molding grips II

[oobxlr8r]

Ok so I've given it a try...

For those that missed it I wanted the grips on the Kimber Warrior grips in black. Being that I cannot find them anywhere and knowing that there are consumer purchasable molding supplies I decided to give it a whirl. Now mind you i am totaly new to mold making and casting all together.

So I started of on google on mold making and stumbled across a site called conceptart.org. There was a thread on there about making a two sided mold for a sculpture of a hellboy bust. I decided to make mine two sided since the right side grip has an indention in it. I don't reall know what it's there for but whatever...

Once that entire thread was read and looked over multiple times I went out and found the material. Alumilite had a kit at hobby lobby that has 28oz of casting resin, and 1lb of RTV silcone rubber. It also comes with a small block of polimer clay which you'll see what that's for in a minute.

I started off by putting the polimer clay on the backside of the grip to be molded and only went half way up the edges of it. This was to stop the silicone from completely encasing the grip and leaving room for another half to be covered by the silicone. I also carved a trench around it to help contain any resin that over fills the mold. The shell was used to have a place to pour the resin.

http://i61.photobucket.com/albums/h43/oobxlr8r/molding%20atempt/IMG_3499.jpg

The next step was to encase the entire grip and clay combo so that the silcone can be poured on top and allowed to cure. I used wax paper since I didn't feel like making a box (It would have been better if I did... looking at it now).

http://i61.photobucket.com/albums/h43/oobxlr8r/molding%20atempt/IMG_3574.jpg

http://i61.photobucket.com/albums/h43/oobxlr8r/molding%20atempt/IMG_3575.jpg

Next up was to mix up the silicone rubber. It was a two part mixture of a liquid rubber base and a catalyst. The ratio was 10:1 base to catalyst. The container didn't say wether it was by volume or weight. I mixed it by volume and everything worked out fine. It took about 5 hours to cure enough to where I felt comfortable to remove and inspect. I used most of the 1lb of rubber to ensure the mold was sturdy enough to not skew make a misformed grip.

http://i61.photobucket.com/albums/h43/oobxlr8r/molding%20atempt/IMG_3577.jpg

http://i61.photobucket.com/albums/h43/oobxlr8r/molding%20atempt/IMG_3578.jpg

http://i61.photobucket.com/albums/h43/oobxlr8r/molding%20atempt/IMG_3579.jpg

http://i61.photobucket.com/albums/h43/oobxlr8r/molding%20atempt/IMG_3580.jpg

At this point it is just a matter of repeating the previous steps but instead of using the clay I am using the reviously cured silicone rubber to stop the new silicone rubber from completely encasing the grip. You have to use a rubber to rubber mold release to stop the silicone from curing to itself other wise you wind up with a block of rubber.

I used straws for vent holes in the rubber to let trapped air out when pouring the resin. you'll see why later... :( and the shells you see here are also being used to have a spot to pour the resin.

http://i61.photobucket.com/albums/h43/oobxlr8r/molding%20atempt/IMG_3581.jpg

Now this time I read more of the literature that came with the kit and realized that the silicone was to be mixed by weight... so I go out and purchase a gram scale and mix it up by weight this time and pour it.

http://i61.photobucket.com/albums/h43/oobxlr8r/molding%20atempt/IMG_3584.jpg

It took 7 1/2 hours to cure. The advertised cure time was 4 hours, close to what I got when mixed by volume....

So now my mold is cured and all I have to do is break it open remove the shells and straws and mix the resin right... Wrong... apparently I dodn't put enough rubber to rubber mold release and it was stuck... I start shaving off the edges of the mold to see if I can see the seam between the two. I find it and it opens easier that way but not before part of it tears but not in a key location. I neglected to snap any pics because I was so frustrated. but at this point I'm sure you have a mental picture.

Now I mix up the resin which was easy because on the bottles it says that it is to be mixed evenly a 50/50 mixutre by volume. You have to add the dye to the clear part of the resin then add the other and mix. This stuff gets hot and sets fast. In 3 minutes it's ready to go on the gun... or so you think. So I pour the stuff into the mold laying flat on the counter. I see it fill up the vent holes and I stop. I wait about 5 minutes the come back in. I see that some of the resin has spilled out between the two halves of the mold and am worried that the mold isn't filled. I pop it open and to my delight it is still good.

http://i61.photobucket.com/albums/h43/oobxlr8r/molding%20atempt/IMG_3586.jpg

I have read on other sites that you have to pour into a mold a few times to get used to it. So you know how it acts and what you need to do to get a good cast out of it.

