The Original Shell Chair Restoration Guide

Here we’re going to walk through an armshell shock mount move and restoral. First of all, in this instance I had run across some orange arm shells that were set up as ‘wide mount’. The first thing that needs to be done is remove the old mounts. I’ve heard a couple ways to go about this such as tightening the bolt all the way down to pull the mount off (which I do not suggest as it can crack the fiberglass on the other side very easily). The way I go about it is to take a sharp flat head screw drive and a rubber mallet and tap around the outside to remove all visable epoxy, then lightly tap under the mount and pry lightly up around the sides untill the mount losens and comes off easily.

After all the shock mounts have been removed, you’ll need to get rid of any existing epoxy left on the chair. I do this by using a coarse sandpaper on an orbital sander to get the majority off, then switch to a medium then to fine for the finish.

Once that work has been completed it’s time to mount the shocks to the standard narrow mount, so it will be able to take any or the various bases available. For this I use a spider base from a tandem set up. I’ve found it to be the best way to get an accurate lay out of the mounts. I first attach the mount directly to the spiderbase finger tight. Make sure that they center in the holes. Then with the chair upside down, place the spiderbase set up onto the chair so that the shock mounts line up on the ‘flat spots’ already on the chair for the narrow mount.

Once that is set and centered outline the outsides of the shock mounts with a marker.

You now have an accurate mark for where to place your mounts. You can use just about any two part epoxy to mount your shocks. I’ve found that JB Weld Quick set seems to work the best for me and looks most original after the fact.

Mix enough of the epoxy so that you can get at least 4 quarter sized globs.

This epoxy sets quick, you only have a couple minutes once you place it on the chair to get your mounts in place. So be hasty when placing your mounts. The reason I suggest a quick set epoxy over one that takes 8 hours to set is because your mounts will drift out of place with other such epoxies unless you keep them held into place.

Once you have them set in place keep them held there for a good 5 minutes to make sure your mounts dont float out of place. After the 5 or 10 minutes, remove the screws and the spider base from the mounts and let the epoxy cure over night. You want to remove the screws before it completely cure as to avoid the screws being epoxied to the mounts.
As far as moving the shocks goes, you’re done. Next we will be restoring the fiberglass back to original luster.
Here we start be smoothing the edges with a fine wet sand. For the wet sand get a squirt bottle, put a couple drops of dish soap on the botton and fill up with warm water. Wetting the area as you sand will prevent fiberglass dust from getting everywhere and save you and your lungs from an uncomfortable itch.

Go around the edges and smooth them out, then move to the rest of the chair doing a fine wet sand to the entire area, until the entire chair is smooth.

Once the entire chair has been done, rinse it off with water to get rid if any of the exsisting dust and let it air dry. (drying with a cloth will leave fibers that will show up in the coating process later).

The chair is now ready to coat. For this I use a product called ‘Penetrol’. This can be picked up at any home center, is used to restore fiberglass and has many other uses such as an oil paint conditioner.
If you are in Europe, Try searching for a product called “Owatrol“. It is apparently the European equivalent!
Try our link to find some Owatrol

Make sure and wear gloves while applying Penetrol, you don’t want to get this on your hands or anything else as it’s next to impossible to get off.
Use a lint free cloth for application. Soak the cloth in the Penetrol so that it is fully saturated. Apply the Penetrol liberally so that it will not leave streaks. Make sure that you don’t put so much on as to cause dripping or sags though. It may take a little practice.

Apply first to the bottom of the chair, let it it set for a couple hours then attach the base, flip the chair over on it’s base and apply to the rest of the chair.

Once it has been applied, place the chair in a safe dust free enviroment and let it cure for a couple days. Penetrol take quite a while to dry as it’s an oil based product. This as well makes it stronger and much more durable than a standard clear coat.

Once your chair has cured, it’s ready for use and will look like new for years to come.

*Disclaimer – This is just what we found effective! We take no responsibility for your chairs :)

Find Owatrol in the UK

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392 Responses to The Original Shell Chair Restoration Guide

  1. John says:

    I’ve come across some side shells which have legs with the holes drilled through the seat. I plan on replacing these with shock mounts, knowing that the holes will be visible. Do you recommend a particular resin or epoxy (other than JB Weld) that is good to fill the holes and other chips around the edges?

  2. Pingback: another Eames Chair Restoration | Maison Kuotidien

  3. Frank says:

    Hi, thanks for the restoration guide…My only concern is…by sanding the surface of the shell chair, are you sanding off the original color, which reveals a grayish undercolor in the sanded spots? OR, is the color of the chair saturated throughout the fiberglass, and the Penetrol revitalizes the grayish undercolor to whatever the original color is?

