Curing time for White Extra Fine Milliput

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Curing time for White Extra Fine Milliput

Joined: January 10th, 2006, 4:30 pm

March 21st, 2012, 6:36 pm #1

I put some Milliput on a model last night to fill an engine nacelle that was "short shot" in the mold. The plastic was so thin you could see through it and the engine nacelle was not the correct shape (an old Monogram kit, BTW). I kneaded the 2 parts of Milliput together (and yes, they were well mixed) and placed it on the weak, distorted area last night around 10 P.M. I tried to sand it today on my lunch hour (around noon) and once I sanded through the upper layer (which was very hard and cured to the touch), the underlying layer was still rather gummy and did not want to sand well. The total depth of the Milliput was about 2-4 mm thick. I stopped sanding and will let it cure out for another day or 2 until it is completely set up. Is this typical for Milliput? I have just started using this filler over the past couple years and usually don't have to put it on this thick. I was somewhat concerned when it was not completly cured throughout. TIA for your input.
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Joined: February 27th, 2005, 4:14 am

March 21st, 2012, 7:05 pm #2

That you either didn't get it mixed as well as you thought you did, or, that it's "gone bad". Being an epoxy putty, there shouldn't be any issues with laying it on thick as it doesn't cure through solvents evaporating. The cure is via the chemical reaction from the two parts interacting.

The soft stuff you sanded into may cure with some more time, but I have my doubts.

But then, others may know different about Milliput as I don't use the stuff, I use Apoxy Sculpt. But they are both epoxy putties and I'd expect them to behave pretty much the same.

Mike
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Joined: January 15th, 2008, 5:48 am

March 21st, 2012, 7:10 pm #3

You might be able to accelerate the hardening by microwaving it. If you mix more than you need, you can freeze the leftover, and thaw it in the microwave when you're ready to use it again. You don't want to over-thaw it, though.
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Joined: March 2nd, 2005, 3:52 pm

March 21st, 2012, 7:28 pm #4

I put some Milliput on a model last night to fill an engine nacelle that was "short shot" in the mold. The plastic was so thin you could see through it and the engine nacelle was not the correct shape (an old Monogram kit, BTW). I kneaded the 2 parts of Milliput together (and yes, they were well mixed) and placed it on the weak, distorted area last night around 10 P.M. I tried to sand it today on my lunch hour (around noon) and once I sanded through the upper layer (which was very hard and cured to the touch), the underlying layer was still rather gummy and did not want to sand well. The total depth of the Milliput was about 2-4 mm thick. I stopped sanding and will let it cure out for another day or 2 until it is completely set up. Is this typical for Milliput? I have just started using this filler over the past couple years and usually don't have to put it on this thick. I was somewhat concerned when it was not completly cured throughout. TIA for your input.
Really old epoxy putty will never really cure to its full hardness. Found that out the hard (no pun intended) way.
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Joined: January 10th, 2006, 4:30 pm

March 21st, 2012, 8:17 pm #5

Bought this Milliput maybe 2 years ago from Sprue Brothers. I think they turn it over often enough that it wasn't old on the shelf. It does have that yellow tint to the one part on the outside. I did mix it. In fact, I over mix it. Usually if it isn't mixed, it won't be a uniform color through it. I mix it until it is uniform, then knead it for about 5 more minutes. I'm gonna see how it does giving it about 12 more hours more to cure and then try sanding it again. I know the stuff gets like granite after a few days. I'm not sure I've sanded any this soon, but I am trying to get to the painting stage on this kit ASAP. Trying to hit a deadline.
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Joined: March 19th, 2007, 1:04 pm

March 21st, 2012, 8:45 pm #6

That you either didn't get it mixed as well as you thought you did, or, that it's "gone bad". Being an epoxy putty, there shouldn't be any issues with laying it on thick as it doesn't cure through solvents evaporating. The cure is via the chemical reaction from the two parts interacting.

The soft stuff you sanded into may cure with some more time, but I have my doubts.

But then, others may know different about Milliput as I don't use the stuff, I use Apoxy Sculpt. But they are both epoxy putties and I'd expect them to behave pretty much the same.

Mike
Have never had the problem again. Add to that it's easier to get, works easier and is a bit cheaper for me, I got rid of the Miliput I had and use only the Avies. A better product in my opinion.
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Joined: February 27th, 2005, 6:29 am

March 21st, 2012, 9:21 pm #7

I put some Milliput on a model last night to fill an engine nacelle that was "short shot" in the mold. The plastic was so thin you could see through it and the engine nacelle was not the correct shape (an old Monogram kit, BTW). I kneaded the 2 parts of Milliput together (and yes, they were well mixed) and placed it on the weak, distorted area last night around 10 P.M. I tried to sand it today on my lunch hour (around noon) and once I sanded through the upper layer (which was very hard and cured to the touch), the underlying layer was still rather gummy and did not want to sand well. The total depth of the Milliput was about 2-4 mm thick. I stopped sanding and will let it cure out for another day or 2 until it is completely set up. Is this typical for Milliput? I have just started using this filler over the past couple years and usually don't have to put it on this thick. I was somewhat concerned when it was not completly cured throughout. TIA for your input.
Sounds unusual. Given it was well mixed, not especially thick and not that old it does seem a little odd. Hopefully it will fire off properly by the time you come back to it.

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Joined: March 1st, 2005, 8:37 pm

March 21st, 2012, 10:15 pm #8

I put some Milliput on a model last night to fill an engine nacelle that was "short shot" in the mold. The plastic was so thin you could see through it and the engine nacelle was not the correct shape (an old Monogram kit, BTW). I kneaded the 2 parts of Milliput together (and yes, they were well mixed) and placed it on the weak, distorted area last night around 10 P.M. I tried to sand it today on my lunch hour (around noon) and once I sanded through the upper layer (which was very hard and cured to the touch), the underlying layer was still rather gummy and did not want to sand well. The total depth of the Milliput was about 2-4 mm thick. I stopped sanding and will let it cure out for another day or 2 until it is completely set up. Is this typical for Milliput? I have just started using this filler over the past couple years and usually don't have to put it on this thick. I was somewhat concerned when it was not completly cured throughout. TIA for your input.
nm
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Joined: July 29th, 2005, 2:12 pm

March 21st, 2012, 11:31 pm #9

Have never had the problem again. Add to that it's easier to get, works easier and is a bit cheaper for me, I got rid of the Miliput I had and use only the Avies. A better product in my opinion.
Sandable the next day.

Jeff
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Joined: April 21st, 2006, 6:55 pm

March 22nd, 2012, 12:09 am #10

You might be able to accelerate the hardening by microwaving it. If you mix more than you need, you can freeze the leftover, and thaw it in the microwave when you're ready to use it again. You don't want to over-thaw it, though.
use White Milliput (and it's the only grade of the stuff that I do use) I mix a little more than I'm going to use. I use the surplus to make some model penguins



which I can then use to see if the Milliput is hardened and ready to stand. I normally give Milliput a day to harden, though it usually takes less. Remember to use exactly equal quantities of the two putties and, when you think you have mixed them together thoroughly, mis them again for the same amount of time. Twice.

Cheers,

Chris.
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