Question about Resin Casting

Treadhead · Post by **Treadhead** » Tue Feb 27, 2007 2:36 pm

Is there something I can add to resin that will allow it to stick to the sides of a mold? I know that microballoons can do this, but I'm afraid that when it comes to sanding that it will leave a lot of pinholes.

There are some fillers that will accomplish this, but what is the best one? I want a hollow casting that has durability and strength, but yet thin enought that will allow me to put an interior in the thing. I thought about fiberglassing, but kinda shied away from that.

Any advice would be greatly appreciated.

modelnutz · Post by **modelnutz** » Tue Feb 27, 2007 2:51 pm

Smooth-On sells a material called Ure-Fil.
Excellent filler for Roto-Molding or slush casting.

Not too much impact to the resin when it comes time for sanding.

Hope this helps ya'

Modelnutz

"the name sez it all"

Treadhead · Post by **Treadhead** » Tue Feb 27, 2007 2:54 pm

modelnutz wrote:Smooth-On sells a material called Ure-Fil.
Excellent filler for Roto-Molding or slush casting.

Not too much impact to the resin when it comes time for sanding.

Hope this helps ya'

Modelnutz
"the name sez it all"

Thanks

This helps me out a lot

modelnutz · Post by **modelnutz** » Tue Feb 27, 2007 2:57 pm

Most welcome

Shinnentai · Post by **Shinnentai** » Tue Feb 27, 2007 5:21 pm

Talc, AKA baby powder. I've never tried microbaloons or the fancy smooth-on stuff, but plain old talc has always worked fine for me.

Vince Hoffmann · Post by **Vince Hoffmann** » Tue Feb 27, 2007 5:39 pm

Microbaloons works very very well.

Treadhead · Post by **Treadhead** » Tue Feb 27, 2007 6:18 pm

Leaky Rowboat wrote:Microbaloons works very very well.

I heard that microbaloons works great as a heat sink that really minimizes shrinkage. My only fear of using them is sanding afterwards. I remember hearing that it leaves a lot of pinholes.

Umi_Ryuzuki · Post by **Umi_Ryuzuki** » Tue Feb 27, 2007 6:28 pm

See if you can't just get a higher viscosity resin that you like.

kenlilly106 · Post by **kenlilly106** » Tue Feb 27, 2007 8:36 pm

Is it possible to pour a thin layer of straight resin in the mold, slosh it around a bit until it sets, then pour another layer with the microballoons, slosh it around until it sets?

This way you would get an outer layer that you could sand without worrying about the filler interfering with the finish, unless you're planning on really going to town with the sanding and need to hog off a lot of resin.

Ken

Vince Hoffmann · Post by **Vince Hoffmann** » Wed Feb 28, 2007 9:09 pm

kenlilly106 wrote:Is it possible to pour a thin layer of straight resin in the mold, slosh it around a bit until it sets, then pour another layer with the microballoons, slosh it around until it sets?<snip>

Yes, but by the time you've poured your first layer, you would have what would amount to as a hollow casting (that is, if you use enough resin to make at least 1/8" wall thickness) At which point, you would not need the second pour.

Good idea though, if you need to make a lightweight solid piece. I'll remember that.

kenlilly106 · Post by **kenlilly106** » Wed Feb 28, 2007 9:33 pm

Leaky Rowboat wrote: Yes, but by the time you've poured your first layer, you would have what would amount to as a hollow casting (that is, if you use enough resin to make at least 1/8" wall thickness) At which point, you would not need the second pour.

I wasn't thinking going that thick, I was thinking more of 1/16" max, depending on the depth of the surface detail. Then add enough resin mixed with microballoons and slosh it around to get to an 1/8" +/- wall thickness.

Since the original poster wants to be able to sand the outer surface, but not deal with all the pinholes you would get if you used microballoons in the surface coat, I was thinking along the lines of what you do with fiberglass, do a gel coat first, then add the glass fiber behind it.

Ken