  4. Larry says:

    The color goes through out the chair. The resin used to make the chairs is dyed, that’s where the color comes from. You cannot sand the color away.

  5. Harry says:

    Thank you for this pictorial and the great images! I have a padded chair from 1983 that I am hopefully attaching some image links here… And I have the base that I also show. How does this base attach to this shell? No mounts needed? I have a set of the mounts you have talked about from ebay – could I use those with the longer screws? Should I? And in that case, is epoxy still needed? Thank you for your help and effort!

  6. Larry says:

    No mounts needed on the upholstered chairs. Just a rubber washer between the seat and the base then a bolt into the threads.

  7. Harry says:

    Nice, thank you! I will see if I can find some rubber washers at HopeDepot or somewhere like that.

  8. Harry says:

    Thanks again Larry – this is what I ended up doing!

  9. ivy says:

    hi, i have a cream colored shell that’s been verrrryy weathered and dinged up. what is the best way to paint it?

  10. Larry says:

    I wouldn’t paint it, I would use our restoration guide to restore it.

  11. Monika says:

    Hi, I have an upholstered original 1971 shell chair that I’d like to reupholster. I see that you can still buy the Knoll Cato fabric. Do you know how many yards are required?

  12. Larry says:

    Though I’ve not done it myself, I can’t imagine that 1 linear yard wouldn’t be enough to do an arm shell.

  13. Ty Milford says:

    Do you have any recommendations for adhesive for the semi transparent shells? I have a lemon yellow that had a white looking adhesive on the original shock mounts and I would love to replicate that look and also not risk the dark of the JB Weld grey seeping through. Would love any feedback you have.

  14. Larry says:

    Two part epoxy comes in a lot of colors. Any good two part epoxy should do the job. I just suggest the JB because for all the chairs I’ve done, it seems to look closest to original.

  15. Dick says:

    Thanks for the great info. Can you give me an estimate of how much Penetrol it takes to do a shell chair? I want to start with one or two but have 10 of them in varying stages of deterioration. How many might I be able to do with a quart? Thanks a lot.

  16. Larry says:

    I would say a quart would do a good 20 chairs.

  17. Sarah says:

    Have you ever tried to put a reproduction Eames base on a Krueger fiberglass shell? I am hoping to do so, it has a cushion that covers up existing holes for what was a base, but when I found it at a salvage place for $5 it had no base. I am hoping the curve of the seat is similar enough to install a repro. rocker base, even if I have to drill holes…

  18. Larry says:

    I’ve not tried to, but I don’t see any reason that it wouldn’t work.

  19. Tiffany & Co says:

    Greetings! Very useful advice within this post! It’s the little changes that make the biggest changes. Many thanks for sharing!

  20. Sean Nelson says:

    I picked up some Penetrol from Home Depot the other day, but the label says “paint additive” and not “paint conditioner.” Is this the same product? Thanks for your help!

  21. James says:


    Ive found some fabric DSX chairs that Im thinking of buying. I was wondering if anybody knew whether its possible to remove the fabric and just use it as a shell chair? The Fabric DSX chairs seem really cheap compared to the shell ones. I could be wrong but Im hoping they’re the same shells. Any info would be great!

  22. Larry says:

    It is the same.

  23. Larry says:

    The shell is the same but instead of epoxying shock mounts on it, they have holes drilled in them and hardware placed through them for the base to mount to. So you can still use them if you remove the fabric and foam, but the hardware is visible.

  24. Julien says:

    Great guide! Many thanks!

    I just bought two chairs with wide bases, and I’d like to replace those for Eiffel narrow bases. Problem is one of them has holes drilled through it.

    I know from a purist standpoint, it’s probably heresy, but how would you recommend I fill these holes? Epoxy? Resin? Any brand in particular?


  25. MAH says:

    This is great information. Does anyone have a fix for the shell seams that have separated? Thank you.

  26. Ruth Biggs says:

    I have a Herman Miller shell arm chair that had been poorly painted baby girl pink by previous owners, including the metal legs, the shell was then spray painted bright green which left light and dark spots. What would be the best method to remove both paint colors. The original color is unknown. Also, there is a small crack on one side of the seat where is starts to curve up. Will be grateful for any information. Thank you!

  27. Larry says:

    Sounds like a lot more trouble than it’s worth. Paint is a tough one. Depending on the type of paint there are various ways to remove it that can be searched out on the web. You may want to identify what type it is first. Oil or latex. After putting in many hours trying to get the paint off the chair, I think you’ll find that the fibers have soaked up a lot of color that is next to impossible to get out. And then there’s the crack. I’ve tried extensively to repair cracks in these chairs. All attempts have failed. I can make them look good, until someone sits in it and causes any stress, then it just cracks again. I have tossed several chairs in the trash for just that reason. So if the cracks not all that bad or in an area that doesn’t take stress, my advise for a chair like this is to just go ahead and paint it again. Sand it all nice and pretty and paint it. I have several like this that I use for outdoor chairs.

