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Everything posted by Not-a-number

  1. Techniset 6435 with catalyst 712. Its a 3 Part system. Part 1 + 2 = 1.8% of sand mass P3 = 3% of Part 1. Sand is #90 so quite fine. 3 part system works way better than the 2 part I used in NZ. Mixes really evenly with hardly any effort.
  2. Ketchup* since im in America. *actually ceramic core paste
  3. Did bit of a time laps video of the camtree casting. Not great but its a start.
  4. Nothing, just that it will be harder to do by hand. Hopefully not but probably. Ive heard if it was G350 that would probably crack and distort it. Since it would be locally annealing.
  5. 4mm mild steel. Though they did them out of G350 by accident. So that may or may not suck. Hopefully they can replace them with mildsteel.
  6. The mandrel is spaced apart like that so that if we cant form it by hand and need to make hydraulic tooling theres some room to put it behind the rail. Ideally it would only be 100mm apart. Save some weight!
  7. Chassis mandrel finished! Exciting stuff. Brunton Engineering in Palmy did an awesome job. If you need fab work Id definitely recommend.
  8. Yeah its pretty big. Banana for scale. Also mm for scale. Its about 1020mm long. About 700mm tall
  9. Another 2 done. Worked well. I think 4 paper weights is enough for now. Time to move on to something big! For reference of where it goes. Houses cam gearing.
  10. Well is sold for a bit under $20m NZD. I forgot to bid!
  11. Finished up 2 more. Added chill blocks to the bigger top bosses and also a bigger flat one to the middle (instead of the tapered one). Still have the same risers.
  12. So the only issue was the back face. It looks like a crack. But what I think happened is the tapered 'disk' type chill blocks have no where to expand to. They are also in really thin sand. So when the chill block started doing its thing and getting hot it expanded, cracking the sand and pushing it into the face that hadnt solidified. The front did the same looking at the sand mould after the pour but it wasnt on a flat face so it didnt matter. May look at changing it to more of a boss like the others.
  13. Definitely open to some advice on the big stuff if you want to help? Im getting a better understanding of the runner system but on the big stuff like the crankcase theres so much going on (and its so big I dont want to mess it up too many times)
  14. They know what theyre doing so that does help. Usually the answer is "you could change X Y and Z and that might help, or it might make it worse you just gotta try it." One of the awesome things with the foundries over here is they are pouring 24/7. I just drive up and take the mould right to the furnace and fill it up straight away! NZ wasnt quite like that!
  15. Well it worked pretty good! Only real defects are on the face with machine allowance. The volume of the chill block didnt really seem to matter so I think going forward I'll size them to at least 100% of the volume that needs chilling.
  16. Not sure to be honest. Atleast 250-300kg.
  17. Basically I find it pretty hard to justify spending $thousands on one off parts. I might as well spend that money on a tool I can use for lots of parts. Example. To pay someone to make regular patterns for just the crankcase (MDF cnc) was going to be $13K. To pay someone to print just the crankcase patterns was $10K. So instead I bought a massive printer for $10K and printed every pattern for the engine for about $1000 material.
  18. Possibly on some smaller parts like the supercharger or waterpump. Maaaaybe! I dont know the cost of Aluminium printing now but when I was doing SS printing it was about $1000/kg. The sump/crankcase are around 20-30kg and would have to be done in multiple pieces and welded together. This camtree part is 5kg and cost $100 to pour. Means once its right they are super cheap. A rough estimate on the cost to do this part: Modeling and pattern design - 250hrs Pattern Printing - $50 material Pattern /corebox prep - 50hrs & $100 material Sand Mould makin
  19. Got the next one ready. Now have 4 chill blocks, 4 risers, 2 main in-gates and 2 small gates. One of the chill blocks didnt pack very well so we'll see what happens there. The sand around that area is pretty thin so theres a chance itll get super hot and fall apart. Bigger problem is I had an issue with the sand strength for some reason and it cracked when bolting up. Hopefully it doesnt fall apart when filled!
  20. So the plan is to add 4 risers to the thick top areas. Then add chill blocks for the bosses in the middle. Couldnt find info on sizing a chill block so Im going to go with making one set total the mass of the boss and the other set twice the mass. See if they are any different. Also doubled the ingate area (back to what its meant to be in theory) and made it feed from both sides.
  21. Made a cool paper weight! As I thought, the in gate was too small and it filled too slowly causing some cold shuts/holes. Also the thicker sections in the middle shrunk and caused some tears. Other than that it looks reasonable. So the plan is to increase the ingate area (maybe add another gate on the front) Then to sort the shrinkage I need to learn about adding heat sinks into the sand mould.
  22. New core done, ingate and risers added. Sealed and bolted up ready for the foundry. Made a mistake on the size of the ingate unfortunately and since its glued closed Im sh#t out of luck. So we'll just have to see how it goes.
  23. Busy weekend. 2nd half worked well. Little removable corner inserts look clean. Next I need to make a new inner core and figure out where to put some risers. Should be close to going to the foundry!
  24. Putting the sand in the freezer before adding the catalyst has given me a good 15-20minutes work time (instead of 5!) Did the outer mould today with 30kg of sand no issues.
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