I was at Alloy Avenue and was told about this forum a few days ago. I see some familiar names. I've just purchased a nice resin printer and I'm hoping to do some patterns/lost resin parts with it once I get the hang of running it. My first try at home foundry didn't get far, mostly helping a friend, maybe this second try will go better. cheers, Michael
Thanks for the welcome! As to what is planned, that is bit of a conundrum. Five years ago, after 45+ years, I became a "retired" racer (vintage for the last half of it) and got rid of all my vintage bike projects (since they were all race projects). There went all my grandiose plans for building some replica engines. I passed the patterns I did for the Webco Yamaha 175 cylinder head over to Jeff but he's had a lot of other things going on and has not attempted casting them. These photos of that project are too large to fit well inline so I'll give links to them: http://eurospares.com/graphics/metalwork/foundry/WebcoCT1_0640.jpg http://eurospares.com/graphics/metalwork/foundry/WebcoCT1_173540.jpg I recently reacquired from a friend a 1978 1L Moto Guzzi project I first bought in the early 1990s. It wasn't planned, but he was making noises about scrapping it, and I couldn't let that happen! The Guzzi cylinder head ports are pretty bad, and I have a set of heads that I'd had ported when I first had the bike. What I'm thinking of is seeing if I can improve the ports/combustion chamber (and maybe valve angles) and then make a pair of heads (the Guzzi is a tansverse 90* twin and the heads are mirror images of each other). The Guzzi has the same issues as the Webco head of fine/deep/closely spaced fins, and the thought of babysitting my CNC mill for days while it carefully chews them out of a big chunk of Renshape (as I did on the Webco head) isn't too appealing now. I've been thinking about 3D printing for 3-4 years, where every 6-10 months I'd look to see what was available and decide that nothing met my wants/needs. But the resin printers have come a long way recently and a steep Black Friday discount had me buying an Epax E10-5K, a medium/large format with a bit better XY resolution than the competitors. My vague plan is to leverage that for either making patterns for rubber (resin) plaster casting, or instead using a castable resin to do an investment casting. Or some combo of that and machining etc, a plan has not yet firmed up. That's about it for personal projects now. I do like to keep some connection with the racing scene by helping/advising friends on their bikes, so maybe one of them will come up with something interesting that I can turn into a shared project. I don't want any more vintage stuff of my own (other than the Guzzi which isn't too vintage, just old) but helping a friend with their vintage project would be OK. cheers, Michael
If you're starting from scratch and don't have any preference or bias toward any given casting process, have CAD modeling skills, only want to make a small number of parts, I would think printed patterns and evaporative pattern casting would be highly favored. Moreover, investment. I know there's the temptation to pull a mold and make waxes, but why if you can print them directly? I seem to recall you had good machining capability, but besides the expendable pattern, it would allow you reduce the job to processing investment. I'd be inclined to have a go without the complication of vacuum (for casting) but still likely needed for de-gassing investment. If they were originally sand castings I would think they could be gravity fed investment. You will need burn out capability though. Then you just need a simple aluminum duty melting furnace and molten metal handling hardware. The heads in the pictures don't look bad to me at all. How deep and thick are the fins? How many pounds per casting? I'm set up and well practiced in lost foam and wouldn't hesitate to make those with that method. No burn out required there. What's your starting point? Best, Kelly
Kelly, the Webco head fins are on 11mm centers and are 58mm deep, with a 3mm radius at the base between the fins. I'm pretty sure that the originals were sandcast, but in the 1960s/70s the Los Angeles area had lots of aerospace-level foundries who could no doubt easily handle something like that. The Guzzi heads have nominal 3mm thick fins almost as deep but on 9mm centers. The bare Guzzi head is 6.5 pounds, but I don't have a weight on hand for the Webco two-stroke head though it will be around that number. It seems likely that the Guzzi heads are permanent mold pieces, the fins have little to no draft on them and Guzzi made many thousands of those parts over decades. I've got a large electric kiln that does a good but slow job for melting, and Jeff and his propane furnace are about 3 miles away. We've both got 4 axis industrial CNC mills in our garages, he works in Solidworks and I mainly use Rhino and sometimes Alibre for CAD. I've