Carbon Fiber Tablet Mount - the Kindle Kradle




Introduction: Carbon Fiber Tablet Mount - the Kindle Kradle

About: I am a perpetual student, researcher, and hopelessly dedicated skill collector. I hope that you can find something inspiring or useful in the instructables I publish.
Intro: I recently joined the ranks of the Gadgetistas by buying a tablet (Kindle Fire HD if you must know).  While that may not sound like a big deal to many, for a guy who hates cell phones and doesn't own one, it's about as difficult as a bureaucrat being honest: it happens, but not that often.

While reading and watching movies on the tablet is super-nifty, holding it for two hours while reading or watching a movie is most definitely not.... and since I tend to do those things while lying in bed, I figured I needed to make a really cool bed mount.  (This is really nothing new for me - about 10 years ago, I built a "bed mount" for a portable DVD player that works like a charm - but this one had to be a step up - See Step 14).

Since I tend to use smaller projects as introductions to new materials, I figured this would be a great opportunity to introduce myself to carbon fiber and epoxy on a smaller scale in preparation for some much larger upcoming projects. 

Cost: is up there - I almost don't want to know - but I'd guess it's in the $300-$400 range with some of that being acquired tooling.  If building a bed mount was my only goal here, I would have chosen a different method, but since I tend to look at projects like this as a vehicle for learning a particular skill set and acquiring specific tools and materials,  I'm OK with the extra expense (how much would a college course cost you?).  A mount of the same design could be built for less than half by choosing different materials (fiberglass) and tweaking the techniques - for example, choosing a wet-layup over foam technique over vacuum bagging in negative molds (but would require more cleanup).

General Materials List:

RAM mount - Model RAP-B-138U (sometimes, it makes more sense to buy something if it will work)
Kipp (brand) Lever Clamps
Hard Maple - or some suitable hardwood not prone to splitting under focused pressure
Carbon Fiber Fabric (8K Twill in this case)
Fiberglass Cloth
Fiberglass Matt
Breather Cloth
Peel Ply
Vacuum Bagging Material (plastic)
Mastic Tape (For sealing vacuum bags)
Polyester Resin and MEKP
Polyester Tooling Gel Coat and MEKP
Epoxy Resin and Hardener
Epoxy Glue - 5 and 30 minute versions
Spray Adhesive (3M Super 77)
Fumed or Colloidal Silica (Smooth-On's Cabosil) (thickener for epoxy)
PVA (Polyvinyl Alcohol - not to be confused with Polyvinyl Acetate) - Mold Release
High-Quality Carauba Wax
Urethane primer - or a good sandable primer
Catalyzed Urethane Clearcoat
Urethane Reducer
Lacquer Thinner
Sulfur-Free Modeling Clay
Petroleum Jelly
Tempered Masonite (hardboard)
Melamine and assorted sheet stock
Smooth-On Plasti-Paste II (not required - just convenient)
Plastic wedges (SUPER helpful - worth every penny)
Chip (disposable) brushes, disposable graduated mixing tubs
Plastic squeegees (a couple will do - if you keep them cleaned off)
Mixing paddles/sticks
Gloves.... lots and lots of gloves.... A tyvek suit would be a good investment, too.
A **quality** Organic Vapor Mask and goggles
Vacuum Pump (some way of generating a vacuum)
Various fittings and tubing to run vacuum lines to your vacuum bag setup
Vacuum gauge - so you can see what's happening (probably not 100% required).
Sandpaper - Wet/Dry 320 and 400 - carbon fiber laminates eat this stuff quickly
Plus a bunch of smaller items like drywall screws, tape, hot glue, wood glue, carpet tape,
Miscellaneous tools: Drill press, table saw, bandsaw, router, dremel, files, wrenches, hand drills, saws, etc.

