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sam
09-15-2009, 08:30 PM
Good day to all!

After looking at milling machines for a pretty long time (and seeing that they are WAY out of my budget), I thought I would have to just try something with hand tools and hope for the best.

I started looking at some carbon fiber, and it's much cheaper (while I don't have a mill). So recently I bought some Carbon fiber fabrics and wanted to start this thread for people who might be interested.

I did my first experiment last Saturday and it was succesful (as in I found tons of stuff that I could improve on :veryhappy:).

I first made a plug with polystyrene using a hot wire cutter (that was home built in one hour). With this and some sand paper I can do pretty much any shape I want in the polystyrene.

I'm gonna upload some pictures latter on.

Sam

nagmier
09-15-2009, 09:17 PM
Pics!!! Uber interested!!! :) At the moment I'm in the same boat it'll be several thousand years in a galaxy far far away that will allow me to buy the shop equipment I want I have contemplated CF and fiberglassing but I don't really have workspace (I live in an apartment for the time being). I'm interested to see your progress and to see what you have done and learned!

Good luck and keep us updated!

sam
09-16-2009, 07:51 AM
Hey Nagmier!

I live in a small apartment too! But I managed to find a bit of space.

Here are some pics (Yes, it's not really nice, but I think that my second attempt will be much better!)

Here is how I vacuum bagged it

http://forums.trossenrobotics.com/gallery/files/1/5/4/9/035_thumb.jpg (http://forums.trossenrobotics.com/gallery/showimage.php?i=1775&c=3)

Here is the final "weird" shape that I tried to make.

http://forums.trossenrobotics.com/gallery/files/1/5/4/9/img_5384_thumb.jpg (http://forums.trossenrobotics.com/gallery/showimage.php?i=1774&c=3)

Other views :

http://forums.trossenrobotics.com/gallery/files/1/5/4/9/img_5383_thumb.jpg (http://forums.trossenrobotics.com/gallery/showimage.php?i=1773&c=3)

http://forums.trossenrobotics.com/gallery/files/1/5/4/9/img_5382_thumb.jpg (http://forums.trossenrobotics.com/gallery/showimage.php?i=1772&c=3)


This is it for the moment.

Sam

Psykoman
09-16-2009, 08:08 AM
I also started to work with carbon fiber because my little milling machine (Proxxon MF70) is too small for some parts. So i started to make the parts for my humanoid robot as a negative form with my milling machine and after that I want to use Carbon fiber for the parts which will be used in the robot. I want to ask if it is necessary to use a vacuum to get the parts in shape?

Best regards,
Sven

nagmier
09-16-2009, 10:59 AM
Wow good deal! Thats looks certainly doable and much easier to fit within budget constraints, I'm really going to have to dig in and take a look online for some more info... Looks great!

sam
09-16-2009, 07:41 PM
Hi Psykoman

I'm not sure that the vacuum is actually necessary. But here is what I found :

1-When trying to make the carbon fiber take the form of the plug (by putting the Epoxy resin with the hardener on the carbon fiber cloth) I had a lot of trouble doing it by hand. I finally kinda "broke the weave" (actually separated it a lot). By using a vacuum to make it form to the plug, it's much easier and will give a nicer carbon fibery "look". :)

2- (Info : You have to keep the vacuum for the first 30 minutes, which is the crucial part, anyway for my hardener) It makes the process less messy and it means that you don't have to try to maintain the position of the cloth by hand.

3-I don't know how big the parts you want to mold are, but you can always put them in a big trash bag (like mine but bigger) and use the normal home vacuum. :D

My next test should be complete by Saturday, So I'll try to upload the newer pics then.


@nagmier

Yeah, I found lots of sites that walk you through the process of molding parts. I also found some places where you can buy carbon fiber (here in the US or Canada). I paid 90$ for 3 yards X 50 inches, which is a lot when working with small robots.

Sam

sam
09-18-2009, 04:44 PM
So I finished my first layer of epoxy on my second test! :happy:

Here are some pictures :

Cutting the carbon cloth with Xacto and some masking tape.

http://forums.trossenrobotics.com/gallery/files/1/5/4/9/img_5385_thumb.jpg (http://forums.trossenrobotics.com/gallery/showimage.php?i=1780&c=member&imageuser=1549)

http://forums.trossenrobotics.com/gallery/files/1/5/4/9/img_5388_thumb.jpg (http://forums.trossenrobotics.com/gallery/showimage.php?i=1781&c=member&imageuser=1549)

The final second shape I made :

http://forums.trossenrobotics.com/gallery/files/1/5/4/9/img_5390_thumb.jpg (http://forums.trossenrobotics.com/gallery/showimage.php?i=1782&c=member&imageuser=1549)

http://forums.trossenrobotics.com/gallery/files/1/5/4/9/img_5393_thumb.jpg (http://forums.trossenrobotics.com/gallery/showimage.php?i=1783&c=member&imageuser=1549)

http://forums.trossenrobotics.com/gallery/files/1/5/4/9/img_5394_thumb.jpg (http://forums.trossenrobotics.com/gallery/showimage.php?i=1784&c=member&imageuser=1549)

Once I take the pink polysterene out of the mold, it looks like this (I could wash it a bit more)

BTW, these images are from the first carbon fiber try

http://forums.trossenrobotics.com/gallery/files/1/5/4/9/img_5395_thumb.jpg (http://forums.trossenrobotics.com/gallery/showimage.php?i=1785&c=member&imageuser=1549)

http://forums.trossenrobotics.com/gallery/files/1/5/4/9/img_5398_thumb.jpg (http://forums.trossenrobotics.com/gallery/showimage.php?i=1786&c=member&imageuser=1549)

I still need to wet sand down the second mold and apply a second coat of Epoxy, but there is a great improvement considering the special form of the second one (even more abrupt).

