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Discussion Starter · #1 ·
I am building a brass railtruck, of sorts.

I have confirmed my suspicions in the R/C forum, and have been told that to have much chance of radio reception, I need to at least make the roof out of wood, instead of brass.
I need to attach the thin plywood roof to the brass supports strong enough to bend the plywood:


Any suggestions?

Thanks,
Matt
 

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We ran into this problem a lot when I had my effects company. We tried quite a number of things, but the best was a good quality contact cement...used properly. I think it was a Weldwood cement and the drying time was something like 24 hrs., but once the bond was made the wood would shred before the bond gave (it never did, actually).
There may be more convenient solutions out there. Have you checked "this to that" site?
Chris
PS. Just checked it and here's the response;
http://www.thistothat.com/cgi-bin/glue.cgi?lang=en&this=Wood&that=Metal

PPS. One other thought; try and design in as much surface area of contact between the two materials for maximum grab.
 

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Discussion Starter · #3 ·
Thanks, Chris. I had never heard of the This to That website, but they suggest - among other things - JB Weld. I think I have some around here somewhere...
If that doesn't work, I'll try the contact cement.


Thanks again,
Matt
 

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Discussion Starter · #5 ·
Have you ever tried the JB Weld? If so, do you think the contact cement works better?

Thanks Chris
 

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JB Weld has very little strength in tension or in shear. It will hold lots of stuff together until you try to pull on or twist it. If you're going to use it in this application, I'd suggest soldering a ledge or lip along the top of the body, to give it some surface area to work with, instead of just along the edge of the wood (and also to keep the stuff from sagging and running down as it cures)
 

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JB weld is an epoxy, and Mik is absolutely right. I t will bond very dissimilar materials well, but not very strongly. If you can, drill some holes, or at least scrape the surfaces so that the adhesive has a little more "tooth". I prefer the contact cement, but only if there is enough surface area. And with contact cement, you only get one shot. If there's any way of preforming the roof piece with a couple of internal wood supports, it will go a long way to aiding the adhesion of whichever glue you choose.
Chris
 

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E6000. It's available form Tap Plastics. I also found it at my local ACE Hardware store. It is a flexible adhesive that is supposed to glue most things together.

Another glue that might do what you want os Omni-Stick. It is supposed to glue many things together, I bought mine on the internet.
 

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I use Welder all the time. It sticks stuff together well, but I'm not sure it will do as you want, though. The joint remains "flexible" for a looong time, which means if you try to force the other end down the already glued end WILL stretch and pop up some.

Is there any way to steam the wood to shape first?
 

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I'm wondering why you don't use a mechanical joint. A couple of 0-90 bolts through the roof, or even some escutcheon pins, into a flange on the top of the walls would do the job nicely. Just sweat a couple of pieces of 1/4" brass L at the corners and you'll have your mounting points. That's what I do when attaching cab roofs, cabs to running boards, etc.

P.S. very cool project, and nice work on the body!
 

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Discussion Starter · #13 ·
Thanks for the info and comments, gents.

The main reason I had in mind (not necessarily correct) to bond the roof was because I had planned to use 1-2mm plywood to allow for the bending of the roof. I didn't think that material that thin would hold up to mechanical fasteners. From what you guys have told me here, I think I'm going to combine the two, and use maybe six bolts to help reinforce the bond. I'll probably use contact cement , and let it cure for a few days.

Thanks again,
Matt
 

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I second Vance's proposal to use 00-90 machine screws. Go to Micro Fasteners, they have brass model hex bolts and nuts in 00-90.

http://www.microfasteners.com/index.cfm

The extra texture from the model bolts will add to the model's appearance


Make a quick nut driver from a 5/64" Allen set screw




Looking good, Bob
 

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Seems to me that if you find a way to place the receiving antenna on the outside of the railtruck, you could make the whole thing out of brass. And yes, if the roof is brass, you've essentially made a Faraday cage and radio waves will not penetrate it. perhaps the antenna could be placed along the rooftop on some type of non conducting standoffs. it could be fashioned into a roofrack of some sort. Otherwise, I concur with the others that you'll need a mechanical bond. I don't know of an epoxy out there that will bond wood to metal very well.

Mark
 

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Matt, a few years ago, I was doing some experimenting with wood to metal adhesives. I found that good old Goriila Glue stuck them together, period. About 2 weeks later I wanted to make a change and wanted to remove the wood. I grabbed it with a pair of pliers, yanked and actually broke the wood. Splintered it, but not at the joined area, the glue held.

Just 1 1/2 cents.. :)
 

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Discussion Starter · #18 ·
Posted By markperr on 02/24/2009 1:41 PM
Seems to me that if you find a way to place the receiving antenna on the outside of the railtruck, you could make the whole thing out of brass. And yes, if the roof is brass, you've essentially made a Faraday cage and radio waves will not penetrate it. perhaps the antenna could be placed along the rooftop on some type of non conducting standoffs. it could be fashioned into a roofrack of some sort. Otherwise, I concur with the others that you'll need a mechanical bond. I don't know of an epoxy out there that will bond wood to metal very well.

Mark




Thanks, Mark. I posted in another thread that I am leaning toward the roof top rack idea. Haven't decided about the roof composition yet.

Matt
 

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Discussion Starter · #19 ·
Posted By Stan Cedarleaf on 02/24/2009 1:52 PM
Matt, a few years ago, I was doing some experimenting with wood to metal adhesives. I found that good old Goriila Glue stuck them together, period. About 2 weeks later I wanted to make a change and wanted to remove the wood. I grabbed it with a pair of pliers, yanked and actually broke the wood. Splintered it, but not at the joined area, the glue held.

Just 1 1/2 cents.. :)" align="absmiddle" border="0" />


Thanks for posting, Stan. 1 1/2 cents is about all I can afford right now, anyway.

I bought some Gorilla Glue some time ago, but have never used it for anything yet. Maybe this will be a first...

Take care,
Matt
 

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I also have used Gorilla glue for wood to brass. I make sure the brass is very clean. I rough up the wood that will attach to it a tad by scoring it a bit with a screwdriver or other tool. Be warned that the gorilla glue will expand. If this is your first use you might want to practice on a throw away item first. Clamping is very important - I usually clamp for a minimum of 4 hours.
 
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