Fun With Carbon Fiber

[mtbbker]

Originally Posted by therivermonster

I had the day off, so I continued with the vacuum press project. The vacuum pump and a few other parts arrived yesterday, so I'm ready to rock and roll.

The paint had set, so I tapped the 1/4NPT threads into the main vacuum chambers.


After the tapping was complete, I threaded the tanks onto the main manifold that I had mocked up for the tank fitting. They fit well.


Then I unscrewed everything and applied Teflon tape in preperation for the final assembly of the manifold.


Next I assembled the pump manifold and attached the free air chamber. The small yellow chamber allows the vacuum pump to restart and spin up while there is vacuum pressure in the system.


I figured that I better get started on the caddy, so I began test fitting the components.


Then I cut out the pieces, hit them with the router, and glued and screwed them together.




It looks OK enough that I feel comfortable that it'll work.

The tanks needed to be fitted. I taped them into place while I fit, cut, marked, fit, and cut some more until I had worked out the clamping system to hold them onto the caddy.


After fitting the vacuum switch, electrical box, and did a bit of wiring it was finished. Now it was time for a leak test.

I closed the main valve and fired it up. It pulled 25" in about 30 seconds and held it. No leaks in the main system. Yay!!!

Here she is, ladies and gentlemen...






I wired the system with two switches. The switch on the left turns the system on with the vacuum switch enabled. Once the system pressure reaches 24", the vacuum switch shuts the pump down. If the pressure rises above 21", the vacuum switch restarts the pump until 24" is reached again.

I added the right switch into the system to allow me to run the system continuously. When I turn that switch to "On" it bypasses the vacuum switch and runs the pump until the switch is turned off.


So the system works, what's the next step, right? We'll lets lay up a few layers of CF in the shroud mold and see what happens.

I layed up 3 layers of CF fabric, then layed down the peel ply, perferated plastic, breather, and finally the vacuum bag. The vacuum bag was the trickest part to apply, but I think that I learned enough to make the next go-round much better.

Here is the mold ready for the vacuum line.


I opened the main vacuum valve slowly while I messaged the vacuum bag into place in the mold.

Here you can see the breather/bleeder fabric absorbing the excess resin from the composite.


Here is the new vacuum press system pulling a nice solid vacuum on the mold. I'll have to say that I'm very happy and satisfied with the days work. The vacuum press works well, and I have a great idea how the vacuum process works. Now we'll just have to see what the part looks like.


I'll post the demolding process for our first vacuum part. More to come soon...

I can't wait to see the result

[JimVonBaden]

Nice work!

Jim

[therivermonster]

Of course the first thing I did when I arrived home from work today was break that mold open. Without further delay, enjoy the video...


This process was a great learning experience, but I have some ideas on how I can maybe make the part quality better. I'm thinking of making a video of the layup and bagging process. I'll post it as soon as I can.

[therivermonster]

mtbbkr and Jim, thanks for the kind words!

Let me tell you, this stuff is a tone of fun.

[JagLite]

Beautiful work!


That vacuum pump is excellent.
Thanks for posting the link to the kit supplier.
You built a top quality shop tool.
Before too long you will be making your own CF wheels!

[therivermonster]

Originally Posted by JagLite

Beautiful work!


That vacuum pump is excellent.
Thanks for posting the link to the kit supplier.
You built a top quality shop tool.
Before too long you will be making your own CF wheels!

Thanks JagLite!

The vacuum system is working perfectly. I really can't express how happy I am with how it turned out.

As for the first vacuum part, the part did end up with a few flaws, however not many. The part feels very light and the lines look very crispt and clear.

I can certainly see how wet layup skills are still very much a requirment to create a quality part, so I need to continue to work on that aspect. Also, there appears to be a certain skill set that comes from experience vacuum bagging a wet laminent. These skills involve being able to cut all materials to the proper size to begin with, which is complicated with a deeper mold. Also, you need to be able to place the materials in the wet mold in such a way as to avoid bridging. All the material needs to settle solidly against the fabric, which in turn is settled solidly against the mold. I believe the final skill is being able to apply the vacuum bag to the mold in such a way as to avoid vacuum leaks, and of course make it possible for the vacuum bag material to touch every single square inch of the mold under it.

