Problems with casting objects in PR.

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Celt40

Celt40

Member
Joined
Nov 26, 2007
Messages
119
Location
Scotland UK
I had my first go at making blanks with "stuff" in the resin. They turned out a bit of a mess.
I set out 3 different molds, 25mm x 25mm x 125mm. I tried to cast Pine cones, in clear resin(broken up) dried corriander leaf & dried red peppers also in clear PR resin and rose petals. in TR Amber.
I pressured the pot to 55psi and left it 24 hrs. When I looked at the results the dried Corriander/Pepper looked not bad, except the mixture had settled on the bottom. This started to thin out about 2/3rd up the mold, getting a bit thin on the last 1/3rd. When I cast this blank I mixed the mixture into the PR resin and let it sit for a couple of hours before adding the MEKP, at 6 drops per floz. When I filled the mold it was full to the top. Even though I placed a lid on before putting it into the pressure pot it came out with a space arround the top in parts. I now realise that the pressure has pushed the mix tight together and I will need to use molds with more depth. The blank was very tacky to touch????
The Pine cones turned out much the same Tacky to touch and a bit less compressed.
The main problem was with the Rose petals. I used the Roses from my Dad's garden. He was very proud of his Roses As he passed away in May I thought it would be good to cast his Roses in his memory, so I broke off the petals and added them into the clear PR resin. Adding 6 drops per floz I mixed it with petals and added the mix to the last mold.
This had not hardened at all.
how much MEKP WILL I need to add when embedding objects in the PR??
Can someone give me some advise to what I have done wrong. I would like to try again espicaly with the petals before the winter frost spoils them.

Dermot.
 
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I have checked the library and have been looking around for info. The reason I did ask was because I could not find any info that was suitable to my question.
I must say that latley most of my questions have met with the same unfriendly attitude. What is wrong has everyone got sore fingers they can't type in a responce??????????
 
No, no one has sore hands but a quick search on rose petals yeilded this:
http://www.penturners.org/forum/showthread.php?t=45679&highlight=Rose+petals

This shows what was tried and how to do it which involved a dehydrator. This may very well answer your question as the petals have moisture in them and moisture and PR do not mix as I am sure you have read. Our library and knowledge base is very extensive and with a little bit of hunting and reading can find most of what you are looking for. Dont think people wont help they just want to be sure you have tried to help yourself first.
 
Celt40 said:
I have checked the library and have been looking around for info. The reason I did ask was because I could not find any info that was suitable to my question.
I must say that latley most of my questions have met with the same unfriendly attitude. What is wrong has everyone got sore fingers they can't type in a responce??????????
Click to expand...

Celt40 said:
Can I ask the moderators to remove this thread please.
Click to expand...

I dont blame you for wanting your post removed.

The friendly people here are very willing to help others with their problems when they can. However, they are not required to do so.
 
Celt40 said:
I had my first go at making blanks with "stuff" in the resin. They turned out a bit of a mess.
I set out 3 different molds, 25mm x 25mm x 125mm. I tried to cast Pine cones, in clear resin(broken up) dried corriander leaf & dried red peppers also in clear PR resin and rose petals. in TR Amber.
I pressured the pot to 55psi and left it 24 hrs. When I looked at the results the dried Corriander/Pepper looked not bad, except the mixture had settled on the bottom. This started to thin out about 2/3rd up the mold, getting a bit thin on the last 1/3rd. When I cast this blank I mixed the mixture into the PR resin and let it sit for a couple of hours before adding the MEKP, at 6 drops per floz. When I filled the mold it was full to the top. Even though I placed a lid on before putting it into the pressure pot it came out with a space arround the top in parts. I now realise that the pressure has pushed the mix tight together and I will need to use molds with more depth. The blank was very tacky to touch????
The Pine cones turned out much the same Tacky to touch and a bit less compressed.
The main problem was with the Rose petals. I used the Roses from my Dad's garden. He was very proud of his Roses As he passed away in May I thought it would be good to cast his Roses in his memory, so I broke off the petals and added them into the clear PR resin. Adding 6 drops per floz I mixed it with petals and added the mix to the last mold.
This had not hardened at all.
how much MEKP WILL I need to add when embedding objects in the PR??
Can someone give me some advise to what I have done wrong. I would like to try again espicaly with the petals before the winter frost spoils them.