I tried it twice last night and got one somewhat usable cast and one non usable. The first was the best the second wasn't so hot. you be the judge.

http://i61.photobucket.com/albums/h43/oobxlr8r/molding%20atempt/IMG_3587.jpg

http://i61.photobucket.com/albums/h43/oobxlr8r/molding%20atempt/IMG_3589.jpg

http://i61.photobucket.com/albums/h43/oobxlr8r/molding%20atempt/IMG_3590.jpg

http://i61.photobucket.com/albums/h43/oobxlr8r/molding%20atempt/IMG_3592.jpg


So I got some red dye since red and black are my favorite colors but it was a little too bright. I tried to darken it up a bit by adding some black dye and it just ended up all bad to me anyway. It looks purple. This time I tried to rubber band the mold together to stop any leakage. I also tipped the mold forward to make certain the mold filled up towards the opposite end from the pour spot. It didn't end up so well either...

http://i61.photobucket.com/albums/h43/oobxlr8r/molding%20atempt/IMG_3594.jpg

http://i61.photobucket.com/albums/h43/oobxlr8r/molding%20atempt/IMG_3595.jpg

http://i61.photobucket.com/albums/h43/oobxlr8r/molding%20atempt/IMG_3598.jpg

The black one also hs some small holes in it from bubbles that were formed while mixing...

http://i61.photobucket.com/albums/h43/oobxlr8r/molding%20atempt/IMG_3600.jpg

http://i61.photobucket.com/albums/h43/oobxlr8r/molding%20atempt/IMG_3597.jpg

[pa_guns]

Hi

Very cool post - thanks!

When you mix the resin, you need to be very careful not to create any bubbles. That's not easy to do at all. Often you get bubbles simply pouring the stuff into the measuring cup. Slow and steady is the key ....

If you get purple when you mix the black with the red, then your black must really be a dark blue. That's not uncommon. A little yellow may help ...

Bob

[oobxlr8r]

http://i61.photobucket.com/albums/h43/oobxlr8r/Windows-1252BSU1HMDAxNTQuanBn.jpg
bad cellphone pic. the grips are red, bright red, kinda like a fire engine red... I didn't think I'd like them but I do. Now the hard part... making the other grip and matching the color. I'll be getting better pics up soon.

(< edited this forum is the most strict i've ever seen for words that cannot be used especially for a 99.9% adult populated community... I couldn't use the word CR A P P Y)

[pa_guns]

Hi

The only way I know to get the color to match is to pour both grips out of the same batch of stuff. You will simply drive yourself crazy trying to mix matching batches....

Bob

[oobxlr8r]

Hi

Very cool post - thanks!

When you mix the resin, you need to be very careful not to create any bubbles. That's not easy to do at all. Often you get bubbles simply pouring the stuff into the measuring cup. Slow and steady is the key ....

If you get purple when you mix the black with the red, then your black must really be a dark blue. That's not uncommon. A little yellow may help ...

Bob

thanks man your tips helped. I have new pics in the kimber section under post your kimbers. At first I was rushing to get the stuff into the mold but I realized that I did have some time to get it right. My last couple of attempts yielded only a few bubbles but only in the back of the grip and were only effected a small amount by trapped air. But I believe that I now have my mold figured out and can consistantly get good casts. Too bad there aren't too many other people that are interested in this. If you have a favorite set of grips and wouldn't mind doing a little dirty work you could have them forever and on every gun you own... Ah well...

[pa_guns]

Hi

While you have your mold set up and working - make up a dozen or so grip sets. You may never use them yourself, but they will make *great* trade goods.

Bob

[oobxlr8r]

Hi

While you have your mold set up and working - make up a dozen or so grip sets. You may never use them yourself, but they will make *great* trade goods.

Bob

yeah I'll have to get to work on making the mold for the other side... this side was just to see if I could do it.

[Jolly Rogers]

I would also experiment with adding some structure to the mix. Just for grins. Like some chopped fiberglass matting or sand. May turn out to have some interesting "grippiness" features. Just brainstorming here. :D Joe

[Richard]

When casting if you can vibrate the mold as you pore the mix into your molds or if you can pull a vacuum on the molding material to evac the air from your mix , you can cut down on the bubbles. Be sure if you pull a vacuum on you mix have a oversize container because your volume can increase 10X's under vacuum. I had a job one time casting epoxy on electronic modules. You will be amazed at the amount of air you can pull from your mix. You need to make sure to not let the mix spill out of the top of the container as you pull a vacuum on it. You can let off on the vacuum and let the air escape and repeat as you need to get the air out

[pa_guns]

Hi

If you hit the mix with ultrasonics while you pull the vacuum, you can significantly cut down on the foaming.

