Need expert advice.

[alix965]

Just finished up the final step in my first ever glove mold. Carefully mixed and applied the print layer, then proceeded to add the remaining thickened Rebound. Waited days for the fiberglass shell mold to cure properly, and today I demolded the master. So far so good right?

Well upon inspection, I found some 'wet' spots on the inside of the mold, which I determined to be....UNCURED REBOUND! apparently, in an over zealous effort to make sure the detail for the inscription came out clearly, I over sprayed the release agent.

So my question is this: Will the now exposed rebound air cure? If not what(short of remolding) can I do to preserve the detail that seems completely lost. Mind you 99percent of the mold is clean and accurate, so I'm leaning towards leaving it as is. It's just that little detail, but I believe the devil is in the details, so it's really paining me in my ass that this happened.

I'm gonna leve the mold alone for a day before I try a pull. Let me know what you guys think.

 

[BenStreeper]

unfortunately it may never cure. The effect you described sounds more like a small bit of rebound was not properly mixed at that point. Most likely something that was on the side of the mixing cup.

 

[BLACKULA727]

unfortunately it may never cure. The effect you described sounds more like a small bit of rebound was not properly mixed at that point. Most likely something that was on the side of the mixing cup.

How do you avoid this? Is there a trick on knowing when everything is fully mixed. I just don't want to run into this issue when I start to mold. Sorry if it was a dumb question.

Thanks!

 

[Brandon McClain]

Mix your silicon like crazy. Rebound has a decent potlife, so once you think you have completely mixed your rebound, pour it into another mixing cup, and mix some more. That should do it.

 

[BenStreeper]

How do you avoid this? Is there a trick on knowing when everything is fully mixed. I just don't want to run into this issue when I start to mold. Sorry if it was a dumb question.

Thanks!

the easiest step is to use 3 cups, 1 to measure out each part, then 1 to mix. also mix like crazy, rebound 25 is slightly difficult as it's thick, but you can never over mix it

 

[Boba Fett]

And since you're painting it on, you don't have to worry about air bubbles. Mix like a wild man, that's the cure.

 

[Unity]

A hotbox may help as well . You may want to give that a try before redoing the mold. just get a pressure switch hot pack , lay it inside of a large box (a cooler works well) , then get a insulated box, set that inside of the cooler and WALA! now all you have to do is tape the pressure switch down and leave it there for 6-8 hours. If it isnt fully cured, throw it back in ! It may be most efficient to just redo the mold though lol

Hope that helped!

Jacob

 

[alix965]

Thanks for all the tips guys. I was thinking about using a hair dryer on high, but that may not be enough, I understand 'roasting' also helps to extend the moldlife, so I may just go the hotbox route. The other thing I was thinking about was excising the offending area on the mold and then placeing that half into the mother mold and then press molding that ONE particular area against the master. It sounds tricky and I'm not sure the new rubber will bond with the old but imagine if I could actually pull it off. I would be the pioneer of the Patched Mold(patent pending)

For the record gents, I used the mix/mix/pour method in an effort to be thorough, but apparently not thorough enough. I will say this, while I was stirring the Rebound I noticed a butt-load of light colored air bubbles getting pushed around, they became elongated while I mixed and they looked like streaks. I ignored them at the time, but now I wonder if some REALLY were streaks, and not air bubbles, which would indicate incomplete mixing.

 

[BLACKULA727]

@ BenStreeper, Brandon McClain, Boba Fett, & Jbetts97. I appreciate your help. I will def mix like a mad man. One more question. Is it possible to do a glove mold using rebound 25, when the helmet has undercuts? The helmet I’m working on, did not have that many to begin with, but I’ve been putting detail in areas and I’ve created multiple undercuts in the model. Specifically around the cheek area and front vents. I was thinking I could go the glove mold route and just split it in the back (from the top back of the model down to the neck line. I’m still not close to molding yet, I just am trying to get an idea on how I should do it

 

[BenStreeper]

@ BenStreeper, Brandon McClain, Boba Fett, & Jbetts97. I appreciate your help. I will def mix like a mad man. One more question. Is it possible to do a glove mold using rebound 25, when the helmet has undercuts? The helmet I’m working on, did not have that many to begin with, but I’ve been putting detail in areas and I’ve created multiple undercuts in the model. Specifically around the cheek area and front vents. I was thinking I could go the glove mold route and just split it in the back (from the top back of the model down to the neck line. I’m still not close to molding yet, I just am trying to get an idea on how I should do it

yes, just make sure to use thickened rebound to "smooth" out the undercuts after your first 2 coats of non-thickened rebound. Undercuts are really only a problem for the mother-mold, so if you smooth them out on the mold itself your good to go

 

[Brandon McClain]

Personally I prefer dragon skin for glove molds, it is has far greater stretch and tensile strength, and seems to be more robust when really going at it when trying to demold. It can handle the undercuts no problem. Rebound is great stuff, it's just not as good as the dragon skin for glove molds.

