Jump to content

Welcome to Da WAAAGH
Register now to gain access to all of our features. Once registered and logged in, you will be able to create topics, post replies to existing threads, give reputation to your fellow members, get your own private messenger, post status updates, manage your profile and so much more. If you already have an account, login here - otherwise create an account for free today!
Photo

Basic rubber(y) molds.


  • Please log in to reply
5 replies to this topic

#1
MaddaMek

MaddaMek

    Gargant Krew

  • Deathskullz
  • 2,775 posts
  • Gender:Male
  • Location:Warsaw in PROPPAland
  • Army Name:Freak'd out Skulls
Hello (yet again)!

Today I'll show how to make very quick and hopefully easy single-side mold for flat details (so called "flat mold"). It's perfect for making flat, one sided pieces - glyph plates, tank tracks, boxes... basically very simple objects that are mostly flat.

One condition - with this method You can't recast resin and shouldn't try plastic pieces either (I had problems with some of GW... sprues). They WILL/MAY melt and/or warp. For that I will make silicone tutorial...

You will need:
*A glue gun with glue rods
*An B-grade pencil ("B" stands for black, it's very soft when compared to H or HB. I use B8, third softess. Feel free to use B10 if You have one, lower than B8 also should work). Optionally You may also need a small piece of fine sandpaper (to make graphite "dye") and old/worn off brush (to "paint" with dye)
*If You are lazy, instead of graphite dye You can use crumbled charcoal. It's easier than file pencil but it may not work as good.
*Paper that isn't water resistant (newspapers works nice. Filmsier, the better)
*A needle/pin, preferably with some sort of heat protection on blunt end (wrapping end in masking tape seem like a plan). You may also use wooden toothpick, but it will get permanently covered in glue.
*Super Glue (or such)
*Glass of cold water, spoon may be useful too
*A cotton bud for cleaning mold, in needed.
*Your piece made from heat resistant material (putty, metal, cardboard are ok)


For start, quick overwiew of whole process:
We want to glue model on piece of paper, cover it in graphite (as it will act as release agent, hot glue is very sticky) with special care applied to any crevices, then cover whole thing with hot glue and after curing remove newspaper and model.

With that said...
First step is attaching our model to paper, just glue it with Super Glue (try to not "bleed" around model, just a tiny drops that'll hold it for a while).

Posted Image
As I've sculpted my glyphs on paper, they were already attached to it. Note subtle ridges on edges, as well as "punched" rivets.


After this is done, time for covering model in graphite. Did You knew graphite is used in machines (like hand watches) as lubricant? Graphite will make hot glue not stick to Your piece and unlike Vaseline/petroleum jelly or WD-40 is NOT affected by glue temperature. Cover whole thing with graphite, using dye and brush on crevices (use sandpaper to make graphite dye). Try to cover small area around Your model too, drawing "halo" on paper it's stuck on (1-3mm wide). It will make removing process easier, as well as "clean", crisp edge of mold.
Posted Image
Graphite was applied (drawn?) on every surface I could reach with pencil...
Posted Image
... and to make things a little more interesting I've used charcoal dust to lube crevices. It also work, but graphite is always better.

Now, You need to somehow cover whole thing in hot glue but before You'll proceed...
*****Use EXTREME CAUTION, hot glue is very hot (around 200*C/390*F/473.15K, You CAN get painful first degree burns and quite possibly scars [I have 1 so far, stupid accident during "pimpin' my crib"]). One purpose of glass of water is to provide You with quick way of "extinguishing" glue that had contact with Your skin.*****
*****Also it looks like cheap crappy glue guns like to overheat glue, this make it more fluid but apparently may give some air bubbles. It's generally good idea to make test "trail" on piece of paper. If it have tiny bubbles, unplug gun for a short while and try again.*****