Bob

[oobxlr8r]

http://i61.photobucket.com/albums/h43/oobxlr8r/kimber%20warrior/kimber13.jpg

Here is the one that'll probably stay on until i can get the other mold made. this time i'm going to make the mold a stand up mold so that the pour hole is the vent hole. I think it can deal with it as long as the vent hole is long enough to hold enough material to replace any displaced air. currently I have to tip the mold up to make certain no air is trapped down towards the top of the grip then rock it once the mold is full to release any remaining air. I guess I didn't add enough vent holes to it...??? ah well you live and you learn.

I need a name for it... i wanted something along the Warrior lines but not just plane warrior. I plan on sticking with the red grips... I've had "Ultimate Warrior" as one suggestion. I am wanting to hear more...

[pa_guns]

Hi

Above a certain size the bubbles will rise in the mold. Below that size they just sit there forever. The little bubbles are the ones that ruin your day.

If you keep a little of the dyed resin, you can mix it up after you open up the mold. A few days with a pin and resin will patch up a lot of holes ...

Bob

[Richard]

Also you can use a small electric sander and set the mold on top of the pad that the sandpaper would go on and use that to vibrate the mold to help release the air bubbles

[oobxlr8r]

Ok now i have a problem. The grips seem to have shrunk a bit. Enough to where they have to be tapped onto the (??? can't remember the name of the part) raised nipple screw things... It's only about the thickness of half a credit card or so but they grips don't just drop down to the frame. When I put the first set on they didn't do this but now they do. I'm assuming the Plastic I'm using is curing more even after the 10 min cure time and are shrinking ever so slightly.

Now for the problem. I was in a hurry the other day and I wanted to put the red grips back on so having had them on there before they went on fairly easy with only a slight tap but still didn't go all the way down. I put the screw in and started turning and tightened to about torque it would take to hurt your ear ( something i learned from playing woodwind insturments... don't ask.) but now when i went back to remove them the nipple screwhole thing came out with it and is now stuck in the grip. any help???

[pa_guns]

Hi

Check your mold. It may have shrunk. You also can use fillers to reduce shrinkage. If nothing has changed, you may have a mixing issue (ratio of hardener to resin).

Bob

[Richard]

If you do add a filler, be sure to re-adjust your color mix also as the color will change a little. You can make the filler from the grips that did not work or any of the molding flash. You will need to grind it up very fine (like talcum power).

[oobxlr8r]

Hi

Check your mold. It may have shrunk. You also can use fillers to reduce shrinkage. If nothing has changed, you may have a mixing issue (ratio of hardener to resin).

Bob

Yes sir, it is definitely the molds. the original grips don't just drop in like they did when i first broke open the molds.

[pa_guns]

Yes sir, it is definitely the molds. the original grips don't just drop in like they did when i first broke open the molds.

Hi

Sounds like it's time for some better mold material.

Bob

[oobxlr8r]

Hi

Sounds like it's time for some better mold material.

Bob


sounds simple... like what???

can't use plaster cause it shrinks up big time.

uh that's the only stuff i can think of right now.

pretty much all silcone shrinks to a certain extent or so i have read. i'll have to call the company that makes the stuff i have to find out the specs on the stuff that I have. so if i do try some other silicone so i don't wind up getting another companies equivalent of what I already have.

[pa_guns]

Hi

In the past I have used two part Silicone RTV materials that are guaranteed near zero shrink. The stuff came from Dow Corning (I think). A Google on RTV and mold should turn it up pretty fast. It's also nice because it come up with *very* fine detail.

Bob

[oobxlr8r]

Hi

In the past I have used two part Silicone RTV materials that are guaranteed near zero shrink. The stuff came from Dow Corning (I think). A Google on RTV and mold should turn it up pretty fast. It's also nice because it come up with *very* fine detail.

Bob


http://i61.photobucket.com/albums/h43/oobxlr8r/Windows-1252BSU1HMDAxNzEuanBn.jpg

I am using two part RTV silicone from Alumilite. I have read that all silicone has some shrinkage the better stuff is somewhere in the neighborhood of .02% but in 3 dimensions that can add up pretty quickly. I don't know maybe i'll just give up...
Do you tink that a harder curing silicone would do better? I don't konw what the shore rating on this stuff is but they did have a harder one in the store.

[pa_guns]

Hi

The stuff I have used all has been pretty soft.

Depending on how tight the original grips are at the bushings, just about any shrink could be to much. The holes are about 2" apart, so 0.02% should be about a half of a thousandth. My guess is that the grips are doing real well if they are made to +/- 10 thousandths. If the compound is in spec, I don't think it's your problem.

The whole "play with the mold so things shrink right" thing is a challenge. It's a standard part of plastic mold making. One way to make it happen in this case would be to mess with the original grips. Bondo and files kind of stuff ...

Bob