# Plastic repair question



## james4beach (Nov 15, 2012)

I have an office chair with plastic armrests. I don't know exactly what the material is, but it's a bit spongy (could be foam) and quite dense. It's not visible in the photo below, but there is a crack or tear on the surface of the plastic which is gradually growing.

Any ideas how fix this? I could put a patch of some flexible tape over it, but that will look ugly.

Is there a kind of glue that I could brush over the crack, so that it seals the crack, more elegantly than tape?

For now, I put a bit of Gorilla Glue super glue (this stuff) into the crack but I doubt it's going to hold, since I can't apply pressure on both sides. It's also tough to get the glue into the crack. Imagine that the foam has a cut from a knife... that's what it looks like.


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## Retiredguy (Jul 24, 2013)

I have leather seats in my 14 yr old car and the side panel is cracking from being squished when I get in/out. I asked a friend who is a car guy and been in the automotive repair business his entire career and he did'nt have any suggestions. I just used a bit of crazy glue to hopefully help prevent it from getting worse.


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## 30seconds (Jan 11, 2014)

Loctite 4070 is one of the stronger glues I have found that works well on a variety of plastics. Depending on what the plastic-type is you could find a specific glue for it but this is the best I got without knowing the plastic type. 









Loctite Hybrid Adhesive Clear 11 G Cartridge: Amazon.com: Industrial & Scientific


Loctite Hybrid Adhesive Clear 11 G Cartridge: Amazon.com: Industrial & Scientific



www.amazon.com


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## james4beach (Nov 15, 2012)

30seconds said:


> Loctite 4070 is one of the stronger glues I have found that works well on a variety of plastics. Depending on what the plastic-type is you could find a specific glue for it but this is the best I got without knowing the plastic type.


Thanks! I haven't tried that kind of glue. Do you think it would be suitable for brushing a thin layer on top of the cracked area?

I also thought of trying the classic gorilla glue (this one) the same way, applying a thin layer on top


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## Plugging Along (Jan 3, 2011)

I would look into Mod Podge. There are different finishes, and types. It's glue and sealer at the same time and can be used on a porous surface. I have used to for some of the strangest crafts, but it's versatile. The company keeps coming out with different ones for different surfaces with different finishes. I would check if there something that can match what you need.


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## MrMatt (Dec 21, 2011)

These armrests are difficult to repair.

Shoe Goo. It's a flexible adhesive designed for that.
Also shoes are made out of similar TPE type materials, so it _should_ have good adhesive compatibility.

If you can't find that you could use rubber cement, but the armrests are likely TPE not rubber. So sub-optimal.

Next would be a glue gun.

The problem with crazy glue is it's really stiff, which is bad for mechanics as if it sticks, it will hold the joint, but tear out the next bit.
I'd go with putting a slip cover of some type before doing krazy glue (ie CA/cyanoacrylate adhesives)


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## nathan79 (Feb 21, 2011)

You could also go to a fabric store and buy some imitation leather (or fabric) and recover the whole area. If using imitation leather attach with contact cement.


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## birdman (Feb 12, 2013)

MrMatt said:


> These armrests are difficult to repair.
> 
> Shoe Goo. It's a flexible adhesive designed for that.
> Also shoes are made out of similar TPE type materials, so it _should_ have good adhesive compatibility.
> ...


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## birdman (Feb 12, 2013)

I used Shoe Goo on a good pair of leather ski mitts and it stood up well to 45 days skiing this season.


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## twa2w (Mar 5, 2016)

There are lots of vinyl repair kits that work well. Canadian Tire has some, and then there is this one from Amazon Coconix Vinyl and Leather Repair Kit - Restorer of Your Furniture, Jacket, Sofa, Boat or Car Seat, Super Easy Instructions to Match Any Color, Restore Any Material, Bonded, Italian, Pleather, Genuine: Amazon.ca: Automotive.

These kits are similar to what City transit people use to repair cuts to seats on buses and trains. It does take some time to get really good at it and to match the colour well. But if you are careful and take your time, it is not too difficult to make a passable repair.

My ex FIL did these repairs as a side job for a City transit facility many years ago. The commercial kit he had was identical to a consumer kit - just larger quantities.

I am sure these have advanced in quality over the last 40 years.


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## Juggernaut92 (Aug 9, 2020)

I have an extremely similar arm rest for my office chair. I had the issue as well with the rubber/foam cracking. I ended up just replacing it by buying replacement arm pads from amazon. Here is the exact one I got:






Chair Arm Pad Office Chair 10" 4" Replacement Part Armrest Cover #1043 for Office Desk (Pack of 2) : Amazon.ca: Home


Chair Arm Pad Office Chair 10" 4" Replacement Part Armrest Cover #1043 for Office Desk (Pack of 2) : Amazon.ca: Home



www.amazon.ca





Also, I did try gorilla glue and gorilla tape to hold the arm pad together and prevent it from cracking more but nothing helped and replacing it was the best solution.


