clear resin

[macroadster]

Is clear resin suitable for casting small model pieces, like 1/4"? This is my first time trying to cast in resin, and I am not sure if I am doing the right thing. For now, the casted pieces are some what sticky. Is this related to the resin, or related to the ratio of catalyst and resin? In addition, the clear n' casting resin texture is a little rough. Is this caused by the property of the resin or the mold?

[honneamise]

Hello macroadster!

From my experience clear resin is a hell to work with. Yes you have to stick EXACTLY to the ratio of catalyst and resin as stated by the manufacturer. I tried to make clear resin pieces and gave up after LOTS of trials. After a while I got decent looking, bubble free parts but they did not fully dry in months so I got rid of them.

One day I purchased a Starcrafts Star Trek resin kit that came with clear parts for the warp engine collector thingies. They were tinted red and looked perfect. Finally a guy who can actually work with this stuff I thought. Well as always I had no time to build the kit and after a few months I found the clear parts had become sticky and gathered dust (absolutely unremovable). Unusable.

Another point of concern is the shrinking factor. While a good brand opaque resin does not have a noticeable shrink ratio, clear resin WILL shrink. At 1/4" this will be not too visible but if you need a perfect fit to other parts you will have to build a master part with an increased size determined by the shrink ratio (and you have to find this out by trial and error).

To cut a long story short I ´d avoid the use of clear resin at all cost. I hate this stuff and will never use it again. Don´t let it spoil your first time working with resin. Do you really need it to be clear? If it is a canopy or something similar I would try to smash a heated piece of clear plastic sheet over a master and you will get a good looking part if it is not too angular.

If possible use opaque resin. Mix it, pour it and in five minutes you will have a solid part that looks like your master and stays like it.

That´s of course just my point of view and I hope it does not seem too discouraging. Maybe someone here at MW knows better. Actually, working with resin can be fun!! (though I alway get sticky fingers in the process)

[Guest Bromgrev]

Huh, it's fun until the allergies and dermatitis kick in ...

I try to avoid clear resin. As Honneamise says, vac-formed sheet is the way to go. For small pieces I try to use bits of clear sprue or whatever, sculpted to shape, polished (on a polishing mop attached to a bench drill) and clear-varnished. My wife thinks I'm a nut because I save every interesting-looking bit of clear plastic I come across.

[Chas]

Hi, Just thought I'd put my 2 cents in. I work in the rapid-prototype industry and do a-lot of vac-casting (different from vac-forming) and we use polyurethane resins.

Now while I'm not at all familliar with the retail resins I can tell you that the mix-ratio of the resins we use all have a window of about 5 grams. BUT the smaller your shot weight (total weight of Part A &B ) the less wiggle room you have.

As a rule I don't go lower than a 100g shot (Especially with the clear resin as it is the least forgiveing) if possible.

Now the resins we use are cured in a 70 degree celsius oven for various amounts of time before we demould them. If after demoulding a part I shot with clear resin I find it is still a little soft (not Toffey soft mind you!) I will try to carefully put it back in the cavity side of the mould, put it back in the oven for about 10 minutes for it to reshape itself, and then remove it from the oven and let it cool still in the cavity-side of the mould untill it (hopefully ) hardens up.

As for the rough suface I would think that is more due to your mould rather than your resin. But as I said I have no experience with retail resins so take what I say with a grain of salt.

(edit) forgot to mention we use silcone moulds.

Edited April 5, 2005 by Chas

[macroadster]

Hello macroadster!

From my experience clear resin is a hell to work with. Yes you have to stick EXACTLY to the ratio of catalyst and resin as stated by the manufacturer. I tried to make clear resin pieces and gave up after LOTS of trials. After a while I got decent looking, bubble free parts but they did not fully dry in months so I got rid of them.

One day I purchased a Starcrafts Star Trek resin kit that came with clear parts for the warp engine collector thingies. They were tinted red and looked perfect. Finally a guy who can actually work with this stuff I thought. Well as always I had no time to build the kit and after a few months I found the clear parts had become sticky and gathered dust (absolutely unremovable). Unusable.

Another point of concern is the shrinking factor. While a good brand opaque resin does not have a noticeable shrink ratio, clear resin WILL shrink. At 1/4" this will be not too visible but if you need a perfect fit to other parts you will have to build a master part with an increased size determined by the shrink ratio (and you have to find this out by trial and error).

To cut a long story short I ´d avoid the use of clear resin at all cost. I hate this stuff and will never use it again. Don´t let it spoil your first time working with resin. Do you really need it to be clear? If it is a canopy or something similar I would try to smash a heated piece of clear plastic sheet over a master and you will get a good looking part if it is not too angular.

If possible use opaque resin. Mix it, pour it and in five minutes you will have a solid part that looks like your master and stays like it.

That´s of course just my point of view and I hope it does not seem too discouraging. Maybe someone here at MW knows better. Actually, working with resin can be fun!! (though I alway get sticky fingers in the process)

I guess that's 10 dollars going down the drain. I had the feeling that I must be using the wrong type of resin because my resin kits don't look and feel so soft. I am only trying to cast regular pieces, but I couldn't find opaque resin in the local Michaels store. I am afraid to order resin from online because it's flamable. I wonder what would be a good place to buy resin near the San Jose, CA area.

