Smooth on 65D incorrect mix

M

Moviepropmaker6

Active Member
Hey Guys,

Sorry for yet another thread about 65D, but it's my first time using it and i'm making a lot of mistakes, So don't judge me! haha.

Anyway i mixed up some 65D to rotocast as a mask and i think i've put more part a than b. It's cured normal, but it's a clear, yellow colour and appears to be exuding a very very small amount of "grease" on the surface. I wiped the grease off and it appears normal now, but is still that colour, should i be worried?
 
Isn't D65 equal mounts by volume?

If so, get clear plastic cups with marks or ridges on the sides and place then side when you pour each part into a different cup to ensure you have the same height on each cup, hence the same volume.

I don't have smooth on here, but the product I use is the same as far as I know.

I mark each cup as A and B for sole purposes of measuring. I finish the day by pouring both into the one cup then the other. When they set, I don't have residual product left unmixed and thought both cups out.

Sent from my SM-G900I using Tapatalk
 
That doesn't sound right, as 65D is supposed to cure a bright white. If you're getting yellow you must have used too much A. Did you do a 2:1 mix or something? 65D is 1:1 by volume and very very forgiving. Do what cavx said and get measuring cups with indents and use them as reference.


As for your question.. should you be worried? Yes, if you plan to paint. That casting will continue to leech oil for a very long time.. the most evident way to see this is by putting it on a brown paper bag and checking it periodically. Once it stops bleeding into the bag you'd be good to paint. If you tried to paint the piece too soon, it will have a very high chance of delaminating from the resin.
If you don't plan to paint, the casting may be fine but being mixed so off ratio, your guess to its longevity is as good as mine.
 
Mr Mold Maker said:
That doesn't sound right, as 65D is supposed to cure a bright white. If you're getting yellow you must have used too much A. Did you do a 2:1 mix or something? 65D is 1:1 by volume and very very forgiving. Do what cavx said and get measuring cups with indents and use them as reference.


As for your question.. should you be worried? Yes, if you plan to paint. That casting will continue to leech oil for a very long time.. the most evident way to see this is by putting it on a brown paper bag and checking it periodically. Once it stops bleeding into the bag you'd be good to paint. If you tried to paint the piece too soon, it will have a very high chance of delaminating from the resin.
If you don't plan to paint, the casting may be fine but being mixed so off ratio, your guess to its longevity is as good as mine.
Click to expand...

Thanks Guys, i've left it overnight, and it seems to have stopped exuding oil. I wiped it off last night and it hasn't leeched again. I had run out of cups, so i only used 1 cup, and tried to have a correct mix by roughly adding the b over the a until it doubled volume. It worked twice, but third time definitely wasn't a charm. I've added more A, because I feel like it's also a tad softer and if i'm not mistaken, b is the hardener. Are there any Safety issues like fumes even after curing due to the incorrect mix?
 
Moviepropmaker6 said:
Thanks Guys, i've left it overnight, and it seems to have stopped exuding oil. I wiped it off last night and it hasn't leeched again. I had run out of cups, so i only used 1 cup, and tried to have a correct mix by roughly adding the b over the a until it doubled volume. It worked twice, but third time definitely wasn't a charm. I've added more A, because I feel like it's also a tad softer and if i'm not mistaken, b is the hardener. Are there any Safety issues like fumes even after curing due to the incorrect mix?
Click to expand...

If your cup was tapered (as most are), then you needed less of the Part B than twice the height to make it 1:1 by volume.

When you are in the bad position of having just one cup, you can measure this stuff using gram scales at 100:90 ratio. 10 parts of A to 9 parts of B. If you have good gram scales, they will read in 1/10th gram increments and you can mix quite precisely. However, remember time is not on your side with this stuff as it kicks in 3mins, so don't be fussing over 0.5g too much or not enough. Measure, Mix, Pour, repeat after 3min.
 
A way to get around single cup measures is this -

1. use water to find a given level.
2. mark that level with a permanent marker.
3. tip that water into any other container.
4. refill the cup to the marked level.
5. pour your "saved" water back into the cup to get a new level.
6. mark that level.

Now you have A level and B levels.
 
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