Bicycle Mechanics - Epoxy Needed any help please

Bikeforums.net is a forum about nothing but bikes. Our community can help you find information about hard-to-find and localized information like bicycle tours, specialties like where in your area to have your recumbent bike serviced, or what are the best bicycle tires and seats for the activities you use your bike for.




View Full Version : Epoxy Needed any help please


BrightDogMan
09-06-09, 11:30 AM
I have begun a bicycle cart project :crash: where i plan to attach a bicycle to a shopping cart and since i have now way to weld nor get welding services :( i am hoping someone can point me in the direction of an epoxy or other way to attach them so as to allow for the stress :cry: of riding. Thanks for any help. :thumb:


jgedwa
09-06-09, 11:40 AM
First of all, you are insane.

Okay, now that that is out of the way, keep in mind that as strong as the epoxy bond can be, it will not stand up at all to any kind of lateral or flexing stress. Even if you are making this monster for a one-time use, merely bonding a frame to a cart with epoxy will not make it through that one use most likely.

j

neil0502
09-06-09, 11:50 AM
jgedwa is right on both points, IMHO.

If your address isn't Mars ... there's almost got to be a welder close enough to you, no??

Things like JB Weld are great ... but they're NO substitute for welding in applications where your teeth/skin/life/cargo depends on it.


Fidelista
09-06-09, 02:18 PM
First of all, you are insane.

Okay, now that that is out of the way, keep in mind that as strong as the epoxy bond can be, it will not stand up at all to any kind of lateral or flexing stress. Even if you are making this monster for a one-time use, merely bonding a frame to a cart with epoxy will not make it through that one use most likely.

jFirstly, epoxies do flex. If they didn't, a lot of boats (and planes, and a few cars)would have disintegrated a long time ago. My last boat was bonded entirely with epoxy, and I've seen a tow-hitch epoxied onto a bumper bar and used to pull a 4000lb. boat out of the water.(It was a very expensive epoxy!)
However...there are epoxies...and there are epoxies. There are also limitations on what can be done with epoxies, and to get the best results from them they have to be applied by people who know how to use them. There are epoxies that will join steel very well, in some applications exceeding weld strength, in other cases...not. Those epoxies are not available in hardware stores, they are only available in industrial quantities, they are very expensive and they require specialist knowledge to use them.
Without knowing where you want to do the join or why you want to do this, I can't offer any more advice, except to say that a combination of mechanically fastening and epoxy bonded thick plywood brackets MAY provide a stong enough bond to ensure your safety, but unless you have the training, knowledge and experience to join dissimilar materials, my advice,FWIW, is to find a welder prepared to do the job. You can expect a few issues to arise there too.
Secondly, I also think it's an insane thing to try and I don't mean insane in a good way either. I mean insane as in "dumb".


*shakes head*

Wordbiker
09-06-09, 03:18 PM
I'd go for the bolt-on approach.

Get some straps, L-brackets, hose clamps, etc. and go to town. The most you'll need is a drill and a vise to bend brackets into the shapes you'd need. This approach would also allow you to return the bike to a usable state if the plan doesn't work out. Stay away from epoxy. Used as duct tape, epoxy is brittle and will fail you at the most inopportune time.

AEO
09-06-09, 03:33 PM
btw, epoxy works better if you mix it with a fabric.
that's what 'carbon fiber' is. carbon fiber sheets or threads with epoxy.

that's not to say that you should try it for a first time project if you never worked with it, especially if the part in question is of high importance to the structural integrity.

Jeff Wills
09-06-09, 03:33 PM
I have begun a bicycle cart project :crash: where i plan to attach a bicycle to a shopping cart and since i have now way to weld nor get welding services :( i am hoping someone can point me in the direction of an epoxy or other way to attach them so as to allow for the stress :cry: of riding. Thanks for any help. :thumb:

No epoxy needed:
http://www.instructables.com/id/Cart-Bike/
http://www.instructables.com/files/deriv/FDU/RN97/F5HVPDC8/FDURN97F5HVPDC8.MEDIUM.jpg

That being said, a friend of mine had a Tour-Easy recumbent clone built for him by his students. They didn't weld it, they used a lot of J-B Weld. The tubing joints overlapped a lot, so there wasn't that much stress on the epoxied joints. They held together for several years, so it's possible.

I agree that welding is probably more practical. There's got to be someone near you who has a welding rig- even in the smallest town there's usually someone who has a hobbyist setup.

BrightDogMan
09-06-09, 06:47 PM
There is some great information here. Thanks forthe input.I thinkim going to go with a combo of brackets and J B Weld. It should be strong enough for the Job. Thanks Again!

urban_assault
09-06-09, 07:25 PM
Please return with photos of the completed project. I'd love to see it.

Panthers007
09-06-09, 08:11 PM
Building a taxi for the homeless?

norwood
09-07-09, 12:52 PM
No epoxy needed:
http://www.instructables.com/id/Cart-Bike/
http://www.instructables.com/files/deriv/FDU/RN97/F5HVPDC8/FDURN97F5HVPDC8.MEDIUM.jpg


The flip-flops are the crowning touch.

Jeff Wills
09-07-09, 09:33 PM
The flip-flops are the crowning touch.

I said "no epoxy needed".
I refrained from saying "needs more brains".