Casting: where am I going wrong?

[Robert]

So I bought some resin stuff (this one, the 1kg tin) and have been making blanks, mixing with coloured mica powders ordered off ebay, but apart from the one success all the other 10 or so blanks I've made have failed. They keep breaking when I turn them.

I've tried varying the catalyst quantity, but it seems the more I add, the softer the blank is, compared to the first few which were too brittle. Temperature wise, they've all been made over the last couple of months, so it cant be because it's too cold. I generally leave them a good 12 or more hours in the tube to set, and over 24 hours before I drill and work on them.

I love making them, but frankly it's proving a waste of time and I'm close to throwing the towel in, which I don't really want to do.

Any suggestions?

 

[chas_41_uk]

I'm guessing it would be something to do with the mixture, but hjaving never done any casting I couldn't say for definite.
Brody, Rowdy and Buckeye seem to know about casting. Hopefully one of them will know the answer.

 

[Buckeye]

The normal mix of MEPK is 1-3% I use 1%. The more you add the quicker it will set and the more brittle it will be. If you are getting softer resin by adding more MEPK I can't help you. It probably would have been better to buy a casting resin rather than a general purpose resin like this but a water clear resin is probably better and easier to use even if you mix in colours.

Peter

 

[brody2123]

Im far from an expert but, from my limited experience Rob, I agree with Peter. Water clear casting resin is the best I've used. Be sure to mix the hardener before adding any pigment as this can affect how well the catalyst mixes with the resin, especially if you are using dry mica powder.
I use this
Water Clear Casting Resin - East Coast Fibreglass Supplies
and have had good consistent results in and out of the pressure pot.

hope that's of some use mate

 

[wm460]

. I generally leave them a good 12 or more hours in the tube to set, and over 24 hours before I drill and work on them.


Any suggestions?

I leave mine in the mould for 24 hrs. then leave the blank for a couple of days before I drill them.

 

[smoker]

So I bought some resin stuff (this one, the 1kg tin) and have been making blanks, mixing with coloured mica powders ordered off ebay, but apart from the one success all the other 10 or so blanks I've made have failed. They keep breaking when I turn them.

I've tried varying the catalyst quantity, but it seems the more I add, the softer the blank is, compared to the first few which were too brittle. Temperature wise, they've all been made over the last couple of months, so it cant be because it's too cold. I generally leave them a good 12 or more hours in the tube to set, and over 24 hours before I drill and work on them.

I love making them, but frankly it's proving a waste of time and I'm close to throwing the towel in, which I don't really want to do.

Any suggestions?

East Coast Fiberglass recommend you leave the casting 5-7 days

Steve

 

[Woody]

I would love to have a go at this but its the pong factor that puts me off from what I have read the water clear resin seems the most popular method

 

[rowdyyates115]

Rob,

What do you use for measuring the MEPK, I use a syringe so that I can get quite accurate mixes. Easily obtained on EBay.
This is the stuff I use Casting Resin - East Coast Fibreglass Supplies and I have also tried their water clear which is also pretty good.

Hope you have better luck next time

 

[Buckeye]

I would love to have a go at this but its the pong factor that puts me off from what I have read the water clear resin seems the most popular method

You could use polyurethane resin, that doesn't have any noticeable smell and I have used it in the house, but it has a much shorter working time.

Peter

 

[Vic Perrin]

Although casting looks a very interesting subject I don't think that it is something I would get involved in. I am not very adventurous.
I will just stick with buying the occasional plastic blank now and then.

Vic