[macroadster]

Huh, it's fun until the allergies and dermatitis kick in ...

I try to avoid clear resin. As Honneamise says, vac-formed sheet is the way to go. For small pieces I try to use bits of clear sprue or whatever, sculpted to shape, polished (on a polishing mop attached to a bench drill) and clear-varnished. My wife thinks I'm a nut because I save every interesting-looking bit of clear plastic I come across.

I read about vac-formed sheet a lot, but I haven't seen an online tutorial that will walk a newbie step and step. My master piece is a plastic, would vac-forming work?

[macroadster]

Hi, Just thought I'd put my 2 cents in. I work in the rapid-prototype industry and do a-lot of vac-casting (different from vac-forming) and we use polyurethane resins.

Now while I'm not at all familliar with the retail resins I can tell you that the mix-ratio of the resins we use all have a window of about 5 grams. BUT the smaller your shot weight (total weight of Part A &B ) the less wiggle room you have.

As a rule I don't go lower than a 100g shot (Especially with the clear resin as it is the least forgiveing) if possible.

Now the resins we use are cured in a 70 degree celsius oven for various amounts of time before we demould them. If after demoulding a part I shot with clear resin I find it is still a little soft (not Toffey soft mind you!) I will try to carefully put it back in the cavity side of the mould, put it back in the oven for about 10 minutes for it to reshape itself, and then remove it from the oven and let it cool still in the cavity-side of the mould untill it (hopefully ) hardens up.

As for the rough suface I would think that is more due to your mould rather than your resin. But as I said I have no experience with retail resins so take what I say with a grain of salt.

(edit) forgot to mention we use silcone moulds.

Is there any tutorial on vac-casting?

What type of resin do you recommend that I can buy from the local stores like Home Depot or Michaels? I am only casting regular pieces, therefore clear resin is not required factor. I also like to find a local shop for Silcone. I casted my previous piece in InstaMold, which is way too rough to get a model piece out. Right now, I am casting my new piece by layering with Mold Builder. It's taking me 3 days to put 0.5" thick of liquid latex on the master. It seems like it will take weeks before I have a usable mold.

I was looking at starshipmodeler.com for casting tips. However, the resin and molding material are so expensive from the recommended vendor. If you know a place that has cheap/easy cast resin, let me know. Thanks

[Grayson72]

I ordered a whole bunch of resin from Micro-Mark, didn't seem to care if it was flammable or not and I live in CA.

Edited April 5, 2005 by Grayson72

[azrhino]

I have no personal experience with Ace Resin, but I know the owner and have

heard good things about it. They carry resin and RTV mold material in fairly

small quantities. They can be found at

Ace Resin

Hope this helps.

(edited for being a dumbass)

Edited April 6, 2005 by azrhino

[Chas]

I wouldn't be so quick to get rid of the resin you have. I just got back from work and while I was there I was thinking about your problem; if you are confident that you have the measurements correct it could be the mix time or the thoroughness of the mixing that is preventing the resin from curing properly. Could you post the instructions for the product you are using, it would give me an idea of the things that could be going wrong. It could also be due to the ambient humidity where you are casting.

I'm sorry but the only resin suppliers that I am familliar with are industrial.

Vac-casting is a process in which the closed-up mould is placed in an air thght chamber from which the air is then removed. The resin is then mixed and poured into the mold by a machine in an attached chamber above the mold. It is an industrial process, not really something one could do at home.

[honneamise]

Well macroadster I can tell you it took me a LONG time to get a supplier for SMALL amounts of resin. Here in Germany it is impossible to find this stuff on the shelves of even the most specialised hobby stores. They only sell this clear stuff or some cold-cast-porceline but this shrinks too much.

I checked out the site of my supplier but he has NO representative in the States, nearest one is in Mexico.

Look at azrhinos reply. I checked the link to Ace Resin and it appears it is exactly the same stuff I have over here just mine is not white but slightly cream coloured. Urethane resin is the magic word-this is the stuff all the good quality garage kit makers -and Verlinden etc. use. I´d give Ace Resin a try, he seems to sell even small amounts AND you get the proper RTV silicone there, too. Prices seem OK, I don´t get it much cheaper over here and the minimum amount I have to order is 1kg.

[macroadster]

I have no personal experience with Ace Resin, but I know the owner and have

heard good things about it. They carry resin and RTV mold material in fairly

small quantities. They can be found at

Ace Resin

Hope this helps.

(edited for being a dumbass)

Their kit seems very attractive. I will probably place an order after I am settled in my new apartment. Thanks.

[macroadster]

I ordered a whole bunch of resin from Micro-Mark, didn't seem to care if it was flammable or not and I live in CA.

I didn't want to order online because I am moving my apartment in two-three weeks. I will check out Micro-Mark after I try out Ace Resin. Thanks

[macroadster]

I wouldn't be so quick to get rid of the resin you have. I just got back from work and while I was there I was thinking about your problem; if you are confident that you have the measurements correct it could be the mix time or the thoroughness of the mixing that is preventing the resin from curing properly. Could you post the instructions for the product you are using, it would give me an idea of the things that could be going wrong. It could also be due to the ambient humidity where you are casting.

