back to the future nike mag scratch build wip (pic heavy)

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krispikarim

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You making a wear pair or display pair?
i want to be able to wear it

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@cavx i am going to be molding the soles in polyeurathane rubber with a kinda high darameter (im thinking from 50 to 70), and i meant that the technique i used to make the mid sole is how i make alot of other things, and once i mold the prop, or in this case the sole, i can cast the sole from plastics to rubbers
 
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JLeezy23

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i want to be able to wear it
Nice! What size is this? From the looks i would guess size 9? For the sole texture, I seen paint drops used and dried on before casting, there's also "popcorn texture" spray that people use for their walls/ceilings sold at hardware places. Depending on which look you're going for, the paint drops seem thicker and controllable, while the spray stuff is more fine and grainy looking.
cavx the first test was stretch fabric, but spray glued to the foam frame so it was stiff where needed, the only stretch I used was to wrap around the frame and to wrap around the funger pull area. Other than that, no stretch is really needed, its just the look of the weave that is needed for show/accuracy
 
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cavx

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i want to be able to wear it

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@cavx i am going to be molding the soles in polyeurathane rubber with a kinda high darameter (im thinking from 50 to 70), and i meant that the technique i used to make the mid sole is how i make alot of other things, and once i mold the prop, or in this case the sole, i can cast the sole from plastics to rubbers
Nice. I am keen to see how you do this. Is darameter the same as shore hardness? is 50 to 70 for the midsole or out sole?

I am inspired by your work, so today I had a play with some custom MAG stuff as well.

I have been working on these for a while, but they really need too much work to make these work, so I probably just used them for profiles.



So after a reality check on how much work these need, I decided to have a go at a scratch build using layers of core-flute (sign plastic).




I kind of have an advantage as I have various V2s in pieces right now. The parts are in backwards just to show the fit.

The profile of the foot frame inside the mid-sole is supposed to be higher at the heel than it is at the ball of the foot, so why I was grinding the V1 soles out, but I am almost through the base now and still don't have the recesses I need for the outer soles to sit in. I can get both the shape and flatness I need by layering this up and because of the type of plastic it is, glues really well with liquid superglue.

Like was discussed earlier, I made a master template and traced and flipped it to make this pair. When this is done, I will place the soles onto the flat bed scanner (with a steel rule for reference of scale) and then import the image into SketchUp which will allow me to scale the patterns to fit the uppers. That is the plan anyway :)

For the sole texture, I seen paint drops used and dried on before casting, there's also "popcorn texture" spray that people use for their walls/ceilings sold at hardware places. Depending on which look you're going for, the paint drops seem thicker and controllable, while the spray stuff is more fine and grainy looking.
@cavx the first test was stretch fabric, but spray glued to the foam frame so it was stiff where needed, the only stretch I used was to wrap around the frame and to wrap around the funger pull area. Other than that, no stretch is really needed, its just the look of the weave that is needed for show/accuracy
Texture: I am thinking Vaseline and sand when I am ready to do mine. You have to be careful with what you use as some stuff can react with the silicone and you end up with a big gooey mess that never sets. I've found this out twice now with two very different base materials. I know both Vaseline and sand will be "safe" as is the core-flute as I have used that before as mold walls.

Uppers: With the exception of 3mm Neoprene, I want to avoid stretch if I can. The Neo works but is too hot to wear and does not come in the right colour. It can be sheathed in a different fabric, but having made a start on that, is way more work than I first though. At least I worked out the hidden seam. The hardest part and where I am right now is the laces. They just stumped me and why I shelved that for now.
 

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krispikarim

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@cavx yeah darameter is the hardness, and i meant 50 to 70 for the clear sole itself, if u cast a midsole on anything over a 50a it would be a pretty stiff and uncomfortable midsole, but im not 100% sure what i am gonna use, because these numbers are just based off my experiences with polyurethane rubber, but i have reynolds am (smooth on store) near me, so when i go to buy the rubber i can just ask them for their opinion , and your midsoles look good so far, the magic of basic prop building techniques lol
 
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cavx

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@cavx yeah darameter is the hardness, and i meant 50 to 70 for the clear sole itself, if u cast a midsole on anything over a 50a it would be a pretty stiff and uncomfortable midsole, but im not 100% sure what i am gonna use, because these numbers are just based off my experiences with polyurethane rubber, but i have reynolds am (smooth on store) near me, so when i go to buy the rubber i can just ask them for their opinion , and your midsoles look good so far, the magic of basic prop building techniques lol
It depends on where you buy the product from.

