New to Casting

Hello all
Been interested in casting for a few years now and would like to get into making reproduction castings for old marine hardware for small craft vessels. Retired from the military in 2017 and now I have a small boat building shop in the Adirondacks of New York state. Thanks for welcoming me into the group. I hope to meet new craftsmen and women and learn some new techniques. I have posted a few pictures of my recent work. Thanks

 

Bronze stuff?? Very nice. People pay up the bucks on fleabay for really unique bronze cleats. Welcome aboard John.

 

Welcome John.
Have any trouble with sand dropping out of those flasks? That's a lot of real estate! I had a set of 16x16 x3-1/2" flasks for some large plaques I was making and while my petrobond was new I had pretty good luck, but after awhile.... dropout city. Reinforcement strategies worked for awhile too, but then I finally broke down and made a deeper cope.

Pete

 

Thanks we will see how it goes

 

I hear you on the size issue. The picture here was the first try. I rammed this one up to see if it would hold...new sand as well here. The flask is 12 x 19. My next issue will be how to build the gates. Not sure if I should build them in the cope or drag on my match plates. My parts are thin.

 

I would personally put the sprue on one end and place the runner between the sets in the drag for the full length of the mold. Then gate each piece, 2 positions each, primarily in the cope. You could scrape out a little sand from the drag right at the point where the gate will hit the pattern to give you full thickness entry. As the runner fills up it will want to push a majority of the metal through the last gates. In order to even out the flow it's been recommended to decrease the height of the runner after each set of ingates so it's at its minimum at the far end. (I'm talking out of school).

For copper alloys it's also been recommended that your runner be deep and narrow as opposed to wide and shallow for aluminum. If your incorporating your runner or gates on the matchplate Id make the draft on them a little generous so you can concentrate on your pattern details and not worry about the gate pattern pulling up sand.

I'm not an expert, but that would be my first stab at it.


Pete

 

Very fancy.
Are those hinges for a 17th century Galleon salon door?
I make a few parts for small tinnies.

 

They are for a old boat

 

Thanks for the information.

 

Jeff,
I built the match plates in a 2 part process. I first built a small box my part would fit in. 3 inches tall but yours may vary depending on the size of your flask/part. This box will eventually will be cut in half but first I drill 1/4 inch holes vertically through the walls on each side using a drill press. These are used to line up the mold in part 2.
I set the box aside
Using a 3/4 inch piece of plywood (same thickness as your match plate) trace your part and then using a router bit cut down to the parting line half your pattern. Then set your pattern into the plywood. You can use molding clay to fill in the gaps between your parts and the plywood. It's a tedious job doing this part. Once your happy with it. Get the box back out. Cut it in half on a table saw.
Set the box over your part and center it and drill the holes through the plywood so you can bolts the box half on the plywood around your part.
You will need a silicone rubber to pour into the box over your parts. Reynolds materials sells the items you will need. You must use a release agent as well to release the parts from the molds.
This will be done on the other side as well by bolting the box together and cleaning up any clay that was used.

When the rubber mold is made it will be used to bolt on both sides of the match plate and a polyester resin is poured through a 1/2 hole through the plywood match plate into the center of the rubber molds.

This is a complicated process and may be easier to explain by phone if you need further explanation.