Dermot.
Click to expand...

Dermot

I am always willing to help when I can and share my experiences with others. Some of the problems and issues you mention I have experienced and are common. Trust me no one is an expert at casting especially when it comes to embedding objects in resin. There way too many variables that effect PR. I will try and address a few of yours that I have experienced. You mentioned shrinking now PR does shrink some but also you cast under pressure 50psi. I do too in some cases what type mold did you use if it was something a bit flexible or very flexible like silicone the pressure will squeeze the silicone mold then the resin will set and when you take it out of the pot the mold will return to it'd original shape giving the appearance that the resin shrank this drove me nuts till I figured it out. The tackiness on the top and sides is common. When you take the cast out of the pot before you remove it from the mold put it in a warm place. I am in Florida USA so it is warm outside 3 hrs in the sun takes care of it. When it is cold I find a warm spot with air movement like above a heat duct with a small fan blowing on it. Some post cure in a toaster oven at about 150f' but I think that can make the resin more brittle. Now the one that didn't set a couple things could have happen. First thing that comes to mind is temperature. If it is cool say the room temp. is below 65f' the resin will be very slow to cure and will need more MEKP if it is below 60 it will not cure heat your pressure pot when it is cold I put 2-3 60 watt light bulb facing the pot over night wile it cures. I give it 12 hrs curring time in the pot. I use 3-4 drops per once then again that depends on volume of resin for instance. The same 3-4 drops will work good say casting your pepper seeds in a mold that is 1" deep and 6" square. Now the same mix will not cure in a 1/2" square mold. The more mass the more heat you generate and you have to adjust your MEKP accordingly.

Finlay after reading your post again your concerned with frost so I am thinking you are working in a cool environment. 6 drops per once should work just fine but your working temperature should be no less than 70 better yet 75 or 80 deg. F. Warm up your process during and through the curing stages. Preheat the mold with the objects and all to about 100. I put my resin in a container then put that into another container of warm water to preheat the resin. Be very careful not to get any moisture in the resin. Moisture is another big enemy of resin.

Well I covered a lot for now and there is much, much more to talk about. Just when you think you got it figured out something will change and screw you up. Even the humidity plays into it.

It's playing with resin fun :rolleyes::biggrin:

Bruce
 
Celt40 said:
I have checked the library and have been looking around for info. The reason I did ask was because I could not find any info that was suitable to my question.
I must say that latley most of my questions have met with the same unfriendly attitude. What is wrong has everyone got sore fingers they can't type in a responce??????????
Click to expand...


Hold your horses here. This is exactly how things get blown out of proportion. Here is another example. It is not a case of being unfriendly at all. Far from it. If you follow my posts I am more than willing to share ideas. Rob just answered with some generic answer and Bruce just wrote a book. If you would have said you checked the library or the search featuire and then could not find your answer you would get a better response. Your question is alot more involved than a simple do this answer. All 3 things you tried to embedd have different reasons othey could have failed. What works for one does not work for all. So if you check the info available first you may get answers from past experiences. Not everyone is going to answer each and every question over and over again. There is alot to your question and alot of people do not like to type pages.

Now if I offended you that was not my intention. Please accept my apology. Hopefully someone will be able to specifically answer your question for you. :)

Here is a start:

In the search mode punch in casting in cold weather and you will get alot of hits.

http://www.penturners.org/forum/showthread.php?t=6644&highlight=casting+rose+petals
 
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I'm going to refrain from closing this post at the present time, as I think we're mature enough to continue without going down a bad road.

The library does have plenty of articles, but it is useful to ask for help, sometimes! Let's keep an open mind to beginner questions - it's a daunting hobby sometimes! I think John was just trying to say that specific questions are easier to answer - but maybe he could have done it in a different way, eh? :)

Dermot, if you disagree and would like me to close your thread, please PM me and we'll go from there. Otherwise, let's keep the discussion to the question, and not accusations, or I'll be forced to close it, ok? :)
 
Glenn
Thank you for your link. I added words when searching like: MEKP, flower petals, Pine Cones, Objects. I did not get anything that helped me. I do try and search, just not entering the right words.

Rob
Thank you again I have PM PR Princess before for help. She was very helpful to me and I did thank her for her time and info.

