Using baby/talcum powder for mold release for master

[Hawk312]

Ok, I think I finally have my resin issue solved! I have a resin master that looks acceptable, but it is in primer. I am considering using baby/talcum powder this time as a mold release on my master. Will this work? I know a lot of you guys use this for the resin copies you are making, but what about the master when making the mold?

Thanks!

[wisdonm]

I wouldn't. First, a silicon mold will pick up all surface details and imperfections, like powder residue. Second, silicon doesn't stick to anything, but silicon. I don't use any release on my masters.

[Hawk312]

Thanks wisdonm. So basically you are saying to just pour the Silicon directly onto the bare part, no release? That would certainly simplify things for me, as you might guess if you are familiar with my previous thread regarding the chrome issues.

Thanks!

[Ace-Garageguy]

SiliconE. SilicoN is sand.

Don's absolutely right by the way. The mold will duplicate even the TINIEST flaw on the surface, including talcum powder, and transfer that flaw to every single part you make from the mold.

My own molds will have a 400-grit-sanded surface if the final sanding of the master was done with 400, a 1000-grit-sanded-surface if the final sanding was done with 1000, or mirror-polished if the master was mirror-polished. The parts made in the molds duplicate that surface as well.

Baby talcum powder most likely also has some kind of skin conditioner like lanolin in it, and unknown chemical contaminants should be avoided.

Edited December 9, 2014 by Ace-Garageguy

[Ace-Garageguy]

If you're interested, this company (that makes a full line of the products professional tool and model builders use regularly) has produced an excellent series of FREE videos on master and mold making, including release agents, available to watch online HERE... http://www.freemansupply.com/video.htm

[Greg Wann]

Hi David,

You will not need a mold release until you are ready to pour the inner core if you intend to create a two part mold. I would not use a powder for a mold nor would I use some homemade witches brew either. Get a good spray type mold release. A spray type release will help lubricate and act as a thermal barrier against the delicate detail of your mold. I was using a Price Driscoll product. I either got a bad batch or the formula has been changed and has been a problem for me. I also switched the silicone I was using and casting has just been a real mess for me lately. I'm in way too deep to give up now, so I'm slowly working through the problems. I bought a can of MANN 200 ease release my resin guy suggested. A new mold will come apart very easily now but I am finding that the first couple of copies seem to be sucking up the release making copies that do not fully cure. It would be nice if the cans of release had a shaker ball in them. I did purchase a really nice item that is very overbuilt to shake spray cans. It fits on a sawzall. You strap the can in and pull the trigger and it will shake it really hard. The guy that invented it was pretty smart. You can get a sawzall type cutter from Harbor freight pretty cheap I would imagine. Here is a link to the shaker and a sawzall.

http://www.ebay.com/itm/MIXKWIK-Aerosol-Paint-Can-Foam-Insulation-Mixer-Shaker-/310206425972?pt=LH_DefaultDomain_0&hash=item4839be6b74

http://www.harborfreight.com/6-amp-reciprocating-saw-with-rotating-handle-65570.html

Edited December 9, 2014 by Greg Wann

[Casey]

Ok, I think I finally have my resin issue solved! I have a resin master that looks acceptable, but it is in primer. I am considering using baby/talcum powder this time as a mold release on my master. Will this work? I know a lot of you guys use this for the resin copies you are making, but what about the master when making the mold?

How smooth is the master part? Unless you're going for a sand-cast look (like the exterior surface of an engine block casting), the smoother the surface is on each part, the better. If you can polish every millimeter of the outer surface up to 12,000 grit, do it. Yes, it's a lot of work, but the better the master, the better your copies will be.

RTV silicone rubber has a very low surface tension, which is why very few things "stick" to it. Adding baby or talcum powder does nothing to decrease the surface tension of the cured mold rubber.

[george 53]

Do ANY of you guys REALLY cast? I use talcum powder an most of my open faced molds AND 2 piece molds. I've NEVER had any problem with it, I use Smooth On 300 thru 305 and its NEVER left ANY impressions. I use a spray release on the OLDER more tired molds but I STILL powder them with NO problems. What resin /Mold making products are you using? Been workin with Smooth On for over 5 months now with NO problems at all.

