Casting

Tim Herman · Apr 6, 2009

am confused. the blue stuff in the tubes from GRS is the best for making the mold to then make castings from that will show every fine line and bulino dot? Or does the Alumilite silicone rtv mold making kit is as accurate as the blue stuff?

Im doing a pair of all bulino dot technique of 2 gorgeous tigers and would love to be able to make castings of them.

FANCYGUN · Apr 6, 2009

Tim
I would suggest you use what Mike suggested to make your molds and castings. He uses it becuase it works and so do I. It really isn't "rocket science"
Good luck with them

Mike Cirelli · Apr 9, 2009

Mike I have some FEGA castings you do a wonderful job on them. I was wondering what type of black paint you use and do you give it a coat of crystal clear after.

FANCYGUN · Apr 9, 2009

Mike
I use oil based printing ink or fingerprint ink on mine. I then clean the ink off the surface when dry-"ish" with a little paste wax. It can get messy. I do not coat them afterwards. I think Bissel told me he uses paint but i could be wrong.
Marty

Mike Cirelli · Apr 9, 2009

I'll have to try your method Marty. I have been using Winsor & Newton artist lamp black oil and rustoleum flat black. The rustoleum is hard to get it off the fingers though. Where do you get finger print ink I've looked for it in the past with no luck.

FANCYGUN · Apr 9, 2009

Mike
I really don't remeber where I got the fingerprint ink from. It might have even been from my local police station way back when. The oil based etching ink seems to work good also and that can be had from a decent art supply house. Make sure it is oil based and not a relief printing ink but for intaglio printing. I rub it into the engraving, let it dry a bit and then rub paste wax into the ink so it mixes together. I let it dry and then with a paper towel wipe it off gently. If i have to work it too hard I put a little paste wax on the towel and rub gently and that seems to do the trick. It is time consuming but works well. This was posted before a while back but this an inked in casting that I scanned on my scanner.

Fred Bowen · Apr 9, 2009

Hi Tira,
To get back to your original question, I have made molds & castings of the percussion cappers and small boxes for Cash Mfg to offer to the muzzleloader market. I've also done a few knives. I haven't tried guns or gun parts yet, though.

Ron Smith · Apr 9, 2009

Here is what I do:

I "butter" the part I am copying with a thin layer to get out bubbles off the surface. I then add another thin layer on top of that all the way around and on the edges to make the reservoir for the Alumilite (on knives and gun frames).

I then turn the mold over and make a frame to put around the rubber mold. I put the rubber mold upside down inside the frame (the frame a little larger than the perimeter of the rubber mold) and I pour plaster of paris over that. This gives the mold a base that is level and keeps the rubber rigid. This saves a lot of the blue rubber mold material also.

To get the finished copy out, you just remove the rubber from the plaster base and it becomes flexible enough to peel off. The plaster base keeps the rubber mold rigid and level during the pouring of the Alumilite.

I also use fingerprint ink and paste wax to color the engraving and clean the finished copy.

Ron S

monk · Apr 10, 2009

tira, once i learn the art of photography- i'll take up the casting technique.

Mike Bissell · Apr 10, 2009

Mike - The type of ink that I use is Speedball Block Printers ink (oil base), A few years ago I use a clear spray over the top of the casting but I no longer do so.

Mike

rfattig · Apr 10, 2009

I am a rank beginner in engraving, and greatly appreciate the wealth of information and assistance flowing freely on these pages.

Molding is something I have had a little experience with so maybe I can can contribute a little and suggest a different perspective. Since there are no undercuts and with a vacuum pump to de-gas the resin, up to about a shore 60A resin would capture every bit of the detail. This would allow a single pour and eliminate the mother mold. (plaster) This resin is a little fussier about proportions, so a scale is best to weigh the parts, usually 10 to 1.
1. level the engraving
2. make a fence of clay or clay/wood - be sure to go down around the sides to make a cup to pour the casting in
3. de-gas the mixed resin about 6 min at 27 in.vacuum - not longer
4.pour from one corner forcing the air out of each corner in the engraving as you go
5. pour about 3/4 - 1 " over the top of the engraving. after 15 min blow on the bubbles formed on the surface to leave a solid base to cast.

This all needs to be done in about 10 min.

If necessary, the initial covering of the engraving can be thinned 10% with a silicone resin thinner to release bubbles easier.

These molds, esp. platinum cure will last many years on the shelf, and will make many castings. No need to keep track of all the mother molds.

These same molds can be used to pour pewter if the silicone is the correct type. Platinum cure I believe.

Again, thanks for all the answers to all my questions about this art.

Roger Fattig

www.rogerfattig.com

Leonardo · Apr 12, 2009

Hi Tira and all,
I was reading this interested thread and realized that you do not mentioned the ALGINATE.
This is a natural material that mixed 50/50 with water can give you a great mould. Unfortunately it can only be used once but it cure quite quickly (in about four minutes) and you can buy this material at good prices (let’s say about 20/40 euros/Kg depending on the material quality and brand)
Best regards, Leonardo.

Kevin P. · Apr 12, 2009

Mike, Harbor Freight sells boxes of nitrile gloves for very little. It's an inexpensive way to protect your hands.
Kevin P.

Kevin P. · Apr 12, 2009

Roger, what is the commercial name for the silicone product that you use?
Kevin P.

rfattig · Apr 12, 2009

Hi Kevin - As mentioned above Smooth-On makes very good products . My favorite for price and performance is Silicones Inc P60. Both product lines are carried by Eager Polymers at reasonable prices. They also carry all the casting polymers from smooth-on.
Roger

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