Roto Casting And Smooth On 305 Questions

[SteelSpartan]

Hi...

I normally cast wax to make bronze sculptures... so smooth on 305 resin is kind of new for me.

I have made most of my pep models, I have resinned them and I'm now planning to use 305 in place of fiberglass for toxicity reason... I then plan to mold my pep pieces to make casts.

I have made the handplate (no problem there... it's flat) but when I tried to do the biceps, I've found out that the 3-5 is way more liquid than wax and it's hard to get an even coat when it starts to solidify after 6 minutes of hand slushing.

Any tips? (I have capped one end to help the slushing, but it is still hard to get the coat up the the edges.

Question one:

Can I layer the smooth-on 305... will it adhere to itself? any tips for getting an even coat?

Which brings me to: Roto casting machine

I tried to find the thread I had seen with the plans to the roto casting rigg... but I don't seem to find it anymore even with the hefty search button.

Question two:

I've seen roto casting machine on youtube, etc... do you really need that to get the best possible result?

Question 3:

Do you really need to "power the central frame" or will it turn by itself?

Thanks for your time guys

 

[rube]

Hi...

I normally cast wax to make bronze sculptures... so smooth on 305 resin is kind of new for me.

I have made most of my pep models, I have resinned them and I'm now planning to use 305 in place of fiberglass for toxicity reason... I then plan to mold my pep pieces to make casts.

I have made the handplate (no problem there... it's flat) but when I tried to do the biceps, I've found out that the 3-5 is way more liquid than wax and it's hard to get an even coat when it starts to solidify after 6 minutes of hand slushing.
Any tips? (I have capped one end to help the slushing, but it is still hard to get the coat up the the edges.

Question one:

Can I layer the smooth-on 305... will it adhere to itself? any tips for getting an even coat?

Yes it will adhere. The only way to get an even coat (without as rotocaster) is to use many thin layers. Getting resin to stick to sharp corners and the edges of a mold is a problem for me too. I mix a small batch of resin and paint it on with a brush just as it's beginning to gel. You have to work fast though.

Which brings me to: Roto casting machine

I tried to find the thread I had seen with the plans to the roto casting rigg... but I don't seem to find it anymore even with the hefty search button.

Question two:

I've seen roto casting machine on youtube, etc... do you really need that to get the best possible result?

I haven't seen plans for a rotocasting machine here. Having a rotocasting machine is not required but it will save a lot of time.

Question 3:

Do you really need to "power the central frame" or will it turn by itself?

Thanks for your time guys

Yes, the two frames must rotate independently of each other. Some machines have two motors and other use gears to transmit power to the internal frame.

 

[SteelSpartan]

Yes it will adhere. The only way to get an even coat (without as rotocaster) is to use many thin layers. Getting resin to stick to sharp corners and the edges of a mold is a problem for me too. I mix a small batch of resin and paint it on with a brush just as it's beginning to gel. You have to work fast though.
I haven't seen plans for a rotocasting machine here. Having a rotocasting machine is not required but it will save a lot of time.
Yes, the two frames must rotate independently of each other. Some machines have two motors and other use gears to transmit power to the internal frame.

Thanks for your tips... just finished one biceps... took 4 small coats to get it done... but it was less messy and fairly quick...

I might by some smooth-on 320 or 300 since the pot life is shorter than the 305 I'm using now...

Thanks again

 

[Beau Nidle]

I use the 320 almost exclusively for generic slush casting. It doesn't take a long time to set up, so you're not sitting there rolling a mold around for ages, and it has a pretty gradual set up time. If you were to do it in several thin layers as you've already tried, I think you'd be pretty golden.

As for doing the edges, I try and wait until it has started to set up a little, and then roll it down to the edges, since it won't just spill out everywhere.

Hope that helps.

 

[rube]

I had been using 300. I tried ROTO but I don't like it since it seems to not have much heat resistance. The helmets I gotten from other people were made from 320 and it seems stiffer.

 

[LastSpartan]

Un truc si tu veux diminuer la viscosité du mix est d'y mettre la poudre du plâtre de paris. Soit sûr que la poudre est scellé parce que tu veux pas d'humidité dans ton mix.

C'est qui ton distributeur de smooth-on au fait? J'ai déjà de la misère à en trouver un près de moi à Mtl...

En tout cas, montre nous des photos!

---------

English :

If you want to lower your mix's viscosity, you can use the powder of plaster of paris. Make sure it's scelled before opening it, you don't want moisture/humidity in your mix.

Show us pics!

 

[Beau Nidle]

I had been using 300. I tried ROTO but I don't like it since it seems to not have much heat resistance. The helmets I gotten from other people were made from 320 and it seems stiffer.

I tried the roto...it had great impact resistance, but yeah, heat resistance sucked. It wouldn't even support its own weight without deforming, if it was left in the wrong position. Very easy to fix with a heat gun, but just a pain. Haven't had that problem with the 320, it's a LOT stiffer.

LastSpartan, maybe you meant increase the mix's viscosity? Don't think he wants to lower it...that would make it more runny.

 

[UNSC Leatherneck]

I just checked out the Technical Bulletin for Smooth-cast ROTO and Smooth-on recommends backfilling hollow castings with foam if they are going to be exposed to temperatures above 85 degrees F.

Smooth-Cast ROTO Technical Bulletin

A post-cure of Smooth-Cast 300 can improve the physical properties of the casting.

 

[Ithica]

I have heard horror stories for roto. I have used 300 and 320 and I will swear to 320. I use 320 for all my work and I have done drop tests, hammer tests and skid tests with great success. Alluminiate is also a good product but if the clear is to thin you get alot of flexibity which may be good for some projects but not most. If it is thick enough it stands up to 300 and 320. The Alluminite black is pretty strong though.

Ithica

 

[LastSpartan]

I tried the roto...it had great impact resistance, but yeah, heat resistance sucked. It wouldn't even support its own weight without deforming, if it was left in the wrong position. Very easy to fix with a heat gun, but just a pain. Haven't had that problem with the 320, it's a LOT stiffer.

LastSpartan, maybe you meant increase the mix's viscosity? Don't think he wants to lower it...that would make it more runny.

Oh yea, thanks.

 

[SteelSpartan]

C'est qui ton distributeur de smooth-on au fait? J'ai déjà de la misère à en trouver un près de moi à Mtl...

Sial à Laval... fait une recherche sur google "Sial laval" 80$ pour un kit 2 gallon de smooth cast

English: telling about a store where he can get the smooth cast near Montreal


Right now i'm using 305 for my molding... will go for a quicker set resin for my next purchase... (7 minutes is a long time sloshing... but I'm used to do wax for sculpture... and to make a human size cast... you don't want your batch to set in 3 minutes...)

What is the main difference between the 300 series and the 320? beside the 320 series being marketed to better accept pigments?

Thanks again guys for all the tips... I'll post picture of all my peps and of my 2 casts of handplates... (I'm so proud... I'm actually finishing some pieces...)

 

[rube]

What is the main difference between the 300 series and the 320? beside the 320 series being marketed to better accept pigments?

320 is stiffer and a little more brittle and seems less dense. I've just cast my first helmet with 320 and it beats 300 for slushing hands down. 300 would behave like a liquid-liquid-liquid and oh look, I'm a solid. 320 has a much longer transition time from liquid to solid which helps get a decent coat over a larger area. 320 does seem to like to trap bubbles though.

 

[LastSpartan]

Sial à Laval... fait une recherche sur google "Sial laval" 80$ pour un kit 2 gallon de smooth cast

Okay, ouais c'est le seul que je connais.