Plastic repair Q...

Posted By: Anonymous

Plastic repair Q... - 02/22/09 05:11 PM

Okayyy I know the deal with taking acetone and plastic shavings to make repair media for grills and tail lights but...

What can you do if theres no spare item to get shavings from?

My situation is my 72's rear tail light, a buddy of mine whacked it with the soap brush at the car wash and cracked it up in the corner.

Now seeing as I only have those two tail lights in the car and nothing for donor material, can I grab something similar at the junk yard or is the composition different?

Posted By: ScottSmith_Harms

Re: Plastic repair Q... - 02/22/09 05:13 PM

Anything made of ABS will work. You can buy sheets of it at Home Depot,Hobby shops, etc. Most other makes from the same vintage used ABS as well, so you can cut up a Ford Granada Grill and use it if you want. Quick test for the right stuff at a junk yard, burn a small piece, ABS should make a deep orange flame, light on fire as opposed to self extinguishing, and make allot of thick black smoke.

Posted By: Anonymous

Re: Plastic repair Q... - 02/22/09 05:29 PM

Quote:

Quick test for the right stuff at a junk yard, burn a small piece, ABS should make a deep orange flame, light on fire as opposed to self extinguishing, and make allot of thick black smoke.

Hahaha... how in samhell did you come up with that idea???

Thanks for the invaluable info!

Posted By: Darius

Re: Plastic repair Q... - 02/22/09 09:01 PM

If you KNOW the piece you want to repair is truly ABS, you can simply go to Home Depot, Lowes, etc. and buy some ABS glue in the plumbing dept. It is the BLACK (as opposed to purple or clear type)type used to fuse ABS drain and waste plumbing pipe at the joints by plumbers. It WILL fuse ABS back together.

Posted By: ScottSmith_Harms

Re: Plastic repair Q... - 02/22/09 09:03 PM

Quote:

Hahaha... how in samhell did you come up with that idea???

Well, spending 20 years in the plastics injection molding and thermoforming industry doesn't hurt

Posted By: Anonymous

Re: Plastic repair Q... - 02/22/09 09:38 PM

Quote:

If you KNOW the piece you want to repair is truly ABS, you can simply go to Home Depot, Lowes, etc. and buy some ABS glue in the plumbing dept. It is the BLACK (as opposed to purple or clear type)type used to fuse ABS drain and waste plumbing pipe at the joints by plumbers. It WILL fuse ABS back together.

Have you tried this method?

Is it sandable? paintable?

My repair will definitely be "seen."
Whatever method used will have to be able to clean up as if it was never there, ya kno?

Posted By: ScottSmith_Harms

Re: Plastic repair Q... - 02/22/09 10:04 PM

The ABS glue is basically a solvent that melts the plastic allowing the two melted areas to join when held together under pressure (like pipe fittings, etc.) I don't reccomend it for repairing cracks.

Posted By: mopartial

Re: Plastic repair Q... - 02/22/09 10:37 PM

Please tell more about the acetone method...Makes your own gap-filling glue?

Posted By: 1_WILD_RT

Re: Plastic repair Q... - 02/22/09 10:42 PM

Quote:

Please tell more about the acetone method...Makes your own gap-filling glue?

As posted By Scott Harms Smith quite some time ago..

Start with 100% pure Acetone, buy a gallon.
Pour an ounce or so into a glass jar (small open mouth jar). Take a scrap grill and using something sharp, scrape off peelings (like pencil shavings size) into the jar of acetone. Put allot of shavings in, the acetone will gradually melt the plastic into a goo. Add enough plastic until the goo reaches toothpaste consistency. Once you have a good batch melted put the lid on the jar tightly and set it aside. Now, prep your grill as normal, V out cracks on both sides, etc. Use clamps near the joint to align the two sides flush and parallel. Smear on some plastic goo, leave it crowned up over the crack like a regular weld looks, let it cure overnight. Sand to flush the next day, fill any pinholes with JB Weld. The crack will practically disappear at this point, paint as normal

Posted By: ScottSmith_Harms

Re: Plastic repair Q... - 02/22/09 10:45 PM

Thanks Wild RT, here's a more recent posting with a few more details.

Quote:

This is not how I repair grilles but it's a good DIY method I've used.

Start with 100% pure Acetone, buy a gallon. MEK will work as well but IMO Acetone works fine and is safer to handle, either way wear gloves, either chemical can cause cancer and is easily absorbed through your skin.

