I'm looking for advice on installation of ALM diaphragms on BB F7's. I have the ALM 9813 kits (also includes close coupling). Even though I had a bit of trouble assembling the diaphrams (my bad, old eyes and fumbling fingers) I really cannot come up with a suitable method to glue them on the loco. Several issues with this 1) getting them all mounted at the same height and centered the same on the loco doors 2) what's the best glue to use (I was using canopy glue, but it seems something tackier is needed to hold the parts in place) and 3) what kind of paint adheres well to the ALM shiney plastic? Thanx!
Are these kind of hard or rigid plastic? I can't tell from their web site.
Heres a discussion on diaphragms from a couple of weeks ago,
http://cs.trains.com/mrr/f/88/t/274260.aspx
Maybe something there you can use.
Mike.
My You Tube
If you're speaking of the diaphragms from American Limited, I use the ones meant for passenger cars, as my layout era predates the majority of diesels.
Ordinary solvent-type cement (I use MEK) will cement the fixed portion to your diesels. If you can't get them all centred or at the same height, make a simple fixture which fits fairly snugly around the protrusion on the diesel where the diaphragm will mount (pieces of strip styrene, the same thickness as that of the around-the-door-protrusion - you need only a piece for the bottom and one for each side.
The fixed plate for the diaphragm is likely larger than that protrusion (it is on all of my passenger cars), so the next step is to add a similar "U"-shaped section on the face of the first one. It will need to have the sides farther apart, so you'll need to measure the width of that plate, determine how much wider it is than the protrusion around the door, then divide that amount by two. Add a length of strip styrene to the face of the first fixture, setting it that measurement away from the inner edge of the original strip fixture - do this for both sides.
If the diaphragm is also taller than the doorway, decide if you want to split the difference on the vertical position or simply place the bottom of the diaphragm even with the bottom of the protrusion around the door.
To use this fixture, simply place it on the diesel's end, tight to the bottom, then drop the backing plate into place. Use a small brush to apply a small amount of solvent cement to the joint between the plate and the diesel's end at the top of the doorway, and another very small amount of cement to either side where the plate touches the diesel - the object here is to use the cement to simply hold the plate where it belongs, so that you can remove the fixture. Once the fixture is out of the way, carefully apply cement to solidly fasten the plate, and once it sets, you can add the other components.
As long as all of your diesels are of the same type and make, the fixture should work for all of them.
I'm not sure if this description will be sufficient, so if you need more info, send me a PM, and I'll either make a drawing of what I'm trying to describe, or make a mock-up of the fixture itself, as it's actually very simple.
If I don't respond immediately to a PM, it's because I have some painting to do on a roundhouse I'm building - should take only a couple of hours...I hope.
Wayne
Hi Mike,
They are solid. They are a sandwich of a plate glued to the diesel, a floating center part (diapragm) and an end plate (simulated mating surface to adjoining diesel).
OK, I like the really flexible diaphragms that were discussed in the link I posted in my first reply.
I'm going to be adding these to my cars, when I get that far with my passenger train.
Hello Wayne, thanx for the in-depth reply.
doctorwayne If you're speaking of the diaphragms from American Limited
If you're speaking of the diaphragms from American Limited
Yup, one and the same!
doctorwayne Ordinary solvent-type cement (I use MEK) will cement the fixed portion to your diesels.
I used Tamiya plastic glue (the real thin, runny stuff) to glue the striker plate to the bellows and it worked quite well. I wasn't sure if I had to scrape paint off the Athearn diesel to glue the other end to the loco, and decided to postpone doing anything till I checked around. I have MEK as well as most common brands of plastic cement, but when I saw that the plate that mounts to the loco was wider than the mating surface on the loco, I really thought I was doing something wrong.
doctorwayne If you can't get them all centred or at the same height, make a simple fixture which fits fairly snugly around the protrusion on the diesel where the diaphragm will mount (pieces of strip styrene, the same thickness as that of the around-the-door-protrusion - you need only a piece for the bottom and one for each side.
