The Bucket Foundry

[Flettner]

I have to remake patterns for this cylinder head. Ill post the pattern making process as I go.
These after market heads for the EA81 Subaru, takes them from 72HP with standard heads, to 130HP with these heads, no extra revs needed. Just shows how bad the original Siamesed ports are.

[WilDun]

Unbelievable the difference in power! - hope there are plenty of EA motors (both pushrod and ohc) lying around for them - they seem to have been quite strong units!
Over in OZ (Brisbane)at the moment, met Darryl, very nice guy and bike enthusiast, lots of projects on......... What a dummy I am, I sat gawping at a B31 Beeza he was working on which was sitting on his workbench and didn't even notice that the bench was actually a highly maneuverable hospital bed! - most ingenious ready made solution for working with bikes I've ever seen!

[ken seeber]

Will, wonderful stuff. Great to see that kiwibiker brings people together.....face to face

Now, remember that the hospital bed is for BSAs only !!!!!!!

A simplified urine test that may be relevant for us!!??*
Go outside and pee in the garden.*
If ants gather:- diabetes.*
If you pee on your feet:- prostate.*
if it smells like a barbecue:- cholesterol.*
if when you shake it, your wrist hurts:- osteoarthritis.*
if you return to your room with your penis outside your pants:-
Alzheimer*

[Flettner]

Will, wonderful stuff. Great to see that kiwibiker brings people together.....face to face

Now, remember that the hospital bed is for BSAs only !!!!!!!

A simplified urine test that may be relevant for us!!??*
Go outside and pee in the garden.*
If ants gather:- diabetes.*
If you pee on your feet:- prostate.*
if it smells like a barbecue:- cholesterol.*
if when you shake it, your wrist hurts:- osteoarthritis.*
if you return to your room with your penis outside your pants:-
Alzheimer*

Great, now the wife keeps looking at my shorts, not sure if that is such a good thing.

[Pursang]

It was great to be able to meet with Will. He is also a very nice guy, knowledgeable and with an interesting history.

The Hospital bed is a great work platform.
Raises, lowers, tilts (to roll bikes off & on) and can lift one wheel up to make it easy to put a centre support under the bike.

I'm scheduled for 2x knee replacements, the bed might get put to it's actual purpose during my rehab.


Q: What does it mean when the ants just curl up & die?

Cheers, Daryl.

[ken seeber]

[Q: What does it mean when the ants just curl up & die?

Cheers, Daryl.[/QUOTE]

A: Too much antacid....

[Pursang]

[Q: What does it mean when the ants just curl up & die?

Cheers, Daryl.

A: Too much antacid....[/QUOTE]

Cheers, Daryl.

[WilDun]

Back from OZ, had a good time there - Brisbane's a nice place and it was good to meet you Daryl.

Great! - now the thread has a bit of life in it again! - we will be very much looking forward to the pattern making process by Neil - (non 3D printed .... of course!).

I most probably will not be doing any more of the foundry stuff - not in the near future anyway - moving next year sometime.
Now beginning (reluctantly) to offload all my gear and I have sold off all my beloved bike books and engineering books (making sure that they went to the right people of course!), little pedestal drill, lathe which was acquired just a couple of years ago, along with other "junk".

Talking about peeing problems Ken, I wouldn't even attempt it outside in NZ these days, - it's so bloody cold that there are no ants around! - and with that icy wind - if I shook it there would always be the danger that it might shatter!

BTW Daryl I kept spelling your name wrong, sorry about that, - now rectified!

[lodgernz]

I've just done another pour of my exhaust extension insert using the lost-wax method.
This time I used beeswax and definitely noticed less shrinkage in the wax mold.
I'm using plaster of paris and fine sand in equal amounts as my negative mold material (what's that called?) in the flask.
I let the flask dry out for a week in a warm place, then melted out the wax at 100ºC, leaving the flask in the oven for a few more hours.
While getting the furnace and crucible up to temperature. I had the flask in the oven at 250ºC for about an hour.

After all that, when I pour the alloy into the mold, it bubbles frantically like it's boiling, and the resulting casting is pretty shit.

Clearly I'm doing something wrong. Any advice welcome please.

[ken seeber]

I've just done another pour of my exhaust extension insert using the lost-wax method.
I let the flask dry out for a week in a warm place, then melted out the wax at 100ºC, leaving the flask in the oven for a few more hours.
While getting the furnace and crucible up to temperature. I had the flask in the oven at 250ºC for about an hour.
After all that, when I pour the alloy into the mold, it bubbles frantically like it's boiling, and the resulting casting is pretty shit.

