Using Clay for Molding?

darthviper107 · Post by **darthviper107** » Thu Jun 30, 2011 10:31 am

I've got a kit that has a detail that broke off. There are identical details on the piece so I was wondering if it might be OK to use some clay and get an impression of one of the other details and then use that to cast a replacement detail. Would it work to use clay for a temporary mold like that?

Rogviler · Post by **Rogviler** » Thu Jun 30, 2011 10:34 am

I've used clay before, as well as hot glue, liquid latex, silicone caulk, and the like. All are good for single use or very few uses.

What will you be using to make the new part out of?

-Rog

Ziz · Post by **Ziz** » Thu Jun 30, 2011 10:52 am

The only trick with pulling the clay off will be not distorting it. Beyond that, it should work although you might have to do a little cleanup of the surface depending how porous the clay.

Stu Pidasso · Post by **Stu Pidasso** » Thu Jun 30, 2011 10:58 am

Like Ziz says, watch the distortion when you pull it off. I suggest putting the whole part + clay in the freezer before you do, unless there's an undercut.

darthviper107 · Post by **darthviper107** » Thu Jun 30, 2011 11:08 am

yeah, there's no undercut, it's just a detail on a surface that's too detailed to rebuild. What clay would be best, would sculpey work?

I haven't gotten any resin yet, this is on a kit for the future so it's not something I'll be doing for a bit. What's a good resin for just a small detail part Smoothcast 300?

Stu Pidasso · Post by **Stu Pidasso** » Thu Jun 30, 2011 12:41 pm

I don't want to prevent you from learning a new method of modeling, but if you only have a small part, no RTV or resin, and only need 1 or 2 casts, PM me, I'll make a copy or 2 for you no problem. If you would like to try it yourself, you can send me a pic, and I'll be glad to give you some pointers or advice. Sometimes, it's just too expensive to learn something new.

darthviper107 · Post by **darthviper107** » Thu Jun 30, 2011 12:46 pm

It's part of a star destroyer hangar detail on the outside, I'll post a picture once I get home so you can get a better idea of what it looks like.

Kekker · Post by **Kekker** » Thu Jun 30, 2011 6:42 pm

IIRC, you can dust the part with talcum powder, press it into the clay and get a one-shot mold that way. I'm pretty sure someone used this in an FSM article in the 90's.

Kev

darthviper107 · Post by **darthviper107** » Thu Jun 30, 2011 9:13 pm

Here's a picture of it:

http://img189.imageshack.us/img189/8466/detailpiece.jpg

Stu Pidasso · Post by **Stu Pidasso** » Thu Jun 30, 2011 10:55 pm

Which kit is this? I might have it here, I might be able to do it for you.

darthviper107 · Post by **darthviper107** » Fri Jul 01, 2011 1:03 am

It's the Anigrand SD

Regular chips on the corners are fine and easy to repair, but this part would be obvious

Stu Pidasso · Post by **Stu Pidasso** » Fri Jul 01, 2011 10:57 am

As a matter of fact, I do have that kit. Would you like me to send the part, or do you want to try it yourself? Let me know, and if you do, PMme your address.

darthviper107 · Post by **darthviper107** » Fri Jul 01, 2011 12:00 pm

That would be awesome, thanks. Sent you a PM

AbsoluteSciFi · Post by **AbsoluteSciFi** » Fri Jul 01, 2011 8:04 pm

darthviper107 wrote:yeah, there's no undercut, it's just a detail on a surface that's too detailed to rebuild. What clay would be best, would sculpey work?

I haven't gotten any resin yet, this is on a kit for the future so it's not something I'll be doing for a bit. What's a good resin for just a small detail part Smoothcast 300?

Go to the hardware store, get a tube of 100% silicone. Apply a mold release to the area. Take the silicone and brush it on carefully. Let it dry then apply another much thicker coat and press a quarter inch piece of plywood into it, equal to the area's size that you are covering. Let it set up and pull the whole thing off, and there is your mold. Works great for any detailing along a flat surface.

Stu Pidasso · Post by **Stu Pidasso** » Tue Jul 05, 2011 12:49 pm

So I open the box to my Anigrand SD, find the piece, and guess what? I have the same exact chip!!!

Pic 1

But I did a quick mold of the surrounding ones, and I got a few good casts:

pic 2

So they'll be on their way to you tomorrow, I missed the mail lady today.

Rogviler · Post by **Rogviler** » Tue Jul 05, 2011 3:02 pm

AbsoluteSciFi wrote:Go to the hardware store, get a tube of 100% silicone. Apply a mold release to the area. Take the silicone and brush it on carefully. Let it dry then apply another much thicker coat and press a quarter inch piece of plywood into it, equal to the area's size that you are covering. Let it set up and pull the whole thing off, and there is your mold. Works great for any detailing along a flat surface.

A better way I've found is to mix the silicone with a dab of artist's acrylic paint and then gob it on. It's a lot faster and the moisture in the paint makes the silicone set up. (Normally a big wad of silicone will never cure in the center.)

You could still do a thin layer initially to make sure you get it in all the details, but a nice big chunk of it is a lot more durable. That kind of silicone is pretty flimsy to begin with.

-Rog

darthviper107 · Post by **darthviper107** » Mon Jul 11, 2011 12:56 am

Got the detail casting put in. Since the bottom was cast as well I ended up just cutting out that section and then fitting the replacement in. There's a bit more cleanup to do, but once it's painted it shouldn't be noticeable.

http://img695.imageshack.us/img695/6017/pic0146t.jpg

Stu Pidasso · Post by **Stu Pidasso** » Mon Jul 11, 2011 7:55 am

AH! I lost the bet...

I bet myself that you would cut out the whole "section" I cast along the "trench" line, and just replace the whole section. Glad to see you got that little fiddly bit off. Cool!

darthviper107 · Post by **darthviper107** » Mon Jul 11, 2011 2:04 pm

hah, I win...

It wasn't too difficult to get the piece in there, it ended up working really well.