If you can't get them all centred or at the same height, make a simple fixture which fits fairly snugly around the protrusion on the diesel where the diaphragm will mount (pieces of strip styrene, the same thickness as that of the around-the-door-protrusion - you need only a piece for the bottom and one for each side.
Great minds think alike! I was about to do that exact thing.
doctorwayne The fixed plate for the diaphragm is likely larger than that protrusion (it is on all of my passenger cars), so the next step is to add a similar "U"-shaped section on the face of the first one. It will need to have the sides farther apart, so you'll need to measure the width of that plate, determine how much wider it is than the protrusion around the door, then divide that amount by two. Add a length of strip styrene to the face of the first fixture, setting it that measurement away from the inner edge of the original strip fixture - do this for both sides.
Yes, the diaphram plate is considerably wider than the mounting plate on the loco. This surprised me since the diaphrams are advertised as being specifically for Athearn F7s.
doctorwayne so the next step is to add a similar "U"-shaped section on the face of the first one.
so the next step is to add a similar "U"-shaped section on the face of the first one.
One question here, to clarify. Are you saying add a "U" shaped structure to the loco (to support the wider diaphram plate), or just make the "jig" wider?
doctorwayne If the diaphragm is also taller than the doorway, decide if you want to split the difference on the vertical position or simply place the bottom of the diaphragm even with the bottom of the protrusion around the door.
The heights are close enough (lucky for me).
Thanx for the insight. I'll probably get back to that project soon (many things going on right now, and I don't multi-task well any more).
MikeyChris doctorwayne so the next step is to add a similar "U"-shaped section on the face of the first one. One question here, to clarify. Are you saying add a "U" shaped structure to the loco (to support the wider diaphram plate), or just make the "jig" wider?
The latter: the first "U" (squared-off, obviously) is to ensure that once the fixture is built, it will always fit on the same type of diesel in the exact same place - in other words, the inside face of the "U" fits precisely around the protrusion which surrounds the door on the end of the diesel. You don't need to make the original "U" wider, but only add a somewhat wider "U" to its face (use smaller stock) to accomodate the mounting plate for the diaphragm.
The addition of the second, wider "U" to the surface of the first one, is to ensure that the plate to be cemented in place on the diesel will always be in the same place, side-to-side, and at the same height, too. If you can measure it accurately to build the fixture, you'll not need to make those measurements again, and all of the diaphragms will be centred on the ends of the diesels and all at the same height, too.
For mounting the assembled diaphragm to the loco, I've used Goo. It will likely affect the paint, but not sure anything that will hold on the ALM plastic would be any different. Besides, it's a somewhat hidden area that would naturally have some rust and grime, so any damage if it came off later could be weathered away IMO.
I'm not sure on this next bit, as it was some years ago. I seem to recall needing to do some sort of adjustment for the coupler length/drawbar. IIRC it's maybe because the mounting surface for the diaphragm is deeper on the model than the prototype? Ends up being more diaphragmage than room for it between units or something like that. In any case, worth a look to ensure everything fits like you think it will before things get too deep as is often possible to more easily adjust for any issues if known beforehand.
Mike Lehman
Urbana, IL
I built a suitable jig, but now am facing another issue- how to acyually glue the diaphragm in place without bluing the the jig and diaphragm all together. Also, the inner surfaces of the diaphragm mounting plate are somewhat "shaded" by the diaphragm centering springs, so it would be real easy to glue the jig, the loco and all moving parts of the diaphram into one big mess ;-) I'm thinking Goo may be the answer if I thin in with some Acetone. The Goo can then be applied to the loco (at least at the top and bottom), then the jig positioned and the diaphragm set it place. After the parts are positioned, I might be able to use a small brush to apply MEK to the joints. Now that I'm old(er) O Scale is looking real good!
Since the jig is only around the sides and bottom of the door opening, I'd suggest applying the MEK (with a small amount on a small brush, and working within the opening in the diaphragm) first to area at the top. Give it a minute-or-so to dry, and it should be enough to hold the diaphragm in place so that the jig can be removed.
You can then apply more solvent to make the joint more secure.