Main challenge is to try to not caught any air bubbles, especially in crevices (hot glue is very thick. Use needle/toothpick to gently pop/push any bubbles that have contact with model). Try to work steadily but slowly, covering model in thin layers at first. Like a pro. You can do it (after some practice)!
Also try not to touch glue too fast, cheeky devil may LOOK cold... this is how You can get scar for life. Another use of water is spilling a little on warm glue (with spoon or by dripping with finger, don't touch glue tho!) or even drowning whole thing.
Posted Image
Managed to snap photo before glue cool down and became milky. I have few bubbles under glue surface but they are small (and will shrink, via magic of thermodynamics)

In case paper with model isn't wet already after completing last step, make it wet. Wetting it will make it easy to peel off. Then You can gently remove model, mold is made from "rubber" so it have some degree of flexibility. Now use cotton bud to gently clean graphite from inside of mold, You don't want it on Your unpainted models.

And this is it! You should have nice little mold in Your hand. It isn't made from best material but should survive several attempts of gently filling it with putty (I suggest milliput, it's stiffer than Green Stuff. You may experiment with resin glues, wood glue mixed with plaster and such) and removing when it set (by that I mean it can be took out of mold without losing details. Sometimes You may want to take it while it still can bend and wrap around something). In case You'll try to get smart and make putty getting harder by heating it be careful to not melt mold in process.

Posted Image
Famliy photo!

'Ere we go! Don't burn Yourself.

[edit]
I think I'll make it dedicated compilation of moldmaking (maybe mine, maybe someone else would contribute?) rather than spam several topics. Next step - flat/glove molds from sanitary silicone!
[edit 2]
Nope, sanitary silicon just suck and while it DOES work and DOES cost less than proper sillicone it isn't just worth Your time to use it. So, good one! Also I'm still gonna make simple flat mold just to show overview of work flow and bare basics.
Moldmaking tutorials [part 1] [part2]

#2
MaddaMek

MaddaMek

    Gargant Krew

  • Deathskullz
  • 2,775 posts
  • Gender:Male
  • Location:Warsaw in PROPPAland
  • Army Name:Freak'd out Skulls
Hello again!

This is very basic tutorial about making silicone mold.
I'm not gonna cover casting (for now), making more complicated molds (...for now), molds for pewter (DON'T TRY IT... for now! Seriously, pewter casts are spongy and You need to prepare them. Learned it hard way.) neither sculpting (for now). Also not mixing (for now!), just refer to manual. Also make small test batch and look how it work - how hard it stick to material You want recast (if it goes away badly then "ha ha,too bad!"... for now, until I'll get to release agent!), does it glue to itself (what happen if You put another layer on hardened rubber. It change Your workflow so be prepared.)... get familiar with it.

I started by mounting my pouches sculpts (both in FIMO and Green stuff. Plastic is cool too. JUST-NOT-PEWTER/WOOD/MATERIALS WITH TINY LITTLE HOLES) on lacquered paper. Covered it in previous post.
Models should be covered with release agent but most silicones doesn't requite it that badly for simple sculpts. I will cover it in-depth when mentioning pewter models.

One thing - Your mounting base have to be lacquered or made from non-soakable material (like plastic or metal or... oil clay, I'll cover it later). Or lubed with release agent, but it's just easier to use proper surface.
Posted Image

Next thing is building "a box". Box is basically boxy shape for containing rubber inside (like small bath tub). I did mine by just gluing strips of paper with super glue. It can be done in few other ways, not gonna cover it for now. btw You may measure how much rubber You need by filling box with some throwaway grainy material (sand, rice, grains, just be sure to clean it up.) so models are covered by 2-3mm layer. Then put in the cup and You know how much rubber You need.
Posted Image

Now the fun part. Mix small batch and pour it inside (don't bother with math, just make a little of it). I call it "detail layer" and this is exactly what it is - a layer that is supposed to hold details.
Posted Image

Using dry "toothpick brush" (take toothbrush, chew tip to make "brush", dry it) smear Your first batch into all crevices and places that can catch air bobbles.
Posted Image

