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Post by superba on Dec 2, 2006 17:38:49 GMT 1
Thanks to Only87 (peter), I now have some great projects on the work bench right now:
1963 Rambler 880 four door sedan 1964 Ford Country Squire 1964 Mercury Maurader 1963 Mercury Maurader 1961 Oldmobile Dynamic 88 four door hardtop 1961 Cadillac Deville 1960 Lincoln Premier 1957 Packard Clipper 1957 Nash Rambler Wagon 1960 Rambler Cross County 1972 Plymouth Fury I Four Door Sedan 1963 Lincoln Continental 1950 Checker A2 Taxi
Peter introduced me a mold making product (Hydroshrink) that allows the resulting mold to shrink by about 50%. Working off a 1/43 model the mold will shrink to about 1/87 scale.
All of the above cars have been molded off of Dinky, Corgi, Motorific, Brooklyn etc. prototypes. I have been buying junk dinky's and corgi's off of ebay so the investment has been minimal.
To date the 63 Rambler and the 64 Country Squire are almost at 1/76 scale. It's truely amazing, no warping or misshaping, an even reduction. Curing time has been almost a month. The other molds are in varying points in curing.
I plan on experimenting to see if 1/64 can be reduced to 1/87 scale, but first I want to achieve success with the 1/43 scale. I believe buy reducing the water to Hydroshrink ratio a different reduction percentages will be achieved.
I have also made one mold off of a 1/25 AMT 61 Ford Galaxie Town Coupe. That model should reach about 1/50. The resulting master will then be put through the Hydroshrink process again. If I can reduce the reduction ratio, again I should ba able to get to 1/87.
If truely successful, this will open many new opportunities for 1/87. The only problem I have had to date, is that pulling the original master out of the mold can be a problem.
I have been coating the master model with silicone, which has improved the ability to pull the model out the mold, but the ultimate master model will require more finishing as the surface will have some minor rippling
The other problem is that the mold material originally sets in about 45 seconds. It's crazy fast. In my first try the mold set while I was pouring! To use Hydroshrink you have to be fast and organized.
I'll keep all posted with the results of this experiment. I hope to make the first 1/87 cast in about a week. From that casting I will mill and rework a new 1/87 master to be put through normal casting techniques
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Post by jackfitz1944 on Dec 2, 2006 18:06:23 GMT 1
Lee, This is amazing. This could open up a whole new way to duplicate cars. I have a small collection of 1/43rd scale discasts (my favorite vehicles). Where did you get this stuff and how much does it cost? I would love to duplicate my '41 Chevy and Plymouth Pickups. Thanks for sharing.
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Post by superba on Dec 2, 2006 19:25:29 GMT 1
Jack: Here is the web site: www.sculpt.com/catalog_98/CastingMaterials/HydroShrink.htmI think the two week estimate is not correct, I have been observing about 4 weeks for the mold to get to the orange tone you see depicted on the web site. I bought the gallon product and have made about fourteen good and four bad molds that had to be thrown out. So from a pricing standpoint it actually seems to be the most affordable mold product I have ever worked with to date. I have yet to actually have a successful cast, I'll make my first attempt next weekend. I am pretty excited about the product so we'll see if the product really works. Joe
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Post by superba on Dec 2, 2006 19:27:38 GMT 1
One down side to the product its that it appears to create a haze over the master subject. I have been using crappy masters. It will ruin good models.
I took apart a Brooklyn Checker A2. The mold took off all the decals. So beware that you may ruin a good starting master model.
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Post by cfesmire on Dec 2, 2006 19:30:33 GMT 1
Yow! Good news Joe, and to add to your already extensive repertoire is great news. Please keep us posted.
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stanhas87
87thScale addict
1978 Dodge Monaco CHP
Posts: 4,906
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Post by stanhas87 on Dec 2, 2006 19:41:05 GMT 1
Dear Joe:
Like all of the projects.
The only early 1970's Plymouth that I know was made by Majorette (Ref. #216) and is quite difficult to find.I saw one of these 're-decorated' by a collector,and it looks great.
Matchbox has the #10,1976 Gran Fury which was also made by Dinky around 1/43 scale.
A great list there,pure and simple.
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Post by nickvoges on Dec 2, 2006 20:34:40 GMT 1
Hello Joe, thats great news! Even that there is a material with standard shrinking parameters. But I will warn for too much hope. I experimented a lot with shrink bigger parts. I used a mass to make cakes, thats not a joke, but it was the only thing I noticed is shrinking for about 25%. One big problem is that its shrinking to the nucleus. For a round thing like a ball there is no problem. But a longer thing like a car for example will shrink more in width than in length. A ring for example would be smaller in the extern width, but bigger in the intern width, because the material is shrinking to the middlepoint, which is not in the center of the ring, but in the circle. Hope that it is a good explanation. For me it worked fine with parts like the grille or bumbers. Hope we will hear good progress soon. Best regards nick ingmar By the way you made a very good choice for the selected cars....
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Post by superba on Dec 2, 2006 20:36:40 GMT 1
Nick:
I used the 1/43 White Rose dicast Plymouth four door. Some of the propotions are not correct so the I will have to rework the resulting master.
I have a Majorette 1/64, it too hass pretty awful proportions, really not suitable for a casting subject.
