Dynamic brake blister removal

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mopacbuff

mopacbuff

Missori Pacific RR
Gents,

Inspired by the thread about building a scrapline SD7/9, I'm converting an Athearn blue box GP7/9 into a rip/scrap line unit (mostly because of missing parts and it being about 10 years old).

The prototype I love (MoPac :D ) and base some of my freelance RRs on, used units w/o dynamic brakes (mostly), and my specimen has DBs. In short, I want to remove the DB from this shell, and I'm not sure how to handle a certain part of it prototipicly. Specifically, the radiator(?) housing that overhangs the rear of the DB blister.

I hope these photos, and my description/questions, make sense.

View attachment 24137

View attachment 24138

This is the part I need to remove.

How do I handle this area?

View attachment 24139

Do I cut a straight line down through it to the back of the DB blister? Do I cut around it? Sorry of this sounds like a dumb noob question, it's my first surgery on a shell (hopefully not my last).

Thanks for any help (especially photos).

MPB
 
Does that winterization hatch come off (the rectangular grill cover that is just aft of the rear exhaust on the dynamic brake blister)? If it is molded on, you've got some work to do.
 
"Winterization hatch", thank you!! Now I know what to call it.

It is molded in.

Please explain the "work" I have to do.

Thanks

MPB
 


The blisters on the GP9 will come off. There are three tabs on the back holding them in place. The winterization hatch needs to be surgically removed as does the dynamic brake fan.
 
This one is definately molded as part of the shell, no tabs or anything holding it in place.

Guess I'll look at proto photos and see if I can find an overhead view.

MPB
 
MPB,

I did an Athearn GP-9 once -- took a while, but I was happy with my results.

On the old Athearn "blue box" GP-9s, the radiators that faced to the side were mounted to the shell by three pins -- all I had to do was push them out from behind (inside the shell).

Then the 48" fan and its attached housing, as well as the winterization hatch had to be cut out. I was careful not to cut into the 36" fans at the end of the long hood. To fill in the resulting gaps, I glued a piece of sheet styrene inside the shell. I then filled in the holes with more sheet styrene, cut as close to size as I could manage. Next, I filled in the gaps with putty (I use Testor's). After the putty dried, I carefully sanded down the "repaired" areas, and sanded a curve into the edge of where the dynamic brakes had been, to match the curve of the rest of the model.

I purchased a couple of EMD exhaust stacks (from either Detail Associates or Details West, can't remember which), along with some lift rings. I carefully shaved off all of the lift rings on the model, drilled small holes at the places the lift rings had been (including the ones on the section I'd rebuilt), then glued the lift rings and stacks into place.

At that point, all I had left to do was re-paint, decal, and weather my GP-9.

Don't think I'll ever go to this much trouble again, as there are plenty of GP-7s and GP-9s without dynamic brakes available from other manufacturers, but I had fun doing the one!

Hope this helps!

Regards,
Tom Stockton
 
The old Athearn always had a removable Dynamic blister. I've done several, I'd fill the top with a piece of styrene and the sides have three holes on each. I fill those by heating a sprue up and stretching it out till it pulls apart, then stick the small end in the hole till iits in allthe way, then I super glue it in place, when the glue dries cut off the excess with a knife. Sand and you may have to add some filler. I can post some picks later of what I have.
 
Gents,

Based on this proto picture;


View attachment 24164

and others turned up during my research, I've decided that my blue box geep most closely resembles a MoPac GP7, w/o DBs and plus a winterization hatch.

Now my plan is to make this my very first loco detail project (not super duper detail, just detail), before I make it a rip/scrap unit. I think I'll do the DB surgery, add appropriate smoke stacks, proper horns (cab mounted instead of short hood), add wire grabs and MAYBE do some side sill surgery. Who knows, maybe it'll come out so good that I send it to a paint shop (custom painter, as loco painting and lettering is out of my league yet) instead of consigning it to the scrap track. If it doesn't (highly probable), I'll just slap some paint and weathering on it and continue with the scrap track plan.

I'm going to start a seperate thread detailing my progress on this project (with pics), so please follow along.

MPB
 
This is a project that could be more trouble than it's worth. The surgery to remove and replace the dynamic brake blister and winterization hatch can be done like tom described but can you replicate the bolts and rivets on the top? I know that Front Range made a geep 7/9 shell without the dynamic brakes and a simular shell is made by atlas, life-like and others.
Are you planning to build an engine sitting on the srapline or one still in service? If it's sitting on the scrapline you could remove the dynamic /brakes and drap a tarp over the hole or use walthers emd 567 ptime mover inside.
 


Glen,

I know this is gonna be a PITA, but what better way to get my feet wet? If I screw it up too bad, I'll weld/tarp over it for the scrap track.

If it works out, then it's a unit in service. If I foul it up, then it's a scrap line unit, nothing ventured, nothing gained.

MPB
 
Okay, another way to patch the hole where the dynamic brake is to cut and use the top hood off an athearn sw7 switcher since it too is one of the wide-body engines and should match the width and give you the rivet detail.
 
CNR Glen said:
Okay, another way to patch the hole where the dynamic brake is to cut and use the top hood off an athearn sw7 switcher since it too is one of the wide-body engines and should match the width and give you the rivet detail.
Click to expand...

Glen, OK, you have me curious now. Exactly what section would he be using from this SW7???

100_1509.jpg
 
Okay in theory (my theory that is) you could cut the entire dynamic brake section including the rounded edges off the geep shell, then cut the top center section of the sw7 shell between the taper and the rad grill to fit. you would get some of the rivet detail, the location of new exaust stacks and all you would have to sand would be the access hatches and handrail mounts on the sw shell. That and the shells are both close to the same width.
pics.png
 
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And the only problem I see with that is, the SW7 has a beveled roof, the GP7 has a flat roof. You'd have to sand it down and it would be dangerously thin to get all of the bevel out of it.

Now the S12 has a completely flat roof section. But then again your cutting up a good shell for 1 small part that can be made out of styrene.

100_1510.jpg
 
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The best way to get rid of the fan is to simply cut out that slightly raised square area around it, and glue in a piece of styrene.
 
bnsf971 said:
The best way to get rid of the fan is to simply cut out that slightly raised square area around it, and glue in a piece of styrene.
Click to expand...

Right, that's how I do it for my Soo units. There really isn't Rivets or bolts o to deal with on that section. The bumps on each corner are supposed to be Lift rings.

IMG_2840.jpg

IMG_2842.jpg




If the unit wasn't for Pass Service then you should remove the Steam Generator on the front hood.

IMG_2841.jpg
 
kjd,

I owe you an apology, you were correct about the 3 tabs holding the blisters on, I was looking for a way to remove the whole assembly including the fan, so I did not see what you meant. Now I do (there is none so blind as one who will not see).

flh80,

Your pics are exactly what I have in mind for this unit, including the short hood, thanks for the inspiration.

I removed the DB blisters tonight (thanks to kjd) and now the shell looks like this;

View attachment 24170

My next step is to deal with the winterization hatch, and this fan;

View attachment 24171

Then I should just be able to make the area flat with styrene, add the appropriate exhaust fans, tackle the short hood and then add other details (like wire grabs).

My progress on this project is chronicled here;

http://www.modelrailroadforums.com/forum/showthread.php?t=21158

Thanks for all the help gents!

MPB
 


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