JB Weld + carbon fiber for broken frame repair

[zoltan87]

I have a Thinkpad T500 with broken magnesium frame close to the left hinge. I am thinking about trying to repair it with some JB Weld, that I would reinforce with carbon fiber, as I have quite a lot of carbon cloth material left from past projects. Do you guys think this could work, would be significantly stronger than the plain JB Weld epoxy alone?

Also I have a Thinkpad T22 whivh has the usual broken plastic right next to the keyboard on both sides. Does anyone know what type of plastic is is made from? If it's ABS, then I could melt it with acetone, and could incorporate some carbon fiber there too (from underneeth so it wouldn't be visible from the outside).

[atagunov]

For what it's worth here's a description of a somewhat similar repair on a T60 structure frame: https://thinkwiki.de/Frankenpad#Structu ... .C3.A4rken

google translate advised for those who like me do not speak German They used a brass angle + screws + UHU. I suppose UHU is similar to JB Weld. So at least our German comrades didn't think epoxy alone would be enough and also used metal.. Sorry no experience with carbon fibre.

Is there a recycling symbol on that plastic part you mentioned earlier? Perhaps that would point to which material it actually is.

[zoltan87]

Is there a recycling symbol on that plastic part you mentioned earlier? Perhaps that would point to which material it actually is.

I will disassemble it tomorrow and have a look. I think I even remember that on the bottom of a T60 palmrest it said ABS, but it doesn't mean it's the same for the T2x series machines. On T60 the plastic parts have no (or little) structural importance due to the metal cage inside. On earlier models the construction was different. Will see it tomorrow. I might try a drop of acetone on it even if I can't see any ABS sign, just to see if there is any effect.

[RealBlackStuff]

Been there, done that palmrest on various T23: viewtopic.php?t=60282

[MikalE]

I have used JB Weld on many repairs. I've even machined it and drilled and tapped it. It is very strong adhesive. Do not use the 5-Minute formula. It may not hold up. The faster is cures the more brittle it is.

Use the 24-hour cure formula and the repair should hold.

[zoltan87]

Been there, done that palmrest on various T23: viewtopic.php?t=60282

Nice, so reinforcement is definitely worth a try. I will look around if I have some nails that are sufficiently thin and have some texture/ ribs on them, I will probably try to use those, instead of carbon fiber (which sounds good, but probably would be a lot more difficult and messy to lay it down in the epoxy).

@MikalE Yes I will use the normal 24 hour JB Weld, I have only heard bad things about the fast curing variants.

[zoltan87]

Just a quick update on this project, someone might will find it useful info. The JB Weld + carbon fiber repair worket out great, it's is super strong on the T500 magnesium frame. I actually think it will be stronger then it was originally.

It also worked on the T22 keyboard bezel, where the thin plastic bridges broke around the keyboard. On one side it was an easy fix, but on the other side of the keyboard it was much more difficult, as there is no space there for additional material to go. I remember cutting away a tiny bit of plastic there inside the frame, to make some space for additional layers of JB Weld + carbon fiber mix.

[atagunov]

The JB Weld + carbon fiber repair worket out great, it's is super strong on the T500 magnesium frame. I actually think it will be stronger then it was originally.

I'm very happy to have been proven wrong, pls accept apologies for my earlier scepticism. I'm now wondering how exactly the carbon fiber that you used looks and where to get it. Could you by any chance let me see a photo too? Not necessarily of the repair - since it's now probably hidden inside, but at least of the material. Thx!

[zoltan87]

I'm very happy to have been proven wrong, pls accept apologies for my earlier scepticism. I'm now wondering how exactly the carbon fiber that you used looks and where to get it. Could you by any chance let me see a photo too? Not necessarily of the repair - since it's now probably hidden inside, but at least of the material. Thx!

No need to apologise, I think you would have been perfectly right with JB Weld not being strong enough just by itself. It really needs some material to strengthen it. I happened to use carbon fiber, as I have a ton laying around from other projects. Also it was ideal because of the space constraints, the fiber incorporated in the epoxy can be pushed around before it sets, so can make it as thin as required where space is limited.

I should have taken some pictures about it when it was done, missed opportunity as I have sold the laptop after the repair was done. Sorry about that. But I will take some pictures about the material itself. I basically have a big roll of carbon cloth, and have lots of scrap pieces from different projects all different lengths.

I used sandpaper to make the magnesium frame clean and more rough where I knew I would apply the epoxy. I cut a few very short strains of carbon fiber, mixed up the two part JB Weld, and applied it onto the broken laptop frame. The frame was broken at that long thin piece around the left hinge, that goes along in front of the exhaust vent, from the screen towards the palmrest (the same issue is present on many 15 inch T60 Thinkpads, same spot). And also at the bottom of the frame underneath the heatsink fan, that part of the frame was broken too due to the same stress from the screen hinge. I tried to apply the epoxy as thin as possible, then pushed some carbon fibers into it, and did my best to lay those strands as flat and close to the frame as possible, as I knew after the epoxy solidifying I will need to grind it further down to make it smooth, and be able to fit the frame back into the plastic bottom case. When I ground it down, some the carbon pieces resurfaced at a few places, and I had to cut through some to make my repair flush, but most of them stayed intact. I am sure it will be plenty strong, as I tested it a few days after the repair, and felt super strong.

