CNC Molds N Stuff Posted June 29, 2016 Report Share Posted June 29, 2016 (edited) I posted a tip a while back about getting a tough plastics mold to fill and one of the things I heard back was akin to, "If you know its going to be tough you just shouldn't make it." I disagree. I should make what the customer wants if I can and figure out how to make it work. So lets skip that silliness. If the first sound of difficulty sends you to somebody else that's ok. They may know a better way. Personally I think some things just take extra effort, but its up to the customer to decide if its worth the extra trouble to get what they really want. Often customers want me to make lead molds that I know up front are going to be a problem. Often I'll do some test cuts to just test those feature I know will be an issue. One of the big ones is long amounts of lead with minimal clearance around another object. Hook shank, wire core, pin, etc. I think there is a limit beyond which its just not going to be possible, but often the answer is graphite spray in the mold to act as an insulator to prevent the lead from cooling to fast, and get EVERYTHING HOT. Not just the mold, but everything that goes in it as well. Hooks, Pins, Cores, Screws, Etc. Obviously certain objects can't take it so that may be a limitation. In retrospect it seems obvious now, but it sure seemed to take me a while to get there. What got me to realize I should have just accepted it as the answer sooner is when a customer told me, "No problem Bob. I have a hot plate I use for heavy hooks when I am pouring jigs. I just shake out as many hooks as I'll be using and let them heat up on the hot plate on low while the lead is heating up." DOH! Seems to obvious when somebody spells it out for me. I was just testing one of those molds today. Super heavy hook acts as a heat sink and cools the lead before the "feature" can fill. I got out my old hot plate I used for lead melting before I got a lead pot and tossed some hooks on it. Then for efficiency since I only work lead with heavy insulated gloves on I used some needle nose to pick and place parts quickly. All cavities poured perfectly. Even the smallest tightest ones. I wasn't even using great pure lead. Just some salvage I've skimmed a bunch that a friend gave me. So, sometimes the answer may be as simple as just getting EVERYTHING hot. I'm sure this is just restating what's been said before, but I posted in the hopes that somebody might not resist the answer for so long like I did. Edited June 29, 2016 by Bob La Londe 2 Quote Link to comment Share on other sites More sharing options...
JLS Posted June 30, 2016 Report Share Posted June 30, 2016 Thanks so much for sharing that, Bob! I've been pouring lead for a long time and never would have thought of that on my own. Quote Link to comment Share on other sites More sharing options...
goodtimesfishing Posted June 30, 2016 Report Share Posted June 30, 2016 electric skillet works great for keeping hooks, wire forms, ect hot. Quote Link to comment Share on other sites More sharing options...
Kasilofchrisn Posted June 30, 2016 Report Share Posted June 30, 2016 Definitely helps especially with bigger hooks and small areas around the shank etc. Some molds just need the parts heated up. thanks for the reminder Bob. Quote Link to comment Share on other sites More sharing options...
BLT Posted July 1, 2016 Report Share Posted July 1, 2016 When I pour and pull the jig out of the mold, I put the next hook in and close it, then cut the sprue a while and that gives the hook enough time to heat up for me. Quote Link to comment Share on other sites More sharing options...
Painter1 Posted July 1, 2016 Report Share Posted July 1, 2016 Great report, Bob. I need to do that more often but using gloves has been an issue for me. I really struggle with gloves - have you found any that protect without hampering you? Quote Link to comment Share on other sites More sharing options...
CNC Molds N Stuff Posted July 1, 2016 Author Report Share Posted July 1, 2016 Great report, Bob. I need to do that more often but using gloves has been an issue for me. I really struggle with gloves - have you found any that protect without hampering you? Nope. I just use needle nose to pick and place. I've used a pair of needle nose nearly every day for a couple decades so I am nearly as dexterous with them as with my fingers. Quote Link to comment Share on other sites More sharing options...
JSC Posted July 10, 2016 Report Share Posted July 10, 2016 For lighter wire hooks. Sheet metal pan ... Light bulb 60 W + Spread the hooks out In the pan and adjust light bulb above to get proper heat.. Quote Link to comment Share on other sites More sharing options...
