The Bucket Foundry

[ken seeber]

Michael,
Great post. Looking forward to the splashing of hot metal and seeing the fully machined final product. Will you be using green sand, CO2 or another, like Fenotec? I presume 6061 T6?

[Michael Moore]

Ken, Jeff and I have bought A356.2 ingots from a local foundry supply company. I will do a -T6 heat treatment on it.

We've got sodium silicate binder and a tank of CO2 and also some Techniset (phenolic urethane) binder/catalyst The latter is nice to work with as it gives an even cure and lets the binder get well mixed with the sand before the catalyst is added. The sodium silicate/CO2 didn't seem to harden consistently. There's also Petrobond on hand.

I will first see if I can get Petrobond to work. That is the least wasteful on materials and would let me avoid having 50-70 pounds of sand being purchased and thrown away with each mold. I made a pneumatic vibrator to attach to the match boards and hopefully between that and jacking screws I'll be able to pull the pattern without damaging the mold. But hard sand is available if it is needed.

cheers,
Michael

[husaberg]

Ken, Jeff and I have bought A356.2 ingots from a local foundry supply company. I will do a -T6 heat treatment on it.

We've got sodium silicate binder and a tank of CO2 and also some Techniset (phenolic urethane) binder/catalyst The latter is nice to work with as it gives an even cure and lets the binder get well mixed with the sand before the catalyst is added. The sodium silicate/CO2 didn't seem to harden consistently. There's also Petrobond on hand.

I will first see if I can get Petrobond to work. That is the least wasteful on materials and would let me avoid having 50-70 pounds of sand being purchased and thrown away with each mold. I made a pneumatic vibrator to attach to the match boards and hopefully between that and jacking screws I'll be able to pull the pattern without damaging the mold. But hard sand is available if it is needed.

cheers,
Michael

How do you mull your petrobond.

[Michael Moore]

I've got a fresh bag of it so I haven't had a need for mulling. It seems fine straight out of the bag when it hasn't been used before. I thought mulling was largely needed only with green sands or when adding the Petrobond compound to older Petrobond to freshen it up.

[husaberg]

I've got a fresh bag of it so I haven't had a need for mulling. It seems fine straight out of the bag when it hasn't been used before. I thought mulling was largely needed only with green sands or when adding the Petrobond compound to older Petrobond to freshen it up.

No idea, i thought it had to be done to reuse or do you just sieve out the burnt bits?

[Muciek]

Guys I wanted to ask a question, If I want to have a head like this cast, how to do a pattern for it? Should it be split in few places? Any examples of similar stuff? Thanks in advance

[Michael Moore]

Yes, we've been picking out the burned bits of Petrobond and put the rest of the used stuff in one container. The next mold gets fresh Petrobond seived over the pattern to start and then once a good layer is packed next to it fill in with the good used material next.

It appears that eventually the oils/chemicals will get burned out of the Petrobond, but I think you can buy cans of liquid to use to refresh it, and mulling might well be in order at that point to get the Petrobond back into a uniform consistency.

cheers,
Michael

[Michael Moore]

Muciek, you might be able to split it where that reinforcing rib is, but you'll probably want the fins to draft from the middle to the front and back ends so you can pull the pattern. So the parting line would be through the middle of the combustion chamber out to that rib.

cheers,
Michael

[Flettner]

I don't think these pipes stick out any more than a normal 125 MX bike, a bit of work in these pipes. These photos are terrible, I'll try again in the daylight, that's better.

[F5 Dave]

It looks like a bunch of work. Stacked mufflers? That is going to turn heads at the track. Awesome

[husaberg]

[Michael Moore]

With a CNC mill I'm not clear why he had centers for each throw instead of just rotating the crank around the centerline and having the tool move up/down/sideways as needed. I suppose he might want the centers for grinding the journals at a later point, but they seem redundant for the milling operation.

[Grumph]

With a CNC mill I'm not clear why he had centers for each throw instead of just rotating the crank around the centerline and having the tool move up/down/sideways as needed. I suppose he might want the centers for grinding the journals at a later point, but they seem redundant for the milling operation.

I agree but suspect that they're for finish grinding also. I've never seen a crank grinder small enough to do that crank so I'd assume he's going to have to use a toolpost grinder...

You can never assume holes in cranks are there for an obvious reason...Guy I know here made a replacement crank for a GP Delage - 1927, straight 8, roller bearing big ends - split rod bearings. One piece...Tasty but bloody awkward.
Anyway, the original had 3 X 8mm bore holes right from end to end through the webs. Two problems - what were they for and how do you bore them. Crank I should add is about 3 feet long...

We reckoned in the end that they were there for checking the crank was straight while away from the factory race shop and the right jigs. Just carry a piece of accurate and straight 8mm rod with you for checking.
Boring them was harder - he used hardened guide blocks between the webs and it finished up pretty good.

[Flettner]

The edge forming machine for hydroforming exhausts. Both Heath and Robinson but it does the job. Yamaha 100 twin rod, old washing machine motor and just bits found and cobbled together, I probably built this about thirty years ago.
Anvils are removable for other jobs as it was originally built to make dished ends for fourstroke (I know what was I thinking) mufflers.

[Flettner]

Pull start total weight is the same as YZ 250 kick start leaver on it's own.