TargetTalk

Looking for ways to cast my grip, to be used as a mold to produce grips for different guns.
Any particular procedure I should follow?
Suggestions for materials to use in the original mold are much appreciated.
Dentists use a type of rubber/plastic material to make teeth molds, do you know of anything similar that could be bought over the counter?
I have been working on a free pistol grip for over six months and it seems like an impossible task to get it right, it feels my grip is always changing shape, could that be right?

I use epoxy wood to replicate finger and palm shape over my different grip.
I'll take all from a Rink grip that fit me well, and then squeeze the new shape on a existing grip with fresh epoxy wood (oil the original mold to separate pieces). Function quite well but not perfect obviously because i cannot make one single mold for all the grip because of the different curves and angle of the wood; so i made a cast for the finger, cast for the palm and another cast for the line under the palm with finger union.

The stuff dentists use is called alginate. You can find it by googling "body casting supplies". It works well for reproducing just about anything. The alginate is not good for multiple parts. Most times the alginate cavity is filled with plaster to make a copy and the production molds are pulled from the plaster copy. You might also try using casting silicon in place of the alginate. The silicon will allow multiple copies and has the benefit of being very flexible so you can mold undercut and odd surfaces a rigid mold will not release. The downside is making the silicon mold rigid enough it doesn't distort when used.

paulo wrote:....Suggestions for materials to use in the original mold are much appreciated. Dentists use a type of rubber/plastic material to make teeth molds, do you know of anything similar that could be bought over the counter? I have been working on a free pistol grip for over six months and it seems like an impossible task to get it right, it feels my grip is always changing shape, could that be right?

I used to be a dental tech and had access to the dental materials. Oral impression rubber is a polysulfide, and other formulas, and it's very expensive. It can be used on a grip. I lined a TOZ grip with it years ago and it will make a perfect impression of your hand anatomy. Setting time is about three to four minutes, so you have to work fast. You might have better success with an RTV casting rubber.

http://www.shopmaninc.com/moldmaking.html

Btw, your hand size will vary with body temp fluctuations, and the amount of salt you've consumed which alters fluid retention.

Kevin6Q wrote:The stuff dentists use is called alginate. .

Alginate is a water based product. As the water evaporates, the alginate will shrink to maybe 1/5th it's original size. It's only good for making immediate castings.

I was thinking of using a wood piece in the middle of the material I will cast the grip on latex/epoxy wood/... , use latex gloves and then squeeze the material against the wood stick.
The idea of the wood core was so that later I could saw it in half for fitting to the guns.
The casting rubber comes in three types , do you recommend any.
Soft will give more detail less structure, medium, and harder like a tire with little detail.

I have started with a basic wood grip and added bits using car body filler.

Step 1: Apply filler to grip.

Step 2: Cover hand with linseed oil.

Step 3: Take grip and wait for filler to set (gets hot)

NB. A perfect moulding doesn't necessarily make for a good grip.

Once I have a good master transfer to a nice piece of wood with a copy router - they aren't hard to make.

The pantograph was also my idea in the beginning.
I am more inclined to do a direct mold now, because the pantograph is a tricky technique, I tried to do a walnut riffle stock duplication, it is a lot harder than it looks.
I agree that a grip mold and a good grip for a gun are two distinct things, but I guess this process can help me understand what the important variables are. Angles in all 3 dimensions in relation to everything since humans are not straight objects but guns are, angles of finger segments, griping of fingers against palm cheeks,...
The grip on my air pistol looks very ugly from all the different fillers and sanding I have done through the times, but fits perfectly and gives me the best hold with correct sight alignment on 90% of my raises, and my best scores.
The starting grip was a Marschall grip but it now way different in all aspects from the original, specially angles of barrel to grip.
I am trying to accomplish that with my free pistol, but the grip angles are way different to just replicate the air pistol grip, so I am looking for an alternative to get that 90% or higher average on my raises.
With the free pistol each day the raise feels different, I have a morini grip I have been working on for months, but it is not working for me. Everyday the sight alignment on my raises is different.

paulo wrote:I was thinking of using a wood piece in the middle of the material I will cast the grip on latex/epoxy wood/... , use latex gloves and then squeeze the material against the wood stick.
The idea of the wood core was so that later I could saw it in half for fitting to the guns.
The casting rubber comes in three types , do you recommend any.
Soft will give more detail less structure, medium, and harder like a tire with little detail.

The harder setting rubber makes a better grip. IMO, there is no gain if the grip surface is soft and pliable.

Making a master pattern will be an infuriating can of worms when trying to adapt the resulting form to other pistols. You will still be challenged with positioning the grip to reach the neutral "point" when the pistol is raised to the eye's line of sight. YMMV, but after my experiments with the same idea, I'd recommend treating each pistol as an individual project.

Lots of good ideas. One more: "Sculpey"- a ceramic-like sculpturing compound. Stays soft and pliable until baked at 250F.
http://www.sculpey.com

I have also made a master grip, made silicone moulds and then moulded polyurethane grips.

Need to find a harder polyurethane and to get hold of a vacuum chamber to do the casting properly.

Really I like a wood grip though, hence I use a pantograph/copy router.
The polyurethane grips are good for trying things out, once right they can then be copied onto wood.

I'm planning to do a trial grip with 'sugru'; new material which looks interesting, it may be of use for moulds. Waiting on a sample pack to be delivered. If it's successful will report.
http://www.sugru.com
Joe.

You might want to give Friendly Plastic a try. It is very firm when cool, but molds very nicely when heated in water to about 150 Fahrenheit and reusable. I wouldn't call it permanent, but as a way to get a fast and accurate mold I think it should work.

I don't know what the rules about links to commercial sites are here, so I'll just say that Luthiers Mercantile has it at a good price.

For casting small plastic parts, there are two cheap ways to pull a decent vacuum -- a Mighty Vac as used to bleed car brakes, or a Seal-A-Meal. The former is better for debubblizing casting materials, the latter is great for laminating small parts when using slow-set epoxy or polyester.

Grip areas:

palm shelf
thumb rest
crotch/web
palm ridge
ball
valley
finger ridge line
middle finger shelf
finger grooves

From USA Shooting News vol17 n3 p6

Any ideas out there about angles:
hand to harm
grip to barrel
tilt rotation from the vertical line
...