why do i get the feeling tha... ah forget it. insert smiley here
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Nick,
Been looking 3 years for a bit of Crumpton construction photo porn and here it all is in one thread, thanks for sharing. After trying plenty of different methods i've settled on something very similar to what you are doing which is good confirmation that i'm heading in the right direction. Are the chain stays you use standard enve assymetric or a Crumpton special order?
Bill
Go to heaven twice Nic. At some point I'll move this thread to framebuilders wiki where it belongs.
I spoke with Nick at NAHBS
and that chat
and this thread
just adds to my respect and admiration to this man's skills, craft and perseverence
to start from zero and journey to this level as an independent is fantastic
WTF would you go and get any other carbon bike but one of Nick's?
and I admire Nick's I got to do it this way, the correct way because it is to sate his desire for the purity in the build process.
Bravo!
so now we come to bagging the frame. the publication Vacuum Bagging Technique by the Gougeon Brothers was where i started. plenty of good info on the web but this is trusted complete source for $5.
the frame will go through a heat cure with a potential for 2 atmospheres clamping(~29psi). if doing heat cure, distortion can be factor. factors include the tubes and tacking Tg and the cure profile. and while its pretty easy to find a suitable cure profile, the dummy axle is an absolute necessity
http://farm5.static.flickr.com/4107/...5910a1d154.jpg
plug the threads or chase em out later. also, that tape adjacent to the laminate "flash breaker"
http://farm5.static.flickr.com/4152/...f0a267dcf0.jpg
thats a highly polished, release treated, honeymoon fitting aluminum tube keeping my HT ID nice and round.
http://farm2.static.flickr.com/1413/...57c7553f9d.jpg
pad hard points padded. a source of leeks.
http://farm2.static.flickr.com/1320/...ff60f140e6.jpg
joints covered in release ply, breather and bagging film. inserting the through bag connectors
http://farm2.static.flickr.com/1213/...42c1fd4f46.jpg
pulling vacuum then off to the oven.
http://farm5.static.flickr.com/4045/...6028a827dc.jpg
going to visit mom for a few days so updates to come later.
Hey Nick,
Don't forget to take it out of the oven before you go.
Hi Nick,
I was wondering, you mention with the BB sleeve and Headtube, that the tube is lined and faced with e-glass - is that a necessity considering you're bonding Titanium which is inert?
I'm guessing that with the dropouts because they're Aluminium there's some glass layer between them and the stays, but it wasn't obvious from the photos.
he mentions that the stay IDs are glass.
http://www.velocipedesalon.com/forum...tml#post244322
I should've mentioned I only get the Intarweb for the pictures.
Thanks Nick for posting this, the timing on this thread could not be better! I've been testing and developing carbon joint techniques and processes as well as building head tube and BB shells. Bagging the whole frame is interesting, I've been testing a joint based method so far.
http://img.photobucket.com/albums/v9...BBBagging1.jpg
Some of what I've been working on (both good and bad) can be found here.
back40 bicycleworks
I noticed you use fairly large fillets of epoxy at the joints. Does that make consolidating in the vacuum bag easier or more consistent? Have you thought of mixing the fillet epoxy with glass micro spheres?
Lots of work to do still...
http://img.photobucket.com/albums/v9...ng/BBTest2.jpg
Can't wait to see the rest of your process.
hey back40. i was checking out your blog. i am liking your recent results. man that bagging scheme on the bb cluster looks familiar. i do not miss that. i use a 36" wide LFT(lay flat tube) and just seal the ends. in wet layup days i would layup and bag individual joints, sealing the bag around the tubes just as you are doing there. the clock is ticking right? but with prepregs you can layup a bike on friday and bag it on monday. i do not miss making bags from scratch or sealing around tubes.
that fillet material i am using has properties just like i want at the moment. but i will say your fillet material looks like it tools nicely. is that quickfair? it is epoxy based yeah?
i like your test on shrink tape. its the nature of the tape. the joint radius would be fine but what is really going on is varied radii on the wraps themselves. the more varied the more pressure on smaller radii and less on larger. that means the broad stretch from HT to acute or obtuse side of the DT is a long no radius bit and we get zero compaction there, where we need it most.
back for a quicky to finish up pre paint. the rest will be post paint prep and that may take a bit.
easy enough pulling it out of the bag. remove all the flash tape. then deflash and any other sanding for the painter. best to take care of any porosity issues now lest you get. pinhole riddled bikes back from paint. i don't care how good one is, cosmetic porosity is the crux of working with carbon.
http://farm5.static.flickr.com/4087/...a3742a291c.jpg
most issues should be where the two side of the bag met or on tube ends.
http://farm6.static.flickr.com/5207/...ab8898b1dc.jpg
a word of warning, that epoxy flash can be razor sharp. blood stains raw carbon.
http://farm5.static.flickr.com/4132/...a49dbec155.jpg
clean threads
http://farm2.static.flickr.com/1210/...8501877fc0.jpg
this is what i am after
http://farm2.static.flickr.com/1347/...00ed4d8c63.jpg
nice drill guide for cable stops. again, new sharp jobbers. 135d point if i didnt call that out earlier. i thin the point makes a difference. i put stops on after paint. just my preference.
http://farm5.static.flickr.com/4153/...860d5ed641.jpg
i bond the head tube cups in now. these are made for a final milling and facing to remove material and insure concentricity and all that. i do em with a thread like pattern with a narrow flat peak and wide flat bottom. the peak is a honeymoon fit and the bottom is the bond gap. makes it a total lathe job and a twist to install.
same as it ever was, both the ID of the tube and the OD of the cup. wipe/abrade/wipe
http://farm6.static.flickr.com/5164/...4ee3ca2696.jpg
cup is in there with just enough excess to face nice and clean.
http://farm5.static.flickr.com/4133/...e06691a6e7.jpg
this is all the pics i have to date. when i found some adhesive on my phone from doing these cups... you get the point. i don't think the rest will be all that remarkable but i'll post em when i have em.