Roger, from what you have described, I reckon the bubbling is from steam coming out of the plaster. I don't think the 250 for an hour is enough. Have a look at 2 stroke stuffing when he did his castings, there are a couple of youtubes. I think he observed that 400 was too hot (cracking) and was aiming for a bit less, say 350. However, he also commented that they were held at this temp for a week or so, which maybe over the top.

Also, your timing is good re plaster moulding. We are playing with a different cylinder head for a KTM 250 in a kart. Typically, the standard head can't be turned round so the coolant exits at the rear. Well it can be, but results in total short circuiting of the coolant thru the cylinder and head, and some even do it...why??? So we are doing a 2 piece head with a turned combustion chamber, backed up with a cast cover which provides a natty cooling path and has a rear exit.

Have printed up 2 parts, using stuff called Polycast (see https://www.youtube.com/watch?v=NBxp...ature=emb_logo). The plan is to cast one using your 50:50 plaster (of paris) & sand mix. The other we will try some stuff called Omega Gold Star (https://www.goldstarpowders.com/products/ip-omega).

Here's a couple of pics of how we'll do it, with the down sprue going down the centre.



Great to see you are splashing hot metal around.

[lodgernz]

Roger, from what you have described, I reckon the bubbling is from steam coming out of the plaster. I don't think the 250 for an hour is enough. Have a look at 2 stroke stuffing when he did his castings, there are a couple of youtubes. I think he observed that 400 was too hot (cracking) and was aiming for a bit less, say 350. However, he also commented that they were held at this temp for a week or so, which maybe over the top.

Also, your timing is good re plaster moulding. We are playing with a different cylinder head for a KTM 250 in a kart. Typically, the standard head can't be turned round so the coolant exits at the rear. Well it can be, but results in total short circuiting of the coolant thru the cylinder and head, and some even do it...why??? So we are doing a 2 piece head with a turned combustion chamber, backed up with a cast cover which provides a natty cooling path and has a rear exit.

Have printed up 2 parts, using stuff called Polycast (see https://www.youtube.com/watch?v=NBxp...ature=emb_logo). The plan is to cast one using your 50:50 plaster (of paris) & sand mix. The other we will try some stuff called Omega Gold Star (https://www.goldstarpowders.com/products/ip-omega).

Here's a couple of pics of how we'll do it, with the down sprue going down the centre.



Great to see you are splashing hot metal around.

Yeah, splashing seems the right word. Thanks for your advice Ken, makes sense. My oven only goes to 250, but maybe 3 or 4 days at that temp will dry out the mold for the next attempt.

Is that negative plaster mold called the investment, or is that the wax?

You appear to be adding wax sprues and risers to the printed polycast. Do they melt at similar temperatures?

[ken seeber]

Yeah, splashing seems the right word. Thanks for your advice Ken, makes sense. My oven only goes to 250, but maybe 3 or 4 days at that temp will dry out the mold for the next attempt.

Is that negative plaster mold called the investment, or is that the wax?

You appear to be adding wax sprues and risers to the printed polycast. Do they melt at similar temperatures?

1. Not sure if the 250 is enough, even for an extended time, but is worth a go as it most likely will eliminate the cracking woes others have experienced at higher temps. Keep us posted.
2. The polycast print is a positive and the plaster investment mould will be a negative.
3. The wax melts at approx 80C, whereas the polycast, although it was printed at 210C, will have a higher temp. The plan is to put the mould in an oven upside down at ,say 120 to initially melt out the wax into a tray so it can be gathered up and reused. The it will undergo a test schedule set by Omega which should be enough to burn out the polycast.
4. Sav the beeswax for your manuka honey bees

[WilDun]

I saw a video somewhere in which a guy burnt out his PLA printed pattern in the furnace, - the mould was 50% plaster/sand, but he heated it in the furnace till it started to glow red - he then blew it out with an air hose and poured the metal into the (still hot) mould ..... point is the casting came out fine and there didn't seem to be any cracking problem at all. - possibly he was just lucky!

[Pursang]

For those using 3d printers to make casting patterns......

This stuff might Eliminate some steps!

https://insights.globalspec.com/arti...-manufacturing

Cheers, Daryl

PS. for anyone interested in the kero/oil burner progress....Total failure.

After repairing the valve, cleaning the internal filters and the jet passages, it no longer has an (inconsistent) compact blue flame.

It now produces a 2-3m high, Stream of flaming kerosene. Only practical for alarming the wife, the cats & the neighbors.

[F5 Dave]

So. . .not a total failure