epoxy or do I need to use a special adhesive designed for plastics? I have no idea what sort of plastic material was used in '75 and would hate to melt the plastic or mess something up.

I appreciate the help!
 

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Most 70's GM plastic grilles that I've dealt with have been made from ABS plastic.

I've had good luck repairing cracks with ABS pipe cement from the local hardware store. This works best on clean breaks that fit tightly back together without any gaps or missing chunks.

I've also had good luck using Devcon Plastic Welder. It's an epoxy type adhesive with some added chemicals to help it adhere to most plastics. The epoxy base allows it to fill small gaps so this works good if there are small mising chunks (use maksing tape to form a mold). This also works good when replacing a missing piece using a section cut from a donor grille (it fills minor gaps if the fit-up between the two isn't perfect).
 

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The cracks are all clean breaks. Most you can't even see unless you bend the grill a bit. I'll give the ABS pipe cement a try. Thanks!
 

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I use superglue to hold the pieces in place, Abrade the area properly and use an epoxy to fill and give the appearance you want.
 

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The best glue to use for ABS (Acrylonitrile Butadyene Styrene) isn't really a glue at all.

Since ABS contains polystyrene, it is better to actually "weld" two pieces together than to glue them in the traditional definition of the term.

ABS is also sometimes referred to as "impact modified polystyrene" because of the butadyene rubber additive used which increases the impact strength of the resin. Polystyrene has a low chemical resistance and is easily dissolved with most solvents. The best way to join two ABS parts is to partially dissolve the plastic on the areas to be joined and then mechanically clamp the two together and let them cure.

ABS "glue" usually contains an aggresive solvent like MEK (Methyl Ethyl Ketone) that will easily break down the polystyrene and enable it to be fused with another piece. The solvent simply melts the existing plastic so it can be fused where a traditional "glue" actually bonds the two parts together with the glue as the only adhesive.

Here's a good link:

http://www.eplastics.com/ABS-Glue
 

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I use this product in all my custom styrene body builds in the R/C world. It is a solvent welding product and works well,in most cases, the body will crack long before the welded seems if preped properly.

[ame]http://www.amazon.com/IPS-Weld-On-Acrylic-Adhesive-Clear/dp/B000KZUTEM[/ame]

I have also used MEK and ABS cement, as stated earlier they all use a certain amount of the same chemicals. The Weld-on product is a clear liquid and flows well into the cracks with out leaving a black messy residue like ABS cement to clean and sand.
 

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I have a few cracks in a plastic '75 grill I am refinishing and wanted opinions on the best adhesive to repair them. Can I use a standard 2 part epoxy or do I need to use a special adhesive designed for plastics? I have no idea what sort of plastic material was used in '75 and would hate to melt the plastic or mess something up. I appreciate the help!
ABS Plastic. Use the Harbor Freight Plastic Welder. Works good. Jack

http://www.harborfreight.com/plastic-welding-kit-with-air-motor-and-temperature-adjustment-96712.html
 

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What kind/brand of epoxy?

There are some good, some not so.
I do not remember. It was most likely 3M 08115 or something in the Fusor or SEM line. I do not use consumer products like JB Weld.
My choice if I did one today would be
3M 08115 or Fusor 142/152 because I have them all.
 

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I do not remember. It was most likely 3M 08115 or something in the Fusor or SEM line. I do not use consumer products like JB Weld.
My choice if I did one today would be
3M 08115 or Fusor 142/152 because I have them all.
Yeah, I didn't think you would and neither would I. That's why I asked. ;)

Thanks for the info along with the part numbers. :thumbsup:
 

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I've done 30-40 of them.

http://www.lord.com/products-and-solutions/adhesives/automotive-repair-adhesives/product.xml/314

Plainly says ABS for 142, 152 is a slower open time version.

Multiple 3M reps have told me 08115 will work for any plastic(with proper prep)
Even Superglue will work for a while but there is no one "glue" that works best with all plastic resins. Some plastics bond better with adhesives and some work better with solvents. It depends on the molecular structure of the polymer and the physical properties (chemical resistance).

For the "stryrenics" such as GPS and ABS and acrylics, solvent based glues that partially dissolve the plastic and welds it together is the best way to go.

Solvent-based glues do not work well with polymers with high chemical resitance like HDPE, LDPE, P/P. For these polymers you want an actual epoxy or adhesive rather than a solvent.

Testors model glue is a solvent because model kits are made from polystyrene. It dissolves the plastic.

A solvent-based glue designed specifically for welding ABS is the best thing to use to repair a break or crack in an ABS grille.

Use an adhesive or epoxy to glue two dissimilar plastics together or to glue plastic to a different material such as steel.
 
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