Save Money By Recycling Used Rubber

this week's project was sent in by chris and it's this nice 3d printed model of a horse and looking at it i think the big issues are going to be the base is in the way and if this was a production job i would definitely be casting the body of the horse separate from the base make it much easier to cut and easier to cast in a lot of ways but they're together here and what that might mean is we may have to break the horse off the base the other issue is that it's a big old mold and i'm inclined to break out the chunkage if you don't know what chunkage is because you're new around here stick around and you're about to find out let's get going see how thin that base is in there that is no bueno because when you pour a mold from the bottom this becomes the top surface of the resin and what happens is the resin when it cures it shrinks it kind of cups and so it's going to become paper thin right in through here super thin that is not acceptable the obvious fix when you're designing a piece for casting is you want to make a nice you want to make the base thicker so you have enough material that you can sand it flat later since we don't have that on this piece we're going to add it and to do that i'm just going to appease this piece of scrap masonite so job one is going to be to trace out the space being tight as we can do it that side do this side trace it out all the way around like that and we get it yeah perfect okay hop on over to the bandsaw get that thing cut out the bandsaw is a perfect tool to make quick work out of cutting out this shape just went around and finished the edges of my bandsaw work with a little sandpaper smooth them out a little bit that's good enough and now we get to hit this kid with some beeswax my favorite material on the earth is beeswax the trick to waxing anything is to get the surface here waxing hotter than the melting point of the wax and when you do that it just soaks right in which is what you want by the wax apply some heat get that stuff to melt in now what we want to do is we want to fit this onto here just like that see how that's going to build up that edge to do that let's fire up the sticky wax this sticky wax rod sticky wax stick was provided by our friends at freeman wax so we're just going to dab some sticky wax on this thing get it nice and hot let's get this to fit as close as we can also provided by freeman wax i shaved off brown micro crystal and wax it's just really a sculptor's wax but it's really useful for little bits of things like this like i want the seam of the sculpture to match the seam of the wood that i put on there and it is working like a champ look at that you see that how well that's working sealing up that make that just a nice kind of continuous edge with that so there's no seam to deal with later i'll get this seam all waxed up and then we'll be ready to put the horse in the mold case we need to figure out exactly where we're going to put the vents on this boy and here he is hanging up exactly how he's going to be in space going to pour through the base and right away you can see where all the high points are clearly we're going to have to connect this tail because that is a huge gigantic bubble trap so we're going to have to let the air out of this tail but notice right in the middle of stomach see how that's a high point and then the most obvious one of all of course is this is the front hoof so we know we need a minimum of three vents but there's another one i think i'm gonna do and that's down here under the chin i think we're going to run a vent right in like that we're going to let the air out of that chin and let it flow up into the cavity of the body here i'll do this vent in front here so you can see how i do it just put a little dab of sticky wax right on the hoof and you don't have to have straight fence they can be bent attach that up there get it nicely attached just going to take a little bit of wax sticky wax and attach it then go ahead and just cut it off like that all right that looks pretty well attached so when the resin rises up when the resin rises up it's just going to rise right up that tip and right out of that sprue i'm just going to do the exact same thing back here on the tail just going to put a little rod of wax right in there like that and we'll be ready to go time to design the case for this child for this horse are we going to be able to get this thing in the tank yes or no i would like to pressure pot this kid if i can very much would like to do so what we know right now is that is the biggest block of rubber that we're going to need i'm still not madly in love with wasting this space this amount of material just want to show you guys that it's often useful to fill the mold space so now that we have the dimensions we can start cutting wood to make this box all the wood pieces are cut and drilled and i also waxed them exactly the way you saw me wax the base earlier so let's get this case assembled should go together real nice there we go all right let's see what we got very nice looking good i didn't bother to cut fancy joints because i knew i could just use the brown micro crystalline wax to seal the joint time to get this horse into this case and in order to do that we're going to stick them in with sticky wax just a few drops of sticky wax not too much and get the wax nice and hot get the surface hot so the wax lay flat and then it's a simple enough matter of putting in the horse got the horse mounted in the case looking good we're ready to pour rubber on this boy but i thought it would be a good idea because i don't know what kind of resin this was printed with to test to make sure that the rubber is going to cure against it so i put a little dollop on there last night let's