HELP with casting

[aggromere]

I purchased some resin saver molds and an apprentice kit of the resin and made my first cast a few days ago. It didn't turn out well, but I am now intrigued with the process. I ended up with one or two bubbles and some void areas right next to the material I wrapped on the tube.

The first picture is the upper barrel from a gent kit that I turned and sanded so I could see what it looks like. The ends have not been squared so there is some extra material on the ends, but you can still see - Not good. The next is the lower barrel, unturned. (i figured it wouldn't be any good either). The third picture is a blank I rounded down very small and then glued tobacco leaves to it, sprayed it with a poly acrylic spray from minwax and then did a ca finish on it. It didn't turn out well either, it was just an experiment.

I was careful mixing and pouring the resin. Would using a pressure pot take care of all the problems in casting. These are all tobacco leaves glued to tubes with watered down elmers glue.

Any suggestions would be appreciated. I was thinking about making some pens using tobacco, but actually, based on the way it looks, I think the wood is more attractive, but would still like to learn how to do it. I didn't bake them or anything just poured them and let them dry for a couple days and the one I turned was easy to turn.

 

[bruce119]

I have worked with tobacco leafs myself. There are several problems to overcome. First is moisture resin does not like moisture and Alumilite has an absolute zero tolerance for moisture you didn't mention what type of resin you where using I will assume a PR. So how do you wrap the leaf without moisture you can't they will just disintegrate. So I would wrap and glue glue them on the tube lately I have been using Mod Podge with paper mind you. But it has been working well I let that dry for at least 24 hrs. In your case though the tobacco is going to take considerably longer to dry. I would give at least 3 days in dry conditions maybe longer. Then for insurance and to help with the air bubbles put the dry uncast blank on the lathe and give it a CA finish. I use a medium CA and a plastic parts baggy. Wile the lathe is running slow put a couple drops on and smooth it out I do 2 coats it don't need to be smooth just sealing it. Let the CA cure at least 24 hrs. Now you cast with no worries. A lot of the air bubbles you are seeing may be leaking out from trapped air under the folds of a leaf. I had the same problem with air leaking out from under overlapped pieces of paper and the CA over coat solved that. Now I use finishing delrin bushings when applying the CA and the corner tip of a skew to cut/ score the end so it doesn't chip when removing the bushings.

Maybe that will help.

 

[BRobbins629]

I believe there are 2 generic types of voids you can get while casting. One as described above is from dissolved gas either coming out of solution or forming as a reaction product. These can collect on the object being cast or seen in the middle of the clear resin. The pressure pot, degassing resin with ultrasonics, vibration or vacuum, poking with a pin etc are all valid methods to reduce these. The others is caused by the resin not wetting the embedded or cast around object. The latter are typically not as round as the first type but I have been fooled sometimes. These can be minimized by a combination of cleaning the object well, first soaking the material with resin (either catalyzed or not catalyzed) or in some cases "painting" with CA which I do with snake skin. A few experiments with some of these techniques should get you in a better place. In my experience, each material may have a unique procedure that works best for it.

 

[aggromere]

Thanks for the input, I think I will get a pressure pot and give it another try. To get the leaves around the tubes they have to be very moist. I let them dry for a week before I cast them. Now I guess I have another way to spend my time and money, lol.

 

[bruce119]

Here is one that I did a few years ago.





.

 

[aggromere]

Well I wore everyone out asking a million questions about metal lathes so here I go badgering everyone about casting.

1. What pressure pot should I get? (I assume they are the things painters use with paint sprayers). I saw a post (old i think) on here about a HF one blowing up.

2. What kind of air compressor should I get? (prefer electric)

3. What kind of attachments do I need?

4. What's the minimum pressure I can use to make sure I don't have bubbles in blanks. I will just be casting clear resin over tobacco.

5. What else do I need to do?

 

[Padre]

Well I wore everyone out asking a million questions about metal lathes so here I go badgering everyone about casting.

1. What pressure pot should I get? (I assume they are the things painters use with paint sprayers). I saw a post (old i think) on here about a HF one blowing up. Many people on the IAP use the HF pressure pot. Others will not use it at all. It really is a matter of cost. The HF will be your least expensive way to get into pressure/vacuum.

2. What kind of air compressor should I get? (prefer electric) Will you be using your air compressor for anything else? Running any air tools? I have a 60 gallon oiled 3hp compressor I got from Lowe's. I love it. But I also use air tools to work on cars, etc.

3. What kind of attachments do I need? For the compressor you'll need a hose and some female and male ends. FOr the pressure pot, go to the library and look up THIS article. It is great on how to set up a HF pressure pot.

4. What's the minimum pressure I can use to make sure I don't have bubbles in blanks. I will just be casting clear resin over tobacco. As Charlie said, you can try with 20/25psi to start with.

5. What else do I need to do?

You need to always be very, very careful around a pressure pot. Never take it for granted, ever. Inspect the seals and all connections weekly. Make sure there is no rust.

Then go and have some fun.

 

[BRobbins629]

Well I wore everyone out asking a million questions about metal lathes so here I go badgering everyone about casting.

1. What pressure pot should I get? (I assume they are the things painters use with paint sprayers). I saw a post (old i think) on here about a HF one blowing up. Most use the Harbor Freight

2. What kind of air compressor should I get? (prefer electric) Any will work, even a bicycle pump

3. What kind of attachments do I need? A quick connect connection will do. Pick up at Harbor Freight with the pot

4. What's the minimum pressure I can use to make sure I don't have bubbles in blanks. I will just be casting clear resin over tobacco. Only need 15-20 with PR. Anymore is not needed and you're begging for trouble

5. What else do I need to do? Pray they come out good.

See above