also got a fair-sized Paragon HT oven with programmable control on hand. Jeff has vacuum equipment which he's used for degassing silicone/urethane molding compounds. We've got the infrastructure (and budgets), but we've also got the drawback of living in a city with 25-30' wide lots so we've got to be circumspect to some degree with noise/flames/stink. Printed resin "waxes" are appealing to me, and I saw in a thread here that it is possible to buy pails of premixed investment slurry, and that looked pretty reasonably priced. With "engineering" resins I think that a printed pattern could be made with sufficient strength and flexibility to be used in a rubber/plaster process to make conventional plaster molds, and it may be that would be a good way to go. I haven't finished my model of the Guzzi head but it is looking like it would need a thin/complicated core under the rocker box/above the combustion chamber, so a printed core box could be done for that. I've hopes that a near silent resin printer will turn out to be a faster and easier process for patternmaking vs the milling machine or (shudder) wood (I don't like woodworking). I'm actually more interested in the pattern side of things, and if the price were reasonable I could see sending resin prints off to a good investment foundry and let them deal with that side of things. A friend had some chassis parts done with printed sand molds for a project and says the mold costs currently are about $0.11/cubic inch. He was very happy with the parts he got back. I don't know how that process compares on price to commercial resin/investment, or how commercial investment compares to DIY, since I do place a value on my time. cheers, Michael
I would think if it could be done with coring it could be invested complete with an expendable pattern. That's a strength of evaporative pattern casting. No cores/core boxes required. But without seeing the features, maybe I'm missing something. Sounds like you're otherwise well armed for battle! Best, Kelly
Yes, the invested pattern seems like it would simplify things. I need to find someone with a junk head that I can chop up to see just what is hiding under the rockers. The big goal is to avoid spending a couple hundred hours on traditional patternmaking the way Jeff did with his 2T cylinder!
Heyo! I like to hear this. I have a 3 axis Hitachi Seiki VM-40H in pretty good condition. Also, a 3 axis CNC router on its way to 5-axis. Do you guys do mostly do indexing work with the 4th or true simultaneous? If you are talking about Suspenda Slurry, I have a 5 gal bucket of it. Would work great if I could get my 3d prints (fdm not resin) to be water-tight. Which may not be an issue for resin once cured? The fired Suspenda Slurry can be a bit persnickety to remove after casting I will warn. That 10x5 inch work envelope will be nice! I know my 12x12x12 has come in handy. Scaled up a Christmas village 4x, the lady was quite pleased. Also, welcome to the forum!
I've not used the 4th axis since I got it sorted out and hooked up. I think Jeff has done indexing, and probably some simultaneous stuff. Don't you need a watertight STL before you can slice? Or is it that your FDM printer is leaving small holes and not matching the STL? I wonder if you could put a small hole in an inconspicuous place and lightly pressurize the interior of your print to expose any leaks elsewhere on it so you can patch them, and then fill in the hole you added? UPS just delivered the printer, so time for the "gift to myself" unboxing!
Well then why are you on here schleppin' it up with us?? New tool deliveries are always exciting. It is definitely the printer itself or most likely me. There are overhangs and pinhole leaks, I was trying to get by with the thinnest model to make burnout easier. I have heard of dipping or coating with paraffin wax and will for sure try that next go around. Happy unboxing!
I've got piles of supplies/infrastructure for the printer that I need to organize and figure out where it will go so it can vent filtered air out the back of the garage, so the printer is unlikely to run until late next week at the earliest. Stinking up the house (living quarters above the ground-floor garage) with resin fumes is high on the list of things to ensure doesn't happen. I fear I'm going to have to rearrange some stuff in the garage, and I can't do that until I can move around without stepping over everything (yes, I have packrat tendencies and it is much easier to drag stuff out than to put it away when I'm done ).
I just started printing wax-like resin and cast some knobs for my bolt action rifle but have been resin printing for a while if you need some help. I came here looking to see why my bronze turned out so dark and dirty. I think it's due to what might have been leftover from the resin burnout. The wax sprues looked normal but I have some temp issues I need to get over and now waiting on a new crucible.
