Author Topic: Casting a V8 first ever attempt!  (Read 1260 times)

Offline Graemep

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Re: Casting a V8 first ever attempt!
« Reply #15 on: July 30, 2020, 12:53:52 AM »
 Hi Mark

For foundry supply have a look at Green Sand Foundry in Victoria
There shop has most things you are looking for.


Graeme

Offline gadabout

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Re: Casting a V8 first ever attempt!
« Reply #16 on: July 30, 2020, 01:12:47 AM »
Graeme,
 Thanks I have looked there. Maybe I am expecting too much from my sand mixing , I don't know what is normal in dryness/wetness grain size etc, I see youvids of "sand" that looks so much better than mine!
cheers
Mark

Offline gadabout

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Re: Casting a V8 first ever attempt!
« Reply #17 on: July 30, 2020, 01:24:59 AM »
Graham,
 I have thought about going the sodium silicate route, I have all the requirements to do it, silly question time .... would you remove the patterns before or after gassing?
I wish I could get some fine grained moulding sand here, all I can get is from the landscape suppliers and I sieve that through a kitchen sieve, you are not supposed/allowed to get it from the beach here!
All advise  and help greatly appreciated with my casting attempts
Mark

Offline Mcgyver

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Re: Casting a V8 first ever attempt!
« Reply #18 on: July 30, 2020, 01:46:39 AM »
Quote
Maybe I am expecting too much from my sand mixing , I don't know what is normal in dryness/wetness grain size etc,

A customer of mine is a commercial AL foundry and in response a question about proper mixes for green sand on another forum I asked him.  He says the mix of sand, bentonite and water will vary depending on the size of the casting but suggestions 5-10% bentonite and 3-5% water by volume for smaller back yard castings, all by volume.  The amount of moisture goes up as the size increases.  You can also get bags of premix that make easier. 

Not from him, but I've heard clumping cat litter is just bentonite....makes it easier to source.  You can reuse the sand, add a bit of fresh bentonite as some gets burned.  In commercial ops they constantly scrap a percentage of sand and add new, but they have mullers, shakeout tables, screens and coolers to make processing easy

Offline gadabout

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Re: Casting a V8 first ever attempt!
« Reply #19 on: July 30, 2020, 03:38:09 AM »
I am using finely sieved sand and 12.5% bentonite by weight plus water , its just knowing how much water is enough and not too much, I don't want a little explosion happening! I think with my pour the sand was too dry and a bit crumbly and had some minor drop out happen.
cheers
Mark

Offline Roger B

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Re: Casting a V8 first ever attempt!
« Reply #20 on: July 30, 2020, 07:30:36 AM »
 8)  8)  :praise2:  :praise2:
Best regards

Roger

Offline Alyn Foundry

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Re: Casting a V8 first ever attempt!
« Reply #21 on: July 30, 2020, 12:08:08 PM »
Good morning Mark.

Yes, you'd leave your " well dusted " patterns in the box whilst you gassed. This ensures a " crisp " finish and no likelihood of the sand moving during the set.

Now, the sand used for " Greensand " moulding ain't just any old sand, it's quarried. Beach sand has seen eons of erosion and all those little grains are quite smooth. One of the reasons moulding sand binds is because of their irregular shape and the sharp edges help to interlock the grains. Bentonite can, and is added to increase the bond strength but, with the right sand it isn't always necessary.

" Tempering " is the term used for the addition of water to the sand. Obviously too wet and steam is generated which can cause disastrous results. Too dry and the bond is weak. On the shelf I have a lovely piece of kit for determining the moisture content precisely but I haven't used it in years. Why? Because I was taught the " squeeze test " very simple and effective. With a dry hand pick up a handful of sand, close the hand firmly then open. The compressed sand should have a reasonable bond if squeezed between finger and thumb but, more importantly you shouldn't see too much of the sand adhering to your palm. A good indication of too much water will be lots of sand grains stuck to you.

Back in the days of Rhuddlan and Buckley ( commercial Iron founders ) they used a mix of sand Bentonite and fine Coaldust. This was called " virgin sand " this mix was only used for " facing " the pattern. It was pushed gently through a riddle to liberally cover the pattern then shovels of the used, re tempered sand
" backed out " the moulding box. Then the process of " ramming up " began. This was quite something to see, the guys would, depending on the size actually stand on the mould whilst ramming up with differently shaped Iron tools. Once firm a final " strickle " flatting off of the box was done before being hit by the venting tool. ( sharp pointed wire on a handle ) multiple small holes were placed being carful not to touch the pattern then the whole box and board were deftly turned over and placed on a bed of flat, lightly raked sand. The top box saw the same process but with the addition of " sprue " and risers where necessary.

