Resin mold

[texasbass1]

I made a resin mold last night and kinda messed up the hardener mixture, it set up but I have a couple of sticky spots on the mold. Is there anyway to fix it. One is on a corner so I could cut it off, unfortunately the other is next to the body.

Any suggestions will be appreciated.

Thanks

Pat

[nova]

I've had that happen in the past. It useually comes from not stirring it enough.

I never did find a way to fix it. I tried putting new resin in the "holes" but after a dozen pours it just came out.

www.novalures.com

[texasbass1]

Yea, that was the problem. It is just a spot on the edge of the mold cavity I may try and pour and see how it works. I'm planning on making another one.

Thanks Nova

[Vodkaman]

Although resin is hard in twenty minutes, it can take several days to cure completely in my experience. I don't think it is lack of thorough mixing as I could not be accused of that, yet I still get the problem.

There is no excuse for not mixing this stuff properly, no measuring, it is fairly runny and you get a good five minutes for pure mixing, a couple of minutes to let the bubbles out and then pour. The stuff I am using gives me 11 mins before it strts to change. I suggest that you do a sample and time it, for this information.

Secondly, you can vary the amount of catalyst to affect things. How many drops did you add? I usually add 3 drops for every 10gm of resin. This can be increased for a faster harden, but it gives off more heat. Not a problem for small stuff, but larger castings can crack.

You could try a few hours in the oven (lowest heat and the door slightly open), the process is chemical and so heat will accelerate.

When using any new material, there is always a learning curve. The resin that I am using now has completely different properties to the stuff I bought in the UK, 8 months ago. The new stuff is harder and brittle, a resonant ping when I tap it with my fingernail. My next mix, I am going to halve the catalyst to test the effect.

I suggest that you keep notes and report back with your findings.

[texasbass1]

Thanks Vodkaman. I have made some resin molds in the past the only real difference is the resin was not at room temp it was about 50 degrees when I started. That may have had an effect on it curing. It is pretty cheap so I'll try again. I'll let you know the results.

For the ratio I used 5cc for 14oz.

[Vodkaman]

If your scrapping the old one, experiment with it. Try the heat. Put it in a warm place a few days, if you don't fancy the food oven.

50 deg is pretty cool! Looks like you've figured it out. Post a pic when you've finished it. Thanks.

[texasbass1]

I'll give the oven a try and let you know. I'll post some picks when I'm done.

Thanks

[BBC]

Pat,

I had the same problem with my first resin mold. After about a week it wasn't sticky anymore. I just assumed that I didn't mix it enough. It eventually did cure so I didn't think much about it.

Eric

[Vodkaman]

Formula for one layer casting: if layer is 1/8 in. thick use 15 drops per ounce of resin. If layer is 1/4 in. thick use eight drops per ounce. If layer is 1/2 in. thick use six drops per ounce. If layer is 3/4 in. thick use five drops per ounce. If layer is 1 to 1 1/2 in. thick use four drops per ounce.

Just found this on the web. I had no instructions with my purchase. Seems like we are both roughly on the mark. I weighed 20 drops of water, 20 drops = 1cc. I know this is not the same, but close enough for me.

http://www.eti-usa.com/consum/castresn/castinst.htm

This link covers it.

[texasbass1]

Just an update. The mold finally cured, it took about 4 days at room temp. Now all I have to do is start pouring.

Thanks for the words of advice.

Merry Christmas to all