I have a rather daunting task on my hands, a friend of mine would
like me to fit a fine silver plate of about 2mm thick around the
pistol grip on his Ruger 416 rifle stock to increase the girth as it
were because he has rather large hands.
I plan on making a resin model of the pistol grip so that I can use
the resin model to help me form the plate to go around the grip so as
not damage the wooden stock in anyway, what I need to find out is
what would be the best method to make a mould of the rifle stock
without damaging the wood in anyway.This silver plate will wrap
around the grip and stock and will be hinged for easy removal.
Any suggestions ?
Off hand I would suggest trying silicon RTV. Silicon RTV sticks to
next to nothing and a Vaseline/solvent spray applied to the stock
first will pretty much guarantee the Silicon will not stick. The
Silicon is very good at picking up detail and resins or other casting
material will not stick to it. The main drawbacks to silicon are cost
and it is not as tear resistant as some of the other RTV molding
materials. It can be thickened with chemical thixates or fillers
(thixates will give better detail, at least in my experience) if you
need to "paint" it on in a freestanding mode, or if using some sort
of molding frame for a poured mold or you can use non sulfur clay to
make a 2 piece mold. No matter how you make the rubber mold, you will
need a mother of some sort (plaster, gypsum, fiberglass, etc.). If
you have never worked with RTV's for this sort of work, you are
"biting off a lot" for a first attempt. Need more info/thought/ideas
please feel free to contact me off list. Also see my website at
mlce.net go to the lower of the 3 pictures on the splash page (kilns
on fire at night) and look over the mold making sections that I am
currently working on. Skype or FaceTime are something that could be
used if interested.
Best of luck.
An interesting request looking for an elegant solution.
I would approach this in a different way.
I wouldnt go the mould and resin route.
Taking a mould from the existing is too risky.
I would make a hard wood replica of the pistol grip as follows. Get
some white card, like a large stiff cornflakes packet. Lay the rifle
on its side on this.
take a fine felt tip pen held vertically and draw a profile of the
grip onto the card. Make sure the dimensions are accurate and
identical to the grip.
Repeat this on another piece of card with the grip on its edge. IE
turned through 90 deg. Cut out this profile and lay onto your wood
draw around to copy the profile onto the wood. then band saw this 1st
profile out to make a copy of the original from a suitable piece of
Repeat with the second profile. Now you have a rectangular copy in
the 2 dimensions matching the original. With rasps and spoke shaves
carve this copy to match the original, hopefully the owner will let
you have the rifle for say a morning whilst you do this. Use a vernier
to measure the original to make sure the replica is the same.
Obviously youcan polish it with sand paper etc and varnish it too, as
the customer is paying you to make this pattern its logically his
property, you could give it to him along with the silver mount.!!
If your wood is strong enough and hard enough, you might just be
able to use it to form the silver around. Let us know how you get on.
I would cover the stock with thin plastic food wrap to protect the
wood. Then form a female mold of modeling clay, which will flex
enough for removal. Then cast a plaster duplicate of the stock in
the mold you have made.
I'd approach it like a dental impression. There are various
materials which can be used to make the mold and a variety of
plasters with which to pour the cast. Talk to you dentist for advice
on what would be best for your application.
Make the grip that surrounds the wood in wax. Resin or wax will do,
and while you're at it, why not mould the shooter's hand perfectly by
making the shooter squeeze the wax or resin onto the grip. Add a few
layers of cling film over the wood to allow for the inevitable
shrinkage of the metal casting. Carefully cut the wax off without
damaging the wood...your cuts will be the future join lines. Add wax
lumps where hinges and catches will be fitted.
Wrap the waxes/resins carefully and send them to a casting house.
The waxes will return in any castable metal you choose. Drill for
hinge pins and add your catch mechanism.
I recommend the shooter squeezes resin onto the grip and leaves it
there permanently bonded. Nothing fancy, but it is the most direct
method for better shooting. Hiding the beautiful wood under daggy
resin will improve the shooting but not the look!
Have a plastic vacuum form made of the grip. You can then use it as
a mold to make an exact resin model.