[Mark]

I've done a lot of casting (both for myself, and to sell) and DO use talc...but not during the mold making process.

[Ace-Garageguy]

Do ANY of you guys REALLY cast?

Well, Casey makes some of the best looking, cleanest, most defect-free parts I've ever seen, period.

I make fiberglass parts that are pretty nice too.

[jeffb]

talc for mold making=bad..

talc for casting= good......

[Hawk312]

Thanks guys for all the advice! I took a good bit of time sanding my master and then actually buffing it out a little last night. I then created a new mold with no release agent whatsoever. I cast my parts this morning and I no longer have the issue with pinholes!! I can`t thank you guys enough. Now hopefully I can get these wheels off to chrome, get them installed, and have a unique build for you guys to see.

Oh, and sorry for any contention...definitely wasn`t my intention...

[Greg Wann]

I have been casting for awhile now. I am able to go to the Reynolds Advanced Material store in Tempe, AZ. I can talk to Aaron or Niki face to face and ask questions and take in molds for them to look at and look at the molds they are making. They say I am doing a pretty good job except they think my molds are way to big for some of the parts that I make. I use the Moldstar 30 silicone and the Task 8 resin. Even with all I know and do, not every part is a nice part that is worth selling. I either add it to a kit for paint sampling or give it a toss. I have seen plenty of resin kits that fellow model club members have paid good money for and it is something that I would put in the big O or give to someone to work like a dog to make something good out of it. I gave up thinking I was going to be some great detail model builder but found a reasonable talent in casting. A couple of guys in the club started calling me the master caster. I was actually pretty embarrassed by it in general and a lot at the DSC shows, I'm mostly OK with it now. There is a guy in mesa that is a promo model builder, Bob Peoples introduced me to him. The first time he saw some of my parts he claimed they were Modelhaus quality. I don't really want to claim to be the greatest caster, but I am not the worst. All I need to do is read peoples comments on the forums. I am horribly disorganized and fly by the seat of my pants.

Edited December 10, 2014 by Greg Wann

[IceMan Collections]

Thanks guys for all the advice! I took a good bit of time sanding my master and then actually buffing it out a little last night. I then created a new mold with no release agent whatsoever. I cast my parts this morning and I no longer have the issue with pinholes!! I can`t thank you guys enough. Now hopefully I can get these wheels off to chrome, get them installed, and have a unique build for you guys to see.

Oh, and sorry for any contention...definitely wasn`t my intention...

Glad you got it all figured out. Hope to see those wheels cast and chromed

[Hawk312]

Well, I just got the parts back from the platers, and I think these are worse than the 2 prior batches. I am really at a loss. Some of them look like flat aluminum. Some of them have the bad pinhole issue. Some of them appear to have a yellowish tint. I looked at the backs of them, and the rack that I mounted them on, and the chrome on them seems to be decent. So I dont know what to do, except for maybe start this whole process ever again, fabricating a completely new master from scratch. If anyone has any ideas, I would appreciate it.

[Kris Morgan]

Have you tried a different plater?

[Hawk312]

Have you tried a different plater?

I haven't yet because this guy, after reading the comments on here, seems very reputable. Also, the bumper that came from the kit that he chromed for me looks almost perfect. .

Maybe I will start looking at other players though. Anyone have recommendations besides chrometech?

[Psychographic]

Have you tried a coat or two of enamel over the parts before sending them out? The paint will level out a lot of tiny imperfections.

[Ben]

Been a caster of high end resin parts since 1993 so I have a little knowledge in this. The only thing you want to use baby powder for is to line your cured mold before you pour the resin in. What it does is cause a capillary action to "pull" the resin into tiny voids. The baby powder then dissipates into the resin so it has no effect on the final finish of the cured part. My wheels were made from highly polished aluminum masters and the finish of the cast parts was like glass!

Edited January 1, 2015 by Ben

[Hawk312]

Can enamel paint really be chromed plated? And if enamel, what about lacquer? I am able to get these nearly perfect, at least as far as texture, with duplicolor primer. That`s a simple fix if it can be plated over.