The Corliss project

[MrBrownstone]

Hey Marty,

It Look's very nice... 

much better

some technqiue's also used for air-buble issues in the plaster are Gently Dropping the mold flat right after pouring as well as using a rubber mallet to tap on the table while pouring the mix, those are a couple of ways.

another trick I use:
A light spray of 1 part machine cutting oil to 4 parts water mix.. helps break the surface tension of water and air bubbles will move easier. though it does not effect the look or quality of the plaster. (the oil and water turn white when mixed) (pour plaster until mold is full the spray mix will flow over first and out leaving a nice plaster filled mold with very few if any air bubbles at all)

I use the rubber mallet during pouring after preping mold with spray works pretty darn good.. you've seen our castings 


Mike

[marc_reusser]

Thanks Mike, great tip.

Question though.....does the machine oil in any way affect the dried finished casting in regards to ability to absorb water based paints/stains/washes?


M

[MrBrownstone]

Hey Marc,

does not effect the painting aspect at all...castings come out nice and dry... ready to absorb those subtle washes and weathering.
(with the understanding that I use a light cutting oil and Hydro-Cal types of plaster)

too much oil in the mix will result in some discoloring... but is still very paintable

Mike

[Belg]

Mike, is there a weight to the cutting oil like with engine oil? Which brand do you prefer? Thanks Pat

[lab-dad]

FWIW I use alcohol and water on my silicone molds and it works very well.

For these large/thick ones I think the only way to get all the air out would be with vacuum.
I actually had a back massager clamped to the table I was working on!

-Marty
The last mold is half done!!!!!!

[MrBrownstone]

Hey Belg,

try to find the lightest stuff you can.. I have no label on the jug I got from a machinest friend. (but I will ask him)
I am not sure if there is a wieght ratio on the milling cutting oil...

smooth-on sells a IN & OUT II water soluble release agant...But I think it consists of the oil I am using...It sure smells the same...looks the same... and mixes the same way... so I opt to use my formula... the results are identical in every way

Marty,
I was using the alcohol and water method before, finding more success with the oil and water mix
( I have poured some really thick stuff too)(i.e. Our culvert inner arch modules are a pretty thick piece)
the castings we do for retail are poured with a vacumed mix.

those massage devices are good for helping the air to rise up after the initial mallet shock to acctually get the air bubbles to start moving.

just offering some idea's 

Mike

[lab-dad]

Well the last foundation is done.
I may try again though.......
I have started on the governor too. It is nice to be back at the lathe/mill.
Not much of it shows in the picture, the arms and such still need attaching and I need to find some small brass blass for the ends (mine are way too big) 
Lots of jigs were involved in making the arms, and soldering them up.
Anyway I like to post on Sunday, kinda sets a goal for the week.
I will scan the reference etching for the governor and post it with the finished one.



-Marty

[Ray Dunakin]

Beautiful! Those foundations are much better.

[TRAINS1941]

-MJ

Excellent.  Really like the casings now.  And the machine just as one would expect perfection.

Jerry

[MrBrownstone]

Hey Marty,

Those blocks look much better now...and I see you have been working hard...

still one of the greatest builds on this forum IMO

thanks

Mike

[jacq01]

   this is much better..........Very well done.

   Jacq

[John McGuyer]

Ohhhhh! I like that.

John

[Chuck Doan]

Excellent progress. And that black clamp really looks real!

[shropshire lad]

Excellent progress. And that black clamp really looks real!

  I've got some of those black clamps . Will that make me as good a modeller as Arty Farty Marty ?


   Nick

[lab-dad]

All the prototype pictures of Corliss steam engines I have seen have the big clamp on them.
Right next to the oversize penny.

Nick, I'll never even be half as good as you, even with twice the clamps!

-Mj