Safety:  As you can see from the above list, you'll be working with some pretty nasty stuff.  Since it would take me 30 pages to reiterate what already exists, I'll hit the high points of what goes through my mind when working with nasty/unknown materials:
  • READ the MSDS (Materials Data Safety Sheets) that come with chemicals and know what they can do to you.  This way, when you sprout that third arm because you were too manly to wear a vapor mask, you'll know why.
  • Don't overestimate your capabilities - always bet on the conservative side of what you can handle until you're in familiar territory.  It's far more embarrassing to lie on your garage floor crying for help than it is to approach things thoughtfully and progressively.
  • Think through your process - what safety gear and props (paper towels, solvent, etc) will you need?  What could go wrong?  What will you do if something does go wrong?  When you have a good idea, make sure all the things you need are readily at hand.  Having a helper would be a really good strategy as well - but you should plan as if they're not there.
  • When working with resins and epoxy, be *very* aware of what temperatures can do to your pot life and cure times.  Most pot life estimates are given at around 72 degrees F - and you can figure that for every 18 degree increase in ambient temperature your pot life will be cut in HALF.  Nothing sucks quite like being half-way through a layup or surface coat and have things start to gel - that's a mess with a capital "M".
  • Carbon fiber - once trimmed can be ninja sharpWatch out for those edges - and knock them down ASAP.   I ended up with a littany of little cuts because I'd read about how sharp CF could be, but didn't realize that they meant SHARP-sharp as opposed to worrisome-mother-sharp.
  • I can't stress enough the value of protecting your lungs, skin, and eyes at every opportunity - a $45 vapor mask is far cheaper than glass fibers in your lungs or being sick for a few days from polyester vapor exposure.  You have to live in your body for the rest of your life - don't screw it up if you can help it.
  • NEVER clean resin off of your skin with solvents.  Solvents will carry the resin molecules through your skin - directly into your bloodstream (especially acetone and reducer).  If you get resin on your skin, use waterless hand cleaner like Gojo Orange or similar.
Alright - enough Hall Monitor babbling.

I've included a few drawings - don't take them as set in stone - but they give something of an idea what I was thinking of ;)

I'd also recommend John Wanberg's Composite Materials Fabrication Handbooks

Note that there are SO many photos in this Instructable that I won't be doing a lot of writing - I'm going to let this be a "picture story" (my favorite kind!) :)

FINALLY: If you like this Instructable, please take a moment to vote for it in the UP! 3D Printer competition :)  Thanks!

Step 1: Making the Arm Template

I came up with two basic shapes for the arm.... and settled on the one that was harder to produce - lol.  I wanted to get an organic look with a nice sweep to it - kind of "bone-like" in Steam-Punk kind of way ;)

Step 2: Making the Plug - Part 1

Once the template is established, it's time use it to make the stack for the "plug" which will be used to make the molds.  Essentially, you're making the final shape that you want your part to take once it's transformed to a composite.

Step 3: Making the Plug - Part 2

Step 4: Making the "Tool" (Molds)

Again - polyester resin is nasty NASTY stuff - don't work with it unless you are in a well-ventilated area and have a VOC mask or fresh-air system.

How to apply PVA:  In a nutshell, not the way they tell you to (my first attempts sucked). 
  1. Use a small-orifice gun (1.0 or so)
  2. Use around 100PSI at the gun
  3. Dillute your PVA 50% with water
  4. Turn the needle on your gun all the way closed
  5. Back the needle out about 1/2 to 3/4 turn
  6. If you can see the PVA on the mold as you spray, you're spraying too much.  You should only be able to see the SHEEN from a glancing light.  Use several coats - putting it on this thin makes it dry almost instantly.

Step 5: Carbon Fiber Tips

A few simple tricks with Carbon Fiber material....

If I had to describe working with CF material, I'd have to say it's darn close to herding cats - it's awesome stuff, but you really have to develop a feel for it as it likes to act like it has a mind of it's own...

Step 6: Layup, Vacuum Bagging, and First Pulls

Vacuum bagging is a slightly frantic operation - so you want to have everything laid out before you move ahead: Cloth, resin, breather, peel-ply, bagging material, mastic tape, hoses, etc, etc.  You'll also want to cut everything to size ahead of time - the more prep work you do, the quicker and smoother the operation will go for you, and the less chance of messing up some rather expensive fabric and resin.

Step 7: Tablet Holder Plugs and Layup and Demold

The tablet holder, I decided, would be built using "sacrificial" plugs - both to try a new method and for expediency.  In this case, the PLAN is to destroy the plugs upon removing them.  Obviously, this is a suitable technique for a prototype, but probably not the best for production since it will create a lot of work on the back-end with cleaning up the layups (as you will soon see).