When it's done, quickly mix Your measured rubber (or not-measured, at some point You should do it "more or less right" by just judging it) and pour inside with care (try to do it close to corner and not directly on model) while previous layer is still wet. At this point You want to remove all remaining bobbles, use tooth pick to catch/poke them.
Posted Image

As You can see here, my mold looks like it got shot with pellets. It was NOT supposed to happen but I decided to accelerate process (for You folks, I like You THAT much) with 50W halogen lamp and surface kind of boiled. It still turned out ok tho, at least in this regard! I also trimmed edges as they got nasty edge from rubber that solidified on sides of box.
Posted Image

And here is happy ending. Red line show area that still got some problems, despite my superior knowledge, vast experience and nearly-God-like abilities (I'm so genuinely modest, I know!). I guess this is because I wanted to be over with it quickly and hurried it up. Just take Your time with first layer and You should be ok.
Posted Image

I'll try to provide something more in-depth soon. I'm currently out of juice (that is resin and nearly out of rubber) and that probably wouldn't change in this week (I had to replace "pot-holed" tire in my car, pair of front wheels in fact (so they match their wear) and that stuff is kind of expensive because I have big alloy rims dressed in good quality rubbers. "GW expensive", it's that crazy.).

Maybe next week. Or more likely month, yay :<
Moldmaking tutorials [part 1] [part2]

#3
eddie the troll

eddie the troll

    Da Mole

  • Boyz
  • 1,034 posts
  • Gender:Male
  • Location:At the center of my universe, Whangarei, Noo Zeelund
  • Army Name:Which Army are we talking about?
Did you know that you can get powdered graphite?
the voices in my head sound better as a choir

War isn't about who's right... war is about who's left...

Sumus ubi Sumus

#4
MaddaMek

MaddaMek

    Gargant Krew

  • Deathskullz
  • 2,775 posts
  • Gender:Male
  • Location:Warsaw in PROPPAland
  • Army Name:Freak'd out Skulls

Did you know that you can get powdered graphite?


Yes, I know. Even better, there are paste-like mixes with something (petroleum jelly?) making it very easy to smear around model. I will cover it (and more) during recasting pewter casts and/or lubricant post, whichever come first.

I assume You indirectly wanted to ask why I decided to waste my time on actual grinding pencils.
Here's why - I invented hot glue method as way of nearly instant mold making (the "Oh Zog, Golden Demon is tomorrow and I need to have recast NOW" case) with most common house/hobby products. Yes, hot glue molds are poorly made and probably not strong enough to make several recasts - but perfect for limited runs when You don't have time or proper materials (like Quick Mold product).
Moldmaking tutorials [part 1] [part2]

#5
Big Mek GobSmasha

Big Mek GobSmasha

    Runtherd

  • Boyz
  • 313 posts
  • Gender:Male
  • Location:United Kingdom
  • Army Name:Gobsmasha's Deffskullz
Oooh, nice, add some more and you will be worthy of a pin imo! :D
If it ain't bolted down itz ours...and if it is, I gotz a wrench! 
 
Check out my WIP Log
 

#6
MaddaMek

MaddaMek

    Gargant Krew

  • Deathskullz
  • 2,775 posts
  • Gender:Male
  • Location:Warsaw in PROPPAland
  • Army Name:Freak'd out Skulls
Ok, I have silicones (two types, one super-stretchy for resin and one resisting 300*C/572*F for pewter (two jars, kilogram each). Also resin (0,75Kg), pewter (0,25kg of LC60 alloy, 60% pewter + 40% led), some chopped fiberglass roving, sand (it's great filler for big models! Need to be dry and clean tho), primer (spray can and Vallejo for airbrush/brush) and other goodies.

Now I need pretty detailed but not too complex model for "glove" mold... and I think this will be great example (when it's done, I'm kind of nut when it come to details so it may be finished tomorrow... or next year).
Moldmaking tutorials [part 1] [part2]