Thank you very much for sharing your technique with us how you accomplish your castings

Thanks for sharing this master Kelly

Nicely done Kelly. Thank you for sharing. Your technique and setup is really impressive. You definitely changed my mind and I am going to try it too.

Sonofagun. Did I just find my favorite channel? Smart, tenacious stuff.

@kellycoffield533

3 жыл бұрын

Ya had me on the first word. Son-of-a-gun LoL. I have a new project in the works. Hopefully in video in a couple weeks. K

@eric-8998

3 жыл бұрын

@@kellycoffield533 I'll be watching for it. Thanks for making this available to the world. Is there a refractory slurry product / supplier that you can recommend? While it would be fun to make my own, I'd rather focus on the other inevitable challenges of this process. Thanks!

@kellycoffield533

3 жыл бұрын

@@eric-8998 I use Poly Cap 600 which is made by REFCOTEC. Unfortunately there is a minimum buy of 50 gallons in either a single drum or ten 5-gal pales. There is a link to a forum post I made about it. Thinned, non-setting drywall joint compound may be a more practical substitute for you. Best, Kelly forums.thehomefoundry.org/index.php?threads/lost-foam-dip-coating-rig-%E2%80%93-the-big-dipper.776/#post-20809

I believe you need to add at the opposite side of feeder one riser for venting then you'll never face that problem of missing parts of saucer edges.

@kellycoffield533

3 жыл бұрын

In lost foam casting vents like you describe are not used nor required because the gases vent through the entire surface area of the pattern and the rate at which the gases escape is controlled by the permeable refractory coating applied to the pattern. Best, Kelly.

Well I'm sure you noticed that the elbow was collapsing somewhat when you turned on the vacuum. Now I'm going to watch round 3. thanks.

@kellycoffield533

Жыл бұрын

This video series and the one on finned engine cylinders get all the views. It's sort of funny because I get comments about how I should be using a different process for such parts but they were just me on a lark showing the art of the possible with lost foam casting because people think you can only cast skulls and ornaments with lost foam, not techncal machine castings. -Not true. In fact, I think those videos are the only two times I made parts that I didn't intend to use for some functional purpose. Still, show me a sand casting this size someone has successfully sand cast with only .062" wall thickness with any sand casting process. The best lost foam castings on my channel are the intake manifolds and timing cover. I developed and adapted my processes and equipment to make one-off and small quantity automotive parts of that size and nature but I haven't made videos of my very best castings. I almost regret making this series because everyone thinks they need vacuum to lost foam cast aluminum, and you don't in most cases. In fact I almpost never use it, just gravity fed. It's only because of the extreme thin walled casting that I did so. Now, if you were LF casting iron, the vacuum may become more necessary. Best, Kelly

Great videos. But by chance would it be possible to apply pressure to the top of the pouring basin in place of a vacuum? And a wide sprue along with some way of preventing the molten Al from exiting the basin? I envision applying the following steps: 1) poor Al into a large basin. 2) affix a seal to the top of the basin - so you can apply a bit of pressure from an air compressor. 3) start the Al flowing and turn the pressure on. Not certain how one would block the molten Al. Perhaps a bit of sheet metal between the basin and sprue that can be pulled away right before turning on the pressure. Or a plunger that is lifted up when ready - similar to a sink. One would just have to find a way of lifting it through the pressure seal. Once the Al starts flowing it will solidify along the outside edge thereby creating an air seal so the pressure should work well to push the Al into the foam. With a wide sprue and some pressure the Al should flow fast thereby filling the entirety of the foam before solidifying. And as a bonus, you could use a shorter sprue thereby reducing the amount of molten Al required. At least in theory - probably easier said then done. And lastly, do you degas the Al? Apparently the bubbles are caused by hydrogen gas leaving the Al as it solidifies. Perhaps this is only an issue when using a gas powered furnace. But it looks like it is easy to resolve. I thought I saw bubbles in these castings but it could have been something else. But great work. I wish I lived someplace where I could try it myself. Then I could check if my ideas are complete garbage before suggesting them...

@williamdouglas8040

Жыл бұрын

Ok, saw you other videos. Looks like you perfected the process - results look amazing. Still curious if applying pressure would help but it is hard to warrant the effort when you are already producing results which look perfect.

@kellycoffield533

Жыл бұрын

@@williamdouglas8040 When I started lost foam casting years ago, I drew from commercial practice. Most commercial operations used vacuum but most all was iron casting. I almost never use vacuum for aluminum casting except in extremous......like this case with only .060 virgin ingot in a resistive electric furnace and rarely degas but it was more of a science experiment. I melt I only degas these days when use dirty scrap. Considering joining www.TheHomeFoundry.org......lots more on the topic memorialized there. Best, Kelly

Why are you using the vacuum? The aluminum isn't being affected.

@kellycoffield533

3 жыл бұрын

Vacuum is used to more efficiently evacuate and drive the vaporized foam through the refractory coating and increase the velocity of the molten metal front. All commercial lost foam casting operations use vacuum in this respect. In the home setting, depending upon the part, it most often is not required but can still be beneficial. In the case of this part, which is over 9" in diameter and only .060" wall, you would stand absolutely no chance of filling the part without vacuum assistance. Best, Kelly