Author Topic: What do you use to patch plastic for more strength ?  (Read 1837 times)

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Offline grcamna2

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What do you use to patch plastic for more strength ?
« on: January 03, 2015, 02:07:58 PM »
I've got a headlight bucket and sidecovers that have some stress cracks around the mountings I think from weathering and over tightening/crash damage,etc. and I'd like to patch/strengthen these areas w/ a type of plastic glue/filler type stuff that will be soft enough to go into the cracks but not run out while it's setting-up & then I can sand the area smooth before paint.The main thing is strength.
I was thinking of JB weld but wondered if any of you have something for ABS.
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Offline eigenvector

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Re: What do you use to patch plastic for more strength ?
« Reply #1 on: January 03, 2015, 02:10:13 PM »
Assuming that the material is ABS, you said that in your post.  Why not just use ABS glue?  It welds ABS so if used liberally in theory it should seal the cracks.
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Offline grcamna2

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Re: What do you use to patch plastic for more strength ?
« Reply #2 on: January 03, 2015, 02:28:53 PM »
Here's what I'm trying to strengthen/fill.

i've never used ABS glue before..,is it avail. in an autoparts store also ? No M/C dealers around here.
« Last Edit: January 03, 2015, 02:30:47 PM by grcamna2 »
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Offline petercb750

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Re: What do you use to patch plastic for more strength ?
« Reply #3 on: January 03, 2015, 02:44:26 PM »
What the pro guys do, if the rear side is not visible, is grind some grooves across the crack, obviously not cutting right through, then lay strings of plastic into the groove then weld it over....it effectively reinforces the crack and it shouldn't re-open. Then refinish the front.
But as said, best for when you can't see the back of the item.
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Offline grcamna2

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Re: What do you use to patch plastic for more strength ?
« Reply #4 on: January 03, 2015, 04:00:07 PM »
What the pro guys do, if the rear side is not visible, is grind some grooves across the crack, obviously not cutting right through, then lay strings of plastic into the groove then weld it over....it effectively reinforces the crack and it shouldn't re-open. Then refinish the front.
But as said, best for when you can't see the back of the item.


peter,the cracks aren't all the way through to the inside,only about 50% through...
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Offline Bootsey

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Re: What do you use to patch plastic for more strength ?
« Reply #5 on: January 03, 2015, 04:55:30 PM »
I have some side covers that were pretty much ready for the bin. No body shop suppliers around where I live.
I found you can use some acetone + ABS plastic (I used a ABS resin recorder, you could use lego). Put the two in a jar, and the acetone will melt the plastic into a liquid. You can use it as a glue/putty, depending on how much acetone you add.
Sit it out in the sun, it sets are hard as a rock & it easy to sand to shape.

Here's what I started with, and where I've gotten to.  I need to do a bit more sanding, and will probably need a light smear of bondo, then paint, but looks like it will work pretty well. Saved the covers from the bin anyway.


Offline grcamna2

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Re: What do you use to patch plastic for more strength ?
« Reply #6 on: January 03, 2015, 05:00:35 PM »
nice job bootsey,I'd like to get some stuff that's ready to use in a tube though.
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Offline Stev-o

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Re: What do you use to patch plastic for more strength ?
« Reply #7 on: January 03, 2015, 05:06:02 PM »
I've used JB Weld on side covers with cracks, good for a temp fix.
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Offline BobbyR

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Re: What do you use to patch plastic for more strength ?
« Reply #8 on: January 03, 2015, 05:37:25 PM »
If you are going to paint, you can get a set of perfect sidecovers from Frankenbike that are made from new materials. They are perfect replicas in every respect.
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Offline grcamna2

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Re: What do you use to patch plastic for more strength ?
« Reply #9 on: January 04, 2015, 07:46:43 AM »
I want to get this headlight bucket strong & I think ABS glue mentioned before would do it.There aren't any M/C shops around here but there are a couple autoparts stores.
Who sells ABS glue,the type that's good for this ?

BobbyR,Thanks for letting me know about the repro sidecovers that Franken sells  ;).
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Offline Killer Canary

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Re: What do you use to patch plastic for more strength ?
« Reply #10 on: January 04, 2015, 07:56:44 AM »
Is fibreglas too obvious? ;D
If it's worth doing at all it's worth over-doing.
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Offline grcamna2

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Re: What do you use to patch plastic for more strength ?
« Reply #11 on: January 04, 2015, 08:03:34 AM »
Is fibreglas too obvious? ;D

yeah,I guess it would be because I'll be looking at that spot as it faces me while I'm driving.  ::)
I'd like to get a tube of some type of glue/epoxy that's semi-light and squeeze it into all the cracks(I could do more 'build up' on the inside) and kind of squeegee it in w/ a little putty knife,etc. so it fills all the cracks and then do a minimum amount of sanding before I paint it.
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Offline strynboen

