18 Cylinders Isotta Fraschini (straight six-cylinder x3 )

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ddmckee54

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Foketry:

When you burn-out these parts, could you detail your burn-out procedure? What do you use for a burn-out oven, temperatures used, ramp-times, burn-out time, do you let the mold cool before you pour, that kind of information?

From the results that you get, with the relatively simple process that you use, it almost seems like you may have found the Holy-Grail of Lost PLA that many people have been looking for.

I've probably already asked this, and you probably already answered it - but when you print your patterns, how many perimeters do you print and how much infill do you use?

Don
 

ddmckee54

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Foketry:

Another quick question. You provided 2 links to products, which product did you use when you coated the engine block parts? The Raysin 200, or the Kera-flott?

Don

P.S. - Pouring with the mold in a container of sand is a good idea, as long as the sand is dry.
 

Foketry

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Foketry:

When you burn-out these parts, could you detail your burn-out procedure? What do you use for a burn-out oven, temperatures used, ramp-times, burn-out time, do you let the mold cool before you pour, that kind of information?

From the results that you get, with the relatively simple process that you use, it almost seems like you may have found the Holy-Grail of Lost PLA that many people have been looking for.

I've probably already asked this, and you probably already answered it - but when you print your patterns, how many perimeters do you print and how much infill do you use?

Don
I use a ceramic kiln that can reach up to 1,100 degrees C, the plaster-ceramic block must remain 1-2 days at room temperature to dry
when I create the plaster blocks I use aluminum containers for food, of various sizes, also cut and glued together

The plaster- ceramic is heated in 3 stages:
100 degrees C , 1 hour (plus time to reach 100 degrees) to dry the plaster
200 degrees C , 2 hour ( you see the PLA melting)
500 degrees C , 3-4 hour to burn and vaporize the PLA (some black smoke is emitted and if you open the oven door the PLA ignites and burns)

to automate the process I built an electronic Kiln controller, like this one
 

Foketry

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Lost PLA, my kiln and the burn / vaporization phases

reading Dragondark's post # 10 post referring to M-5 engine, to automate the process I built an electronic Kiln controller, based on Arduino


the first tests on the workbench of my shop



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everything worked fine on the first try and I installed the controller on the kiln

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I use a ceramic kiln that can reach up to 1,100 degrees C, the plaster-ceramic block must remain 1-2 days at room temperature to dry

My sister was a potery instructor. She would put the unfired, and sometimes very wet, pieces in the kiln at 200 deg F for a few ours to dry them out before the temp was ramped up to firing temperature. This technique could save you some time.
 

Foketry

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My sister was a potery instructor. She would put the unfired, and sometimes very wet, pieces in the kiln at 200 deg F for a few ours to dry them out before the temp was ramped up to firing temperature. This technique could save you some time.
Next time I try with the plaster blocks still wet , i think it can work, thanks for the advice
 

Foketry

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Aluminum castings of the engine block (lost PLA)

the engine block is made up of 2 parts, the upper one where the cylinders are housed and the lower one that supports the crankshaft
While the plaster was still hot, about 400 degrees C, I poured the molten aluminum, to be safe I put the plaster in a container of sand, in case the aluminum came out, my feet would remain safe.
Notice many cracks in the plaster, where aluminum could come out

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I made some milling operations on the plane of the 6 central cylinders to test the coupling of the 2 semi-blocks

The oil cover was made with Petrobond sand

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CFLBob

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I have a completely untrained eye, so I see what looks like pits and areas where the metal doesn't appear smooth, and wonder if all that is usable? The oil cover looks better but also looks like rough metal in places (left end of its first picture, still in the petrobond).
 

Foketry

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I have a completely untrained eye, so I see what looks like pits and areas where the metal doesn't appear smooth, and wonder if all that is usable? The oil cover looks better but also looks like rough metal in places (left end of its first picture, still in the petrobond).
The surface is not perfect but I have foreseen a machining allowance of 2 mm, when everything is milled it should improve and have no problems of leakage or mechanical strength . The oil cover needs a file finish.
If I encounter any quality problems, I will remake these pieces. My work is free of charge....
 

Foketry

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Boring of bushing seats for crankshaft
I have built a boring bar that is more than twice the length of the engine block to carry out this machining on the lathe.
I also had to build a fixing base for the motor block on the lathe carriage, the seats for cylinders at the ends of the engine block were used as a reference to align everything according to the rotation axis of the lathe

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usual process, model printed with 3D printer, aluminum casting
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alignment by means of 2 vertical pins with respect to a pin between spindle and tailstock

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block boring

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boring of oil seal seats



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Foketry

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The fixing holes of the remaining 12 cylinders
The holes of the 6 central cylinders had already been made without rotary table, this plane is parallel to the base of the engine block .
Using the CNC rotary table I first milled the 3 planes, again the central one and then the 2 lateral ones at 40 degrees .
It is very important that the crankshaft axis is parallel and aligned with these 3 planes, otherwise each cylinder will have a different compression ratio.
It is also important that the angles at 40 degrees are the same, if they are different, change the timing.
After milling I drilled the 12x6 = 72 holes for M3 screws

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ddmckee54

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Foketry:

It looks like the casting for the top half of the crankcase cleaned up fairly well when you machined it. There's a couple of spots that look a little iffy, but some JB Weld would fix them right up. In that last photo, it almost looks like the right-hand bank of cylinders has sleeves in it, or are my eyes playing tricks on me?

Don
 
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Hi Folks,

This is one heck of a build, and I'm really interested in seeing the mix of conventional, cnc, casting, and 3d printing all in one thread. Interesting and exciting times to have such a variety of techniques within our reach!

Sorry to back track a bit, but the two products mentioned for the initial ceramic coating don't quite match up to a product I can find in the US. The Raysin 100 powder looks like a gypsum type plaster although the packaging matched the provided listing, and I had no luck on the Keraflott product or in fact on searches for "ceramic casting powder". Is this just a translation disconnect or could some kind person point me to the equivalent or similar products in the US. Investment casting materials seem the most likely equivalent so far.

Thanks,
Stan
 

ddmckee54

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I think both the Raysin and the Keraflott are both molding plasters, and not really formulated for burnout. I checked with both manufacturers to see if they had any U.S. distributors - no luck. When I get things set up, I think I'm going to try experimenting using Foketry's Keraflott/plaster-sand method, only using something like Ultavest instead of the Keraflott.

Don
 

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