Broken gears and cast molding new ones.


Ericsauto

Ericsauto

Well-Known Member
Has anyone used Micro Mark plastic casting for making drive gears on a locomotive?
Such as this set from Micro Mark

www.micromark.com

Complete Resin Casting Starter Set

DetailsUse the same materials and techniques that professionals use to build their models. Everything you need to begin resin castingEasy techniques used by professionalsSilicone mold rubber and urethane casting resinsReproduce delicate detailsGet exact duplicates
www.micromark.com www.micromark.com

Long story short. Since Scaletrains has bought MTH you cannot get parts for MTH. Same with the parts from Scaletrains. I was told by scale trains that there are too many parts to stock. I asked them " What do you do when you have a bad part?" He told me he wasn't sure.

So HO scale MTH Veranda Big Blow gears lost some teeth in the drive tower and NWSL has some but not what I need. NWSL said they couldn't make it right now because they had no help. So my next thing is to mold a set of gears. If you have done that before, do the gears hold up well?

Looking for advice. I have looked everywhere!!! Frustrated.
 
Hey there. For my casting needs i have used Alumilite casting kit:
images.jpg



20230309_165211.jpg
20230309_165202.jpg
20230309_165232.jpg

Finished product at the end. I have also casted a gear for all metal gear box because of noise from same material gears. But for the gear i used automotive epoxy available in Auto Zone and every other auto parts stores:
20230309_165254.jpg

After some trial and error i found that this yellow stuff is best, as white one is never really hard after drying. The Allumilite i mentioned first i was able to buy from a friend who did commercial modeling, unfortunatelly he's no longer with us. But maybe Micromark has it available. Hope this helps.
 
KriegslokBR52 said:
Hey there. For my casting needs i have used Alumilite casting kit:View attachment 163870


View attachment 163871View attachment 163872View attachment 163873
Finished product at the end. I have also casted a gear for all metal gear box because of noise from same material gears. But for the gear i used automotive epoxy available in Auto Zone and every other auto parts stores:View attachment 163874
After some trial and error i found that this yellow stuff is best, as white one is never really hard after drying. The Allumilite i mentioned first i was able to buy from a friend who did commercial modeling, unfortunatelly he's no longer with us. But maybe Micromark has it available. Hope this helps.
Click to expand...
I ordered today and will try it sunday. I'll let you know my results. Thanks
 
The easiest way to cast is to have one piece of rubber mould flat. The other piece of mould should then have the actual shape of a part you want to cast. I have first made my master details, which i then glued to flat piece of styrene and build up a wall around it:
20230311_083236.jpg

Then i mixed the two part Allumilite rubber compound mould and poured that into the master part. You have to work carefully here and a tooth pick is good to have, to pop any bubbles that might come out.
20230311_083246.jpg

On this one a took a sharp Exacto blade and carved the excess run off channels after the mould cured, but you can also build them up into the master if you preffer that. These channels i found out are necessary when you will be pressing the flat mould against after pouring in the resin.
20230311_083242.jpg

And all three pieces:
20230311_083229.jpg

The way my friend explained; after pouring the resin into master mould, start pressing in the flat piece from one side like a steam roller (and that in fact worked excellent). This way excess resin will flow on the other side. Good luck and let us know about the results.
 
I tried the gears using the JB Weld this weekend. It came out pretty good but I am still letting them cure. Not really sure about them yet, they seem a bit pliable. I'll let you know. A great technique that you have done.

In the meanwhile, I found the gears ( sort of) from Northwest Short Line. They have the 17-tooth gears that are correct. The problem is the 19-tooth gear. It is the correct diameter but instead of a 2.0 mm hole it has a 2.4 mm hole. Since they can't make a new one for me, I have ordered them.

My fix will be ( I hope) to fill the hole in the new gear with epoxy and redrill it with a 2.0mm hole. That is all I can come up with as of now. I hope this will work. I will let you all know how that comes out.
 
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Ericsauto said:
I tried the gears using the JB Weld this weekend. It came out pretty good but I am still letting them cure. Not really sure about them yet, they seem a bit pliable. I'll let you know. A great technique that you have done.

In the meanwhile, I found the gears ( sort of) from Northwest Short Line. They have the 17-tooth gears that are correct. The problem is the 19-tooth gear. It is the correct diameter but instead of a 2.0 mm hole it has a 2.4 mm hole. Since they can't make a new one for me, I have ordered them.

My fix will be ( I hope) to fill the hole in the new gear with epoxy and redrill it with a 2.0mm hole. That is all I can come up with as of now. I hope this will work. I will let you all know how that comes out.
Click to expand...
If the Nortwest Shortline gear is metal (brass i assume?) you can probably obtain a brass tube. Cut a piece and stick that between the axle and the gear. Just make sure it's tight and use some Loctite:
20230314_182834.jpg
 
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