Ah ha ... a fellow SomaFM listener. I wish I could claim to be the face behind SomaFM but alas it's not so. That's a chap called Rusty Hodge. I am merely a listener and supporter. SpaceStation is my go to but I'll occasionally jump to some of the other 'electronic' channels as my mood takes me. I like their seasonal Christmas channels too ... they generally send my wife and kids round the bend!
Two feet firmly planted on the floor and both hands on the seat, Keeps you from launching off the can. This is how it's done in Turkey when ya got the Turkish trots. Its an EXPLOSIVE experience, trust me! I'll look up spacestation.. thanks!
LOL. I now have a vision of you headed skyward with a great brown plume of ... actually, I'll stop there.
@DavidF ... your suggestion worked a treat. Thank you very much! Plaques arranged at 45 degrees off the central runner. I used a short length of 15mm copper pipe to mould the runner. And this was the end result ... And a close-up of one of the plaques ... That's quite an uneven surface that needs to be polished flat. Thus begins the next challenge. I've also just noticed the voids in the cast where the gate joins the part (on the left hand side of the photo). Not ideal but this is the worst one, the other five look okay so I think I can live with it for the sake of this project. Cheers, Gavin
I think your worst one, had lose sand and turbulence problems with the spru/gate. I personally think, you hit a home run! You can Oxy-acetylene fill the void’s, or TIG them in. But… In some situations small void’s add character.
Exactly. I had the very same defect awhile ago and repaired it with an oxy/acet torch and a bit of gating material for filler. If I recall correctly I used a small drill bit to drill out the cavity as best I could and sprinkled on borax for flux. I don't know if that mattered or not, but it worked. Pete
@Jason I have no TIG equipment unfortunately (and no skill in this area sadly). @OMM & @Petee716 ... I don't have oxy/acetylene equipment either. I do have a propane torch (~1650 deg C - IIRC) ... would it be possible to flow some filler in with that? I'm really showing my ignorance in these matters now! Failing all of the above, I'm very tempted to leave the defect in to add character as OMM suggests. I think the biggest challenge for me is going to be getting that engraving surface super smooth and polished uniformly.
Thank you also for the encouragement. It's nice to hear some reassurance that I must be something right.
That is going to be tricky to smooth that area out. Remind me again why you didn't run ceramic shell?
Sadly I am not equipped to carry out ceramic shell casting at this stage (although I envisage doing some form of lost wax casting in the future). If the smoothing/polishing of these turns out to be too problematic, I will redesign and cast them again ... I have learnt much from this iteration so nothing lost there!
Ahh... That's right it's Kurtis that's running ceramic shell. My bad. You're little plates still came out good. My trick for making an area super smooth is to succumb to the inevitable. I add textures or random patterns on areas that would other wise be smooth. Now if you have to engrave that area, it just means you'll need to engrave it a little deeper. Can you use a small fat dremel sanding disc to smooth it out? The little sanding discs work good but are too floppy. I triple them up to make them more firm. You'll have less headache getting into the corners this way. Another option is some small diamond coated balls on a dremel. Beadblast after the diamond and you'll be surprised how smooth it will be. If ya need a source for cheap diamond burrs let me know. I might have posted it in the chasing tools thread here.
@Jason ... cheers buddy. My mind was definitely going down the dremel route ... I was thinking along the lines of using one of the cylindrical sanding attachments. Keeping the surface uniform is going to be the challenge but I just need to play to see what will work best. Will hopefully get some time this weekend but thanks again for your suggestions.
Even using the drum, afterwards, bead blasting will be your best way to smooth out your work. It hides lots of my sins. High polish? Forget it! That would be big time work on these.
I wasn't able to see what the surface of your patterns looked like. Were they smooth? Your castings look like they were cast in green sand. Oil bonded sand will generally produce a very smooth finish if your pattern is smooth. Pete
I use one of these a lot to clean up castings. https://www.harborfreight.com/oscillating-multi-tool-62866.html I buy sand paper in 4 inch x 10 yard rolls, 80, 120, 240, and 400 grit. I get four wedges to fit the attachment per 4 inches of the roll. The 240 and 400 rolls go quick HF also carries a smaller corner attachment for it.
Here's a picture of the pattern. It's made of plastic sheet which I spray painted to make the surface smoother. But you can see dimples in the paint in this photo which may have contributed to the uneven surface on the brass. I used Mansbond oil sand for the cast. Perhaps I didn't pack it in on the patterns enough?!
