Repair Broken Gas Strut Office Chair?

admin

I'm debating on what to do with this broken chair.  See photos.  Its a gas strut, strut works fine.  Metal at bottom of chair mount stressed, and broke just outboard of weld bead.  I'm not quite sure how to fix this one.  I'd be comfortable TIG'ing this back together, but I don't think I can get it apart.1).  The pivot pin is hard riveted in place.  I'd have to grind off the end of the rivet to remove it.  I'm thinking I would center drill the pivot pin, tap and add a bolt for re-assembly.  That's not great, but certainly do-able.  I can't get to the top of the gas cylinder until this rivet / pivot plate is removed2)   For safety, I'd have to remove the gas strut before welding up the broken piece of metal.  I'd also add a piece of reinforcement for strength.  Gas strut says clearly "DO NOT HEAT" The gas strut appears to be a press fit into the bracket.  There are no snap rings or anything else to suggest anything but a press fit.  I do NOT have a large press to aid in re-assembly.  I have a vise, big hammer, drill press, etc...  Because the actuator for the gas strut is a plastic button on the axis of the shaft, its not an easy thing to push on.  anybody been here before?  Ideas on how to safely proceed?Many thanks,Zip. Attached Images
Reply:I've repaired my chair the same thing happend. As the cylinder does say do not heat. I took a rag soaked it in water and wrapped it around the cylinder to lessen the chance of heat soak. Then I welded small bits at a time like a half inch at a time and then cooled with with a rag also. So far so good and that was 8 months ago. i sure ill get bashed for doing it but its fineOwner G&S Mobile Welding & Millwright Services, LLCSpencerville, Ohio Adult Ed. Instructor at Apollo Career Center Lima, Ohio
Reply:X2 with the wet rag. Fixed several that way. Not my proudest moments, but you got to do what the boss man tells you!
Reply:x2... weld itMillermatic 251Century 180 migSpectrum 625 Syncrowave 250DX
Reply:X3..You can plainly see the problem in the last pic..Just read the tag!I have the same set-up at the shop and as long as the heat stays away from the cylinder there is no problem with the repair..I went one step further and installed 1" spacers between the seat itself and the chair frame..Mine was not tall enough as it was.....zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:I have replaced those struts before all you have to do is grab it by the end the base attaches to and a few firm wacks to the broken part will separate the strut from the chair.
Reply:Just weld it.  I have blown a few cylindeers.  It happens.   I have welded a lot of office chairs.   The last one was broken on top where the seat bolts on.  I drilled a piece of 1/4X6 7" long and welded it in place.   It worked fine.DavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:I had the same problem, looks like the same chair, Welded it and was very careful but still screwed it up. Split a piece of pipe wrapped it around the cylinder tacked it togather at the height comfotable for me. Sit in it every night while on the net checking out all the neat projects on this site.Miller 330 A/BP Bernard SS coolerMiller cst 250Miller Big Blue 251DCentury 210 Mig (first welder I bought)Hypertherm PowerMax 800Victor torch setRu Fong 31 MilAtlas lathe
Reply:I did a couple about 6 months ago.  The first one ended up with a strut that no longer holds gas.  The second one, I am currently sitting in.I used a pipe wrench to grab the strut, and Crescent wrench to grab the plate that it was friction fit into.  A little twist and they came apart with not too much effort.  Once the strut was out, welding the bracket was dead easy.
Reply:I repaired a chair exactly like that a year ago last August.  I wire-wheeled off the paint, ground the breaks to clean off the broken weld beads, clamped it into place, wrapped a wet rag around the end of the strut and buzzed it together with my MIG.  Let it cool, wire wheel clean-up, added some Rustoleum rattle paint and it is just as pretty and stronger than new.  The owner is still using it and happy with the repiar.  I have pictures but don't dare post them here.   As I noted in another thread - no balls.-MondoMember, AWSLincoln ProMIG 140Lincoln AC TombstoneCraftsman Lathe 12 x 24 c1935Atlas MFC Horizontal MillCraftsman Commercial Lathe 12 x 36 c1970- - - I'll just keep on keepin' on.
Reply:Originally Posted by MondoI repaired a chair exactly like that a year ago last August.  I wire-wheeled off the paint, ground the breaks to clean off the broken weld beads, clamped it into place, wrapped a wet rag around the end of the strut and buzzed it together with my MIG.  Let it cool, wire wheel clean-up, added some Rustoleum rattle paint and it is just as pretty and stronger than new.  The owner is still using it and happy with the repiar.  I have pictures but don't dare post them here.   As I noted in another thread - no balls.-Mondo
Reply:Been there many times. Have welded some of the chairs more than once. Ive had to weld them up, then a year later they would break somewhere else. I had a cylinder pop once. Problem is they dont make the metal thick enough on the chairs now, but i dont see that changing anytime soon.Dave
Reply:Yes, the tag 'made in china' is a giveaway but is that where it was put together or where the steel was smelted?  Looks fixable.  Just bevel it for a nice strong weld and go for it.  I would say that warning to not heat the cylinder is just that.  Do not weld on it.  The only problem I would forsee is if there are any plastic bushings or rubber shock absorber in the middle there by the green cap.  Then, it would be a good idea to cut the other weld to take the cylinder off of there, weld the broken part and reweld the rest back on .... or just go buy a new chair that doesn't tip back.  Its hard to imagine but I am sure there has been at least one dummy that tried to make one of these a single height chair if his co-workers kept messing with it.
Reply:These where very common ones to repair. I was considering going around town and attaching a business card to all of them for sale: " when it breaks, call......."Always peeled open where the base spokes met the stem. The little plastic skirt covering the joints was the "cover of shame" Attached Images200amp Air Liquide MIG, Hypertherm Plasma, Harris torches, Optrel helmet, Makita angle grinders, Pre-China Delta chop saw and belt sander, Miller leathers, shop made jigs etc, North- welders backpack.
Reply:If you havent already fixed it, be very careful when you do. I read a story about one of the cylinders exploding and shooting some school kid in china through the bum-bum. It was a few years ago, and there is absolutely no way I could find it, but yeah... These cylinders make me nervous. Just be careful with yourself
Reply:I worked on one a couple months ago for the first time and I can attest to not wanting to heat up any part of that gas strut.  The tip of the shaft has a plastic button to deal with friction from the actuator plate for releasing the pressure in the strut for raising and lowering and due to its make up its soft and melts easily.  Theres also one of several seal rings inside and those melt easily to.  The frame itself is thin and may be chincy like chinese taco's so be sure to remove the paint and clean it good and watch your heat.Welding Supervisor Department of Corrections.
Reply:I always intended to followup on this project, in case anybody else has a similiar repair.--I ended up using a long brass drift and a hammer to tap the chair off of the gas strut.  As it turns out this worked quite well.  I couldn't swing the hammer in close without risk of damage to the strut.--I re-welded all cracks. While I was there I added an other piece of steel to close up the area of the design that allowed the cracks to originate in the first place.  I wasn't totally sure how to perform the plug welds, but I think I got it right.  --I know the welds aren't perfect.  Stay tuned.The chair feels very solid now. Attached Images
Reply:FYI a hammer is what they use to remove the strut from the base on those chairs. Recently had the strut replaced (defective strut under warrenty) on my office chair, and he just came in and beat on it a couple times. just a simple preasure fitting.There are no problems. There are only solutions. It's your duty to determine the right one.Hobart Handler 210Airco 225 Amp MSM Stinger