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Building Tips and technical articles. => Building techniques => Topic started by: Bill Gruby on January 01, 2008, 07:37:02 PM
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I have googled till my fingers are numb. I have sent emails to people requesting info on their products. I'm up against it so I am going to mold my on "Landing Gear"
Question ------ Does anyone have a link to a "How-To" to start me off, this is new territory to me"
Thanks;
"Billy G" H^^
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Bill,
Here's the short version:
I've made my own gear for quite awhile and have several molds. It's not that tough. the basics are to build the gear out of wood (I use scrap balsa). Get it like you want it, then glass it. I use 3/4oz glass and epoxy. Sand it, get it smooth and polish it out. Then build a box that will contain it. Cut drain holes in the ends of the box. I usually put them at the end of the gear. Split the box down the lateral center. Pack the gear in with clay in one side and get the clay smoothed out (I use a dental tool). half the gear (top or bottom) should be exposed. Wax up the surface of the clay and gear or shoot PVC molding release on it. I usually clamp the box back together, sealing the split line with duct tape or silicon. The pour molding material into the holes you cut. Sometimes it's easier to put holes in the area where the mounting plate for the gear is.
Once it's cured, split the box back apart, pull the gear from the clay and put it in the molded half. Seal it up with wax and/or PVC release. Dig all the clay out and clamp the box back together. Pour molding material into the other side. When it's cure, Viola!, gear mold.
It's really not all that complicated. I know this is a really brief description without much detail. I'd post some pictures buy my home computer is down right now (awaiting parts) so I don't have access to the pictures.
Once the mold is done, shoot it with PVC mold release agent. I use carbon fiber cloth and cut it into a lot of strips. You'll have to experiment in how much to use. It depends on the depth of the mold and how rigid you want it to be. I also use carbon tow for this. Usually a layer of cloth and several strips of tow and more cloth and more tow, etc. I use West Systems epoxy. Once the gear is done and popped out of the mold, I use a post cure oven. It's just a styrofoam cooler with a light bulb and a thermostat. Heat to about 175F for 24 hours, let it cool for a day and another 24 hours at 175F and you're done.
If you want to try this, let me know. I'd be glad to get a more complete description and we can jaw on the phone about it.
Try it, it's fun.
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Thank you Randy --- I sent you a PM.
"Billy G" D>K
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Hey Randy, Is there a particular type of West Systems you're using? I've had to go to Resin Services Inc in Michigan for both my gear epoxy and for my tuned pipe epoxies and the smallest amount I can get of either one is one quart. The shelf life is pretty good, but great scott, I hate to chance it with a questionable CF gear on a good ship. I do use it for CF reinforcement rods in my guitar and bass necks I build, but that's only two 18" x1/8" x1/4" cavities per neck, no big usage there either. As far as the other stuff for tuned pipes, I'll probably make one or two more and be done there, so let the stuff go south, I'll be done with it.
Thanks,
Will
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Bruce Perry posted pictures of a mold that looked really simple to make. I'm looking for pictures, but no joy yet. It looks like a mound of plywood, kinda. I believe he wrapped the top surface of the mold with a formed sheet of thin aluminum and plastic wrap. The "mound" of plywood formed the lower surface and edges of the LG.
I did find a file from Derek Moran, that tells how to layup the CF, and other info, but no pics. See attachment below.
Uh, Randy Smith sells CF LG's in many sizes and types. I think Windy may still sell one or more. But to tell the truth, I think they're way too stiff, and it's something about the spring in the CF. Many of the guys with CF gears are putting a 7-strand cable between the axles, to take all the spring out. This sounds weird, when the CF gear is claimed to be too stiff, but it removes the rebound, which is the problem. I don't like this solution. I think fiberglass would be better, actually. D>K Steve
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I haven't had one fail yet and Steve can attest that I've had some, uh, less that smooth landings.
I just use West System 105 with 205 hardner. So far, works fine when used as described. I lay up the mold like I do so I can get an airfoiled gear, but there's certainly nothing wrong with the more simple sort of mold that Bruce posted pictures of. It's all in what you want.
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Some folks over here have made CF landing gear from 1/8 or 3/32 flat carbon sheet. Just cut your shape and heat to bend, like repitching a prop.
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Flat C/F sheet? Wazzat? Wherefrom? ???
