HOW TO: Make a Carbon Fiber Part (Part 7: two part piece and final steps)

HOW TO: Vacuum formed Carbon Fiber Part for $200 (Part 1)
HOW TO: Make a Carbon Fiber Part (Part 2: making a clay mold)
HOW TO: Make a Carbon Fiber Part (Part 3: making a fiberglass mold)
HOW TO: Make a Carbon Fiber Part (Part 4: making the budget vacuum bag)
HOW TO: Make a Carbon Fiber Part (Part 5: mold prep and cutting CF)

HOW TO: Make a Carbon Fiber Part (Part 6: vacuum bagging CF in mold)
HOW TO: Make a Carbon Fiber Part (Part 7: two part piece and final steps)

So after a total of 12 hours the part seemed hard enough to turn off the vacuum and peel away the clay... you can re-use and re-use the clay... I just put it into gallon zip-lock bags and add about two cups of water in to re hydrate the clay again. (This obviously cured at room temperature in my garage.)

Got the part out of the bag and the breather cloth is still on the peel ply etc.

The perforated wax paper worked as a great alternative to peel ply

The little scraps of wax paper peel off no problem

Just for reference the part isn't fully cured yet and to show this I was able to cut some of the loose threads... the part is about as stiff as cardboard so don't take the risk of deforming your part to cut all the excess off or anything.

It's still in the mold 

and a trick to speed up the curing process and possibly make it even stronger than a full "room temperature cure" is by putting it in the oven. HOWEVER, be very careful as your resin or mold may be flammable or if your part is heated too much air bubbles can form in the faster curing set up. So I set my oven to the lowest temp possible of 170 degrees Fahrenheit and kept it cracked open. Turning the set up every couple minutes. 

When it reached about 125 degrees Fahrenheit with this candy thermometer resting on it I decided that was warm enough.

When it cooled back down to room temp (after about 15 minutes) It came out of the mold with little effort.

Here it is fresh out of the mold

After it was out for a couple hours it still felt slightly plyable so I decided to put it in the oven for another warming session... I have no idea if this makes it stronger than if I'd just left it alone for a few days to fully cure. I highly doubt it makes it weaker since I heated it up to only 125 ambient temp in the oven (not a core temp from inside the part). After this last heating, it felt fully cured.

Even in the rough state it was looking good

So to make the cowl be a working part that could attach to the existing hinges I first put a layer of plastic in the trunk (to avoid a mess). Then I piled in my clay and leveled it nice making sure it wasn't compressible in any areas.

For the bottom pan I used just two layers of 12K plain weave CF. And I placed a layer of Syrian wrap in between the clay and the carbon fiber pan I was making here. 

Having already gone over the whole bagging process I won't bore you with the details. Here I sealed the set up under a plastic sheet cut to fit and sealed with duct tape. Hind sight this was barely adequate, but since it's non-structural or even cosmetic I didn't mind. I was more/less just testing the idea of making the part this way. I taped down some tubing to get the CF to better comply with the details of the mold on the outside of the bag, but under the tape. 

Here it is right after about 14 hours of vacuum bagging. Pretty much fully cured.

As you can tell the mechanical compressing of the vacuum was enough to push the vacuum tube under suction into the clay and thus deforming the part. This is valuable info for me not to make a show or structural part on a clay mold.

So now you can measure and cut down your part with a cut off wheel since it's fully cured.

This was just the first rough cut... you can always cut off more. As you can see the flaw that was created from when I was trying to put my wetted out cloth in the mold into the vacuum bag... Again, having some wax paper or plastic over the edges that are tacky and can get pulled away from the mold easily is a good idea. You can also see I completely gave up trying to save my paint job.

Measure, Measure, Measure... here's a second cut down. Just showing you all this in case you can learn at all from my process.

Getting there

Cutting the pan down, using a file for the minor adjustments

Still rough

Almost

Good:

Pan inside cowl, good to go to bond

Since The Max clear 1618 is meant for vacuum bagging it was too thin of viscosity to bond the two parts (think the viscosity of honey or warm ketchup)... it's just going to run down into the crack. This two part epoxy from the hardware store is more like the viscosity of craft clue like "elmer's glue" that has chemicals in it that quickly evaporate within minutes to get progressively thicker until hard. 

While bonding I secured it down

After it was bonded it didn't look that much different

After the two were joined together I added more epoxy to the seam

Great fit underneath when I took the back of my bike off.

