Trunk lid, ABS plastic repair procedure


Information and questions on GL1200 Goldwings (1984-1987)
  • Sponsored Links
Rusty Bike
Posts: 270
Joined: Sun Feb 28, 2016 1:55 pm
Location: New castle, PA
Motorcycle: 86 GL1200 SEi, 78 Yamaha XS750SE, 86 Honda XL125, 4.5 HP belt drive Minibike my dad built, foot clutch!

Trunk lid, ABS plastic repair procedure

Postby Rusty Bike » Sun Sep 18, 2016 10:42 am



The rear corner of my trunk lid had a piece missing about the size of a thumb print. Also had two horizontal cracks running away from damaged area about 3 inches total length.
Web research showed ABS plastic and acetone could be used for repair. I have some ABS plastic sheet here that was purchased on Amazon but a piece of ABS plumbing pipe or fitting will work as well. Cut the ABS into small slivers then add acetone in a small container. A glass babyfood jar would be ideal but i used a SS bowl. The goal here is to make a thick paste so not too much acetone. Let this mix set for a while and stir until the plastic melts compleatly. You want it thick enough to make a runny ball on a small stick about the consistency of bondo. You can add acetone at any time to adjust the mix. While mix was melting, prep the repair spot by wiping area clean with acetone on a clean rag. Make sure to get the acetone into the cracks. Next mask off area around repair. I used masking tape a few layers thick on the inside radius of the missing corner as a form of sorts, to mold the ABS goop to. When the ABS goop is ready for application, (may take an hour) redampen the repair aria with acetone as a primer. Using a suitable tool apply the goop between the cracks gently. Now you can press the cracked peices together and hold in place, they will bond quickly. Next spread the goop across the hole/tape form. Build this aria up somewhat thicker then original. Work fast as the goop wants to dry out quickly at this point, much like bondo does. A damp finger can be used to level out the goop once it starts to stiffen. OK, that part is done, don't mess with it once the goop starts to set! Although the goop sets fairly quick it takes a couple of days to compleatly cure. The acetone needs to dissipate compleatly before the repair is sound. Some light heat such as an incandescent trouble light will speed up cure time. When repair is good and hard, work excess down and shape with a coarse file, then a fine file, then use sand paper to blend in. Repair is solid and strong. Keep sanding aria as small as possible to minimize touchup paint. These GW colors are hard to match.

Note: Automotive spot putty may work to fill small imperfections but I have not tried this yet. I am not sure the stuff will bond to the ABS...Rusty



User avatar
SilverDave
Posts: 367
Joined: Sun Aug 09, 2009 9:39 am
Location: Langley, BC
Motorcycle: 1985 GL1200 GoldWing Aspy

Re: Trunk lid, ABS plastic repair procedure

Postby SilverDave » Mon Sep 19, 2016 4:34 pm

About a year ago, I had to repair an 11 inch split in my top box lower shell... and one end of the tear went thru a mounting hole ( Probably started there )

I found that with well sanded surface , and lotsa tape to hold it all in place , that black JB-weld also worked very well.

A break like mine ( or yours ) will continue to have stresses after repair ... so I would recommend reinforcement .

After my weld had cured, I sanded everything smooth , right down to the black ABS, and placed a narrow strip of fibreglass tape and ( 2 component) glass resin along inside of crack .
When THAT had cured , I removed the holding tape from outside , and added another thin strip of glass/resin ..
Two 2 inch glass patches , and re-drilled the mounting hole and I was done.

My finish was clearly easier than yours will be :
Inside of trunk floor is mostly black , and underneath the "rug" so it got two coats of matte black tremclad.
Outside was blue .... but almost invisible from behind the rear seat , so it was carefully masked ,sanded, and two coats of matte black also .


One Year of bouncing around ... and its still tight and smooth..

:)

SilverDave

Rusty Bike
Posts: 270
Joined: Sun Feb 28, 2016 1:55 pm
Location: New castle, PA
Motorcycle: 86 GL1200 SEi, 78 Yamaha XS750SE, 86 Honda XL125, 4.5 HP belt drive Minibike my dad built, foot clutch!