Thanks Nick,
Been a great thread, surprising the little things you pick up from looking at someone else work, your product is and has been inspirational.Thanks
Bill
I had not thought of bagging the whole frame before. When I get to that point I'll give it a try I think. Have you ever tried folding the bag back on itself between the stays to avoid needing the dummy axle? My shop is about 50F so I could leave the pre-preg out there for more than a few days before bagging. The Stretchlon bag is really easy to get to pull into the joints...500% elongation.
I'm trying fairing compound, it's Aeropoxy Light epoxy based. I'll probably try DP420 and microspheres next.
The shrink tape experiment was more out of impatience, I did not have all the bagging supplies yet and wanted to try baking something. It does a fantastic job on straight head tubes and BB shells I made. Along with the UHWW mandrels I can make nice compacted accurate tubes. The latest head tube came out at 43.96mm ID, perfect for the press fit Inset cups. I can wrap support rings of 90deg fiber where the cups go and it still slides straight off the mandrel. More experiments to go...
Thanks for the feedback and for the thread, your timing is impeccable.
Hey guys, my name is Dimitri Harris and I am new to the forum and have only been building frames for about 3 yrs. now under the brand MEECH. Just wanted to introduce myself and like eveyone else find this thread with Nick Crumpton very interesting.
I have been playing with wet carbon layup in the past but have never tried vacuum bagging and I was wondering about what type of vacuum pump is needed. I have been looking at all kinds and recently spoke to a rep. from Gast but what he recommends
seems much larger than the pumps at say Aircraft Spruce. Just looking for the basics but something that has some lasting quality. Any ideas?
Hey Dimitri, i honestly would get the biggest sucking machine you can afford(within reason) ideal is 29.5Hg on whatever size bag you plan top use. several CFM is in order. you can also use a simple venturi device on your air compressor. this is where i started.
If you just want to try without spending much cash get a compressor off an old refrigerator. They pull about as good a vacuum as you can get, just not in volume. Use a vacuum cleaner to get the bulk out. The one I have runs fine for 24 hours nonstop without issue.
I would love to see the oven. Great thread, thanks!
Thanks for the input guys.
i'll get you pics of my ugly ebay special on the next go around but it is a model 333 grieve with a PID. this pic is from their website.
specs http://www.grievecorp.com/catalog/Ba...ench-Oven.html
http://www.grievecorp.com/catalog/Ba...-Ovens/333.jpg
Hey Nick, I know you have built steel frames as well as carbon, possibly others as well, and I was just curious if one style is easier to align correctly than the other.
Typically, if a carbon frame is bonded or tacked in alignment in the jig, will it come out of the jig in the same alignment or can it spring in one direction or the other like frames
made of metals? I didn't know if curing epoxy can pull the tubes out of place.
I still like the finish on those tubes
Just out of curiosity Nick, do carbon tubes respond well to hand miters? Would half round files tear them up too bad, and is there any other way to miter carbon tubes by hand? Have you done it on a mill since the beginning?
I'm not Nick but using hand tools on carbon isn't a problem, you do have to a little bit careful when cutting or filing not to be too agressive so you don't delaminate layers of carbon as it is a multi- layered structure.Fine tooth hacksaw blades for cutting, steady speed and pressure.I find course files to be the best as fine just seem to clog too easily. When drilling holes, try and support internally as internal layers delaminate easily, I will quite often use a fine rotary carbide bit for drilling holes, less chance of tube damage. When mitering whether machine or by hand, make sure tube is well supported as any clamping forces will damage tubing, carbon doesn't like to be sqaushed. Always wear appropriate safety gear, mask,long sleeve shirt, gloves (don't wipe sweat from your eyes with your shirt sleeve), all those fine fibers are prickly and will make you itch like shit for days, also be very careful with solvents and epoxy glues, that shit does have an accumulative affect on your general health.
Bill
compared to metal? no, they do not respond well. at least not high quality IM carbon tubes of any reasonable wall. its a total PITA to hand miter a carbon tube with a file. and would take 3x time IMO. if you wanna miter on the cheap, tape on a miter.exe template and take it to the 4x48 belt sander. expect a mountain of very irritating dust if you choose to do this.
I just discovered this gem!
Too bad some of the pics are gone.
I wish this still had photos.
It looks like he has stripped a bit out of his Flikr account. There are still some good photos that show his process in a broad picture.
It would be really nice if Mr. Crumpton could reupload the pictures. Its really one of the most valuable "knowledge" post so far.
I think most of us would appreciate it.
This is an example of where it would be awesome to have the pics saved on vsalon. hosting externally has its benefits, but it stinks to have such awesome threads show up without the pics. It'd be a pain in the ass to match up pics with the posts here... it'd probably be easier to make a new thread with new pics.