I have two local suppliers. One is a craft shop and sells pretty much everything related to molding and casting. The other is a specialized fiber-glass place that also has a range of elastomers. The difference between this guys product range and the other is that I can place an order for a specific shore hardness, but I have to buy the minimum product amount about which is about 40% more costly than the same weight kit from the other guys. The true beauty is that if I want a spongy mid-sole, then I can actually place an order for a AA-20 elastomer and continue to use AA-65 for the out-sole. So for one offs, expensive. If I was doing a run, then his bulk pack is actually 10% less for the same weight. Again, I would have to have a need to buy the bulk pack.

All the products are clear and you mix pigments into them. I have a range of solid and transparent pigments now in my stash.

If I do go this route, the other thing I can do is mold and cast my parts as normal, mix a small batch of white rubber and used that to bond the mid-sole to the out-sole. Because it is the same material, it will still fuse to itself. Also what I could do is vacuum bag the parts so there is no air trapped during the bonding stage either. Let it set up under vacuum over night and it won't break, ever.
 

krispikarim

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It depends on where you buy the product from.

I have two local suppliers. One is a craft shop and sells pretty much everything related to molding and casting. The other is a specialized fiber-glass place that also has a range of elastomers. The difference between this guys product range and the other is that I can place an order for a specific shore hardness, but I have to buy the minimum product amount about which is about 40% more costly than the same weight kit from the other guys. The true beauty is that if I want a spongy mid-sole, then I can actually place an order for a AA-20 elastomer and continue to use AA-65 for the out-sole. So for one offs, expensive. If I was doing a run, then his bulk pack is actually 10% less for the same weight. Again, I would have to have a need to buy the bulk pack.

All the products are clear and you mix pigments into them. I have a range of solid and transparent pigments now in my stash.

If I do go this route, the other thing I can do is mold and cast my parts as normal, mix a small batch of white rubber and used that to bond the mid-sole to the out-sole. Because it is the same material, it will still fuse to itself. Also what I could do is vacuum bag the parts so there is no air trapped during the bonding stage either. Let it set up under vacuum over night and it won't break, ever.
oh ok, but i think im just gonna go the smooth on route, because the only products i have experience in is smooth on and cheap silicone caulking, but i really like smooth on's supplier near me because the employees really help alot to know exactly what product i am looking for, but the only down side is its pretty expensive, but the quality is really good, so ima just look for the rubber there, but if i just want to do a one off cast i can just buy the "trial" size and im pretty sure it would have enough to cast both midsoles (the trail size is a ok price) but for the clear out soles im gonna have to look for some alternative rubber, because for clear rubbers smooth on's is just too expensive
 
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krispikarim

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That does not matter where you go. Clear IS expensive. Do you have a vacuum chamber?
i know clear is expensive but smooth on is 200+for a gallon, which is their smallest unit, and nope i dont have one
 

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cavx

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i know clear is expensive but smooth on is 200+for a gallon, which is their smallest unit, and nope i dont have one
A gallon is 4.5 litrs! The same amount will cost over $400 here.

You can get away with not having a vacuum chamber on solid colours, but you end up with clear parts that look like they are made from a soft drink.
 

krispikarim

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cavx with the smooth on its a polyurethane rubber, so i think you dont need a vaccum chamber, i thought u only had to degas silicones
 
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cavx

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@cavx with the smooth on its a polyurethane rubber, so i think you dont need a vaccum chamber, i thought u only had to degas silicones
Anything you mix Part A with a Part B will need degassing. As you stir the pot to mix the two parts, you will by default mix in air. That air has to be pulled out or you end up with bubbles in your parts. As I said, you can get away with a solid colour, but bubbles in clear will stand out.