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## james4beach (Nov 15, 2012)

Thanks everyone, lots of great ideas here

@Plugging Along , Mod Podge sounds very interesting, I've never used that but it sounds extremely useful for many things. Where do you buy it?

@MrMatt , Shoe Goo does sound like a good fit for this. Thanks for reminding me about this stuff. It's been a few years since I used it, I had forgotten. I think you are right that this material is similar to a shoe.


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## Plugging Along (Jan 3, 2011)

james4beach said:


> Thanks everyone, lots of great ideas here
> 
> @Plugging Along , Mod Podge sounds very interesting, I've never used that but it sounds extremely useful for many things. Where do you buy it?


I get mine at Michael, but I think they have it at Walmart and anywhere with a crafting section. I thought It was just over priced white glue. Then my other girl leader (whouses this stuff professional)brought in all these different kind for some of our kids activities. I would start on line and see if there is on that would match the materials and finsh, then Michaels has A good selection or even amazon.


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## 30seconds (Jan 11, 2014)

I misread the post. I thought the crack was on the bottom. Do not use my recommendation for the foam part!


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## james4beach (Nov 15, 2012)

Plugging Along said:


> I get mine at Michael, but I think they have it at Walmart and anywhere with a crafting section. I thought It was just over priced white glue. Then my other girl leader (whouses this stuff professional)brought in all these different kind for some of our kids activities. I would start on line and see if there is on that would match the materials and finsh, then Michaels has A good selection or even amazon.


Very interesting, thanks. Is the Mod Podge flexible, or when it dries, does it become very hard/brittle?


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## Beaver101 (Nov 14, 2011)

Call me cheap but I would either put a small pillow or a folded towel over it as 1. who else is going to notice that splint in the armrest, and 2. rest of the chair looks easily (or cheaply) replaceable. I would put more efforts on preserving the ergonomics of that chair instead (if / when it needs to).


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## Plugging Along (Jan 3, 2011)

james4beach said:


> Very interesting, thanks. Is the Mod Podge flexible, or when it dries, does it become very hard/brittle?


I think they have one for foam that keeps it softer. I am usually putting some soft onto some hard, so the end result is hard. It says flexible on paper if that helps.


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## james4beach (Nov 15, 2012)

Beaver101 said:


> 1. who else is going to notice that splint in the armrest


I'm actually finding it quite comfortable (no back pain whatsoever) which makes it far more valuable to me than its listed price  So yeah, this Staples chair was cheap, but from a health & work productivity standpoint, it's been a great purchase that I'm very happy with.

My previous chair gave me back pain. This one cured that. No matter how junky the plastic is, that makes it a *great* chair for me.

I just want to extend the life of it. The crack is going to keep growing and will ruin parts of it, so it definitely seems worth patching up one way or another. I will try the Shoe Goo or the Mod Podge


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## Beaver101 (Nov 14, 2011)

^ Ergonomically satisfying, then it's all worthwhile to fix. Good luck.


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## Ponderling (Mar 1, 2013)

CTC sells a JBweld plastic adhesive as well. 

lShoo Goo is basically rubber in a volatile organic solvent. It needs something to grab, so abrade the surface with a dish sink stainless scouring pad. I actually use it to fix shoes, and it works well


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## Rusty O'Toole (Feb 1, 2012)

Recover them with a piece of vinyl over a thin layer of foam padding called landau padding in the upholstery business. You should be able to get a bit of vinyl and foam from a fabric store. Take the armrest off to work on it and glue or staple underneath where it won't show. Use spray upholstery glue.


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## m3s (Apr 3, 2010)

I had a Staples chair that slowly fell apart

I bought a Steelcase that still looks new after far more use than the cheap chair. We have crazy expensive chairs at work that look fancier but I find the Steelcase feels higher quality and more comfortable even though they cost less

If you're gonna use a chair a lot for many years Steelcase is a good deal especially on a sale


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## james4beach (Nov 15, 2012)

Plugging Along said:


> I thought It was just over priced white glue. Then my other girl leader (whouses this stuff professional)brought in all these different kind for some of our kids activities


I bought a 2 oz Mod Podge (very cheap) to try it out. It looks like a very interesting product. It's similar to standard PVA glue, except it doubles as a sealer, as you said.

So it can glue things together, and protect a surface. It's designed to dry very clear and can be added in multiple thin layers to seal a surface. I haven't tried it yet on this furniture but I'm going to give it a spin to see if it bonds well. I also want to try it on some other surfaces, to add a thin protective seal.

The 'shoe goo' is likely the superior adhesive to use on a plastic, but that stuff is extremely smelly and the fumes are hazardous. So I'll try the milder stuff first before I resort to the bazooka (shoe goo).