Step 8: Tablet Holder Construction

To improve the surface quality of the tablet holder parts, I decided to try a "float coat" of epoxy.  Overall, it gave me enough thickness to level the surface.  Epoxy is a great way to coat a surface - one layer of epoxy is equal to about 4 coats of urethane clear - BUT- epoxy that will be exposed to sunlight has to be UV protected either with an additive, or, with a UV resistant topcoat.

Step 9: Phenolic Hubs

Since the overall mechanism that locks the arm in postion is friction (via compression) - I wanted a "hub" that I could both glue and screw to the carbon fiber for maximum strength.  I thought about metal, but decided that I wanted to stay with something that I could work more easily - and materials on hand. 

Enter phenolic.

"Phenolic" is a material class unto itself - there are dozens of varieties with a range of substrates.  For the most part, it's a fiber substrate (cotton canvas, paper, etc) and a resin binder usually cured under heat and pressure.  It's a really tough plastic - and I had some on hand - so it became my "hubs" ;)

Step 10: Arm Alignment and End Block Installation

Aligning the arms took a little thought.  I needed to build a jig that would hold the arms in their final orientation and spacing so that they would not be under bending or twisting stresses (due to misalignment) upon final assembly.  I made a jig out of MDF - and cut the "hole" for the main shaft instead of drilling it to make sure it was straight and parallel.

Step 11: Building the Base

The woodworking part of this project went surprisingly fast.  I guess I was used to having to slog through 10 steps to get 1 final object - it was refreshing to work on the final raw material from the get-go :)  Building the mount assembly took less than a day, and is made from hard maple.

Step 12: Finishing

Ah, yes, spraying finish: a time of alternating euphoria and terror.  Moments of glossy goodness punctuated by orange peely and runny terror.  I've always heard the saying, "Nobody notices a perfect finish" ...... which means that all my finishes are doomed to be noticed - LOL. 

Maple - like Pine and Cherry - is very difficult to stain without blotching.  For this reason, I chose to spray NGR dye (Non-Grain Raising) - which is nice because you can "shade" the piece if you wish.  I mixed up a darker version of the base color to add a patina around the edges of the main mount body. 

For the clear finish on this project I used a catalyzed urethane - very tough stuff.

Step 13: Assembly and Final Details

Final assembly is always fun - it's like Christmas - as long as everything goes together the way you thought it would :)  All the pre-assembly and fittings pay off when the parts go together without drama - no last minute cussing and grinding....

Step 14: Beauty Shots

I'm pretty happy with this overall and I learned a TON in the process.  Funny thing is: as soon as I was finished, I was making modifications to the design in my head - lol.  Watch out for Tablet Mount 2.0! :)

I hope you enjoyed reading through this Instructable :)  If you enjoyed it, I hope you'll vote for me in the UP Printer Contest

Thanks for reading!

PS:  Be sure to check out the OM (Original Mount) in the next step...

Step 15: Origins

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    6 years ago



    9 years ago on Step 2

    Maybe you mention it later, but I'm thinking props need to go out to the Zyliss- the Zyliss rocks!


    Reply 9 years ago on Step 2

    Absolutely - I give it a lot more credit in my custom gun stock instructable - but it's one of those tools that once you have one, you kind of wonder what you did without it :)


    9 years ago on Introduction

    Wow .. you have made a text book carbon fiber layup in such detail that it should serve as a pre requisite to anyone that wants to use carbon or fiberglass for the first time!
    its taken me 2 years and alot of failed attempts to get items as good as yours!
    the only things i can think to add is to give the carbon pieces a light going over with a cutting compound like Farecla Profile 500 which will bring it up to a nice shine then spray it with a 2k clear lacquer (mainly used on cars) to give it the glossy look most professional carbon items have


    Reply 9 years ago on Introduction

    Thanks for the tips on finishing! I haven't looked into the cutting compound - but I probably will for my next CF project (an excuse to get a good buffer!). I'm also going to be looking at "GC50" which is an epoxy-compatible gel coat to achieve a very deep-looking finish.

    I didn't shoot a gloss clear on this project mostly because the furniture in my bedroom is semi-gloss and I wanted it to match - but my next project (CF wall cabinets) will probably get a mixed gloss/semi-gloss treatment.


