Waterway core removal
Waterway core removal
(OP)
Looking at old posts Im hoping Greg may shed some light on this!
How do they 'normally' flush waterways of sand cores?
Are the sand cores sodium silicate bound and flushed with water?
I have ten test cores setup of various sodium silicate percentage, and they do take a bit more than just water to dissolve, as in they like to be hacked a bit to get things moving.
Or, are the cores resin bound, such resins could be polyester, or more likely epoxy bound, and flushed with a solvent? Is_there a solvent for epoxy?
What are the common resin binders? Actual resin names/makeup if possible, and not trade names.
Thanks in advance folks,
Brian,
How do they 'normally' flush waterways of sand cores?
Are the sand cores sodium silicate bound and flushed with water?
I have ten test cores setup of various sodium silicate percentage, and they do take a bit more than just water to dissolve, as in they like to be hacked a bit to get things moving.
Or, are the cores resin bound, such resins could be polyester, or more likely epoxy bound, and flushed with a solvent? Is_there a solvent for epoxy?
What are the common resin binders? Actual resin names/makeup if possible, and not trade names.
Thanks in advance folks,
Brian,





RE: Waterway core removal
Methylene chloride will dissolve or soften pretty much anything. It is available from fibreglass materials supply shops.
Also handy to have for cleaning injectors, throttle bodies, carbies etc.
RE: Waterway core removal
Regards
Pat
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RE: Waterway core removal
Pat, of course, that goes without saying, I might close my eyes too,
BG.
RE: Waterway core removal
BG
RE: Waterway core removal
Regards
Pat
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RE: Waterway core removal
Detergent may help you with removal of more ordinary cores.
Core removal is not a new problem. I saw a gigantic fluidic oscillator (think firehose size) installed as part of a machining line in 1967. The line was in tryouts at the builder's facility; I have no idea how the oscillator worked out long term.
Mike Halloran
Pembroke Pines, FL, USA
RE: Waterway core removal
I'd avoid resin cured cores if your water passages are long, narrow, and will be difficult to clean out. Unless you like getting cancer from sniffing methylene chloride.
All core/mold sand removal I've seen starts with a shake-out process. Imagine the biggest dang rock tumbler you've ever seen, lined with heavy gauge screens to let the sand and chunks of core material fall out. After the loose stuff is shaken out, shot blasting, and manual removal with tools ranging from needle scalers to 5-lb sledges, dental picks to prybars, and wire brushes to the kind of automated grit-flinging devices Mike describes get used.
Good mold design includes thought on how (or whether) the core will be removed.
RE: Waterway core removal
Cheers
Greg Locock
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RE: Waterway core removal
RE: Waterway core removal
RE: Waterway core removal
Brian,
RE: Waterway core removal
one resin binder for cores that was popular in the 1970's was urea-formaldehyde (Think Aerolite.), mixed water thin with a slow hardener added, mixed into the sand, then baked to dry, the theory was that the resin would burn out when the casting was poured. Allowing the sand to run out. Phosphoric acid was used to remove the remaining residue if needed.
B.E.
RE: Waterway core removal
Regards
Pat
See FAQ731-376: Eng-Tips.com Forum Policies for tips on use of eng-tips by professional engineers &
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for site rules
RE: Waterway core removal
There are ways to form the cores as shells, with hollow interiors, allowing better venting and burnout/shakeout, but this makes a weaker core, and one that is more likely to float in the molten metal and get out of alignment.
I'd be talking to a foundryman about all this stuff, as they know better what methods might work for your specific part design, metals, etc. Then again, a foundryman might not talk to you, as a lot of what they know they consider trade secrets. You could try posting some questions in the metal and mettalurgy forum, you'll likely get more expert help there. I'm certainly not an expert, just have done a fair number of cast metal designs.