Re: Trunk lid, ABS plastic repair procedure

Postby Rusty Bike » Wed Sep 21, 2016 9:35 pm

Well, so much for that. My repair cracked. Only lasted a few days. :oops:

User avatar
SilverDave
Posts: 367
Joined: Sun Aug 09, 2009 9:39 am
Location: Langley, BC
Motorcycle: 1985 GL1200 GoldWing Aspy

Re: Trunk lid, ABS plastic repair procedure

Postby SilverDave » Thu Sep 22, 2016 10:17 am

Hmmm...

Why did it fail ? Motion ? built in stresses ?? Poor adhesion ?

Give JB weld and a couple of layers of glass cloth / glass resin a try .

The JB-Weld is pretty strong , and the cloth prevents twisting and tearing ... while the
(two component ) fibreglass resin adds strength and sticky to the cloth .

SilverDave

Rusty Bike
Posts: 270
Joined: Sun Feb 28, 2016 1:55 pm
Location: New castle, PA
Motorcycle: 86 GL1200 SEi, 78 Yamaha XS750SE, 86 Honda XL125, 4.5 HP belt drive Minibike my dad built, foot clutch!

Re: Trunk lid, ABS plastic repair procedure

Postby Rusty Bike » Thu Sep 22, 2016 4:13 pm

Motion and poor adhesion I'd say. The repair is right on the outside corner of the trunk lid lip. No room for internal reinforcement due to the trunk lower being a mating surface. If i build it up much on the outside it will look bad. I may just try the ABS goop again. Practice makes perfict. My mix may have been too dry to burn in properly. We shall see.....

User avatar
WingAdmin
Site Admin
Posts: 17047
Joined: Fri Oct 03, 2008 4:16 pm
Location: Strongsville, OH
Motorcycle: 2000 GL1500 SE
1982 GL1100A Aspencade (sold)
1989 PC800 (wife's!)
1998 XV250 Virago (sold)
2007 Aspen Sentry Trailer

Re: Trunk lid, ABS plastic repair procedure

Postby WingAdmin » Thu Sep 22, 2016 8:12 pm

Rusty Bike wrote:Motion and poor adhesion I'd say. The repair is right on the outside corner of the trunk lid lip. No room for internal reinforcement due to the trunk lower being a mating surface. If i build it up much on the outside it will look bad. I may just try the ABS goop again. Practice makes perfict. My mix may have been too dry to burn in properly. We shall see.....


Done properly, this will melt the existing plastic into the repair, and it is very possible to make the repaired plastic even stronger than the original. I have done a LOT of these types of repairs on ABS bike parts.

My technique is to use ABS plumber's cement, which is basically MEK (methyl ethyl ketone) and ABS resin.

Incidentally, I think you might find MEK (available at any hardware store) works better than acetone.

For long cracks, I will cut a "v" into the crack on the back side, to expose more material. I'll then use the glue to glue the crack together - clamp and let cure. Once cured, I'll mix up slurry from ABS shavings and MEK, into a thin paste. I fill the "V" with this slurry, and then spread lots of ABS glue on top of it. On top of all of that I then take thin pieces of ABS, coat them with glue, and push them on top of the glue/slurry mixture. Clamp tight enough to securely bond, but not so tight that the glue is pushed out. The MEK actually chemically melts the ABS, so that the original ABS, the slurry and the new "patch" on top all becomes one solid piece of ABS.

I can usually make crack repairs this way that are completely invisible from the paint side unless you look REALLY closely - and the repaired piece is stronger than it was originally.

Rusty Bike
Posts: 270
Joined: Sun Feb 28, 2016 1:55 pm
Location: New castle, PA
Motorcycle: 86 GL1200 SEi, 78 Yamaha XS750SE, 86 Honda XL125, 4.5 HP belt drive Minibike my dad built, foot clutch!

Re: Trunk lid, ABS plastic repair procedure

Postby Rusty Bike » Fri Sep 23, 2016 5:08 pm

Very good Admin, thank you for your expert advice. You have saved me and others time and aggravation. Cool!




Return to “GL1200 Information & Questions”




Who is online

Users browsing this forum: Tommy Coogan and 1 guest