Although I don't do much here in the " Backyard Foundry " these days my sand is still near perfect after over 30 years of use. What I'm saying is that if you were to buy a reasonable amount of " proper " Greensand moulding sand it would be a good investment.

Cheers Graham.

Offline awake

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Re: Casting a V8 first ever attempt!
« Reply #22 on: July 30, 2020, 06:13:58 PM »
I have thought about going the sodium silicate route, I have all the requirements to do it ...

I am wanting to get into casting ... just don't have the time to add that on at this point. But I have watched lots of YouTube videos, so that makes me an expert, right??

There is a caster called "luckygen" on YouTube, mostly works in cast iron but sometimes aluminum or bronze. I was quite startled to see him using resin + hardener (as would be used for car-body repair, I think) to harden his cores. He mixes in just a tiny amount, and mixes it thoroughly. I've never seen him discuss the merits of this approach vs. sodium silicate, but I have often wondered ...
Andy

Offline tghs

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Re: Casting a V8 first ever attempt!
« Reply #23 on: July 30, 2020, 06:56:54 PM »
I have cast some things and had some things cast for me and done my own lost wax work over the years,, my work on old navy models led me to this one late night,, the 1890's pump that modern folks have a hard time reproducing due to the complex coring of the casting.    http://www.rockisland.com/~marshall/whatsnew.html many of the items we think about casting fall between foundry casting and jewelry casting,, have you looked into delft clay as a casting media, jewelers use it for larger items..
what the @#&% over

Offline ddmckee54

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Re: Casting a V8 first ever attempt!
« Reply #24 on: July 30, 2020, 10:28:05 PM »
Mark:

That block looks pretty good to me.  I always  wanted to see a flathead model with Ardun style heads. (Hint, hint, hint!)

Keep up the good work, because it's all uphill from here.

Don

Offline gadabout

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Re: Casting a V8 first ever attempt!
« Reply #25 on: July 30, 2020, 10:35:12 PM »
Don,
 I have no idea what Ardun heads are I will have to google that!
The casting is I think useable and will be my trial machining block, I do need to do some alterations I think to one of the core molds  and I want to get better sand to get a finer finish. Also I think I poured too cold so a pyrometer would be good!

thanks
Mark

Offline ddmckee54

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Re: Casting a V8 first ever attempt!
« Reply #26 on: August 03, 2020, 09:04:00 PM »
Adrun heads were originally designed as a valve-in-head replacement head for the Ford flathead engine when used in a truck application.  If I remember the story correctly, they were originally designed for use on garbage trucks.  The exhaust ports which were originally routed through the cooling jacket in the block caused over-heating when the engine was under load. 

As a replacement head for a truck engine the Ardun head wasn't very successful, they were kind of expensive for one thing.  BUT, they were the holy grail for the Ford Flathead hot-rodders of the time.  Many speed records were set with Ardun equipped Ford flatheads.

Don

Offline gadabout

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Re: Casting a V8 first ever attempt!
« Reply #27 on: August 04, 2020, 06:51:12 AM »
Don, interesting but I think I have already bitten off more than I  can chew at the moment ! Don't think I will be making any Ardun style heads , sorry
Mark

Offline ddmckee54

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Re: Casting a V8 first ever attempt!
« Reply #28 on: August 07, 2020, 08:54:10 PM »
I know what you mean.  It's WAY down on my bucket list too, and I'm the one that wants to see it done.  Too many other things to do and skills that I need to learn before it's even remotely possible.  I just keep hoping that I can at least experience it vicariously through somebody else's buiid.

Off and on for a couple of years, a lot more OFF than on, I've been working on the drawings for a 1/8 scale Ford flathead with Ardun heads in 2D CAD.  I may have to dust those files off, poke at them a little more, and start getting them in 3D CAD.

If nothing else it keeps me off the streets and out of trouble.

Don

Offline Vixen

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Re: Casting a V8 first ever attempt!
« Reply #29 on: August 07, 2020, 09:57:37 PM »
Hello Mark,

I was thinking about a centre bearing on your V8 Walrus. It may be possible to fit a larger diameter, thin section bearing in the centre without weakening the already whippy crankshaft. The standard Seal crankshaft has an outside diameter of 1.125 " (28.6mm). It would be possible to fit a larger diameter thin section deep groove bearing in the centre, but you would probably have to play around with the casing patterns.

The SKF 61806 (or equivalent) is 30 x 42 x 7, a big enough bore to fit over the 1.125" (28.6mm) shaft.

However, the SKF 61805 (or equivalent) is smaller 25 x 37 x 7 and could be threaded over the other throws to get to the centre position. You would need to design in a short 25mm disc between number 2 and number 3 crank throws. It should be possible with some careful thought.

Stay safe

Mike
It is the journey that matters, not the destination