Plastic in old couplers

[n2mopac]

Some expert on plastics help me out here please. I am customizing an N scale locomotive. I have all the parts EXCEPT the spark deflectors. No one apparently makes one of the type I need that I can find. Well, I was digging through a box and found some old Rapido couplers and saw a portion of the coupler that could be cut and shaped to a reasonable representation of what I need. My questions are a) what kind of plastic are these couplers made of? b) what is the best way to cement them to a locomotive body? and c) what prep do they need before being painted? Any help with any of these questions is greatlly appreciated. Thanks.

Ron

[dstarr]

Couplers are usually made from tough slippery engineering plastics like nylon or delrin.  They don't glue and paint has trouble sticking to them.

[doctorwayne]

The plastic used in couplers is usually some type of engineering plastic, such as Delrin, Celcon, etc.  These types of plastic don't respond well to the usual plastic cements, although there is a cyano-epoxy available that purportedly works well.  The cost of it for a small project is rather prohibitive, though.

If the design of the detail part allows it, drill a hole (or holes) in each of the mating surfaces of the detail part and the locomotive, then insert a short length of wire into the hole in the detail.  This should be a snug fit.  Put a little ca on the edge or tip of an X-Acto blade, then touch that to the point where the wire enters the detail, then use a tissue to remove any excess cement.  This will not actually glue the wire into the hole, but it will create an even tighter fit between the wire and the part. 
Next, insert the free end of the wire into the corresponding hole in the locomotive and use the same method to apply ca from the inside of the loco's shell.  You may wish to bend the protruding wire so that it lies flat on the underside of the loco's shell.  Unless the loco is handled carelessly, the detail parts should remain in place.

Wayne

[RR_Mel]

I have used Loctite Go2 from Home Depot for gluing Delrin with pretty good success, actually I glued some Mchenry coupler shanks together and they’ve held for two years.

 

 

 

Mel

 

Modeling the early to mid 1950s SP in HO scale since 1951

 

My Model Railroad   

http://melvineperry.blogspot.com/

 

Bakersfield, California

 

I'm beginning to realize that aging is not for wimps.

[mbinsewi]

OK, I've searched a little, but I remain a   What are the "spark deflectors".  Is this a diesel thing, or steam.  I've come up with "spark arrestors", but no "deflectors".  I assume this is something on top of the motor exhaust ? Or something to do with the brakes?

Mike.

[BRAKIE]

It might be better to invest in either Plastruct or Evergreen shapes that matches the detail part. I have made spark arresters from Plastruct half round solid  tubing. Its simple. cheap and quick.

["JaBear"]

mbinsewi

What are the "spark deflectors". Is this a diesel thing, or steam. I've come up with "spark arrestors", but no "deflectors". I assume this is something on top of the motor exhaust ?

Mike your question piqued my curiosity, and I had hoped a learned forum member would come up with a definitive answer, so I’m prepared to stand corrected, after all at little knowledge can be dangerous, especially if it’s the result of a quick Google search.

 

Spark deflector, steam locomotive. A sloped steel sheet that can be found inside  the smoke box.

 

Spark deflector, diesel locomotive. A plate fitted above the exhaust. Here’s a link to the only illustration I could find.

 

http://mrr.trains.com/news-reviews/staff-reviews/2010/06/walthers-ho-scale-sw9-and-sw1200-diesel-locomotive

 

Smoke deflectors. Steel plates fitted to the sides of steam locomotives to lift the smoke above the locomotive at speed.

 

Ideally I think any of the multitude of different types of other devices to stop sparks from escaping into the environment from either steam or diesel locomotives should be called spark arrestors.

 

I believe the confusion arises due to the differences in the jargon not only used in different countries but by companies within those countries.

Cheers, the Bear.

[DSchmitt]

I found an old Rapido coupler in a box of junk.  It does not appear to be an engineering plastic.   I successfully glued it to a piece of styrene using Ambroid Pro Weld plastic cement and painted it with Tamiya paint

[mbinsewi]

Thanks Bear, I did do multiple searches, and what I found was the "deflectors", of different design, installed in the stacks of steam locos.

I did see illustrations of diesel locos with spark "arrestors", which ususally included pictures like the one you linked to, and some where two exhaust stacks might be combined with a horizontal fixtures, with one vertical stack.

So my confusion was between "deflectors" and "arrestors", which both are designed, as you stated, to stop sparks, or at least impede the release of sparks. 

Simply a terminology miss-understanding on my part.

Mike.

[n2mopac]

Sorry it took so long to get back to this thread. To answer the question about spark deflectors, the ones to which I refer are on older deisel locomotives and are like a spark arrestor but without baffels or screens to catch sparks--they simply "deflect" sparks back down onto the roof of the hood. Below is an image of the ones I am trying to duplicate. This is a rebuild of an old GP35 (dubbed GP38-3 by FWWR) and these deflectors may be designed specifically for this rebuild. 

Ron

[n2mopac]

BRAKIE I have tried fabricating these out of evergreen shapes, but in N scale they are so small that I cannot seem to make them strong enough to hold up to the stresses of instalation, let alone handling. I need something that is one piece. I thought about designing something and getting it printed by Shapeways, and I may yet, but I though I might give this option a try first.

Ron