Casting Butt Plates & Trigger Guards

[nvandal]

Hello all,
I'm copying a beautiful New England fowler ( not for sale/ no inquiries, please ). I would like to cast the butt plate and the trigger guard. I've used a product called PoYo Putty to make a silicone mold. In this mold, I can make wax patterns. I use a hard casting wax. My question is:
- Can I make a mold out of Plaster of Paris, melt out the wax, and then cast the part with brass. I've attached a sprue to the pattern, and I assume I will need some breather tubes for the air to escape. This is the oldest lost wax method I know of, but will it work here? What should I be aware of? Any further suggestions.
I know this will generate more questions, but I'd really like to hear from someone who has done this, or from someone who has a better way. I know another option is to sand cast them, and I may have to resort to this
I've included photos of each part.
The gun is fantastic, likely a Massachusetts piece from the Worcester area. What a pleasure to have it for making the bench copy.
Thanks, in advance, for all the help,
Norm Vandal
Roxbury, VT
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[David Veith]

The only part that worries me is the Plaster of Paris. I am guessing you have away bake the plaster to get the moisture out and to burn out the wax. If it was me I would be calling up Rio Grande for some investment plaster. Or one of the other supply houses. Witch way was you planning on molding it up in your flask? Was you planning on spin casting or a simple pour and Vacuum? I love the peices
David

[nvandal]

I was only planning on pouring it into a cardwboard flask. Someone told me to paint on some heavy plasterto be sure all the detail is captured. I don't care about the engraving as I will do that later anyhow. When I use the PoYo Putty I will fill it in with wax, as well as the screw holes. I guess I need to be certain all of the moisture is out of the plaster? And the wax melted out, of course.
If I vibrate the flask as I pour the plaster will it work better? I don't know how the vaccuum or the centrifuge work. Will investment plater work in my type of " homemade " setup?
Thanks,
Norm V.

[44-henry]

This is the stuff I buy for our university lab: http://www.progresstool.com/pd_kerr_casting_investment_platinite_pt.cfm

There is probably better stuff for the larger castings (we do mostly small parts). I'm sure you will get better answers concerning the casting method. We use a vacuum table for small parts and for the larger pieces we just pour the metal directly into the mold with nothing but gravity to assist. I would strongly recommend that you do purchase some actual investment powder and follow the instructions very carefully concerning burnout. You really don't want to pour molten metal into a mold that has trapped moisture. A local jewler who visited my class last year mentioned an accident in his company where this exact same thing happend and said it basically caused an explosion.

[Acer Saccharum]

I did some lost wax casting way back, and I recall, there was a thing called 'grog' mixed in with the casting plaster. Lost wax process uses a special plaster called investment plaster, not Plaster of Paris. The mold is baked at high temp to not only melt, but BURN the wax out, and to drive out ALL water. I am trying to remember, but I think the mold is taken up to approx 1000 degrees. Just a mere melting of the wax will not suffice. Casting brass in Plaster of Paris may yield a bomb. PoP is not as porous as investment.

Check with a local University Art Dept, possibly.  As an alternative, if you can come up with decent waxes, you can send them to a founder who does lost wax casting.


Founders:
C.A. Brown, in Cranston, RI.
Another founder is Cranston Casting, in the same town, but I think their flask size is limited to jewelry.

[nvandal]

It's sounding like my best bet is to make some boxes and to sand cast the parts. I've got to figure out how to melt the brass. Would a cast iron forge set up outdoors with no flue ( temporary install ) generate enough heat to melt it. I can likely get a forge up here, a farrier's forge, as we call them. My neighbor has one.
I've got plenty of bullet casings. If I get the primers out, will the impurities simply skin off the top of the crucible? Or, will I have to clean the casings thoroughly beforehand?
I can get sand from Vermont Castings. They make quality woodstoves and are only 20 miles away. Iy should be the same green sand. I'm sure they could tell me. They may have some dude who's willing to help?
I have the Williamsburg video, so I can see how Gusler did it. Any improvements on this? Is there a better parting material than talc?
The advice is wonderful. Thanks for informing me I could be making a bomb! Plaster of Paris mixed witrh hot brass shrapnel...no thanks!
I also have to cast some unusual barrel keys used on Peter Berry rifles. They have an extra long oval head that is so large it appaers to be an inlayed escutcheon. I'm thinking I will modify an standard key using sculpting wax. Then, I'll cast a bunch of wax patterns using the PoYo Putty. Then, since they're quit small, perhaps someone can cast a bunch for me using investment casting. Any suggestions as to who might do this. I'll certainly call the two places mentioned in Rhode Island.
Norm Vandal

[billd]

If you have the ability to make the wax parts, contact Dave Keck to see if he would do the castings.