see how we did feels pretty good feels pretty good oh yeah peeled right off all right so we know we're good to go and if you will recall we used this brown micro crystalline wax to seal up the edges of the box so i thought better check this wax i'm pretty sure because this is a sculptor's wax that this is going to be okay but oh yeah yeah yeah loop came right up look at that no worries we're ready to put the plexiglass front on this mold but first we got to seal it up we got to build the gasket because it'll leak so you could brush it on i'm just using a stick no problem just want to make a nice gasket it's very useful to assemble the mold box with the same materials you're going to pour the rubber in the more different kinds of materials you have in a construction the more mixed media your construction is in mold making anyway the more potential there is for mistakes the more potential there is for incompatibilities and so i like to keep it all the same so why use a gasket material that could react with your rubber when the rubber makes the perfect gasket material this on here just like that let's locate some holes you can just see how those screws are drawing that plastic tight to the box make a nice seal very good we have got a box sealed up and ready to pour if you've watched my channel before you've seen me do this but if you're new to the channel i'm going to show you a technique today that's a super secret a little known only very advanced mold makers know this technique and it's called dunkin chunkies and chunkies are nothing more than cut up chunks of old molds and i just wanted to show you a couple of things the reason that you would do this is there's these big areas of mold that's going to suck up a lot of rubber and chunkies of old molds are a really great way to fill up those spaces you want your chunk with clean sides what you need are pristine chunks and when you have a lot of texture like can you see this texture in there see that when you have a lot of texture that looks like that you have more of a possibility of catching bubbles i like to cut that off like that and just get rid of that those kinds of textures in a perfect world you would keep your molds in sealed up bags so they stay nice and clean but the reality is usually they're laying around the shop and uh they get dirty and they get grimy and you can really see the color difference between a dirty mold and nice clean pristine chunks and you want them to be clean and the reason you don't want this is that could form a really nice resist and it could prevent the new rubber from bonding to the old rubber so what i do i just take a utility knife go through cut the chunks and then you look for the surfaces that aren't clean and you cut those off you are going to have some waste doing this but it's still worth the time to do it again you got to be beware of surfaces and things that could catch bubbles in the chunks because you don't want that let's get to pouring some rubber and dunking some chunkies i mixed up the first bucket of rubber and uh what we want to do is we want to pour as always all the way down to the bottom you try never to drape your model with rubber because you can trap bubbles real easy that way that's the quick way to trap bubbles is to drape or pour your rubber all over the top of your model that's a big no-no because you can really trap yourself a bunch of bubbles now the rubber is coming to this back corner it's doing it just perfectly just perfectly coming in okay so now the whole base is filled and we just go ahead and dump the rest of this rubber now i have found the best tool for inserting junkies is just a sharpened stick all i did was sharpen up a dowel i wanted a long stick because i wanted to be able to reach in like this so you just spear each piece like that and away you go you just jam it in whammer jammer it on in we can really push in a lot of chunks up in this part of the mold this is really where most of the chunks are going to live is in the top half of the mold you can see how much room there was there was very little room down around the base and the body there wasn't a lot of room in the mold up here there's a lot more so we're going to want a lot of chunks to fill up this mold okay let's top this guy last pour and again this is the most critical part we want to make sure that the rubber rises up around that face i'm just going to go no chunkies on the last pour that way they'll be well buried all right mold is poured let's wait till tomorrow and then we'll cut them up and see what we got and let's pull this mold apart okay that's the back side let's do the front side fewer screws on the front [Music] let's see how easy this thing comes apart should just come apart break the suction all right feels good flash is all cured nice okay same thing if we can just pop it off there we go all right coming right off nice okay that was pretty easy flash is all cured let's see if we can get the side pieces off right the bigger the mold the more you have to work to take it apart there we go did get some leakage there a little bit all right now now we gotta pop it off the base pop the sculpture off the case and it's stuck on there by the base it's wanting to pull the mold away from the from the base so there we go let's just put a knife down in there and pop that off of there all right let's see if this piece of masonite is going to pop off looks like it is yeah okay that's what came off this is the piece that was coming off quite a bit of flash but otherwise looking good let's talk about the cut pattern that we're going to use on this boy you got your tail hanging out around here and you got your body of the beast you got the head got the body of the beast more or less like that then of course you've got your