I'm sorry but the only resin suppliers that I am familliar with are industrial.

Vac-casting is a process in which the closed-up mould is placed in an air thght chamber from which the air is then removed. The resin is then mixed and poured into the mold by a machine in an attached chamber above the mold. It is an industrial process, not really something one could do at home.

I think the mold was probably the problem in my initial attempt. The clear resin actually cured after I left it alone for 2 days. It's hard as solid now, but it still shrinks about 5% after it was removed from the mold.

I was using:

The day that I casted, it rained a lot.

I will try again with a real liquid latex mold this week. I am still worried that the clear resin isn't flexible enough to cast thin and small piece like 0.25" x 0.1". Would that be a problem?

[macroadster]

Well macroadster I can tell you it took me a LONG time to get a supplier for SMALL amounts of resin. Here in Germany it is impossible to find this stuff on the shelves of even the most specialised hobby stores. They only sell this clear stuff or some cold-cast-porceline but this shrinks too much.

I checked out the site of my supplier but he has NO representative in the States, nearest one is in Mexico.

Look at azrhinos reply. I checked the link to Ace Resin and it appears it is exactly the same stuff I have over here just mine is not white but slightly cream coloured. Urethane resin is the magic word-this is the stuff all the good quality garage kit makers -and Verlinden etc. use. I´d give Ace Resin a try, he seems to sell even small amounts AND you get the proper RTV silicone there, too. Prices seem OK, I don´t get it much cheaper over here and the minimum amount I have to order is 1kg.

I am going to give my clear resin one more try by this weekend. If it doesn't work out, I will definitely find a place for Urethane resin. I didn't know what it was called, but I like the cream coloured resin. They are so easy to work with during the model constructions. I hope Urethane resin is as easy to cast as to build the models.

[Chas]

Well the wall thickness of alot of the parts I shoot at work are like 60 thou.( that's 60 thousanths of an inch -a quarter inch is somewhere aroun 325 thou. I think) but as I said all of the resins we use are Polyurethane even the clear resins. I tink you have a good plan in place though, try the resin you have with a better mould, if it works -Great!, if not order some Ace. (in fact I think I might order some of that stuff and try it out myself it sounds terrif!

[fernarias]

Since your so close to SF, go here:

http://www.artstuf.com/polyurethane-casting-resin.html

and take your girlfriend with you and make a day of it. For lunch and dinner, I recommend Cioppinos on the Wharf: http://www.cioppinosf.com/ Good food good prices.

F.

[macroadster]

Since your so close to SF, go here:

http://www.artstuf.com/polyurethane-casting-resin.html

and take your girlfriend with you and make a day of it. For lunch and dinner, I recommend Cioppinos on the Wharf: http://www.cioppinosf.com/ Good food good prices.

F.

My attempt over the weekend failed with the clear resin. For some reason the clear resin doesn't dry up for almost 4 days. I also got a lot of unsmooth surface on the casted parts. I suspect that I might have too much talcum in the mold, therefore, the parts became unsmooth surface.

I will drop by artstuf next weekend, and hopefully I have better luck with polyurethane resin. Thanks for the tip, I will go to Cioppino for dinner with my girlfriend, it seems like a good place for food.

[Rob]

only thing i can say is that the best experiance i had with clear resin was with epoxy resin not the polyurethane one as the one i tryed out did nothing but give bubbles.

can be it wasnt compatible with the rtv i used but the epoxy didnt minded it

the mold burns out quick though as its really nasty stuff.

[fudoc]

I have a clear resin kit and the flash was trimmed too close to the parts and left voids that I have to fill. Any ideas on how to fix this and retain the transparency of the kit?

[HWR MKII]

Use a brush and keep applying clear nail polish to the Void to build it up. Its the easiest /cheapest way i can think of.

[Grayson72]

Hey that's a good tip, I was gonna say layer using Future but nail polish would be thicker/quicker/harder.

[fudoc]

Use a brush and keep applying clear nail polish to the Void to build it up. Its the easiest /cheapest way i can think of.

That is a good idea. Never would of ever thought of that.

I've posted this on several forums and the suggestions given, including this, are:

1. super glue

2. clear expoxy resin

3. nail polish

Gotta give them all a try and see what works the best.

Thanks

[Grayson72]

Super glue = bad idea, it will totally fog the clear resin you are trying to fix.

[fudoc]

Super glue = bad idea, it will totally fog the clear resin you are trying to fix.

I figured. But isn't there a type of CA glue that's safe for clear parts?

I experimented with clear expoxy glue and it seems to work fine, except I can't get rid of the bubbles during mixing and it gets incorporated into the kit. For small applications, the bubbles aren't too noticeable but for larger build-ups this is a problem. Good thing I only need it in small amounts.

Edit: To get rid of the bubbles, I kept adding in small amounts and sanded in between applications.

Edited April 28, 2005 by fudoc