Sam

sam
09-20-2009, 06:12 PM
Well, update:

I finished my test 2.1 (putting a second layer of epoxy).

I'm pretty happy about the results. It's really shinny and has a nice carbon fibery look. It weights only 22 grams. I can't wait to tray it for bipeds and quads! But must concentrate on my current project.

Here are some pictures :

http://forums.trossenrobotics.com/gallery/files/1/5/4/9/img_5413_thumb.jpg (http://forums.trossenrobotics.com/gallery/showimage.php?i=1796&c=3&userid=1549)

http://forums.trossenrobotics.com/gallery/files/1/5/4/9/img_5412_thumb.jpg (http://forums.trossenrobotics.com/gallery/showimage.php?i=1795&c=3&userid=1549)

http://forums.trossenrobotics.com/gallery/files/1/5/4/9/img_5408_thumb.jpg (http://forums.trossenrobotics.com/gallery/showimage.php?i=1794&c=3&userid=1549)

Well, that's pretty much it.

Sam

Adrenalynn
09-20-2009, 06:17 PM
You're doing some nice carbon fiber work, Sam!

nagmier
09-20-2009, 06:50 PM
Nice work I think I'll be giving this a shot in the coming months

jes1510
09-20-2009, 07:52 PM
Nice work Sam! You should throw together a tutorial with supplies required and sources once you get everything figured out. It would be a great resource for everyone else.

sam
09-21-2009, 09:58 AM
Thanks for the nice words! :)

Once you get the first try out of the way, it's really easy and fast to build custom parts.

I will probably start witting a tutorial within the next week(s).

Sam

Adrenalynn
09-23-2009, 01:00 AM
Can you step that up? :) I'm _really_ interested!

ooops
09-23-2009, 04:23 PM
Sam, great stuff!!!

Here is a tip for making your own vacuum pump that will work sooooo much better for what you are doing than a vacuum cleaner!
In my shop I have the old compressor from a window unit air conditioner (a refrigerator compressor will work as well). I cut the copper tube that ran to the coils and soldered a 1/4" NPT fitting on, then screwed an air hose coupler to that. Just plug in the air hose and you have a serious vacuum pump! (you could just clamp tubing to it, but bear in mind rubber and soft plastic will collapse under a vacuum)
Now in this day of "green living" I don't recommend you cut the tube without having the unit drained of freon, but maybe the local refrigerator repair place has a compressor that they will part with cheap or free that is already drained.

One other note: I have a rolling cart set up that houses the pump. The top of the cart is made of peg board with a large air cavity underneath. I installed a large 2" pvc one way valve and a coupler which I can hook to the shop vac. (used mostly for dust control while sanding or routing wood) I also added a air coupler to the cavity so that I could hook the vacuum pump to it. It allows for a very fast "pull down" of vacuum with the shop vac then the vacuum pump picks up where the shop vac leaves off. It works very well:)
I could see you doing something similiar without the cart, just the big 1-way valve and the vacuum pump hose.

Anyway here is a link for the DIY vacuum pump:
http://www.instructables.com/id/Making-A-Fridge-Compressor-Into-A-Vacuum-Pump/

Keep us posted on your progress!!!

4mem8
09-23-2009, 04:52 PM
Nice work Sam, I have also used this a lot in the boat building industry Sam, and need to experiment more with robotics. just a thought here Sam i use either Acetone or epoxy thinners to reduce the viscotisy of the resin so it can penetrate the carbon better, i also use a vacuum process. good work

crabfu
09-27-2009, 12:32 PM
Thanks so much for sharing your progress and info. I'd love to find some time and get into this :)
-crabfu

sam
09-27-2009, 04:04 PM
@Adrenalynn : I will try to do ASAP, but a lot of school work means I can almost only work on robotics on Saturdays. :sad:

@Oops : As soon as I find a thrown away fridge, I will try to do what you recommended. Indeed, although my vacuum is very powerful, I have the impression that more suction would help to let the carbon fiber take the form of the mold.

@4mem8 : Thanks for the tip on making thinner epoxy! Hadn't thought of it, it could be practicle for the first layer.

Your welcome Carbfu! The look of this stuff is just awesome! :)

Thanks for your comments!

Sam

Adrenalynn
09-27-2009, 04:13 PM
Sam, no rush - I figured it out. :) Thank you though!