Lost Wax Process? I have a question!

[CTF]

I did a search, but it came up with everything except a thread about the process.

Who here has experience in working with bronze? In particular, making the wax master? I need some advice about the latter.

I'm looking at having a bronze made, but to keep costs down I'd like to pull a wax from a mold I already have, clean that up, then take it to the foundry for the next step. But I want to make sure that I won't damage the mold by doing so. The mold can't be replaced, is all.

The wax will be hot, alright, but no warmer than resin that is curing... correct? Is there any chance that this will damage the mold? And I'm guessing a mold release is pretty important when it comes to using wax? I really don't want any residue left in the mold (even though warm water could clean it off).

Any advice?

Thanks in advance!

 

[SmilingOtter]

What's the mold made of?

 

[CTF]

Rtv.

 

[OdiWan72]

Get in contact with Brian aka handschaub.
He´s done a LOT of lost wax casting in the past (bronze webley´s, helmets etc.)

Markus

 

[Loess]

Here's a link to Freeman Wax. One of these should be good enough, they're listed as being for injection molding into rubber molds, but usually you can get away with open pouring them into a mold.

Temperature shouldn't be a problem for a decent RTV mold, and release isn't necessary most of the time.

 

[Dimclay]

I did a search, but it came up with everything except a thread about the process.

Who here has experience in working with bronze? In particular, making the wax master? I need some advice about the latter.

I'm looking at having a bronze made, but to keep costs down I'd like to pull a wax from a mold I already have, clean that up, then take it to the foundry for the next step. But I want to make sure that I won't damage the mold by doing so. The mold can't be replaced, is all.

The wax will be hot, alright, but no warmer than resin that is curing... correct? Is there any chance that this will damage the mold? And I'm guessing a mold release is pretty important when it comes to using wax? I really don't want any residue left in the mold (even though warm water could clean it off).

Any advice?

Thanks in advance!

If the wax are to hot it can stick to the mold and will be lost, don´t pour wax to hot, the collest the better, usualy about 194 F it´s ok more then 302F you are asking to have problems, at least the wax in Brazil work like this !!

 

[Hangar18Studios]

We use wax in our shop every day. The temperature of hot wax will not harm silicone, silicone is quite resilient to heat. In fact, you'd get a better wax casting if you preheat the silicone mold and pour the hot wax in while the mold is warm, 225 degrees F. should do it.

Keep in mind that wax shrinks as it cools, so if you have the mold topped off, don't be surprised to find the level a bit lower once its cooled. You can always monitor it and keep topping it off as it cools.

It would be best to excercise patience with wax, make sure to give it ample time to cool before attempting to demold it.

Good luck!
Scott

 

[exoray]

And I'm guessing a mold release is pretty important when it comes to using wax?

Well since most mold releases are paraffin based and that is a primary part of most lost wax waxes I'm going to say it's a waste of time... The was shouldn't stick to RTV at all, and if it does simply heat it up and it will come out...

Anyway thats all the advice I can give right now never got to play around with lost was yet, as we are rebuilding our foundry and didn't get past sand casting last time around before we melted the foundry... Yep, melted the concrete into glass we were seeing if we could get cast iron melted as aluminum, brass and bronze was too easy, and we did melt the iron but at about the same time the concrete turned to glass and the crucible started to float... A nice but scary orange glow incident... We are building a new foundry out of some 2800° high heat concrete now, but it's a slow process...

 

[exoray]

BTW look around the Internet for some wax formulas, commercial lost wax can get costly, but there are some home brewed recipes out there that are claimed to perform quite well... And most of them simply revolve around beeswax, paraffin, Vaseline, mineral oil and Lanolin...

The beeswax and paraffin and even coloring tints can be found in the candle section of hobby stores, like Michael's and Hobby Lobby...

The Vaseline and mineral oil in the drug section of Wal-Mart and the Lanolin in the baby isle of Wal-Mart in a small purple tube under the brand name Lansinoh, it's sold as an ointment for breast feeding mothers but it's pure Lanolin...

I never got to play with my mix all the way yet but it fees and cast quite well, and see no reason it should not melt out fine...

 

[Loess]

I took a week long class last summer on medieval bronze casting, and the guy who taught it used plain paraffin candle wax without much trouble. The investment wax is a bit nicer to work with though. Whichever you use should be ok, it's mostly personal preference and how much time you have to clean up the wax model.

 

[CTF]

Thanks for the advice, guys!

I'm still a bit nervous about pouring wax into the mold... so I'll do a bit more research!

 

[CTF]

I'm picking up some microcrystalline wax from the local foundry.

Thanks for the information, guys. :thumbsup