I don't seem to have my fail photos on hand where I did not either have the vacuum chamber or did not know how to use it. Some of those parts came out almost white from the amount of bubbles trapped.
 

krispikarim

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Anything you mix Part A with a Part B will need degassing. As you stir the pot to mix the two parts, you will by default mix in air. That air has to be pulled out or you end up with bubbles in your parts. As I said, you can get away with a solid colour, but bubbles in clear will stand out.

I don't seem to have my fail photos on hand where I did not either have the vacuum chamber or did not know how to use it. Some of those parts came out almost white from the amount of bubbles trapped.
i think it might just depend on the product you are using, because i learned how to mold in school, i am a technical theatre major, and my teacher taught us to use some rubbers that were clear, and we didnt degas them, and bubbles didnt show up because he told us to just to high pour to eliminate most bubbles and he said that silicones should be degassed tho,and ive seen the guys at reynolds am cast with the product i want to use and they didnt degas it, but they didnt end up with bubble, so i dont know, i guess ill try, and if i end up with bubbles ill just have to end up getting a degassing chamber,
 
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krispikarim

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@cavx i think your right, but im gonna just test it out once, and if it doesnt work out, ill just buy a degassing chamber (because i might end up needing it for future projects also, might as well get it for this one)
 

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cavx

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A vacuum chamber is a very handy tool to own. Mine will soon double duty as a reverse (female tool) vacuum form system. I just need to swallow hard and buy that fiber-glass kit to finish the rig.

Clear rubbers like polyurethane and elastomers are thick like honey. If they get bubbles during the mix or even the pour, they can't just rise up to the top and pop. The need help. They need to pulled up and expanded to the point where their surface tension is too thin to support them.

I made a video on degassing if it helps.


I don't degas anywhere near as long as in my video anymore as I have learned that you only need between 2 and 4 minutes with the product I am using. The resin will actually boil under vacuum, and this helps the exotherm kick in. Given the limited potlife it has, you don't want it gelling up during the pour.

Having said that, when I did the texture and splatter on my V2s, I mixed and degassed, then let it sit for an hour before working it. It was thick and I was able to get a pretty cool result by taking a small pointy stick, dip it in the gel state urethane and touch it to the sole of the shoe. It would string really fine and leave a small pimple on the initial point of contact. Very time consuming though and why I will add texture to the master part.
 
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krispikarim

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A vacuum chamber is a very handy tool to own. Mine will soon double duty as a reverse (female tool) vacuum form system. I just need to swallow hard and buy that fiber-glass kit to finish the rig.

Clear rubbers like polyurethane and elastomers are thick like honey. If they get bubbles during the mix or even the pour, they can't just rise up to the top and pop. The need help. They need to pulled up and expanded to the point where their surface tension is too thin to support them.

I made a video on degassing if it helps.

https://www.youtube.com/watch?v=gnMl3n9TwqI

I don't degas anywhere near as long as in my video anymore as I have learned that you only need between 2 and 4 minutes with the product I am using. The resin will actually boil under vacuum, and this helps the exotherm kick in. Given the limited potlife it has, you don't want it gelling up during the pour.

Having said that, when I did the texture and splatter on my V2s, I mixed and degassed, then let it sit for an hour before working it. It was thick and I was able to get a pretty cool result by taking a small pointy stick, dip it in the gel state urethane and touch it to the sole of the shoe. It would string really fine and leave a small pimple on the initial point of contact. Very time consuming though and why I will add texture to the master part.
oh ok, thanks, so i guess ima start saving up for a vaccum chamber lol
 

cavx

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oh ok, thanks, so i guess ima start saving up for a vaccum chamber lol
Not sure what they are worth in the US, but here in Oz, $1800, so I built mine for about 1/3rd that. Do your research and enjoy bubble free casting.
 

krispikarim

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Not sure what they are worth in the US, but here in Oz, $1800, so I built mine for about 1/3rd that. Do your research and enjoy bubble free casting.
yeah, here in the US they arnt thaaaat expensive, i can get one that can hold up to a gallon pail for about $200
 

cavx

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yeah, here in the US they arnt thaaaat expensive, i can get one that can hold up to a gallon pail for about $200
Make sure it can pull a full -30" and if it does, totally worth the investment.

My hoses were the most expensive part at about $350. The pump itself was only 103 delivered. The rest was the chamber.
 

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