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## Plugging Along (Jan 3, 2011)

james4beach said:


> I bought a 2 oz Mod Podge (very cheap) to try it out. It looks like a very interesting product. It's similar to standard PVA glue, except it doubles as a sealer, as you said.
> 
> So it can glue things together, and protect a surface. It's designed to dry very clear and can be added in multiple thin layers to seal a surface. I haven't tried it yet on this furniture but I'm going to give it a spin to see if it bonds well. I also want to try it on some other surfaces, to add a thin protective seal.
> 
> The 'shoe goo' is likely the superior adhesive to use on a plastic, but that stuff is extremely smelly and the fumes are hazardous. So I'll try the milder stuff first before I resort to the bazooka (shoe goo).


I will be really interested in knowing how it works for you. I was only introduced to it a few years ago, but was surprised at its versatility. We did a craft using cushion foam to make 'squeezy' stress balls, and the kids where able to decorate them but covering their balls with fabric and mod podge. It still had the squish to them afterwards, which is why I thought it may work for your chair.


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## gardner (Feb 13, 2014)

I am late to the party, but here's my 2c worth: My guess is that the armrests are polyurethane and a urethane based glue would be a good choice. The Gorilla glue that looks like honey is PU. PU expands and foams as it sets so you'd wind up with a lot of squeeze out. I would put painters tape either side of the crack, then push the PU down into the crack with a toothpick or piece of wire. After it sets, trim the squeeze out with a razor knife and remove the masking tape. The glue winds up a light cream colour. Blend it to the black armrest with a black sharpie.

Shoe goo is also a good choice. That is a butadiene styrene which is not the actual material the armrest is made of (if not PU then it is a PVC blend, most likely) but it should stick well enough. The same masking+crack filling strategy would work, but shoe goo shrinks when it dries so you'd want to plan to fill it a couple or three times.


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## james4beach (Nov 15, 2012)

MrMatt said:


> These armrests are difficult to repair.
> 
> Shoe Goo. It's a flexible adhesive designed for that.


I tried a few things with this plastic (foam-like) arm rest.

So far I've gotten the best results from Shoe Goo. It seems to have adhered to the plastic and (so far) it's flexible.

Does anyone know of a good way to smooth out the surface? I wonder if sanding it would work. It's just looking a bit ugly since I applied a pretty thick layer.

@gardner if this Shoe Goo doesn't hold, I'll try the Gorilla glue next. There are many types of Gorilla Glue. Does this 'original' one look like the right one? What I read online is that it's not flexible, so I'm not sure it can handle this foamy, flexing surface.

@Plugging Along I tried Mod Podge, and although it was flexible at first, it eventually hardened and cannot handle the flex of this foam. But I really like this Mod Podge stuff and have been using it in other places around the home. It's great for hard surfaces, and I've used it on some wood. It can definitely act as a sealing layer, e.g. brushed on top of slightly damaged wood to give it a protective coating.


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## Plugging Along (Jan 3, 2011)

@james4beach Thanks for the update. There are different modge pudge too. The one I had, we used on fabric and it was still pliable.


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## james4beach (Nov 15, 2012)

Plugging Along said:


> @james4beach Thanks for the update. There are different modge pudge too. The one I had, we used on fabric and it was still pliable.


Thanks, that's interesting. You're right, I saw a huge variety of these at Michael's. Maybe I should try the fabric one. It certainly did a great job, until it hardened and became too brittle. I really like the finish and how the surface looks too.


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## Synergy (Mar 18, 2013)

I normally replace the broken parts. Much easier than fussing with repairs. Those armrests are fairly standard. Measure and check hole locations. Here's an example.



https://www.amazon.ca/Chair-Office-Replacement-Armrest-Cover/dp/B07MDYZK4V/ref=asc_df_B07MDYZK4V/?tag=googleshopc0c-20&linkCode=df0&hvadid=320811725945&hvpos=&hvnetw=g&hvrand=17830130102744257893&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=1002287&hvtargid=pla-644305327657&psc=1



Fixed a half dozen office chairs a few months back. Cylinders, armrests, seat upholstery are some of the first items to wear out.


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## james4beach (Nov 15, 2012)

Synergy said:


> I normally replace the broken parts. Much easier than fussing with repairs. Those armrests are fairly standard.


Thanks for this idea. It never occurred to me that they might be standard. I just assumed that this random, Chinese-made garbage would have unique dimensions and parts.


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## gardner (Feb 13, 2014)

james4beach said:


> Does anyone know of a good way to smooth out the surface? I wonder if sanding it would work. It's just looking a bit ugly since I applied a pretty thick layer.


Secrets of Goop: 






> There are many types of Gorilla Glue. Does this 'original' one look like the right one?


That's the one I was thinking of. It is not rubbery when set, but neither is it completely rigid. It remains somewhat flexible and can be trimmed with a razor knife.


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