I taped off and spray painted the graphics I wanted on the part... hindsight this was a HUGE waste of time, effort and resources... it would be far more appropriate to have just got vinyl decals made and clear coat over them.... on the top left you can see how "orange peel" the surface of the part was when I applied a coat of Max Clear 1618 epoxy on the top of the part. Max Clear HP epoxy resin may have provided the "clear coat" effect I was looking for... instead I just used rattle can clear coat that I had been happy with the results to get the final product seen here.

Sanded down the paint job I ruined on my tail

Now to make a Carbon Fiber tail out of a two piece mold... I tried outlining the areas I was to cut out with Elmer's glue to prevent fraying of the fiber matrix after cutting... It seemed to work. I of course let this glue dry overnight so the bead of glue would hold the cut out and the remnant matrix together. Today I don't use the glue technique I simply cut the excess off in manageable squares and stack them up for use in small projects.

You can also see I was repeating the process of using a piece of fleece as a template (the tan fleece)... It's also nice to keep if you ever want to make another part.

The little 3cfm vacuum pump had enough power to do two parts at once

Using carnuaba wax mold release allowed the parts to pop out clean and with a much more smooth finished look.. the chalky appearance is due to the carnuaba wax that isn't wiped off yet.

Before I bonded the two pieces together.

After they're bonded together and before any paint.

Put together on my CBR 929.... now to do the subframe.

(see part one of series to see the picture of the subframe)

"So what's the point?" people ask. Dropping half the weight of your fairings isn't a bad deal is it? (This is a fiberglass cowl I made but never finished... it's a wall hanger just because I ended up getting it signed by Jason Britton and Tony Carbajal

Best of luck on your project!

-Matt Behning

HOW TO: Vacuum formed Carbon Fiber Part for $200 (Part 1)

Hi, Matt Behning here with another $200 high quality mod. This is part 1 of seven:
HOW TO: Vacuum formed Carbon Fiber Part for $200 (Part 1)
HOW TO: Make a Carbon Fiber Part (Part 2: making a clay mold)
HOW TO: Make a Carbon Fiber Part (Part 3: making a fiberglass mold)
HOW TO: Make a Carbon Fiber Part (Part 4: making the budget vacuum bag)
HOW TO: Make a Carbon Fiber Part (Part 5: mold prep and cutting CF)

HOW TO: Make a Carbon Fiber Part (Part 6: vacuum bagging CF in mold)
HOW TO: Make a Carbon Fiber Part (Part 7: two part piece and final steps)

Anyone can go out and start making carbon fiber parts with all the "kits" out there, spending $400+ getting the expensive: peel ply, vacuum bagging film, bagging tube fitments, one way valves, double sided bagging tape, special breather cloth, mold release, and other components. This is a how to on making the exact same high quality CF part with alternative tools for about $200 (start to finish); all the while using the highest quality Carbon Fiber and Resin. I'll show you what works and what doesn't. It's not as easy as the youtube videos and other write ups make it look.

Here I'm going to make a carbon fiber cowl. This is for my 2000 Honda CBR 929 which have built the tail out of carbon fiber. But you can make anything for your car, boat, house, etc. Using these instructions you can learn to make a DIY carbon fiber hood, instrument panel, brace, a boat, cover, tail gate, bike frame, seat pan, etc.

I make rear sets out of carbon fiber

More of my experience making carbon fiber parts

Practiced different mold and vacuum bagging methods until I found the correct process 

Highest quality CF-$17 a yard (you'd need only a half a yard tops for a small part 3 layers)

24oz high quality epoxy resin-$25

small electric vacuum pump-$60

Digital scale:$7

4 mil poly plastic film sheet for bagging- $10

Duct tape- $6

Painters tape-$5

water based clay-$10

carnauba Wax-$5

Fiber glass cloth for mold-$10

fiber glass poly resen-$15 (or you can use the epoxy resin that is about twice the price ounce for ounce)

80grit and 220grit sand paper-$6

clear vinyl tubing 1/8" and 1/2"-$4

foam brushes-$5

rubber gloves-$5

two 1/4 x 1-1/2" bolts-$2

Things you need that you probably already own:

-plastic cups

-cling wrap

-measuring tape

-scissors

-puddy knives 

-a drill

-a wood drill bit (any size around 1/2")

-an old sweat shirt or fleece fabric

-wax paper

-wire brush or wheel

-old spray bottle (use an empty windex or something)

-old piece of 2'x'1'x1/2" piece of wood

-old juice or milk bottle

-piece of card board (cereal box works)

-string

Vacuum bagging is the gold standard in getting the best/strongest end product, as opposed to "free lay up." Which is saturating the carbon fiber cloth the best and most even you can, without adding too much weight in excess resin; avoiding trapped air bubbles; getting the wetted out cloth to conform to the mold with gravity; on and on problems exist when you attempt to save time and effort by not using vacuum bagging.

