Repairing hard plastic(?)

[jeffgrant]

Hello everyone-

I have a Herman Miller Aeron chair that I've loved for the past 10+ years.

It's finally given up the ghost, in that the seat frame that holds the webbing for your ass has failed, and has fractured.

I'm trying to glue/epoxy the frame back together, and have tried 3 different adhesives, but none of them work. They seem to tack up and cure just fine, but as soon as I sit on the chair, the bond immediately comes apart again.

I should also mention that each time I clean the "wound" with my Dremel tool, and ensure that the surface is quite rough.

I was wondering if anyone had any recommendations or suggestions as to what I can try to fix it with?


I've attached a stock pic (not of my chair), but highlighted the cracked area with a red line.


Any thoughts?

[maxnine11]

Try taking it to a shop that 'plastic welds' motorcycle fairings.
They should be able to tell you if their process is possible or not with that particular plastic.

good luck,
max

[VincentVega]

Our 12-year warranty covers everything — including electrical
components, casters, pneumatic cylinders, tilts, and all moving
mechanisms.

Call them.

[jeffgrant]

Originally Posted by Chris Martin

Call them.

Dug out the receipt, and I bought the chair in 1991. Just a LITTLe out of the warranty period.

(I'm actually amazed that I even have the receipt still).

[red-beard]

Go to an ACE hardware store. Look in the expoxy section for "plastic weld". It is different than epoxy, in that it "melts" into the plastic and fuses the plastics together. It does not work on Nylon. It does work on most other plastics.

[red-beard]

Originally Posted by jeffgrant

One of the buildings at my previous employer, they had those chairs. It is bad if you forget you are sitting in one of those and try an sneak one into the chair...

[Tim Hancock]

I doubt this will help, but I have sucessfully repaired some plastic motorcycle body parts by welding the cracks on the back side of them with a soldering iron. Basically you hold the tip on the back side of the crack and dap the plastic around as it melts. This has worked long term for me on "non-stressed" body parts that had been damaged by a mishap, but simply welding the surface of a crack is not going to cut it in your situation as you need full penetration on the relatively thick seat cross section to develop sufficient strength.

If the plastic your chair is made of is "weldable" like my motorcycle parts, you may be able to "v" groove the crack and then carefully melt in some additional filler plastic making sure to start deep in the groove. You would need to cut somedonor plastic away from some other un noticable place on the chair to use as the filler.

[jeffgrant]

Thanks for the tips guys...

I'll try the "plastic weld" stuff first... The last thing I tried was a special "plastic 2-part epoxy" that didn't work worth beans.

Thanks again!


...jeff

[dad911]

Can you reinforce the back side with a steel or aluminum plate?

Or heat up some steel 'pins' and melt them in?

[Rondinone]

Originally Posted by jeffgrant

Thanks for the tips guys...

I'll try the "plastic weld" stuff first... The last thing I tried was a special "plastic 2-part epoxy" that didn't work worth beans.

Thanks again!


...jeff

Have you tried devcon's plastic welder II? It's rated for nylon, which this chair might be. You must order it off the internet.

I used it for my airbox years ago and it's held up fine.

[Porsche_monkey]

Have you inquired about buying parts from the manufacturer? It's unlikely they'll have it, but ultimately it's the best repair if really like the chair.

[porsche4life]

An aluminum plate with some small screws might work best with the least chance of failure.

[jeffgrant]

Originally Posted by Rondinone

Have you tried devcon's plastic welder II? It's rated for nylon, which this chair might be. You must order it off the internet.

I used it for my airbox years ago and it's held up fine.

I haven't... I'll look into it though... thanks.

[jeffgrant]

Originally Posted by Porsche_monkey

Have you inquired about buying parts from the manufacturer? It's unlikely they'll have it, but ultimately it's the best repair if really like the chair.

It's about $300 delivered for the part I need, and I'd rather spend a few hours and a couple of bucks to fix it myself if that'll work.

I don't care about the looks of the thing, only that it'll work.

[red-beard]

The Devcon stuff is exactly what I was suggesting.

[jeffgrant]

Originally Posted by red-beard

The Devcon stuff is exactly what I was suggesting.

Perfect. I remember seeing some in the local Canadian Tire. I'll pick some up today and give it a shot.


Thanks again.


...jeff

[B D]

Drill some holes on both sides shove some round stock on one side and epoxy on the other and push it together. That chair is made to flex and give, with out using a pin aka back bone the chair will fail again in the weakest spot so you need to make that joint stronger.