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Post by only87 on Dec 2, 2006 20:37:43 GMT 1
Jack: I think the two week estimate is not correct, I have been observing about 4 weeks for the mold to get to the orange tone you see depicted on the web site. It depends. Temperature and humidity are important factors for the process, of course. You can fasten things by finding a suitable heat source that doesn't harm the material but accelerates the dehydration. Also all sides of the mold should have access to the air, so the water can suspend uniformly, or at least the mold should be turned upside down and side to side from time to time. All that should reduce the process to maybe a week or just a few days. I use a lamp with a flat closed top as a heater. If I let the lamp burn for several hours it gets rather warm on its top. I put three or four touthpicks between the lamtop and the mold so it can shrink more freely and that way the mold has a little access to the air on the underside. There may be better solutions, a dehydration box for example, but this simple solution is very cheap and does the job for me. One down side to the product its that it appears to create a haze over the master subject. I have been using crappy masters. It will ruin good models. I took apart a Brooklyn Checker A2. The mold took off all the decals. So beware that you may ruin a good starting master model. You could always do a "normal" casting before and use the casting as a master. Or shrink the master itself by making a normal RTV mold and use the Hydroshrink instead of resin. But with the latter method you may have a hard time getting air bubbles out of the cast, you know you only have 45 seconds.
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Post by only87 on Dec 2, 2006 20:44:08 GMT 1
A very nice list indeed. I'm most exited about the 1960 Rambler and Lincoln Premier (that ist the one from North By Nortwest, right?)
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Post by Sylvain on Dec 2, 2006 21:33:31 GMT 1
Mercury, Rambler, Packard, Lincoln, very interesting list indeed, Joe! And very interesting experiment. You've told me about it already, but I can't wait to see the results.
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Post by superba on Dec 2, 2006 23:37:07 GMT 1
As a follow up: Nick brings up some very important points and quite frankly I share his concerns. The American cars I am making molds of have a standard three box design. What appears to happen is that the middle box, the inteior section cures the fastest. The front and rear box seem to have the issue that Nick describe. After the first week I was convinced we had a total disaster. The Country Squire mold bowed like a big white Banana, yet after three weeks the Rambler and Country Squire outer sections started shrinking too. As of today, both the Squire and Rambler have cured almost completely. The Rambler mold is perfect proportionally. I still see some white in the mold so I know I have to give it a little more time for the mold to turn to the translucent orange color. I can insert a CMM Ford Galaxie into the mold snugley, so I know we are almost done I did not used any lamps. The molds have been place on glass and have been turned over regularly. I made the misstake of putting one mold on my good wood and leather desk in my office. The mold does seem to adhere to pourus objects, it ruined the mold and almost ruined my desk. I think Peter comments are right on target as he has had more experience than me. As a follow up to Peter's comment, the Lincoln is the same as the one used in the Movie North By Northwest. One of my favorite movies. The lincoln mold was made four days ago, so we have to wait and see tehe results at about Christmas time. My biggest concern now is mold life, I am afraid I may only have one shot at doing a casting with the resulting mold. I am considering weather I should used some other media....maybe plaster instead of resin. I am going to contact the manufacturer next week for advise Peter's comment about making the master out of the Hydroshrink is brilliant, I sih I thought of it.
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Lee
Senior Member
Posts: 1,899
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Post by Lee on Dec 3, 2006 1:01:35 GMT 1
Most interesting product that you have found Joe. It opens the door to all kinds of possibilities for the cottage industry. My first question is why are you using the HydroShrink to make the molds when the website says to make a silicone mold of the original and then pour the HydroShrink into the new mold? It would seem that the object that you are coping would restrict the shrinking until you could get it out of the mold. Whereas if you made the silicone mold first, then poured the HydroShrink into the silicone mold, there wouldn't be that problem. My first thought is this would open a quick and simple way to make all our vehicles available to the N guage crowd. ;D My second thought is that Jerry would kill me if I made a silicone mold of one of his prized Franklin Mint models.
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Post by superba on Dec 3, 2006 2:45:54 GMT 1
Lee:
The product is described as a "Reducing urethane product for easily sculpture reducing". The photo depicts a large scuplture and a smaller Hydroshrink mold, so I see it as a mold reducer.
I do agree that based on Peter above comments, you could make 1/1 mold off the master, then pour Hydroshrink into the mold the resulting hydorshrink casting would then reduce over a period of several weeks.
From the reduced casting a new mold would be created.
Giving credit where credit due Only87 turned me onto the product. I just went nuts experimenting with it.
As an update, tonight I took the mold for the Rambler and Squire and place them over a floor heat vent in my family room. I set the temp for 72 degrees F and will see how it look tomorrow morning.
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stanhas87
87thScale addict
1978 Dodge Monaco CHP
Posts: 4,906
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Post by stanhas87 on Dec 3, 2006 3:47:17 GMT 1
Nick: I used the 1/43 White Rose dicast Plymouth four door. Some of the propotions are not correct so the I will have to rework the resulting master. I have a Majorette 1/64, it too hass pretty awful proportions, really not suitable for a casting subject. Dear Joe: Forgot completely about the White Rose one.I do like these (I do not have one yet).Have two of the Majorettes. I hope the complications you are going thru will be resolved.I am really excited about the Plymouth (I do love these bodies!!) and the Ramblers for very few models exist of them and they barely exist even in 1/64 scale. Oh,question:any plans to do the Chryslers between 1974-1978? (To me,these were the final of the real Chryslers).Collectable Automobile just had an article on these. Best Regards, Nick K.
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