Willee
This is the second time in less than a week I have been told to search for an answer, when I have indeed done this. Not everyone just jumps to ask questions without searching first. It does come across as being a bit "sharp". If this bothers anyone then what they should do is not reply, by replying this then comes across as being a bit "techy". I do understand that I do not expect an answer.

Bruce
Thank you again for your info, it is most helpful.

John T
It was not what you said that came over as being offensive, but the fact that you automaticaly decided that I had not looked for myself. I do also apoligise to you I did not mean to be bad mannered to you.
I just find it hard to find the right words that will give a result.

What I have learned this week is not to ask questions even though a search has not came up with an answer.
I am only to happy to pass on any information if I can or have time to respond. If not then I just pass it by. I will read from now on and not join in at posting anymore.

I just wanted to capture some of my Dad's flower petels to help me with his death. The winter is setting in fast here in Scotland and I do not have much time left to freeze the petals in time.
 
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Dermot,

One suggestion: Use "generic" rose petals before you use your father's. Create a prototype that is successful, then employ the same methods with your father's roses.

As to them freezing, cut off the flowers and take them into the house, as soon as possible. Then, start drying them, without losing the color. I am NOT a horticulturalist, but I'm sure there are internet articles on how to do this most effectively, even if you don't have a dehydrator. (Actually, a frost free refrigerator is a dehydrator of sorts, but don't know if it works for this application).

Last, and least, "chill". Lots of personalities on IAP, and no body language to tell you the true intent of a post. Because of the time difference between you and the USA, there may be a "lag". As you see above, a whole group of folks tried to help at about 7 AM, CST in US. About noon for you.
 
That is such a great idea! I always grabbed a flower at family funerals, however never thought about encasing some of the petals in a pen. You have to do that. maybe dry them out first. I've heard moisture messes with PR.
 
Dermot:
Ed laid out a very good plan. PR has a zero tolerance for moisture.

I kept an eye out for a jerky maker or dehydrator . I found one at GoodWill for $5. I works well for drying Hydrangia for casting. I bet it will work just as well for roses. But some experimentation will still be needed.
 
Dermot -

If you have a microwave oven, drying flowers is fairly simple. Roses, in particular, take well to drying.

Start with a microwave-safe dish or bowl. Something shallow with a nice lip or sides works best.

Cover the bottom of the dish with borax (also know as sodium borate) which can be found near the laundry powders in many stores. Note: cat litter or silica gel can be substituted for borax. Here's an excellent article on drying and preserving flowers.

Make a small depression in the borax for each flower, then set the flower (petals up) in the depression and cover with borax.

Microwave on a medium setting for one minute, then test a petal for dryness. Repeat the microwaving process as often as is needed to produce dry (brittle) petals. When the flowers are dry, remove any borax (or cat litter or silica gel) from the flowers with a small, soft paintbrush.

Once you have enough dried petals or flowers, place them into your mold. Fill the space without crushing the flowers. More is most often better. Warm your resin slightly then mix in the MEKP. Slowly pour the resin over the flowers, filling your mold. Let this cure for at least a day, maybe two in the cool, moist Scottish air. Keep in mind that the surface of the resin may still be sticky. You can speed up the surface drying in a toaster over or simply turn the sticky surface off on the lathe.

Here is a very detailed article regarding different methods for polyester resin casting.

I hope this helps.
 
Thanks DCBluesman, you have given me something good to work on. I have just came across an artical on dring flowers. It suggests using silica gel, I will get some over the weekend an start the process going.
You did not mention the Pressure Pot, will I not use this method. And last question did I read somewhere that castings with objects need more MEKP than normal, or should I still add the same amount as for swirl casting 5 drops per floz.

Ed i will also cut the best looking rose heads and keep the cool till I try out some different castings.

Thanks
 
A lot of folks have had great success without pressure. Don Ward (its_virgil) wrote a great article on it. http://www.penturners.org/forum/attachment.php?attachmentid=17004&d=1254067788

Also, if you don't have an ultrasonic cleaner, just let the warmed polyester resin rest for a few minutes while the bubbles release, then add the MEKP slowly, trying not to introduce any additional bubbles. Also, more catalyst is not necessarily better. The quicker cure also creates some structural issues, i.e. brittleness. (This is the same for CA with accelerator.)
 
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