Well That Didn't Work

[crokett]

I cast this blank several weeks ago:

Since then I cast one in black also. Both blanks have blown up on the lathe. My method for casting is fill the rectangular mold with swarf and then pour resin over it. I am wondering if I I am using too much swarf in the blank and not enough resin? Or is this one of those ideas that may not work out?

 

[joefyffe]

IMO you have too much swarf and it's too tight. Looser coils will allow more resin to fill in around it. I have successfully done this type of cast but with far less swarf.

 

[theidlemind]

I've got a couple like that that I'm going to turn tomorrow.
I'll post the results.
Questions though.....
What resin?
Pressure pot?
Skew or gouge?
Brass, steel, stainless?

 

[plantman]

It would be intresting to try turning this on my mini metal lathe. If you every cast something like this again, send me a blank and the pen kit you wish to make, and I will make a pen for you. Jim S

 

[crokett]

poly resin, no pressure pot. carbide tool and a skew. The first blank blew up with the skew, second with the carbide tool. I will try another pour with less swarf and see what happens. I may also try straightening the coils some.

 

[dogcatcher]

Have you thoroughly cleaned the swarf? It probably had some oil on the original piece from the manufacturing process, and no telling how the machining was done if they used a coolant some of residue could also be on the swarf.

The resin will have a hard time sticking to clean metal, but I doubt if oily metal will never work without being cleaned.

 

[wouldentu2?]

Too many places for air to get trapped?

 

[joefyffe]

poly resin, no pressure pot. carbide tool and a skew. The first blank blew up with the skew, second with the carbide tool. I will try another pour with less swarf and see what happens. I may also try straightening the coils some.

I think you will find that beneficial, especially if you are not using vacuum or pressure.

 

[joefyffe]

David: Another thought just came to mind, I still recommend less and straightening, but since you are not using vacuum/pressure, it would probaby help to set your cup of "uncatalized" resin in a hot bath such as ultrasonic cleaner or taster oven at about 110 or 120 for a few minutes to thin the viscosity. Catalyze and pour. Thin wicks better than thick Just a thought!

 

[bruce119]

poly resin, no pressure pot. carbide tool and a skew. The first blank blew up with the skew, second with the carbide tool. I will try another pour with less swarf and see what happens. I may also try straightening the coils some.

A couple of my thoughts.
How I would go about it. I think you can get it to work with the swarf you have shown. As mentioned defiantly need to clean the swarf very well in acetone. For it packed like that air is defiantly a concern a pressure pot with about 40 psi is in order. With out pressure (even with pressure) warm the PR before MEKP is added (I put my resin that I pored into a cup in a pot of hot water) Warm your mold with the swarf in to about 150 that will help with air but that much swarf I fear you need pressure. (one more thing to add no more than 4 drops of MEKP too much makes it even more brittle)

Another thing is the actual turning. SLOW be patient I have a metal lathe I would use the tip or corner of my skew like a scraper and take off very little at a time after sanding it round. Also how did you glue the blank to the tube. This is VERY important as it supports the blank from with-in. After painting your tube and drilling your blank just a little over size. I would use epoxy and make sure it is throughly coated.

I think it can be done but it is going to be tricky.

Good luck keep at it.

.

 

[joefyffe]

David: Don't know if this will help, but here's one I posted a few months back. Turned easy and customer loved it Backpainting the blank is suggested

 

[crokett]

Thanks - that is the effect I am going for and you used a LOT less than I did. I will try again with less and will cut them into smaller pieces so they are more random.

 

[joefyffe]

That was PR, but Alumilite will work too, just needs to be under pressure, and you don't want to heat it like PR cause cold it will harden in about 45 minutes. If I can be of assistance, feel free to shoot me a PM!

Thanks - that is the effect I am going for and you used a LOT less than I did. I will try again with less and will cut them into smaller pieces so they are more random.