help with snake skin casting!!! pleeze

[turnersdelight]

I have been casting for a while now but still having the same problem. I'm getting alot of air between the skin and the resin. I have tried all kinds of things to fix my problem, preasure adjustments, time in pot,etc. any help at all would be greatly appriciated.


Thanks

Eric

 

[Skye]

A few tips, may or may not help.

1. Get a pressure pot. Not as easy, but helps a lot.
2. Let the resin sit for just a few minutes before you pour it. Some of the bubbles will float to the top.
3. Wipe the skins down with resin before you pour over them. It'll make sure there's resin on the skin, rather than air.
4. Cast in a small batch, just a pair of tubes. May reduce some of the heat created as it sets.

Just off the top of my head. Really, a pressure pot seems to make all the difference in the world. Mine is in the mail on it's way to me.

 

[Charles]

Skye where are you getting yours from?

 

[Skye]

My pot? It's an old used one from Ebay. If it'll hold pressure or not, we'll see. []

 

[turnersdelight]

Thank You Skye, I do have a presure pot and I will try these things you say.

Eric

 

[cozee]

I've yet to cast a pen blank but have cast many an HO scale slotcar body. Some minor things people overlook can and usually lead to bubbles. Do not get in a rush!! When mixing the resin and catalyst, stir the mixture slowly and evenly. If one's stirring method allows the mixture to overlap itself, air can be trapped. High speed stirring, churning or whipping, will do the same. I'd pour the resin into approiate sized containers for the amounts I would need in advance. They then were allowed to sit at least 24 hours prior to mixing, a degassing time if you wish. Pouring of the mixture is another area when and where air can get trapped. Allow the mixture to flow together, trying to prevent it from overlapping. Patience is a necessity when casting.

 

[TomJ]

Pressure pot 40$ at harborfreight.com

 

[its_virgil]

First of all, welcome to the casting club with all of its complexities. I have probably produced every type of failure that can happen. Here is what I have learned:
(1): pressure casting has greatly improved my success rate. BUT, still having failures. Some of the skins look really cruddy and can't be used. Pre-pressure casting was about 40% success for me and pressure casting has been about 80% successful. I cast at 25-30 psi. Constant pressure is also important. I now hook up the air hose directly from the compressor to the tank and leave it connected. I use the pressure regulator valve on the com[pressor to maintain the pressure. At first I would hook up the hose, let the pressure build to 40 psi and remove the hose. When the pressure leaked down a little I would attach the air and let the pressure build again. Hooking the hose and leaving it seemed to help.

(2) Heat is a real problem. I cast 10-12 tubes per cast using 14-16 oz of resin. When I backed off to 3 drops per ounce my results improved greatly. I had one cast where the skins actually vanished...vaoprized...only brass tubes left in the resin.

(3) I have just recently started degassing the resin with a vacuum pump. This has improved my casting and now 100% of the tubes are useable. I have done 3 castings of 10-12 tubes and not a single tube was ruined. I have also reduced the pressure to 25psi.

(4) I have the tutorial almost finished. I hope to get it to Jeff sometime this week. I've attached a picture of my last casting.

Do a good turn daily!
Don

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