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Does it matter if you primer parts


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#1 my80malibu

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Posted 21 September 2012 - 02:39 PM

I have some wheels I want cast and I primered them will the mold making process affect the outcome adversely

#2 Ace-Garageguy

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Posted 22 September 2012 - 01:44 AM

It depends on several things:

1) How well prepped was the surface and how well is the primer adhered to the parts?

2) What kind of primer did you use ?

3) What kind of mold-release agent are you planning to use?

4) What kind of mold material are you planning to use?

For instance....I had problems making a polyester mold, using a polyvinyl-alcohol release agent over spraycan high-build primer. The mold material attacked the primer through the release agent and stuck to it..... big mess.

I had zero problems with catalyzed polyester primer, polyvinyl-alcohol release agent and a silicone mold material.

I know what works for me repeatedly from years of experimenting, but I don't apparently use the same materials most resin casters do, so I'll leave the 'expert' answers to them.

Edited by Ace-Garageguy, 22 September 2012 - 03:48 AM.


#3 Casey

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Posted 22 September 2012 - 04:51 AM

Which mold rubber are you using? I doubt you will have issues, but remember that the mold rubber will capture even the finest of details, so if the primer finish has an orange peel texture, so will your molds, and eventually, the copied parts. It's always a good idea to polish your masters and get them as smooth as possible, regardless if they are primed, painted, or bare plastic. Ideally, all masters would be bare plastic, but sometimes that just can't be.

#4 my80malibu

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Posted 22 September 2012 - 06:39 AM

I am not sure what materials will be used. I am just making the master, I think Greg Wann, will most likely cast the parts. While building the wheel, to check for imperfections and sprayed a light coat of Duplicolor primer.

#5 Ace-Garageguy

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Posted 22 September 2012 - 07:41 AM

I think Greg Wann, will most likely cast the parts.


In that case, ask the guy who's going to cast the molds what finish he prefers. I have to specify to my own clients exactly what materials and finishing techniques to use, or I simply can't guarantee my own part of the job.

#6 Jim Whalen

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Posted 22 September 2012 - 08:56 AM

Hi, Would it be possible to prime the parts to check for imperfections and then remove the primer before casting? I know it may be difficult with parts that have a lot of detail meaning it would be hard to get the primer off but its just a thought that may help.

Cheers,

Jim

#7 MAGNUM4342

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Posted 22 September 2012 - 10:46 AM

A better solution would be to give them a good coat of gloss paint and let it cure about a week. Otherwise the wheels will have the rough texture of the primer. I know Jacen (Futurabat) has cast alot of painted items with no problems.

#8 Greg Wann

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Posted 22 September 2012 - 08:38 PM

I do prefer a nice shiny part and a good coat of paint will do it. I have spent countless hours setting quietly polishing a part to prepare for the mold process. Especially the Cosma Ray bubbles and windshields in general. Did you know you can spray paint in a mold and after it dries you can pull a painted part from the mold? Pretty cool. I can make some pretty decent parts but I am a horrible painter and a horrible body man. I prefer to let someone in my club do major prep work for me. I don't consider sink holes a problem. There are too many other aspects of details on parts that are more important to me when I make a mold. I have seen parts that club members have paid a lot of money for that I would have thrown away. I suppose that not everything I make is perfectly perfect but I sure do try. Someone told me the Eleanor hood is high on one side and teeters. I checked my part to the master. They are exactly the same. I took some of the Smooth - On 300 resin I used to use and created a new mold with a hood that does not teeter. Hopefully it is a better part.

#9 monkeyclaw

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Posted 23 September 2012 - 02:00 AM

I always try to put put a show quality finish on parts prior to casting; especially body parts. For engine castings I will use textured finishes; such as sand cast; or wrinkle finish to get just the right look prior to casting...........Matt