Resin leaking into tubes

[Bob Kardell]

I am trying casting for the first time and decided to try alumilite. It has taken me a few times to get it crystal clear but I still have a couple of issues...

First, the cast turns white on the outside soon after I remove it from the mold - is that normal? I left it to cure in the pressure pot for nearly 4 hours.

Second, I bought a pink silicone mold with the tube stops built in for a Sierra blank and I am using Sierra tubes. The times I have tried the resin makes it into the tube - I have been using about 40 PSI - is that too much pressure for these molds?

Thanks for any help in advance!

Bob

 

[eharri446]

From what I have read, you have to push those plugs in real tight and then pull the ends of the mold back to make sure everything stays leak proof.

I have those same type of molds from PTownSubbie and that is what he shows in his video on how to use the molds.

 

[Monty]

I had the same problem with the molds that have the built in tube plugs, besides the problem of the plugs breaking off after numerous castings. I have switched to the mold that uses stoppers like the ones PTownSubbie sells.

 

[jsolie]

From what I have read, you have to push those plugs in real tight and then pull the ends of the mold back to make sure everything stays leak proof.

I have those same type of molds from PTownSubbie and that is what he shows in his video on how to use the molds.

This. Once I started mashing the plugs in and then pulling back on the sides, I started having more success. As for your Alumilite turning white, I know that for small pours (like a sierra or two), it's super important to watch the weight measurements.

 

[George Watkins]

the white resin isn't normal and is a combination of two factors:
1.the small amount of resin being used to cast a two tube resin saver mold means the mixing ratio needs to be perfect.
2.due to the small amount of resin the exothermic (warmth) reaction that occurs during curing is also very small. so it helps if the molds are warm so that the cold silicon doesn't act as a heat drain and interfere with the curing.
Also it helps if you can pour more than one mold at once, that way you are mixing a larger amount of resin and the exothermic reaction is bigger.

the built in plugs are more difficult to stop leaks with, try wrapping an elastic band around the mold to help squeeze the silicon onto the tube ends.

hope this helps

 

[Gary Beasley]

If you use a stopper with a hole drilled end to end the air will equalize in the tube and not be able to pull resin in from the mold.

 

[rd_ab_penman]

I fill the tube with Play-Doh for 2 reasons.
1. It prevent any resin from getting into the tubes.
2. It squeezes all the air out of the tubes.

Les

 

[Bob Kardell]

Thanks for the replies - I ended up reading on an Alumilite forum about warming the resin and hardener before mixing. I put them in warm water and the solution worked very well. I do use a small scale to measure by weight ....

I ordered the molds with the plugs but I am going to try the suggestion to drill holes and play dough - thanks again!


Sent from my iPhone using Penturners.org mobile app

 

[vmsherp]

If you use a stopper with a hole drilled end to end the air will equalize in the tube and not be able to pull resin in from the mold.

That is genius...



Sent from my iPad using Penturners.org mobile app

 

[Eldermike]

I used a toss away white plastic bathroom cup and found the resin started to dissolve the cup. Made my casting cloudy.


Sent from my iPhone using Penturners.org mobile app