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Re: What do you use to patch plastic for more strength ?
« Reply #12 on: January 04, 2015, 09:37:45 AM »
i have uset the lego/acetone metode..its perfekt..just fill some lego in a glass and fill some acetone inn..let it sit for 12 auers..and  vhen it is meldet...put..some acetone on the broken part(to soften the glue point) so it melts together better..and fill the stuff in the holes..let it harden for 12 auers..and it can be vorked on..
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Offline eigenvector

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Re: What do you use to patch plastic for more strength ?
« Reply #13 on: January 04, 2015, 10:40:05 AM »
You can get ABS glue in any hardware store.  It's what plumbers use to install ABS pipes.
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Offline grcamna2

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Re: What do you use to patch plastic for more strength ?
« Reply #14 on: January 04, 2015, 10:45:00 AM »
eigenvector,
Do you mean the stuff that plumbers use to glue together PVC pipe ?
I think that's a little 'runny' for my application,it would just run right out of the cracks I'm trying to fill.
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Offline Killer Canary

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Re: What do you use to patch plastic for more strength ?
« Reply #15 on: January 04, 2015, 11:29:32 AM »
Is fibreglas too obvious? ;D

yeah,I guess it would be because I'll be looking at that spot as it faces me while I'm driving.  ::)
I'd like to get a tube of some type of glue/epoxy that's semi-light and squeeze it into all the cracks(I could do more 'build up' on the inside) and kind of squeegee it in w/ a little putty knife,etc. so it fills all the cracks and then do a minimum amount of sanding before I paint it.
You reinforce the inside with fireglas and bondo the appearance side. Silly guy. ;D
If it's worth doing at all it's worth over-doing.
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Offline grcamna2

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Re: What do you use to patch plastic for more strength ?
« Reply #16 on: January 04, 2015, 02:09:27 PM »
ok,so a plumbing store ?
75' CB400F/'bunch o' parts' & 81' CB125S modded to a 'CB200S'
  I love the small ones too !
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Offline grcamna2

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Re: What do you use to patch plastic for more strength ?
« Reply #17 on: January 04, 2015, 02:16:48 PM »
Or a Home Center. Definitely not a bakery.

lol  :D  no 'mud pies' then.
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Offline Retro Rocket

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Re: What do you use to patch plastic for more strength ?
« Reply #18 on: January 04, 2015, 04:56:35 PM »
Or a Home Center. Definitely not a bakery.

hahaha....nice... :P
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Offline Steve F

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Re: What do you use to patch plastic for more strength ?
« Reply #19 on: January 04, 2015, 07:48:05 PM »
I've patched from the inside with fiberglass cloth and epoxy to strengthen.  I've also filled in small imperfections with the thin superglue that you can get at model hobby shops (the ZAP brand) and used their "kicker" spray to instantly harden the CA glue.  Sand and repeat if necessary over the cracks.  They also used to have a product called micro bubbles (or something like that) that can be used as a filler with the superglue.  Sand, prime and paint.  Do a little research on the PlastiZAP formulated for plastics as some plastics like ABS can get soft if the regular CA glue is too "hot".

Offline Don R

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Re: What do you use to patch plastic for more strength ?
« Reply #20 on: January 04, 2015, 09:26:18 PM »
Some parts of the country don't seem to have abs plumbing. I rarely saw any here in central Illinois. Mostly cpvc and pvc.
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Offline grcamna2

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Re: What do you use to patch plastic for more strength ?
« Reply #21 on: January 04, 2015, 09:47:43 PM »
Some parts of the country don't seem to have abs plumbing. I rarely saw any here in central Illinois. Mostly cpvc and pvc.

I'm not a plumber or even inclined toward any of that work(I'm not a homeowner)but this is the first time I've heard of ABS glue.
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Offline FunJimmy

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Re: What do you use to patch plastic for more strength ?
« Reply #22 on: January 04, 2015, 10:19:36 PM »
ABS glue and Acrylic glue are interchangeable.
Look in the Yellow Pages for plastics companies.
They'll have everything you need to fix that bucket up just like new.
You can also get epoxy putty at Home Depot.
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Offline grcamna2

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Re: What do you use to patch plastic for more strength ?
« Reply #23 on: January 05, 2015, 06:13:34 AM »
Thanks Jimmy  ;) :)
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Offline flybox1

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Re: What do you use to patch plastic for more strength ?
« Reply #24 on: January 05, 2015, 09:33:06 AM »
Fiberglass drywall tape!  Great to reinforce stuff.  Get it any any home improvement store.
Sticky on one side.  Cuts easily to any shape you need. 
Lay down 2-3 layers where you want it, and then paint a good plastic glue/epoxy right over it.
Its mesh design lets the epoxy get right down to the surface.

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