First project from scratch - mushroom sinker mould - Queenstown/South Africa

[Riaan]

Hi guys,

I finally have all the equipment pieces in place to tackle small casting projects.

The first one is a mould for my favourite fishing sinker and even with all the power outages I managed to get a decent print (took me 5 tries).

What do you guys think?

Regards

[ThomasPowers]

Using one hobby to further another---double plus good!

[JNewman]

Either clamp the mould closed or put some weight on the top of the mould and you will get much less flash.  You have hydraulic pressure from the liquid metal lifting your cope. 

[Kozzy]

42 minutes ago, JNewman said:

Either clamp the mould closed or put some weight on the top of the mould and you will get much less flash.  You have hydraulic pressure from the liquid metal lifting your cope. 

Commercially, deflashing units are often used.  They basically freeze the parts and tumble them frozen to deflash because one can deflash large volumes of product quite quickly.  Similar is actually done on a lot of injected "rubber" parts also which are nearly impossible to deflash unless frozen solid so the flashing breaks instead of bends.

On small quantity fishing weights, I'd either not worry much about it or if I went for a second mold, I'd have the alignment pins installable after casting so the mating face of the mold can be surfaced for a better match--"as cast" will never be perfectly flat or straight.

In any case, it's a great project and darned good results as it stands.  Better yet, it got me thinking about what can be done in terms of cores from my 3D printer....

[ThomasPowers]

I believe he was talking about the original Al pour as he mentioned the cope and not the subsequent use for sinker casting. And I would advise the same: either weight it or use latches on them. Just as a safety precaution if nothing else, if a cope "pops" up having molten Al coming out the sides is unpleasant... 

[Frosty]

I"m thinking you can gang a LOT more sinkers in the same mold. Lead is a low temp pour you don't need nearly so much room between cavities. If you alternate their direction you can gang lead in an aluminum mold less than 1/4" apart. Stems overlapping and nearly touching the head of the alternate molds. I'd have to play with gating to decide which worked best. My first thought is to gate to the base of the stem but access might be better through the heads and let me pack them closer.

Thinking about it it'd probably work better technically gating through the head to allow for shrinkage. Either way you're looking at two sprues and gates one on each side of a vertical mold. The gates would need to be large enough to supply metal while the castings cool and rather large sprues will supply hydraulic pressure to keep the patterns full.

This sounds like a fun thing to fiddle with. I'd make test molds from plaster of paris and when I got one I liked use it for the master pattern to cast my permanent aluminum molds.

Use wax to make the test molds, a silicone rubber mold to make the wax shroom sinker patterns then just stick those to the wax gate/sprue, (riser?) patterns.

Matched mold halves should be enough to prevent excessive flash, if not I'd have to experiment some more before casting my aluminum permanent mold.

Once I had a mold I liked well enough to pour it in aluminum I'd make sure it had enough room to allow me to drill and tap it for closure clamps. Two or three steel bolts through one half screwed into the other and tightened will hold the halves together tightly and because steel has a lower COE (Coefficient Of Expansion) The mold will expand more as it heat from the molten lead than the bolts will so the seal will get better.

You went to a LOT of work making a nice mold, but it's seriously flawed in just being a bunch of individual molds in one bit tool. A gang mold would make them 10, 20, however many at once. If you like casting individual sinkers I'd just make two mold cavities fed from the same sprue with attachment points for a pair of vise grips to hold it closed. You could melt a pot of lead, make a pour, let it cool for a few seconds, pop the vise grips open give it a rap on to remove the sinkers, close the mold and make another pour. You'd have to cool the mold after a few pours or it'd take the sinkers forever to solidify. As kids we used to cast sinkers around the camp fire using a tin can as a flask and store bought sinker molds. Trim the flash with a pocket knife, fish don't care how a sinker looks you know.

Frosty The Lucky.

[Smoggy]

Looks like you got all the basic techniques covered, and you're going to have some fun developing your skills I'm sure. From what I can see from the pictures it looks it's been a successfull session. Well done.

What alloy did you use to make the sinker moulds?

[Riaan]

15 hours ago, ThomasPowers said:

Using one hobby to further another---double plus good!

Thanks alot

13 hours ago, JNewman said:

Either clamp the mould closed or put some weight on the top of the mould and you will get much less flash.  You have hydraulic pressure from the liquid metal lifting your cope. 

Hi JNewman,

Thank you for the advice, I will start weighing my cope down in the future.

 

[Riaan]

On 9/13/2016 at 3:20 PM, Frosty said:

I"m thinking you can gang a LOT more sinkers in the same mold. Lead is a low temp pour you don't need nearly so much room between cavities. If you alternate their direction you can gang lead in an aluminum mold less than 1/4" apart.

 

Hi Frosty,

I will definitely try ganging up the  sinkers to up my productivity since this sinker in particular is a high commodity among anglers in SA and they are quite expensive as well. So naturally I will eventually try to sell them to local fishing shops.

The flashing on the sinker problem started out when my electricity company decided that my printer are not allowed to finish printing. ie. the black spots on the printed mould are actually severed pawn heads from an old chess set I had sitting around. These heads are almost the same as what was needed but this mould still needs some work t ensure a flat contact between the two halves. Meanwhile I printed new hemispheres on the correct size and glued them on. I will try them like this as soon as my melting furnace are complete.(ridgidizer and drainage hole still needed)

I will design a new mould and post it for comment. Thank you for all the advice.

 

Regards

On 9/13/2016 at 2:31 PM, Kozzy said:

Commercially, deflashing units are often used.  They basically freeze the parts and tumble them frozen to deflash because one can deflash large volumes of product quite quickly.  Similar is actually done on a lot of injected "rubber" parts also which are nearly impossible to deflash unless frozen solid so the flashing breaks instead of bends.

Kozzy,

If I must say, I`m quite chaffed with the flatness of the adjoining surfaces but I will definitely look into making the alignment pins detachable in order to get the surfaces flattened.

If I can ask, I would like to start using sand cores. Any advice?

[Les gouvea]

Are there anyone that can give me a quote on a mushroom mould.  im from boksburg

[Glenn]

Please ask the question again. 

Do you mean mold spores to make bread, certain cheeses, and even medicine (Penicillin), or to reproduce mushrooms?

Or a mold for making a mushroom from say concrete?

[ThomasPowers]

So is this a 2 oz sinker or a 5 pound sinker?  1 cavity or 6?   You know exactly what you want; we don't; what you commonly use may not be what we might be using them for.

Also you do realize that custom made items cost MORE than if you can find a commercial source for them.

BTW are you willing to pay for international shipping and customs?

[Irondragon Forge ClayWorks]

For casting lead sinkers a steel or aluminum mould block will work and much faster than a sand mould. Any machine shop can make one for you pretty easy. They just need to know what weight sinker you want. A google search brought up quite a few companies making them.

[ThomasPowers]

I was thinking: take a piece of plate or bar. Heat and drive a ball bearing 1/2 way into it. Grind/file flat. Place another piece of bar on top and drill out the stem hole and a pouring cup.  Drill holes to drop in alignment pins. done.