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Post by Adrian on Apr 29, 2016 9:04:38 GMT -5
I'm just getting into moulding some small car parts (trim parts, little clips etc.). I started out testing with some of the Amazing Casting Resin and that seemed to work quite well in the moulds I've made but it's a bit on the brittle side. The Performance 65D and 80D products looked to be what I'd need for production pieces so I got the local distributor to get some of each for me (being in Australia it took quite some time). I've now been testing with both the 65 and 80D. I'm only testing some small bits at the moment (around 12 to 15cc per part). Mixing 8cc of each side seems to give a good volume without much waste. I've been very careful with the volumes, at first just using measuring cups but then using syringes and finally scales (I very accurately filled syringes to 8cc of each and weighed them which resulted in 9.8g of A and 8g of B = 16ml). The 80D cures without any problem using amounts measured in cups, syringes or by weight however no matter what method I use I can't get the 65D to cure in the mould. Moulds were heated prior to use but even after a few hours it's still soft. If I post cure it in the oven for an hour or three it seems to firm up. I'm a bit stumped as I'm sure my measuring is accurate (as proven by the fact that the 80D cures as expected).
Any ideas what might be going wrong?
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Post by mike on Apr 29, 2016 12:39:10 GMT -5
Couple of quick thoughts ...
Make sure to shake both sides of the 65D before measuring.
The specific gravity of the 65D a & b might be slightly different than the 80D. So if you have not measured accurately and weighed the 65D, please do it. Don't use the 9.8grams and 8gram measurement from the 80D. Being off ratio even a small amount in these quantities is a big percentage.
Are you adding dye or anything else to the 65D?
If you mixed the full 16ml and just let it set up in a cup, would it cure or be the same.
Last item, warm your molds up to 46-48 degrees C. You shouldn't need more than that.
Mike
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Post by Adrian on Apr 30, 2016 8:05:12 GMT -5
I haven't been shaking the bottles much so will definitely try that, plus getting the moulds hotter. I've been zapping them in the microwave for about 1:30 and they were warm but a thermometer said < 40C so a bit more time seems to be needed. I have been using dye (the tiniest spot squeezed onto the end of the stirring stick). Black and just recently one white test, plus a couple with no dye to see what they looked like. The results seemed pretty much the same with or without dye. Looks like my measuring might have been a little off after all. I just did a range of measurements for each about as accurately as I can manage and got the following:
| 65D
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| 80D |
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| Vol (ml)
| Weight A (g)
| Weight B (g)
| B/A
| Weight A (g)
| Weight B (g)
| B/A
| 1
| 1
| 1.1
| 1.1
| 1
| 1.2
| 1.2
| 5
| 5
| 5.6
| 1.18
| 5.3
| 6
| 1.132
| 8
| 8
| 9.4
| 1.175
| 8.4
| 9.7
| 1.154
| 10
| 10
| 11.7
| 1.17
| 10.5
| 12.1
| 1.152
|
Ignoring the 1ml measurement as it'll have the most error percentage the average ratio for 65D is 1:1.175 and 80D is 1:1.146 (1:1.154 if the 5ml sample is also ignored). Larger samples should give better accuracy but I'll play with those ratios for a couple of tests. I suppose I could use syringes for measuring each time but if using clean syringes for each batch I'll be going through them very rapidly. At least going by weight means I can just use one mixing cup. I've currently got one of each curing so I'll see how they look tomorrow.
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Post by mike on Apr 30, 2016 9:52:02 GMT -5
Thanks for the update and please keep us posted. Once you start shaking and get the measuring dialed in, I believe you will see notice a big difference.