As much as I like thinkpads, the thickness of these magnesium inner frames around the hinges, especially on these large 15 inch laptops is just laughable. I am surprised they manage to hold up in many cases for years, until the hinges lose some of their strength. They weight next to nothing, so doubling their thickness at those crucial points would have cost nothing to Lenovo.

[kfzhu1229]

I am surprised they manage to hold up in many cases for years, until the hinges lose some of their strength. They weight next to nothing, so doubling their thickness at those crucial points would have cost nothing to Lenovo.

Pretty sure it's also that the hinges got stiff over the years because dust gets inside the opening and turns the lubricant into some sort of slime. At least that was what happened when one of the hinges shaped exactly like the T500 one used in a Dell broke its magnesium lid. Have you tried dripping some lubricant in the opening on each of the hinges?
Also I am curious how much wobble do you have on the hinges currently after tightening the screws?

[zoltan87]

Have you tried dripping some lubricant in the opening on each of the hinges?
Also I am curious how much wobble do you have on the hinges currently after tightening the screws?

I didn't use any lubricant, they didn't feel that stiff, but in hindsight it probably would have been a good idea. They had quite a bit of wobble. I actually observed this with many of the large 15 inch Thinkpads, be that the T500 or T60 series. Also what I noticed on my T60 is that the actual place, that wobbles in the hinge assembly, is the part where the hinge axle/rod connects into that long metal rail, that goes along the side of the LCD. The metal just seems to be too thin there, and after some use the fitment just gets loose. Lenovo were supposed to stress test these hinges when designed them, not sure what they messed up in the test procedure. Of course it's nowhere near as bad on the T60 or T500 than on the infamous T61 screen hinges, but it still bugs me. In contrast on smaller models like X32 or X61 the hinges have absolutely no wobble even after years of use, they just lose some of their stiffness. Although I am sure most of that has to do with the fact, that those hinges don't have to be as tight for those smaller and lighter screens, so the stresses are considerably less.

And as I promised earlier here is a link for an uploaded picture about a piece of carbon fiber, that I used in my repair. Of course for a job like this I only had to use a few short strands, the pictured piece (which is about the size of two palms) would be enough probably for like a 50-100 similar repairs.
Here is the link:
https://imgur.com/a/bJ2CdUq

[kfzhu1229]

I didn't use any lubricant, they didn't feel that stiff, but in hindsight it probably would have been a good idea. They had quite a bit of wobble. I actually observed this with many of the large 15 inch Thinkpads, be that the T500 or T60 series. Also what I noticed on my T60 is that the actual place, that wobbles in the hinge assembly, is the part where the hinge axle/rod connects into that long metal rail, that goes along the side of the LCD. The metal just seems to be too thin there, and after some use the fitment just gets loose. Lenovo were supposed to stress test these hinges when designed them, not sure what they messed up in the test procedure. Of course it's nowhere near as bad on the T60 or T500 than on the infamous T61 screen hinges, but it still bugs me. In contrast on smaller models like X32 or X61 the hinges have absolutely no wobble even after years of use, they just lose some of their stiffness. Although I am sure most of that has to do with the fact, that those hinges don't have to be as tight for those smaller and lighter screens, so the stresses are considerably less.

Well that's exactly the kind of wobble that I face with many of my Dell Latitudes that I have to fix up. That has to do with Dell's hinge design which actually ThinkPads used on their first widescreen models like T61 T400 T/W500. Those steel encased hinges are designed to be strong but not elegant and also has this kind of wobble problem after wear because the glue they used to secure the various metal parts together falls apart.
My solution of first dripping lubricant and let it smooth up for 2-3 days and then drip good branded superglue into the same hole and let it dry at a single position for 1 hour so that it fills in the gaps formed by the wear of the hinges actually worked on a number of my Latitudes and a Toshiba Satellite, makes the hinges turn smooth and also with minimal seesaw.

[zoltan87]

Those steel encased hinges are designed to be strong but not elegant and also has this kind of wobble problem after wear because the glue they used to secure the various metal parts together falls apart.
My solution of first dripping lubricant and let it smooth up for 2-3 days and then drip good branded superglue into the same hole and let it dry at a single position for 1 hour so that it fills in the gaps formed by the wear of the hinges actually worked on a number of my Latitudes and a Toshiba Satellite, makes the hinges turn smooth and also with minimal seesaw.

Interesting, I had no idea they used some sort of glue there, I always just assumed that they somehow sort of riveted them together, and the wobble was caused by the actual metal giving way after a while. Next time I will take apart the screen assembly I will have a closer look at those hinges, and will try something to remedy the wobble.