Bill

[Acer Saccharum]

I have cast brass in a forge before. A temporary tower of fire brick surrounds the fire and crucible. I bought my crucible from Dixon in New Jersey, a million years ago. A major art/jewelry supply should have crucibles and molding sand. Graphite clay crucible is what you need. Tongs to lift the crucible. Broken glass sprinkled on the melted metal will help keep the zinc from burning off. Zinc fumes will make you sick. So do this outside.

[Captchee]

 You do realize that the parts your showing in your photos are probably not cast  but plate /sheet  brass  that’s been formed  

As to casting .

First off Acer is dead on . Casting plaster is not plaster of Paris.
 The baking of  casting plaster also ensures that all the moisture is gone  .
  If its not , when you pour to the mould  with  high temp fluids “ Brass 1650-1720  the higher being a casting temp “
 You get a steam explosion. If  the  molten brass gets on you . Its like hot metal to foam. It will burn right down to the bone .


 Yes shell casing brass will work .  Be prepared and have 2 times the amount you think you will need . There is not as much brass there as  one would think . And make sure all the primers have been popped out .
Most casings are yellow brass not red .  Thus you get a nice  color .   But remember it also has more zinc .
 Normally around 33-35% zink and 65-70% copper .
 Most red brass as is often sold for castings  through places like ToW  , are not true brass   they also have tin mixed in  and contain less Zinc . Thus the colors are more  gold then yellow

 Yes you can melt  brass to casting temp in a forge . It takes a little but   work .
  Bring your crucible with one or two of the casings in it , up to temp .
 When they reach proper temp they will create a pool . Keep the heat on ,,, and add  another casing to the pool . Keep adding to the pool tell you have enough liquid to pour  from “ remember its always better to have more then not enough .. Once you think you have enough  melted brass . Keep the heat on it  and climbing  tell you reach your pour temp
 With my  furnace what I do is  once I have   the material in the crucible  melted  I  let the furnace run on high for another 5  minutes  before I pour ..
 Now im saying that from experience with my furnace and crucible combination  . If you go to long you will start burning off  to much of the Zinc and your brass will become more red in color  as your % ’s change so keep that in mind  

And yes the contaminates will float to the top .   There are a couple ways to remove it
1) by laddering it off  like one does with a lead pot .
2) with a  pouring ladle that has a skimmer  , IE the ladle does not pour from the surface of the liquid . Thus the floating slag is held back while  the  more pure liquid is poured

 With sand casting , yes ,you need green sand  or a  fine sand with a binder that’s been added  .
 With the right sand you can actually cast details  far greater then you would think .
 I have actually had finger prints  show up   which  inadvertently left  in the sand while making  the moulds .
 Yep talc  makes a good release  as does fine chalk

   When you cast to sand , the sand will be wet .   You don’t have the issues that you would with  plaster because the sand is so porous that the  steam isn’t trapped in the casting .
 The ability  of this gas to escape is  why  sand makes a great medium to do lost foam casting .
 IE a part is made from blue  foam . Packed in sand  and then a pour hole is  set to the part . The hot  metal incinerates the  foam   replacing the cavity with molten metal .

. I would also  comment , that casting Butt plates is not fun  to do in sand  if they have a concave   surface.
 Remember you must lay  it up so as to be able to  remove the part from the cope and drags  without  disturbing the surrounding sand  which is your mould.
  So you can quickly see that ist not just a mater of laying  starting a base .  Powdering the part with release and then  pounding your sand .
 The part also need to be at least 3/16 thick
 that’s where lost wax casting really shines . . Not only do you get very good detail but you also  don’t have to pull the part . The wax is simply melted  out .  Thus leaving you a cavity to pour to ..
  Your part can also be thinner because you can  apply a vacuum or  centrifugal  application to pull the fluid into the smaller finer areas .
Something that you cant do with sand  

Again . And this is just me . But if I were to be  needing the parts your showing , I would be making them from sheet brass   and not casting them unless I wanted a large number of the same part

[Captchee]

Graphite clay crucible is what you need

steal crucibles  work  fine for  melting lower temp alloys like Brass and aluminum and are much cheeper to learn on
  They however not good for minerals  or  higher temp alloys
Steel will  also  slowly erode as the carbon is  burnt out of it  . Thus you need to maintain them  or you can end up with slag falling into your pour
 But they also do not need to be pre baked and they  are no where as easily broken as clay /carbon .

