First castings

[smoky10]

Yesterday I wraped some tubes with snake skin, shark skin, and lizard skin that I got from Gary Max, thanks Gary, andgot them ready to cast this morning. I didn't have any BBs to weight the tubes down but I fish so I ahve a lot of sinkers. This morning I went out to do my casting and the skins were covered with white and I thought I might have a problem but I wipped it off and they seemed OK. I poured them, no problem, put them under 40lbs pressure and left them for 8 hrs. When I let the pressure off and looked at them they looked clear as can be but when I went to take them out they were still soft on the top. They felt solid but the top was still wet. I put them back under pressure and will leave them a few more hours. Has anyone an idea what I did wrong? Did releasing the pressure cause any problems?

 

[JimGo]

The surface of PR castings frequently still feels "squishy" even after several hours, and after the PR has cured. If you put a little acetone on the top, that will help coerce that last little bit of PR to cure, and get rid of the gummy feeling.

 

[ed4copies]

REALLY!!!???

Never wooda thought of acetone. HHHMMMMMmmmmmmmm.

Thanks Jim

 

[JimGo]

Someone here told me about it Don, and it made dealing with my castings MUCH easier. I used to hate that gummy film on top, and now I don't have to deal with it any more! I find that the acetone even helps free the castings I do in the ice cube trays when they get stuck. Just a few drops on top, and a little wiggle of the tray, and the castings are MUCH more willing to come out!

 

[Skye]

Originally posted by smoky10...they were still soft on the top. They felt solid but the top was still wet. I put them back under pressure and will leave them a few more hours...[]

8 hours will be plenty, releasing the pressure shouldent have caused a problem.

How many drops of hardener did you use per oz of resin?

If the centers feel hard, there's not much sense in pressurizing them again.

The outsides always feel sticky because the resin hardens from the inside out, so the centers are hard, the outer edges are not quite as set.

 

[bananajeep]

I was speaking with a guy from Tap Plastics a couple of days ago. He suggested covering the pour with some plastic wrap. He said the top is exposed to air during the cure, so it will have a tacky feel. The sides and bottom of a pour are not exposed to air and thus fully cure. I had never heard of that, but again I just started pouring PR blanks. I have not used plastic wrap or acetone as suggested above on any of my pours yet. I'll try the plastic tonight on some more blanks. I like the idea of using acetone on the "icecube" balnks to get them out easier.

This place is full of good ideas

 

[smoky10]

I took the casting out of the pressure pot, used the acetone, and I saw a problem. The shark and lizard has what looks like air trapped around the skin, could this be from the CA glue? I haven't cut them apart yet, I'll do that tomorrow and maybe I can tell more about it. I'll let you know and, maybe take pictures so you guys can tell me what I did wrong. [][]

 

[its_virgil]

Tom,
The surface exposed to the air will always be sticky when first cured but will dry or finish curing after a day or so. But, if you want it can be wiped off as JimGo explained. Copngrats on a successful cast....feels good, huh! I'm really jealous...success on FIRST cast[]
Do a good turn daily!
Don

Originally posted by smoky10
<br />Yesterday I wraped some tubes with snake skin, shark skin, and lizard skin that I got from Gary Max, thanks Gary, andgot them ready to cast this morning. I didn't have any BBs to weight the tubes down but I fish so I ahve a lot of sinkers. This morning I went out to do my casting and the skins were covered with white and I thought I might have a problem but I wipped it off and they seemed OK. I poured them, no problem, put them under 40lbs pressure and left them for 8 hrs. When I let the pressure off and looked at them they looked clear as can be but when I went to take them out they were still soft on the top. They felt solid but the top was still wet. I put them back under pressure and will leave them a few more hours. Has anyone an idea what I did wrong? Did releasing the pressure cause any problems?[]

 

[Gary Max]

Glad to see you found your way to the shop. Heck Tom I cut up some 16 penny nails and use them for weights---not as much fun as chaseing BB's around but works great.
Oh the guys are right ---once the resin sets up you do not need pressure any more.
Hope you have good luck