base and it's in a box it's in a mold so it's just for fun draw them all all right beautiful there's our boy now the classic cut pattern for a four footed animal would be to just do this come right up the middle this is on the underside all the way up to the tip of the nose you got your legs of course are here and generally speaking all you have to do to free it up you might even have a tail it's like this so you've got holes you can see where the holes are show you where the holes are this right in here that's a hole this is a hole um there might be others oh yeah this foot up here touches to the base because there's a vent there so that's a hole so you got holes in in various places but the classic way to cut a four-footed animal is just to cut up the center and don't forget too there's a vent so we have we know we have a vent here and we have a vent in here and we have a vent in the tail in there somewhere or in here so we got to make sure we cut through all of those vents so the classic way to do it is to just cross like that and so the mold that mold halves look like this like that this should have cut all the way to the end like that oops drew that wrong this is a hole so this has to also cut down like this so that's an interesting i'll show you what to do about that this one we have to cut this vent the complication is this very unhappy base that's in our way because this base is blocking me from being able to make these cuts on the inside here there's no way to get to these cuts because the base is in the way it's very likely i'm going to have to break the horse off of the base to be able to make that cut i spent my career as a wax sculptor so it's very common for me to break my models when i take them out of the mold so yeah i'm not that worried about breaking a model frankly you can just glue it back together this is a 3d print it's not precious you just print another one so if it breaks it breaks if i can get it out without it i will if i can't i won't as predicted there's essentially no way for me to get in to where i need to cut with this space in the way so let's uh see if we can't do something about that sorry chris but it's gotta come apart let's see if i can even do it i'll see if it'll even come apart let's see if this will even come apart well maybe maybe if i could get to it over in here i believe we could cut down this vent which i have to do anyway just almost always the hardest part when you're cutting a mold is when you start it's hard to start especially on bigger molds they always put up a fight once you get more rubber to grab then you can usually get them apart there is just no way i'm going to be able to reach in there and cut this apart without breaking this base but this resin was a lot tougher than i thought it was so i'm just gonna i'm just gonna just yank on it just really there it goes okay got it there it went all right got it out gotta say that plastic put up way more of a fight than i expected it to but we did get it so now we're just gonna try to cut down to the middle cut these legs free cut that tail free here i am cutting across to the legs got that leg breathe that leg and see that see i freed that leg i'll see if we can free the other leg and we just cut that hole i can see that hole that i just cut between the legs and the this would have been a hole if this was all connected it's not connected anymore so it gave us access to it now we have to do the same thing over here i know i have complained about this before but it's way harder to cut these things so that you can see me do it than it is to do it just when i'm off camera even with the base off this horse is pretty tricky to cut molds this size put up quite a fight and it's difficult to get them started and more than that it's difficult to see where you're going you just have to plan it out and cut carefully and hope that you get and hope that you get the piece cut the way you anticipated cutting it sorry that you didn't see the end of the cutting but my camera shut off and didn't tell me and these things happen we did get the horse cut out as predicted i had to break him off his base this resin was shockingly difficult to break it was much tougher than i expected it to be but it did break clean and it can easily be repaired but something else happened that i'm not pleased about and uh we'll have to deal with it next week when we cast these pieces and that is that i trapped a piece of rubber in a really difficult place in here between the legs and the tail and it just totally got trapped and i was left with no other alternative but to turn my beautiful fantastic one-piece cut mold into a two-piece cut mold so there's the big giant piece and then there's this little bitty piece it's not a big deal it actually fits back in really neatly and the and the mold closes up neatly so it's going to make good castings but i can't stand when this thing happens because you got to not lose this little chunk as long as you're casting in this mold and it's one more step to fit it back in and carefully close the rubber around it these things happen and you just got to adjust like i said i'm very confident that this mold is going to give us good castings even with this flaw this the flaws and the extra parting lines are pretty well hidden inside where they're not going to be seen but they're still fairly easy to clean up we'll be dealing with that next week hey i hope you got something out of this video and i hope you liked it if you did hit that like button because it really does help the channel thanks for watching i will see you next week

Channel: Robert Tolone

Views: 33,847

Keywords: silicone rubber, moulds, rubber moulds, making rubber molds

Id: gM0fEZEprxY

Length: 23min 49sec (1429 seconds)

Published: Sat Oct 23 2021