Springing & painting

[BryanJohnson]

Is there any benefit in masking off the back of w-irons on sprung wagon chassis and coach bogies when spraying the whole underframe / bogie in order to give a metal-to-metal contact area with the bearing carrier? The alternative is to have the bearing carrier rubbing against the hardened paint.

I can see that the friction between the two parts controls 1) the freedom of the vertical movement and 2) the damping of that movement. For our purposes, I would think that allowing free movement is more important than its damping, so I have gone for smooth metal surfaces on both parts, but am wondering whether the extra masking is really needed.

Bryan

[jim s-w]

I always do. You probably need someone who doesn't though to tell you if it's a problem or not.

Not much help, sorry

Jim

[Lord Colnago]

Hi Bryan,

I usually hand paint my wagon underframes so I don't get paint on the inside contact surfaces by and large. However, if I use a Rumney underframe then I airbrush them and mask the contact areas. I think you're right to mask off and keep the contacting surfacex clean for the reasons use give.

John.

[hughesp87]

Bryan,

I always mask these surfaces before spraying, on the basis that the paint is likely to generate more friction to impair free movement of the bearing carrier. There's also a potential problem that build-up of paint could reduce the distance between the bearing cups and therefore result in tightness over the pin-points.

If necessary you can always paint any visible surfaces away from the bearing carrier with a fine paintbrush, once the wagon is assembled and checking for free running.

Hope this helps,

Geraint

[Philip Hall]

The other alternative is to chemically blacken, either with an etch marker pen, or gun blue, the back of the W-iron and the moving bits. After blackening they can be polished with a cotton bud or a nylon brush in a drill so they will be darkened but not gummed up.

Philip

[BryanJohnson]

Thanks for all the responses.

They confirm my thoughts so I'll continue to mask off that part of the w-iron when spraying.

Bryan