CNC Router Build with Lost Foam Casting Part 1

[@makingcookingfixing]

your patterns are a piece of art, and your ability to actually have them cast like the pattern, is mindblowing!!

[@kellycoffield533]

It is great to see a good casting after working the pattern. Thanks for the comment. Best, Kelly

[@X_Studios]

Oh, well isn't this just great! Now I find myself with a brand new obsession - lost foam casting! 😂

[@russtuff]

This is magnificent

[@willbaden7563]

Great work on the castings and thanks for going over your thought process on the parts.

[@notsure6182]

your castings are art.

[@handdancin]

those parts are absolute works of art- thanks for the videos!

[@rolanddube2169]

Great project, thanks for sharing!

[@tinayoga8844]

Very much interested in the CNC. I plan on using a CNC router for making patterns for casting along with other things.

[@kellycoffield533]

XPS Foam is such an easy machining media, even very modest (economical) hobby CNC Routers can do a good job. There's some learning curve but well worth the effort. Best, Kelly

[@ExMachinaEngineering]

Oh, now this is something I'm interested in! Let's go Kelly! You have my attention!

[@kellycoffield533]

Thanks K. This one will be ongoing for a while. Best, Kelly

[@stevesrt8]

you never fail to impress! well done sir

[@kellycoffield533]

Thanks Steve, much appreciated. Best, Kelly

[@MyCatSleepsAround]

Wow!!! You do amazing stuff.

[@kellycoffield533]

Thank you so much! Best, K

[@jamest.5001]

This is awesome!

[@AhH-o6w]

Thank you for sharing your videos and expertise, castings are second to none. Could you let me know the most suitable aluminium to cast similar parts to produce a rigid cnc machine? Thank you in advance.

[@kellycoffield533]

The engineering/elastic modulus is essentially the same for all cast aluminums so as far as rigidity for a given shape structure it won't matter much. The shape of the structure does matter. Steels/iron have 3x the modulus of aluminum but also weigh 3x as much, so if you're trying to keep inertial mass low on a moving structure like a gantry, it's possible to achieve a stiffer gantry for a given (lower) mass, with a material like aluminum by optimizing the shape of the structure. Best, Kelly

[@AhH-o6w]

@@kellycoffield533 Thank you very much for the in depth explanation, much appreciated as always.

[@jamest.5001]

Can you "glue" the foam together with a wax? Like jewelers wax or something? If not I guess coating in wax could give a exceptionally smooth surface finish, especially in areas where there is multiple joints. Over a sanded finish?

[@kellycoffield533]

I suppose you could use sticky wax to assemble foam pattern parts but I strive to keep the joint very thin. Polyvinyl Acetate glues ("white glues" like Elmers) work fine but used very sparingly. Good old rubber cement works well, and also low melting point in glue guns. I achieve satisfactory finishes (for me) with just sanding. you can rub the surfaces with coats of paste wax, but check your paste wax on a sample of foam first as some are reduced with solvents that will attack foam and some are not. I do sometimes seal imperfect joints or gaps with wax. I use a formula specifically formulated for LF casting available from Freeman Supply. Best, Kelly

[@Rick.123]

How your castings are so smooth, what aluminium alloy do you use, thanks

[@kellycoffield533]

I sand them, and the refractory coating reproduces the pattern finish and isolates it from the coarser mold sand. Best, Kelly

[@henrygomez5820]

Where you buy the foam? Tia

[@kisoia]

Thanks for the video, love your work!

[@kellycoffield533]

Glad you enjoy it! Best, K

[@dave_ecclectic]

How important is the packing sand since you have a refractory on the foam part? The few times I did LFC there was no refractory, I put the foam part in the sand only. Which leads to the other question, Do you need to use refractory as you have that super sand packer system.

[@kellycoffield533]

Not all that critical. The packing sand just needs to be very dry and better if relatively uniform grain size. I use ~55mesh but it's just the fine sand available at the big box store (not play sand). The coating controls the rate at which the evaporated pattern gases escape to the mold. It also produces much better casting finish and prevents sand inclusions which is especially benefical if you machine your castings. It provides little in the way of mold structural integrity. Best, Kelly

[@jamessheets9205]

In your opinion how hard would it be to use lost foam cast an engine block? Something similar to the way Steve Morris does his billet smx blocks. Dry sleeves and deck with plates covering the water jackets.

[@kellycoffield533]

There are many fully water jacketed engine blocks being produced by lost foam casting. Mercury Marine uses the process and many non-US manufacturers. I think it's more of a challenge to a hobbyist than it is to the casting process. I can pour 60lbs of Aluminum. My intake manifold molds have 450+lbs of sand. That's big by hobbyist standards. I'd estimate a full size V8 block at say 100lbs. I'd probably need 150lbs of molten metal capacity (Crucible in my case) and a >=900lb mold. In a commercial operation with sufficient budget, that's not much of an issue, but to a hobbyist.....that's big. A cast block will never be a strong as a billet block just due to materials and flaw population.......but obviously, cast blocks are the norm, and billet the exception due to economics. On the other hand, I could cast a scale model.....Best, Kelly

[@jamessheets9205]

@@kellycoffield533 I'm wanting to create a block that doesn't exist. The basic architecture would be a Mopar 440 or Hemi style block. The bore spacing would be stretched from 4.800 to 4.900. With a raised cam tunnel and the necessary lifter adjustments to work with the mid 2000's Mopar pro stock head castings that I have. If I could pull something like this off I would have the casting hip'ed and then heat treated before machining. I really like the idea of making the mold from foam. You're only limited by your ability and the amount of aluminum you can melt. Do thick areas need to have hollow inside the foam to increase fill/pour speeds? I don't remember, but do you buy certified ingots to melt?

[@kellycoffield533]

@@jamessheets9205 Yes, I use certified A356 ingot. No, I would not hollow out any of the foam pattern as I have found pattern voids produce undesirable results. Best, Kelly

[@joell439]

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