The thing is, you have to cut the vacuum bag larger than the mold is so that it can reach down into the mold and into all the nooks and crannies, which the mold we have been using has many of. The vacuum bagging material that was used in the above video is Stretchalon 800. This material does have the ability to stretch a bit to reach those tight corners, but you don't want to count on it.

I think that I'm going to layup one more part in the mold today with six layers of CF, but I'll make the following changes to the procedure.

First, I'll place the vacuum bag tape directly to the bagging material in the prep stage. Then, when the layup is in the mold, I'll apply the bag and tape to the flange. This will allow me to more accurately place the bag on the mold and make it easier to create the pleats in the bag which are necessary because there is a larger surface area of vacuum bag then there is mold, and the pleats allow the bag to be "tucked" into the mold with out wrinkles.


This video shows how the bagging process works with the bag tape first applied the the bagging film, then applied to the mold.


Second, I'm going to do this next one without the peelply material. This material is really only needed if you are going to be doing secondary bonding on the surface. Instead, I'll be applying the perforated plastic directly onto the wet carbon stack.

Third, I may pre apply the resin to the cloth, and maybe even make the stacks of cloth 3 deep before applying them to the mold. This may allow the CF fabric to be better fitted into the mold without too much hanging over the edges, and it may also make it easier to simply apply the fabric.

Last, I think that too much resin came out of the layup last time. Two aspects can be changed that will effect this; a perf ply plastic sheet with fewer holes, or lower vacuum. I think that I'll try around 20" of vacuum this time. The lower vacuum pressure will press less on the composite stack which in turn will not press out so much resin.

I'll let you all know how it goes...

[Twin-shocker]

For simple bike parts compression moulding is the way to go. For any small parts which are more complex RTM light is the best possible option. For larger parts its feasible to use a combination of RTM and vacuum.............but all of this stuff is likely to be hard work for anyone who hasnt mastered the basics of contact moulding!

[therivermonster]

Originally Posted by Twin-shocker

For simple bike parts compression moulding is the way to go. For any small parts which are more complex RTM light is the best possible option. For larger parts its feasible to use a combination of RTM and vacuum.............but all of this stuff is likely to be hard work for anyone who hasnt mastered the basics of contact moulding!

RTM Light looks like it might be interesting to try sometime if I needed to do a lot of production work.

[therivermonster]

The exhaust shroud mold is a terrible mold now due to the under cut ends. Releasing parts from it is not a fun job. So, needing a part that was strong, and would last a while for testing, I started the process of laying up in the mold for possibly the last time.

The new part would be made of carbon fiber and Kevlar. Here the fabric is layed out ready for casting.




Of course I was going to vacuum this part as well, but I decided to apply the sealant tape to the bag, and then to the mold. This worked out much better than putting the tape on the mold first.




With the vacuum pulled, the part cured nicely. Now we'll see how long it'll last on the bike.


This is probably the last you'll see of the exhaust shroud mold, and I'm sure that you're not too sad about that...

The next parts that I am going to start working on are these.


But first I need to learn how to make proper molds that can be hand laid, with vacuum, and with resin infusion.

Project #4: Epoxy Gelcoat Experiment and Carbon Fiber Bowl Construction

I've filled the past couple of weeks with research on just how to go about creating high quality molds that will last a long time. I was excited to try poly tooling gell coat and poly resin with chopped strand mat fiberglass to make molds until I started reading about the experiences that people have working with such materials. There are a couple of things that are keeping me away from the poly products. First, gellcoat is very temperamental. If you don't apply it perfectly, it'll wrinkle, crack or do all kinds of nasty things. Also, poly tooling resin likes to shrink, and requires very strick layup schedules so as not to overheat the mold and the plug. All this on top of the fact that the styrene in poly products stinks very badly, and requires that you wear a respirator at all times. If your shop is attached to the house, forget about using it (or so I read). Lots of people have spent a lot of time and money trying to make this work, and reading about their experiences just makes me cring.

I know, I know, many molds are made around the world out of these products every day, but I have made the decision to forgo the poly products for now. Take some deep breathes, Twin-Shocker, the world is still movin' round.

