New to PR casting

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diicode

Member
Joined
May 28, 2012
Messages
7
Location
Sherwood Park
Hello all,

I'm looking for some advice...

I've been "successfully" casting pr blanks for a couple of weeks, worked out a few kinks and now am able to turn them into stoppers and pens.

I'm having a slight issue though, the colors I'm making when they harden change from before the reaction. I'm using what the guy tells me is Clear Cast, I mix that with smooth-on dyes and mekp hardener.

My blue becomes purple, red is orange, green becomes pea green... Though my white stays white. I have been adding white to my resin to ensure they become opaque.

Though I tried some metallic oil based paint, And those cast very well (black and silver).

Does anyone have a thought? I can mix some more, take pictures of the before and after if it helps.
 
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Just a SWAG, but your white you are mixing in the PR very well could be the cause of all your color shift problems. Depending on the base of your white and the colors you are using, the colors you describe easily could be from the white you are using. To kill the translucency, try painting the hole in the blank before you glue in the tube.

Charles
 
Two things, use the proper type colorant for the resin you are using! Most of the problems stop when using the CORRECT colorant. Yes you can use other stuff but it tends to cause problems. Wasting resin, and costing more than the colorants.

If you use the cheaper Pr resin used for fiber glass, at any time it will yellow or turn brown with time and age it can cause a slight color shift when starting out, since they tend to be on the yellow side.

Adding white to any color will change it, it can lighten it and depending on what colors are used to make the original colors it can do a color shift. I am assuming that you are using paste dye.
:clown:
 
I'm not sure the exact brand of resin I'm using, whether its for fibreglass or not, but maybe... I liked it because its local, and while I'm trying to get good at this, I want to be able to run out every couple of weeks and get it, being in Canada, waiting 2 or 3 weeks for a shipment hinders my progress.

I would have assumed that the color when mixing would be the color it comes out at after curing, but during the curing prcess is when it changes.

I'm sure you're right that the white is the problem, I'll cast later today and see what happens without the white.
 
diicode said:
I'm not sure the exact brand of resin I'm using, whether its for fibreglass or not, but maybe... I liked it because its local, and while I'm trying to get good at this, I want to be able to run out every couple of weeks and get it, being in Canada, waiting 2 or 3 weeks for a shipment hinders my progress.

I would have assumed that the color when mixing would be the color it comes out at after curing, but during the curing prcess is when it changes.

I'm sure you're right that the white is the problem, I'll cast later today and see what happens without the white.
Click to expand...

Smooth on has distributors in Canada Smooth-On, Inc. - Mold Making & Casting Materials Rubber, Plastic, Lifecasting, and More

Miapoxy has one also Miapoxy

Check alumilites web site they probably have somebody selling it Alumilite - Products - Casting Resins

As a last resort Sculpture Supply Canada - About Us as I have heard slow things and long wait for reorders but have no first hand ordering knowledge.

Don't know if Hobby lobby, Micheal's or Joann fabrics have stores in Canada, but the larger craft stores have some casting materials.

And as with paint the color tends to change when it dry's. With resins the effects of the hardening can have changes on the materials in the colorant used. An advantage in using the colorants for the brand of resin is they are tested and only ones that aren't effected are sold.
:clown:
 
The place I buy from is selling smooth on, but the clear cast resin isn't made by them. It's purely a cost thing, clear cast is cheaper than the smooth on resin.

What's the difference between polyester resin and polyurethane resin?

We have michaels, but no casting stuff there. Hobby lobby here isn't affiliated with hobby lobby US.

I'm buying from vikingplastics.ca which aren't a lot of help as they look to be more a fiberglass shop and movie/zombie casting stuff.

Thanks for all your help so far.
 
Consumer Products | Environmental Technology Inc is the company that makes castin craft

polyester resins are pale colored, fairly viscous liquids consisting of a polyester and styrene solution.

Polyurethanes are in the class of compounds called reaction polymers, which include epoxies, and a host of other products. Polyurethanes are produced by the polyaddition reaction of a polyisocyanate with a polyalcohol (polyol) in the presence of a catalyst and other additives.Which control what the items turns out to be from ink to a floor coating.

Simple short answers :wink:

Check out some of the other links they all are in Canada.
:clown:
 
I had the same problem of my colors turning to an orange color. I played with the pr a couple weeks and found that too much hardner will cause the color change. I use a fraction of the amount of hardner that I was using befire, and more of the dye, and that fixed the problem. It takes a lot longer to dry, but it keeps it's color. I use pr from Michaels.
 
diicode said:
Will do.

So for blanks is polyester or polyurethane recommended?
Click to expand...


Just my limited experience, others may have a better insight:


Polyester is harder but not as tough (break and chip resistant)

Polyurethane is tougher, softer, (not softer to the touch) turns easier, far more resistant to breaking and threads much easier. It also sets up much faster (the Alumilite stuff I use vs the Castin'craft PR I've tried) and I like the feel of it far more that of PR. There's two Alumilite products I've used, one white and one tan, the tan seeming to be the tougher of the two but harder to get a color to come out the with the same purity as the white.

There's also the clear cast (which I think is polyurethane) which makes nice transparent blanks and looks nice with the mica powders, but I haven't really done anything with it except to make a couple of short round blanks to try turning it for practice.

As with everything, I imagine it's more of a personal like or dislike than anything else.
 
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