    Reply 9 years ago on Introduction

    i havent used that one before sounds interesting for the polishing/sanding capability... i have had the clear epoxy gel coat from and its a nightmare to spray you need at least a 4.5mm nozzle which is not easy to get at a reasonable price which is why id suggest car clear coat which is a lot thinner.. the ones listed as 2k ive found best and most forums will advise...
    however the gc50 looks good just find out how difficult it is to spray before you get it as while it can be painted its never easy to get an equal layer with a brush and sanding is never fun hehe


    Reply 9 years ago on Introduction

    Thanks for the information on the GC50 - it's good to hear someone else's experiences with it. I would imagine the only way to apply it would be with a cup gun - and they're not cheap.... hmmm... maybe I should stick with spraying urethane.... The project I have in mind is mostly subtly curved flat panels - so getting a good even coat would be about as easy as it would ever get.... Part of the reason I was interested in the GC50 was because I want to use a heavy carbon spread tow as a "beauty layer" and didn't want to have to deal with print-through on the clear coat (which may or may not be a problem coming out of a female mold....

    Just to be clear, when I said a mixture of gloss and semi-gloss, I'm talking about a piece of furniture where the CF would have a gloss finish, and the wood and supporting parts be semi-gloss.


    Reply 9 years ago on Introduction

    Yeah I don't plan on making the lamp but the carbon fiber instructions are very useful.


    9 years ago on Step 15

    Stop doing this...!!! You are wasting your talent...!!!
    With your craftmanship level proper of a master artisan you could build Airplanes!!
    Very instructive and awesome!


    9 years ago on Introduction

    That is very VERY nice! I've made a couple of tablet/phone mounts for my vehicles out of sheet metal that have a similar cradle portion. Maybe that is what will be the project that makes me cross the carbon-fiber line that I've been putting off for so long! It just seems so cost & space & labor-intensive!


    Reply 9 years ago on Introduction

    Thank you! :)

    Yeah.... CF isn't a cheap date, that's for sure. A decent quart of epoxy resin and hardener (West Systems) is going to set you back $50-60+ and a yard of fabric will run around $40. Admittedly, I built tooling that would work for small-scale production and not really typical prototype tooling (because I wanted the experience). As far as the room required, it's not excessive, really - but you do need a space where having polyester resin fumes hanging around isn't going to be a problem for a few days. If you have access to sheet metal working tools, you can make forms for your shapes that will yield a nice surface finish - I would have gone this route for the "cradle" portion had I had access to the right forming tools.

    I'm planning on trying two other techniques for CF - a positive silicone insert for the mold and possibly a fiberglass male/female mold. Both of these techniques use more mundane clamping pressure during curing, and don't require a vacuum pump, mastic, bagging material, peel ply, breather, hoses, valves, etc, etc. so the layup process should be a little easier. I'd also like to try using Hydrocal as the mold material - just to see what it would take to get it to work (it'd be much less expensive than fiberglass) I'll be sure to post Instructables on those techniques when I get to them.

    Sleep E
    Sleep E

    9 years ago on Step 15

    You have the character of an old world craftsman and the technical acumen of a modern day master. Beautiful work!!!


    9 years ago on Introduction


    Please inform your selves.
    Carbon fibers may be more cancerous than asbestos.


    Reply 9 years ago on Introduction

    While I can't find any information that backs up the claim of CF being a carcinogen (what *isn't* in sufficient quantity?) this just reinforces what I've always believed: Read the MSDS's. Protect yourself from dust of any kind. Keep solvents and chemicals off your skin. Most chemical damage is cumulative - so it can seem like they're not affecting you until a ways down the road when suddenly you might suffer some pretty serious reactions to exposure.

    While CF itself isn't that dangerous (no more than fiberglass), sanding epoxy resin that isn't fully cured and breathing the dust is - so always wear a good quality mask or use a fresh air system.  I don't think anyone ever ended up with cancer from breathing too much clean air


    9 years ago on Introduction

    Holy cow! First off, I have no current plans to do any carbon fiber work myself, but I'm so glad I took the time to read your Instructable. It is so excellently done, the photos are fantastic and the level of detail compelled me to read every bit of it. Thank you so much for taking the time - just stopping and shooting all the photos had to add hours to your project, plus the time and effort you clearly put in to your annotations and uploading the entire thing.

    The actual project itself seems rather daunting to me given the "positive-negative-positive" steps required, combined with all the layers of chemicals and whatnot, but sadly, my wife just looked over my shoulder and saw the final page of beauty shots. The sound she made means I'll likely be attempting this (or something similar) at some point in the future. At least I know where to come for a fantastic set of instructions.