Pour an ounce or so into a glass jar (small open mouth jar). Take a scrap grill and using something sharp, scrape off peelings (like pencil shavings size) into the jar of acetone. Put allot of shavings in, the acetone will gradually melt the plastic into a goo. Add enough plastic until the goo reaches toothpaste consistency. Once you have a good batch melted put the lid on the jar tightly and set it aside. Now, prep your grill as normal, V out cracks on both sides, etc. Use clamps near the joint to align the two sides flush and parallel. Smear on some plastic goo, leave it crowned up over the crack like a regular weld looks, let it cure overnight or longer until completely dry and hard. For the strongest welds do not sand the backside or in hidden areas, the added plastic makes the repair much stronger. Sand visible surfaces to flush the next day, or wait a couple days, as before just be sure the material has hardedend completely. Fill any pinholes with Bondo or JB Weld. The crack will practically disappear at this point, paint as normal.

You'll likely find that labor and experience are your biggest "expenses" and that the amount of time you invest will show in the results.

Posted By: mopartial

Re: Plastic repair Q... - 02/22/09 10:52 PM

Nice, thanks.

As far as original post: there is a special epoxy for plastic.(Lowes) Normal epoxy/JB weld will not bond.

What about plastic model glue, you know, the sniffing kind?

Posted By: Devil

Re: Plastic repair Q... - 02/22/09 11:03 PM

I've used PC-7 to make stuff for my 71 Challenger grille, worked great.

Ryan

Posted By: Pool Fixer

Re: Plastic repair Q... - 02/23/09 12:13 AM

3m 8115 panel bonding adhesive works too. it's @40 bucks though. I used to make major repairs to my 68 charger grill and it worked very well. sands well too.

Posted By: Anonymous

Re: Plastic repair Q... - 02/26/09 05:47 PM

Quote:

Anything made of ABS will work. You can buy sheets of it at Home Depot,Hobby shops, etc. Most other makes from the same vintage used ABS as well, so you can cut up a Ford Granada Grill and use it if you want. Quick test for the right stuff at a junk yard, burn a small piece, ABS should make a deep orange flame, light on fire as opposed to self extinguishing, and make allot of thick black smoke.

Scott, I don't want to set my taillight on fire, can you tell me what the red plastic material is (don't think it's abs) and if it will work with the method you mentioned?

Posted By: ScottSmith_Harms

Re: Plastic repair Q... - 02/26/09 06:20 PM

Most lenses are acrylic based (high temperature resistant to keep the bulbs from melting them). You will need to use Acrylic plastic welding rod to attempt repairs, any industrial supply should carry it, about the dia of a cocktail straw available in a variety of lengths, apply with a soldering iron if you don't have a plastic welder.

Posted By: ChickMaggot

Re: Plastic repair Q... - 02/27/09 07:26 AM

Quote:

I've used PC-7 to make stuff for my 71 Challenger grille, worked great.

Ryan

Where can you get PC-7?

Posted By: HEMICUDA

Re: Plastic repair Q... - 02/27/09 09:19 AM

Quote:

Quote:

Anything made of ABS will work. You can buy sheets of it at Home Depot,Hobby shops, etc. Most other makes from the same vintage used ABS as well, so you can cut up a Ford Granada Grill and use it if you want. Quick test for the right stuff at a junk yard, burn a small piece, ABS should make a deep orange flame, light on fire as opposed to self extinguishing, and make allot of thick black smoke.

Scott, I don't want to set my taillight on fire, can you tell me what the red plastic material is (don't think it's abs) and if it will work with the method you mentioned?

Or, you could get a pair of brand new "acrylic" lenses.

Attached picture 5056718-133-72.gif

Posted By: moparclown

Re: Plastic repair Q... - 02/27/09 09:29 AM

I have used a product by devcon called plastic welder,it's a two part in a a syringe style dispenser.

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Posted By: moparclown

Re: Plastic repair Q... - 02/27/09 09:30 AM

new piece attached

Attached picture 5056720-000_0977.jpg

Posted By: moparclown

Re: Plastic repair Q... - 02/27/09 09:32 AM

1 more

Posted By: Devil

Re: Plastic repair Q... - 02/27/09 03:47 PM

Quote:

Quote:

I've used PC-7 to make stuff for my 71 Challenger grille, worked great.

Ryan

Where can you get PC-7?

I was able to get it at the local ACE hardware, and a few other home improvement stores.

http://www.pcepoxy.com/where.asp

I haven't finished this grille, I got a better one, but I can grab some pics of the fixes.

Ryan

Posted By: Big Bad Bee

Re: Plastic repair Q... - 02/28/09 04:45 AM

Plumbing drain pipe and fittings are ABS plastic. Would those work? You could buy one 2.5 inch elbow and have enough to do all kinds of repairs. big chunks of abs pipe scrap are abundant at any construction site. A good way to get shavings from plumbing pipe is to run it through a chop saw a few times. It's like fine grating cheese.