There are a number of reasons that epoxy molds are better than poly molds. One of those reasons is not cost. Making epoxy molds is more expensive, so don't go this route to save money, on the front side anyway. Mainly, epoxy molds are much stronger, more rigid, and easier to make. In essence, the molds will last longer and will allow for more pulls. You can also make your own epoxy tooling gell coat which is awesome. There are also purpose made epoxy surface coats that are very high quality, so I may look into this solution in the future.

I ordered a bunch of supplies today that should help us make some quality epoxy molds, but I wanted to get started with the experimentation, so I broke out the wife's mixing bowl.

I waxed and polished the bowl a couple times.




I'm excited to see how this detail transfers to the mold.


Next I mixed up some of the US Composites 635 thin epoxy, mixed in some Cabosil to thicken the epoxy, and then mixed in a pinch of aluminum powder to add strength and color to the new epoxy (gellcoat).

I painted this mixture on the bowl. This picture shows the bowl with the second coat freshly applied.


I cut out all my fabric and vacuum bagging pieces. After the gellcoat had setup to a point where it was tacky, but wouldn't transfer to my finger, I layed up the bowl.


Then I placed the peelply, perf plastic, and breather onto the layup. Here is the whole package ready to go into the vacuum bag.


I made a vacuum bag for this mold. I decided to go with the bag because there aren't any flanges to attach the vacuum bag to. Here you can see how the vacuum bag is constructed.




You simply slide the composite layup into the bag and peel the tape at the opening to seal the bag. The vacuum port is set on a strip of breather material to make a sort of trail that leads up to the bowl. This ensures that all the air is drawn from the composite.


Here you can see how the underside of the bag is pressing on the inside of the bowl. It's wonderful letting the atmosphere do some of the work for you.


I'll post more to ley you all know how this experiment worked.

[mtbbker]

I was taught a part will only be as good as the mould

I have had very good success with epoxy moulds using the following Gel coat (It is actually more like a paste)
http://www.amtcomposites.co.za/sites...13-tdsi-gb.pdf
When cured the surface is as smooth as the the original plug (So the better plug you have, the better mould you have!) You could also still sand the moulds surface to remove any (if any) imperfections

[therivermonster]

Originally Posted by mtbbker

I was taught a part will only be as good as the mould

I have had very good success with epoxy moulds using the following Gel coat (It is actually more like a paste)
http://www.amtcomposites.co.za/sites...13-tdsi-gb.pdf
When cured the surface is as smooth as the the original plug (So the better plug you have, the better mould you have!) You could also still sand the moulds surface to remove any (if any) imperfections

Thanks for the link. That looks like some good stuff.

After all the research that I have done, I am very stoked about making molds out of epoxy. Sure, it is a bit more expensive, but if it is easier to do, doesn't take as long as poly molds, and will last longer with better quality than I am sold.

I'm excited to see how this home brew epoxy gel coat has layed up. I'll pull the bowl mold tonight and post pictures. I think for giggles I'll layup at least one bowl in CF in this mold. Might as well do it with respect to totally testing the mold.

[100mpg]

Originally Posted by therivermonster

I'll pull the bowl mold tonight and post pictures. I think for giggles I'll layup at least one bowl in CF in this mold. Might as well do it with respect to totally testing the mold.

Tap Tap Tap....Its tonight. Hurry up I have to go to work in 90 minutes!

[therivermonster]

Originally Posted by 100mpg

Tap Tap Tap....Its tonight. Hurry up I have to go to work in 90 minutes!

I've been working on releasing the mold for about an hour now and so far its no joy. Sorry 100.

I might have to break out the Dremel tomorrow and trim halfway around the bowl and see if it wants to come off there.

Crappy!!

[100mpg]

Originally Posted by therivermonster

I've been working on releasing the mold for about an hour now and so far its no joy. Sorry 100.

I might have to break out the Dremel tomorrow and trim halfway around the bowl and see if it wants to come off there.

Crappy!!

that sucks. Hope it is ok. I'm going to work so you can take your time now.
Plenty of time tomorrow.

[mtbbker]

I have used Mirror Glaze wax before as release agent, with avg results:-( Then I tried RAM wax, with great results. The point I am trying yo make is, experiment and try a few products first:-) It pays in the long run!!!


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