 Now if one really wants to get down to it , then IMO the carbon graphite or  graphite crucibles are the way to go . But if one is only going to be melting  brass  or lesser materials then there isn’t any real need .
 But if  at sometime one thinks they may want to do say Gold  or silver . Then  get a good crucible

[Bryce]

Sorry to diverge from the topic slightly but on the note of crucibles, where could one find one suitable for steel casting?

[Ben I. Voss]

Casting sounds like too much work if you're only making one or two; I'd form them out of sheet!

[Captchee]

Sorry to diverge from the topic slightly but on the note of crucibles, where could one find one suitable for steel casting?

any number of casting suplies will carry diffrent grades of  Crucibles
 here are a couple links for you

http://www.budgetcastingsupply.com/index.htm

http://www.foundry101.com/

 here is where i have goten mine from in the past
http://www.graphitestore.com/items_list.asp/action/prod/prd_id/126/cat_id/12

 past that a quick google should give you  many , many others

[Robby]

Are using a vacuum or centrifugal apparatus essential in casting the lost wax process, or is it to mote insure success?
Robby

[Acer Saccharum]

Vaccum/centrifugal stuff is nice, but but you will spend so much money, it's not worth it, unless you are going into the business. Even lost wax setup is pricey, with the kiln you need to burn out the wax and bring the mold up to temp. A used small ceramics kiln may do the job for you. Better vent it so the vaporized wax does not explode the kiln. @!*%, what the $#*! is hubby doing in the garage?

Make your sprues and runners of healthy size and melt extra metal in the crucible so you develop plenty of pressure from the weight of metal in the sprues. Also a massive sprue stays liquid while the parts solidify. The parts continue to draw metal from the sprue as they shrink. Small runners solidify before the parts, and then you get parts with sinks and voids as they cool, because they cannot get more metal from anywhere while the metal shrinks.

[44-henry]

Sorry to diverge from the topic slightly but on the note of crucibles, where could one find one suitable for steel casting?

You open up a whole nuther can of worms when you start talking about steel castings. I've looked into the induction furnace for our labs as a first step, but there are other issues that have kept me from going ahead with the process. Long and short of it is that it doesn't appear all that simple and is actually quite expensive to get setup for it. Some of the guys that post here have done this in the past and would be your best source of information on these issues.

When I pour silver I generally pull my flasks out of the furnace at about 1100 degrees, some prefer 1000, but I figure they get pretty close to that before I actually pour anything inside. Before that I really try to get them much hotter. I feel pretty safe if I can look inside the mold through the cavity and see nice bright red, tells me that there isn't much chance of moisture present and I can relax and let them cool down a bit before I pour. Not technical probably, but I rarely have a bad casting so I must be doing something right.

I purchase a lot of casting supplies from places like Rio Grande and Budget Casting Supply. I also like to scrounge brass at garage sales during the summer and so keep a good inventory of the stuff. If you are looking at sand casting than definitely check out the oil bonded sands like Petrabond. We use this stuff and the detail is excellent and you don't have to worry about moisture much either. Happy casting.

[nvandal]

After considerting all the advice, I'm considering taking a larger buttplate that accomodates all the features of the buttplate I need and re-working it. I can trim it, anneal it, and hammer it closer to the pattern I need. Is this a crazy idea? One buttplate that works is an Edward Marshall buttplate from Muzzleloader Builders Supply., # 20690.
I will also buy a small acorn finial trigger guard from Track, # TG-FOWL-SA-B. I will gring off the forward section and silver solder on a new on shaped to the pattern I need.
Any opinions on this? Any caveats?
Norm Vandal

[James Rogers]

If going that route, I would go with Reeves Geohring's stuff

[nvandal]

Good point. I've spoken with him a few times and he's been very helpful. I don't believe he has any catalog or photos to check over? Does he have a website?
I've somehow lost his phone number. Can anyone out these please send it to me so I can call him?
Norm V.

[tallbear]

Reeves Goehring  717 684 2022