I had a request to post how I cheaply cast my own foam bodies for odd sized or rare species fish. It is fairly easy and time efficient IF you do it while you are working on other things. It is NOT time efficient if you are going to sit there and watch OR if you want to mount and skin a fish in a day. The whole process takes very little time but explaining it does. I would suspect I have about one total hours worth of ACTUAL work time in making a cast body....about the same as I would have in carving one......and I HATE carving.
The process is similar to mounting a half cast fish.....only you cast both halves. Also similar to molding a fish with Plaster.....only you do not need to worry about detail or even accuracy all that much.
Materials: Plaster of Paris
2 part foam
DAY ONE - USE GLOVES FOR THE WHOLE PROCESS
Have 3 fish ready. Two to skin.....the other that needs a "form" made.
First take a towel and "dry" your fish. Nothing too thorough, just get the main slime off. On really slimy fish like muskies ....sprinkle borax over the whole fish and then wipe towards the tail. The slime will come off in a big pile
Lay your fish in position. I lay mine in a bed of wet sand. I have a sand box from the old days when halfcasting was common. You can use high fiber as well. Either one works fine for this. I dig a trench to get a good curve and then tuck the material under the head and tail to get good position. Make sure and have the MOUTH in the FINAL position you want in other words OPEN or CLOSED. If OPEN I prefer to fill the mouth with old newspaper. Fill the belly. Some people fill the fish with CALK.....I just stick the air hose in the vent and give a few PUFFS. That really fills out the belly.
Once the belly is full and I have good position I tuck sand/fibre all around the fish half way. Just like you were going to do a Reproduction cast. Then I build a halfhearted dam to save material out of waste cardboard that is lying around. Just stick it the sand around the edges.
Mix up a KAYRO SYRUP consistency of plaster and pour it on the fish from the eyes back to just past the tail junction.
SKIN ONE OF YOUR OTHER FISH
Mix up a batch of PEANUT BUTTER thick plaster and smear some on the cast. Then take a piece of burlap and lay it on the wet plaster. Smear the rest ON TOP of the burlap.
DETAIL FLESH ONE OF YOUR OTHER FISH. PUT IN WATER
Pick up the plaster cast FISH AND ALL and flip it over. Rinse the sand/fibre off in the sink. The cast is STRONG enough at this point to handle but CAN BREAK very easily. Just be cautious. Do a decent job. No need to have it perfectly clean. The less water the better.
Pat dry the open side. Look at the edges and get rid of any funny places the plaster may have run "funny" along the edge near the fish. The plaster is fairly soft at this point I just scrape away any funny edges.
I make a CLAY DAM along the edge of the front mold just to help hold the next pour. Take VASELINE and thickly smear it on ALL EDGES where the plaster will come in contact with itself. I cannot stress the importance of using PLENTY. This is NOT a detailed REPRODUCTION. A ROUGH SEAM is not a problem. You want these to pull apart easily.
Mix up a KAYRO SYRUP consistency of plaster and pour it on the back side of the fish from the eyes back to just past the tail junction. Keep inside your dam best you can.
SKIN YOUR SECOND FISH
Mix up a batch of PEANUT BUTTER thick plaster and smear some on the BACK cast. Then take a piece of burlap and lay it on the wet plaster. Smear the rest ON TOP of the burlap.
DETAIL FLESH YOUR SECOND FISH
After an hour or more has passed check the hardness of your mold. Stick your fingernail in it. If it EASILY leaves a mark WAIT LONGER. When it seems hard enough start to pry apart the two halves....USE CARE. It should pretty easily pull apart. Take out your fish and rinse the plaster off the skin.
Wipe the edges down to remove the Vaseline off of your mold. Set aside to dry. Whenever possible I set them out in the SUN, OPEN.
SKIN THE FISH YOU JUST MOLDED.
I personally like to wait a fewdays of drying BUT you can make your body the NEXT DAY if the mold is dry on the inside
CASTING THE BODY
Check the two halves and see how they fit together. Since we took LITTLE care in the molding keys will NOT be necessary......the mold should only fit together ONE WAY.
Cover the inside of the mold with WAX. I use whatever the cheapest hard car wax in a can I can buy. Rub it into the mold and especially thick on the edges where it MEETS.
I like to pour my foam from the HEAD to the tail SO. Start wrapping your mold in duct tape from the tail towards the head. Seal it GOOD! When you get to the head area I take strips and go across the BIG opening leaving just enough room to POUR the foam in.
Set your mold up with the opening towards the top. Mix up your Two-Part foam(your choice of density I have used them all) per instructions. As your are stirring it will go CLEAR and DARK suddenly.....start pouring immediately.
Once you get enough in take a couple strips of duct tape and cover your pour hole.
Myself I like to wait 24 hours before removing my form....BUT you can follow the foams advice. Pull apart the plaster halves and remove the form.
If you did it right you should have a nice foam body to mount on. It will take a little rasping to remove fins and other artifacts but all in all it will be ready to go.....AND it will be strong.
When doing coldwater fish remove the HEAD before molding. It makes it easier. In fact it works on all fish but I don't really like to remove heads on most fish.
If you do remove the head VERY LITTLE work will be need to use the form. If you leave the head on you will have to shape the head, collar bone and throat areas.
If you break or CRACK your mold DON'T FREAK OUT. Just save the pieces. When they are dry hot glue them in place and cover them with some cloth. Remember this will be a form you can sand and rasp. A little BLEMISH here and there is NOT IMPORTANT like it is on a REPRODUCTION mold.
You can add the wood block at any time. However I find it easier to cut the form and put it in after it is cast. they tend to move around if you do it prior.
Take your time the first couple until you get the hang of it. It really is VERY QUICK after you know what your doing. Almost automatic.
When pouring plaster make sure you mix enough. If you fall short QUICKLY mix some more and get it poured before the first batch is fully set up. Use your hands to smear the seams together.
You CAN use BONDO for your molds BUT it is more expensive and really the molds for these odd shaped fish are USELESS.
I have used CANNED FOAM for filling holes in your house.....it works BUT the form is much softer AND it is only good for pan fish sized forms.
PATIENCE, PATIENCE, PATIENCE. Like I said ACTUAL WORK time is negligible BUT WAITING until things have set up takes PATIENCE. Don't wait until the last minute to do these. If you can just let each step get properly set up you will have very little headaches.