Ward-O
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Bill,
Here's an example of a mold.
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If I can make my stunt ships look half as good as Randy's gear mold I'll be a very happy camper!!!!! y1 y1 y1 y1 y1 y1 y1
Will
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Will,
It's not my mold. It's one done by Dan Winship (I think).
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Ah yes, good old Dan - I learned everything I know about CF and proper resins from Danny. He is one super dude to know! I had the wonderful privelege of watching Dan lay up a CF prop at a seminar at one of our first Fellowship Of Christian Modelers C/L weekends at AMA in Muncie. I learned a lot there and have pestered him several times since. He always has the time to help!
Blessings,
Will
(It's still a beautiful mold.)
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Hi Randy,
Thanks for the great "How to" and the photo.
FWIW: I think the flaps on the CL plane behind your mold are way too small. You may want to consider making them a little larger? The "small" ones your using may only give you a 1 foot radius on your corners! LL~
Regards, H^^
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Rudy,
That would be Dan's plane, I suppose. Looks like some kind of <gasp> RC plane.
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Hi Randy,
I was just pulling your leg. ;-) It looks just like the AL on one of my Dark Arts 3D planes.
Your right to "gasp". As a CL "retread", I am surprised and disappointed to see the extremely negative attitude toward anything to do with the Dark Arts. I feel that CL flyers could learn a lot from the DA. Just like we all learned a lot from the original modelers, our free flight brothers. :-)
PS: I know you meant your "gasp" as a ;-)
Regards, H^^
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Rudy,
I was "turned" for awhile to the dark side. Never did 3D, but flew pylon (Quickee and Formula 1), jets briefly and finally turnaround pattern. When I was sitting there flying back and forth between markers doing maneuvers was when I finally figured out that what I really wanted to do was go back to flying CL. So I saw the light and returned to the Force. :##
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Well said Yoda! AP^
I too had fun pylon racing, and 25 yrs of flying IMAC. But I also enjoy flying CLPA, I just wish there were not so many people working hard to take the fun out of it!
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Hi Guys,
Since my lame joke got us a little off topic, I will attempt to make amends and get back on the interesting subject of this thread. In Reply #6/#7 there was a question RE: where to get CF plates. I don't think this was answered?
An Excellent source for CF products of all types: plates, CF for the molded gear discussed here, and many other applications for our CLPA planes.
http://www.acp-composites.com/ACP-CAT.HTM
These are great people to deal with. I have done business with them for decades and have always been a happy customer.
Regards, H^^
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ACP is good and I also like dealing with CST. I couldn't find the website quickly, so just google CST and you should come up with them.
Will
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Just a comment in response to the longevity of WEST epoxies. If you can keep them in the can they are good for a long time. If you get the WEST pumps to measure and dispense, not so long cause the things siphon over time... Try getting unreacted epoxies off a counter! I have been a boat builder as well as modeler most of my life and even though I live in Michigan where WEST epoxies are from I use Epoxies from System Three in Washington state, just because they have resins that kick in lower temps and in my normally unheated shop they are more winter friendly. Both are top quality materials. I just pulled down some System Three that had been last used 7 years ago, so its another year old, and it kicked normally. While I have not personally tested WEST epoxy at that age I have used it at 3 years with fine results. So don't fret that its a year or two old. Still good stuff. Oh, and getting cold doesn't hurt them. Even if they froze in a garage during the winter. If there are any particulates, just heat it up in a double boiler pot til they disapear and you are good to go.
bob branch
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Bob,
That's been my experience. The West Systems sitting on the shelf is at least 5 years old and I used it a couple of days ago without a problem. I did have to bring the piece in the house so it would cure. It has to be above 50 degrees for it to kick. If I leave the part out in the shop, it will take a very long time, even if it's heated up later.
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Randy
Yea, that was my issue with WEST in a non heated Michigan shop. System three has resins that kick off down in the 30 degree range. There was the occasional part in the living room.... and an occasional small boat.... well, up to 17 ft. Yup. Been married 34 years. Boat building in the living room creates a strong marriage (or an early divorce).
bob
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Bob,
Yep. 31 years here. My wife has put up with plenty of workbenches in the living room and wonderful smells permeating the house. Hey, I put up with saddles in the bedroom and a wife that smells like Secretariat. As you say, makes for a strong marriage or an early divorce.