 

[BLACKULA727]

yes, just make sure to use thickened rebound to "smooth" out the undercuts after your first 2 coats of non-thickened rebound. Undercuts are really only a problem for the mother-mold, so if you smooth them out on the mold itself your good to go

Thanks for the help Ben! It's appreciated. Good luck on the Spartan Lazer. It's looking good.

Personally I prefer dragon skin for glove molds, it is has far greater stretch and tensile strength, and seems to be more robust when really going at it when trying to demold. It can handle the undercuts no problem. Rebound is great stuff, it's just not as good as the dragon skin for glove molds.

Yeah, Thats what I heard. I may have to try this next time. Unfortunately I already have the rebound. I got super excited about doing my first mold, I went ahead and ordered all this stuff without researching as thoroughly as I normally do. BTW, your sculpting skills displayed in your Noble Team Collaboration WIP are very good. Keep up the good work.

Thanks again, to both of you on answering a noobs silly questions. I appreciate your guy's help!

 

[alix965]

Hey Blackula,how dare you steal my experts!

I'm not sure if you already know this but it bears repeating. I found the Rebound for the print layer to be a little difficult to apply due to the fact that Rebound out of the container is pretty darn thick, it kept sticking to the brush and pulling away from the master. So next time I'll use a thinning agent.

I was tempted to use left over-almost cured, still in the cup Rebound for the undercuts, but then remembered I had a bottle of THIS in my closet, so I didn't have to Rube Goldberg it. also I strongly suggest tinting the layers, just so you get even coverage. I didn't...but I will next time.

Good luck on your molding/casting. It certainly is an adventure for a first timer. Throughout the process My nerves were shot. Did I apply enough release/too little? Did I miss something with the clay-up? Will I ruin the msater? Did I wait too long before pouring? How bad will the air bubbles be?! And MY project is small. As long as you prepare and plan you should be alright.

I Completely forgot about Dragon Skin. Imma get some

 

[alix965]

Let me say first that FOUR of these are accounted for the other 3 are not fit for trade/sale. I may make a limited run in the future that I will post in the classifieds, but for now I'm sorry guys and gals, the shop is closed.
These are hollow smoothcast 320 slushed with alumite 610 expanding foam inside for strength. They're pretty damn light and durable. Very screen accurate with some changes for practicality/fake real-life sake. But I think my little m9, "Emmy", is asthetically intact.

I was experimenting with coloring and tones so there's one in the bunch that looks like it's for desert ops.

The UNSC symbols look like smiley faces, but with a nice dark wash and the'll be more convincing.

This pic reminds me of the terra cotta soldiers of China

I made the hammer off and away from the body because in real life a grenade's arming component usually screws into the body. You can't do that when it goes in flush against the fragmentary modules, which is how I was planning to fit the top part of the kit onto the body. But after making the modules and various waste molds, I decided that going through with the construction of this thing as a kit was meant as punishment for people stuck in Dante's ninth circle. So I gave it up.

Tell me what you guys think.

 

[Roadwarrior]

When I was doing the print layer on my helmet, the rebound 25 wasn't thick at all, in fact quite runny.

The grenades came out pretty nice

 

[ShadoKat]

Same thing happened to me!!! I ended up calling Smooth-On tech support, and they said the same thing as everyone else... it will probably never cure. Then again, they also made it sound like silicone can be pretty fickle, and even looking at it wrong could cause it to become offended and decide to not cure out of sheer spite. I could have sworn I read this thread thoroughly, but I seem to have missed the part where you described how you fixed the issue. Did it ever cure? Did you try the "patch" method, or the oven, or did it... just... cure? Silicone should stick to itself wonderfully, as long as you have completely excised the offending contaminant/unmixed spot.

I know what you mean about the "pulling away" effect from the viscosity of the mixed Rebound, too. I was actually looking for a thinning agent at one point, but couldn't find one... is that a new product? I gotta try me some of that (if I can ever finish this f#@%^ng shoulder bell)! Same with the Dragon Skin, it's not too much more than Rebound, and... well, it's called effin' DRAGON SKIN!!

It certainly is an adventure for a first timer. Throughout the process My nerves were shot. Did I apply enough release/too little? Did I miss something with the clay-up? Will I ruin the msater? Did I wait too long before pouring? How bad will the air bubbles be?!

I LOL'd when I read this bit... I know EXACTLY what you mean!!!

LOVE the grenades, by the way, they look fabulous! Nice work!

 

[BLACKULA727]

Hey Blackula,how dare you steal my experts!

