To make the seat stand fully up at all time I needed a cylinder (excellent compression resistance when the force is perpendicular to its circular bases) that I could slide along the strut, ideally without play –so a perfect fit. And I found just the thing I was looking for: a piece of PP water pipe, 32mm exterior diameter and 1.6mm wall thickness; it fits so well, it might as well have been designed for this purpose.
To prevent the edges (bases of the cylinder) from splitting, I tensioned them using zip-tie loops. I found the zip-ties in a Corsair computer power supply box, so if you kept everything that came with the power supply of your old computer you might find some there.
--Polypropylene(PP) water pipe: 32*mm ext. diameter, 1.6mm thickness, length bigger than 130mm but anything you have laying around the house is ok if it fits your optimum seat height;
* different chairs may use different thickness gas struts so make sure the outer diameter of the shiny part of the strut exactly matches the inner diameter of the PP tube !
--rubber head hammer or regular hammer wrapped in a cloth so as not to damage the chair
--measuring tape or other measuring tool for measuring the optimal length of the tube
--a marker for marking where to cut
--a cutting tool for cutting the PP pipe with;
--optionally, a 4*mm hexagonal key or 10*mm hexagonal socket for removing the seat and backrest ensemble in order to make handling easier.*my seat uses hexagonal screws that require the 4mm key, yours may require a different size so take a look at it first.
Step 1: Optional Step – Remove Seat and Backrest Ensemble
Step 3: Step 2
Step 4: Step 3
* If you want a lower seating position then cut a smaller length piece; however, by cutting a piece smaller (say 90mm) than the length of the strut(127mm), when you sit on the chair it will collapse 127-90=37mm and ram the PP tube with the momentum of your weight times the speed it has gained in those 37milimeters, potentially reducing the tube’s life. You can increase the tube’s strength by adding zip-tie loops, tightly tied to its circumference; then, it should be fine.
Voila! the part you need. I tightly tied zip-ties at the points where I thought it was most likely to fail in case of uneven loading;
Step 6: Step 5
Step 7: Step 6
Step 8: Step 7
Step 9: Step 8
You've done it! The seat is usable once again.