The parts I made were made using the professional industry standard of vacuum bagging, (but in my budget method)

First thing to understand is there is some basic Carbon Fiber terminology to know before you buy. (my un-official understanding)

1.) Never buy anything except the PAN manufacturing process (pitch process is less quality)

2.) Never buy CF that doesn't come on a roll... usually they come on rolls 50 inches wide and can be purchased by the yard... average price is $20-25 a yard that is 50 inches wide. Folded or remnant fabric left over from other people's projects is just a gamble.

3.) Pre-preg carbon fiber- is great. However it needs to be stored in a freezer because the resin pre-infused CF cloth will cure at room temperature eventually. (can be shipped to you at room temperature fine). ALSO, you need an oven big enough to bake your part in on a mold that can tolerate up to 500 degrees... take away: leave pre-preg CF for the pros that make lots of parts from expensive molds in big ovens. 

4.) Weave- that is the orientation the groups of tiny strands of carbon fiber are arranged in when the manufacturer produces the "cloth" sheet of carbon fiber. Not all weaves are created equal

HOW TO: Start DIY Carbon Fiber. (Layers, weaves, resin) Test results too!

For example there is:

Twill: the classic "carbon fiber look"ie: 2x2 twill ... that means two bands of CF are patterned next to each other in the weave 

Plain: that is the classic checker board looking weave... 

5.) Tow- that is talked about in "k" or thousands of units. I test 3k tow (2x2twill weave) CF that means there are 3,000 filament strands of CF in each thread group of CF that is being weaved. I also test in this experiment 12k tow (Plain weave) that means there are 12,000 filament strands of CF.... naturally the higher the tow, the thicker the fabric will be... but as you will find out in the testing... that doesn't mean it'll be stronger. See the picture of the ebay seller I bought from and the two fabrics I purchased from them:

6.) weight or GSM- it goes up with the higher the tow and better weave you buy. My 3k tow 2x2twill weave has a weight of 5.7oz per yard squared If I wanted to pay 30% more I could get an even tighter plain weave from Hexcel with the same 3k tow strands weaved in a product that is 5.8oz per yard squared. these two 3k products can be converted to a weight of about 200 Grams per Sq meter. The 12k product I was using is 300 GSM. 

7.) Resin- is the liquid product you mix with the supplied hardener that cures (without the need for air, because it doesn't dry). Usually a 2:1 formula. Google it if you want to know more. The main thing you need to know is that you should buy epoxy resin

as opposed to cheaper polyester resin that is available at the hardware stores. Epoxy has superior strength, UV light protection, and clarity. You get what you pay for with resin so do your research. I used "Max Clear 1618 epoxy resin" I've also used "Max Clear High Performance epoxy resin"... but the 1618 is slightly more fluid and better for vacuum bagging since it soaks into the CF better.

I come to you with this budget how to after completing basic experiments like this:

That Vaseline is NOT a good mold release:

Strength testing and weight comparisons with different weaves and layers of Carbon Fiber:

And making these couple two piece parts:

Plus lots of messing around with free lay up etc wasting CF and epoxy to self teach myself:

or "a single piece of duct tape will seal a home made vacuum bag fine" That's false, along with 13 other designs I tried. Everything from medical tape, truck bed liner sealer, hot glue, heat gun sealed, plastic, ziplocks, and different types of plastic.

You can also save a lot of time here learning the skills no one else really posts about, like how to make a clay mold. 

1.) Clay was too moist when molding the clay so it dried incorrectly and cracked (turns out you don't have to let the clay dry)

2.) tried to salvage job 1 and found clay was too inconsistent to proceed to casting

3, 4, 5) was a week long pain staking attempts to use foam and it turned out to be FAR more time consuming than working with clay

6.) Complete restart, made this up in short three hours... now to casting

7.) LOL, spraying some "great stuff" foam into a mold was a disaster