  28. JD says:

    I just purchased 2 fiberform chairs that are white/cream with lots of surface scratches/cracks. Will this restoration process remedy those?

  29. Larry says:

    So long as they are fiberglass, yes.

  30. JOJETT says:

    I am restoring some Light Ochre shells and the epoxy is a yellowish color (I’m guessing to match the chair color somewhat) and once I removed all of the shock mounts I used a heat gun to remove the remaining epoxy and its leaving a bright yellow spot even after sanding. It seems like the epoxy permiated into the fiberglass on the bottom of the chair because I cant even sand it off? They are on the wide mounts and I am changing it to the narrow mounts so it looks terrible with 4 bright yellow spots (even though its only on the bottom of the chair). Have you ever had this issue? They are the older chairs with only the Herman Miller insignia embossment and a sticker.


  31. John says:

    Hello, I love your restoration guide. I recently purchased and restored 4 white shells. I have sanded them and cleaned them up but now I would like to seal them. I have read that penetrol causes yellowing after some time. My question is what is a product that I can use to seal or at least protect the fiberglass from getting dirt lodged in it? Thank you very much.

  32. mark ilvedson says:

    My sister scored a couple of 1960s seafoam shells on the cheap that were in sad, sad shape. Honestly? Upon seeing the images, I feared they were probably a lost cause. Never mind how filthy they were. There was also rust. Paint splotches. Odd staining of indeterminate origin. Yikes! Yeah, I wanted to be stoked at the find, but bah! They seemed to me to be beyond hopeless. But she cheerfully sent me the link to your restoration guide and I was like, um, sure. Lets try it…
    I’m always up for a project and if we failed it’d be a nobel failure…

    WOW! It really was pretty damn easy! We faithfully followed your finish guide step by step (our shock mounts were a-okay) and the results were mind blowing. And with very little effort. I mean it didn’t take THAT much wet sanding even.

    Here is my — been there, done that tip. Definitely invest in the Oxiclean laundry stain remover spray. We used that to deep clean the chairs — I think we got that tip from another website that had used the Chairfag guide as well — and it worked SO much better than just plain soap and water. (Which we tried with not great results before heading out to Target to grab some Oxiclean.) We liberally rubbed and smeared it all over the place — then simply let it sit a good while before eventually wet sanding — or oxi-sanded the shells. ALL of the deep down ingrained dirt simply vanished.

    The Penetrol step was the hardest — but by taking out time and not rushing it, the chairs came out great. I simply can’t believe how great mine looks. I love it!! It really was rewarding to basically bring such an icon back from the dead — or, shudder, the dumpster! Thanks, Chairfag! Don’t be intimidated, folks. It really is just as easy as Chairfag makes it out to be.

  33. Larry says:

    It’s tough to over sand, you can do quite a bit of sanding. Don’t be afraid of hurting the chair, fiberglass is really tough. Smooth as in not being able to feel the fibers, yes.

  34. Larry says:

    I’ve not run into that problem at all. I’m sorry, I have no good solution for you.

  35. Larry says:

    I would still use penetrol. I started restoring these chairs 10 years ago, and have a white arm shell I did way back when. It hasn’t had any problems with yellowing. You won’t find a better finish for your fiberglass chairs then penetrol.

  36. Larry says:

    I love when people have a great experience with our guide. Thanks for the kind words and further advise.

  37. I am hoping this restoration will work for me. I have a round white fiberglass Contemporary (pedestal) Hollen table and five swivel chairs that I love, but it looks grungy and is hard to clean. The white doesn’t seem to be as uniform as it was once. It will be a lot of surface to restore. It has never been as shiny as the shell chairs shown in this string. Should I be concerned? Any suggestions or tips for me?

  38. Dave says:

    Ran across two armshells painted red. They were cheap so I decided to restore. I had them blasted with crushed glass. It got all of the paint off except the stuff soaked into the fibers. Turns out they are seafoam green. I dont want to give up on them. Any advice on how to remove the stubborn stuff? Thanks.

  39. Larry says:

    I don’t have any good advise for that. I’d have thought bead blasting the chairs would have destroyed them. I tend to just repaint already painted chairs and use them for outdoor furniture. Sorry I’m no help.

  40. Larry says:

    I’d just dive in and do it. If you feel it’s too shiny in the end, you could always hit it with a super fine steel wool to change the finish.

  41. Erika says:

    Where can I get a spider base to help mount the shocks? If there are flat spots on the shell where the old mounts were do I need the spider base?


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