Mike
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Post by skullsquadronaddict on Jun 4, 2018 13:49:36 GMT -5
Hey, did you manage to solve the problem? I also can not get my 65D to cure in the mold. I haven't been shaking the bottles much so will definitely try that, plus getting the moulds hotter. I've been zapping them in the microwave for about 1:30 and they were warm but a thermometer said < 40C so a bit more time seems to be needed. I have been using dye (the tiniest spot squeezed onto the end of the stirring stick). Black and just recently one white test, plus a couple with no dye to see what they looked like. The results seemed pretty much the same with or without dye. Looks like my measuring might have been a little off after all. I just did a range of measurements for each about as accurately as I can manage and got the following:
| 65D
|
|
| 80D |
|
| Vol (ml)
| Weight A (g)
| Weight B (g)
| B/A
| Weight A (g)
| Weight B (g)
| B/A
| 1
| 1
| 1.1
| 1.1
| 1
| 1.2
| 1.2
| 5
| 5
| 5.6
| 1.18
| 5.3
| 6
| 1.132
| 8
| 8
| 9.4
| 1.175
| 8.4
| 9.7
| 1.154
| 10
| 10
| 11.7
| 1.17
| 10.5
| 12.1
| 1.152
|
Ignoring the 1ml measurement as it'll have the most error percentage the average ratio for 65D is 1:1.175 and 80D is 1:1.146 (1:1.154 if the 5ml sample is also ignored). Larger samples should give better accuracy but I'll play with those ratios for a couple of tests. I suppose I could use syringes for measuring each time but if using clean syringes for each batch I'll be going through them very rapidly. At least going by weight means I can just use one mixing cup. I've currently got one of each curing so I'll see how they look tomorrow.
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Post by paraviper on Jun 30, 2018 23:43:42 GMT -5
The performance material must be mixed in equal amounts. failing to shake both sides prior to mixing will have a negative effect. Adding too much dye into the material will have a negative effect. Make sure you degas the material as this will increase the physical properties of the material once it's cured. I vacuum degas then poor into a warmed up mold and finally pressure cast. This has given me the best results. Cure times with this material can take up to five hours. Don't be in a rush to remove your parts from the mold. If you have to make a lot of parts with this material.I would suggest making a high production mold.
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Post by Adrian on Oct 21, 2019 8:18:13 GMT -5
I've had a bit of a break from trying to use P65D. I've been concentrating on using P80D and it's been working very well for everything I've been making. One thing I found was that last winter I couldn't get it to cure very well. It's not spectacularly cold here (maybe down to 10C or a bit less on really cold days) but it appears to be enough to make a huge difference to the curing. I eventually found the solution and it was heat. I ended up heating my pressure pot by sitting it on a small food warming tray and that made all the difference! I've been using a heated pressure pot for everything now no matter how hot it is outside - Hard, soft and making silicone moulds (with the silicone I'm using it cuts the cure time down from a day or so to a few hours). One other idea I came across was to wrap the heating element from an electric blanket around the pressure pot but I haven't gotten around to trying that yet.
Just recently a friend asked me to replicate some small parts that needed to have a little bit of give in them so I thought I'd give P65D another shot.
-Get pressure pot heating so it's nice and toasty warm inside (I haven't bothered to measure the temperature it gets to) -Warm mould in the microwave -Mix by weight using the ratios I worked out (1:1.175 A:B by weight for 65D) -Vacuum degas -Pour -Into the pressure pot -Keep the heat on the pressure pot for at least 2 hours -Turn heat off and keep under pressure for another couple of hours until completely cold
The P65D parts seem to be coming out perfectly. They have a bit of give and will bend slowly with a reasonable amount of force applied which is exactly what I was looking for.
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Post by notoes on Oct 22, 2019 12:01:02 GMT -5
That is awesome! Heat is definitely a factor in curing a lot of the other products from the molds to the resins so I can definitely believe that the cold was stalling out the curing stage. As long as the pot is getting up to around 70 degrees, you are good to go to get a good cure. Great job on getting it down pat to perform flawlessly for you and thanks for sharing - I don't use a pressure pot so it didn't even ring any bells in my head that the pot also needed warming too.
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