I'm not sure if you already know this but it bears repeating. I found the Rebound for the print layer to be a little difficult to apply due to the fact that Rebound out of the container is pretty darn thick, it kept sticking to the brush and pulling away from the master. So next time I'll use a thinning agent.

I was tempted to use left over-almost cured, still in the cup Rebound for the undercuts, but then remembered I had a bottle of THIS in my closet, so I didn't have to Rube Goldberg it. also I strongly suggest tinting the layers, just so you get even coverage. I didn't...but I will next time.

Good luck on your molding/casting. It certainly is an adventure for a first timer. Throughout the process My nerves were shot. Did I apply enough release/too little? Did I miss something with the clay-up? Will I ruin the msater? Did I wait too long before pouring? How bad will the air bubbles be?! And MY project is small. As long as you prepare and plan you should be alright.

I Completely forgot about Dragon Skin. Imma get some

Lol, Sorry. I have a bunch of questions, because I'm a noob. I'm glad you posted the original question even though I kind of side tracked for a bit. Thanks again for the heads up. I appreciate it. Also, the nades look fantastic. I love the detail especially the UNSC on the bottom. I like when people pay attention to the little things. It makes it more believable. Keep up the great work!

Same thing happened to me!!! I ended up calling Smooth-On tech support, and they said the same thing as everyone else... it will probably never cure. Then again, they also made it sound like silicone can be pretty fickle, and even looking at it wrong could cause it to become offended and decide to not cure out of sheer spite. I could have sworn I read this thread thoroughly, but I seem to have missed the part where you described how you fixed the issue. Did it ever cure? Did you try the "patch" method, or the oven, or did it... just... cure? Silicone should stick to itself wonderfully, as long as you have completely excised the offending contaminant/unmixed spot.

I know what you mean about the "pulling away" effect from the viscosity of the mixed Rebound, too. I was actually looking for a thinning agent at one point, but couldn't find one... is that a new product? I gotta try me some of that (if I can ever finish this f#@%^ng shoulder bell)! Same with the Dragon Skin, it's not too much more than Rebound, and... well, it's called effin' DRAGON SKIN!!



I LOL'd when I read this bit... I know EXACTLY what you mean!!!

LOVE the grenades, by the way, they look fabulous! Nice work!

I read through your Samus build before, I remember the whole not curing ordeal and how you were afraid of loosing your model (One of the best sculpts I've seen on that helm BTW).

 

[alix965]

@Blackula. I'm glad I was able to post something that could actually help someone...so sidetrack all you want LOL.
Thanks for the compliments on the M9. I gave a lot of thought to practicality on this thing. First was scale. I refused to make HAND grenades the size of grapefruit. Also I took some artistic license with the look of the thing. Especially the hammer part and the detail at the base (the in-game model is plain and flat). The hammer sticks out a bit but not so much that it's a drop liability. And I made the arming button more pronounced.

@Shadowkat. I don't know if you remember me, but YOUR build was what got me off my ass and got me started on my negelected M6g(which is again on the shelf GAH!). I was inspired by your excited updates and the incredible leaps and bounds of progress you made. So seeing you here handing out kudos is pretty effin' neat. As far as the offending piece of non-cured rubber.

this. "FRAGMENTATION M9 HE-DP"

became this "balkaghghdghahgjajahhgahja"

I used some baking POWDER to 'soak' up the uncured rubber then I rubbed it all off with some paper towel. It dried up pretty nice but now there is a bump where there should be lettering. I decided to dremel down the final product with a round cutting bit and lightly bouncing it to try and regain some of the stippled texture of the original finish. It's looking pretty good. I'm experimenting with some home-printed water slide decals for the white lettering which I may include with future runs.

I'm going to buy some silicone adhesive before I try my technique as I'm not sure how well new rubber will bond to old/cured rubber. The undercuts and the nodules on this thing really put a strain on the rubber everytime I demold and I'm afraid any weak spot will create a tear that will run like an old french burlesque dancer's well worn stockings.

 

[alix965]

When I was doing the print layer on my helmet, the rebound 25 wasn't thick at all, in fact quite runny.

The grenades came out pretty nice

I thought about this and then remembered I had the kit stored under my stairs near the outside door, and the winter in New York has been unusually long. Plus I'm not sure how long the retail store I got the stuff at had it on the shelf. I'm sure that had something to do with it. Just ordered some Dragonskin from the online store though, first time working with that so lets see what happens.

 

[Akademee]

I have seen on the Smooth-on demo videos that they do something called double mixing. You mix your mold stuff as normal, but you pour it into a second cup to make sure it is fully mixed. This seems like the best way to avoid the unmixed material on the sides of the cup since you are mixing it for a second time in a clean cup.