resin foams when sets

[Lownslow]

up until a while ago it was fine now it foams and expands when it sets did it go bad? weathers been mild but not humid

[Mike Kucaba]

up until a while ago it was fine now it foams and expands when it sets did it go bad? weathers been mild but not humid

It probably went bad(absorbed moisture). I read once that putting resin (the A & B separately) in a vac chamber will alleviate that somewhat but the best thing is buy what you will use quickly and use that gas blanket (extend and other brands I'm sure).

[Art Anderson]

up until a while ago it was fine now it foams and expands when it sets did it go bad? weathers been mild but not humid

Low,

The weather in Chicago isn't that much different than in my part of mid-north Indiana, and it's been humid enough here all summer long to make birds grow fins, scales and gills! What you describe is the result of moisture contamination of the polyol side of the urethane resin. That stuff is extremely hygroscopic, it soaks up moisture from the air, certainly when the container is opened, but to a lesser extent even through the polypropylene bottles it came packed in.

Some have suggested using a vacuum chamber to draw out the C02 gas that is causing the foaming, but that almost never works. I've had limited success using pressure pots though, but even 75psi isn't enough to overcome severe moisture contamination. About the only solution is to get some fresh resin, and only that quantity that you will use in fairly short order.

Art

[Lownslow]

yea im gonna have to get the nitrogen stuff i think it got it when it got really bad 3 weeks ago.

what about sealing them inside a gallon ziplock bag?

[Reliable Resin]

up until a while ago it was fine now it foams and expands when it sets did it go bad? weathers been mild but not humid

We've been having that same problem ALL SUMMER ...

on a lil' large scale

This Summer was the Hottest on Record here ,

it's not the Heat so much , as the Humidity

The combination of Heat & Humidty plays Havoc on the resin curing process causes the resin to accelerate / react faster

Steve & Lownslow ... I have a technique that will work for you smaller scale casters

(depending on the resin mfr your using & the "pot life" flash time of the formula your using)

feel free to email me > ReliableResin@aol.com

Build ON !

Don

[Chuck Most]

Wow. Guess milky clearcoat isn't the only bane of a modeler on a muggy day...

[Karmodeler2]

I use Smooth On products (Task 9) and it only foams when it is NOT pressurized. Are you using a pressure pot and it's still foaming?

Harbor Freight has them for about $50.

David

[Lownslow]

I use Smooth On products (Task 9) and it only foams when it is NOT pressurized. Are you using a pressure pot and it's still foaming?

Harbor Freight has them for about $50.

David

i have a pressure pot but its out of comission

[shucky]

Can I ask why use a resin that has to be pressured when there are plenty that do not which cure wonderfully and without bubbles? I live in Chicago burbs and it's been extremely humid this summer and I have left some spare jugs of resin in my somewhat humid/damp basement with zero issues that you speak of. I would switch to a different brand.

[Mike Kucaba]

Can I ask why use a resin that has to be pressured when there are plenty that do not which cure wonderfully and without bubbles? I live in Chicago burbs and it's been extremely humid this summer and I have left some spare jugs of resin in my somewhat humid/damp basement with zero issues that you speak of. I would switch to a different brand.

Well... I'm waiting to find out what this super resin is. I can't improve unless I know what the improvement is.

[Karmodeler2]

Well... I'm waiting to find out what this super resin is. I can't improve unless I know what the improvement is.

Me Too!!!ME TOO!!!!!!!!!

I have EXCELLENT results and very beautiful parts with Task 9 and pressure. So please, show and tell this new "non pressure" resin. I did not know they made one that would produce pin hole free parts like the Task 9 does.

David

[shucky]

The problem discussed here is the "foaming" the OP is getting as well as others apparently. David mentions he uses a resin that only foams when not pressured. My thoughts in reading through the posts were, "why use a resin that requires pressure, or risk foaming/does foam at all ...?"

I'm not stating I use some miracle resin. I use Alumilite white. I get fantastic results w/out pressure. Do I get some pin sized holes from time to time? Sure. But this is the exception and not the rule. I've not done any large items like bodies, but mostly engines, wheels, seats, etc. So far, most of what I've poured does not have any bubbles or pin sized holes.

With sticking to the topic, I was just commenting on why use a resin that foams (if not pressured), or foams when humid, or foams at all. Plus, I live in the same vicinity as the OP and know that my resin which I've left in my basement for the past 2-3 months (summer) has not foamed at all ever. I actually left it down there as an experiment to "see" if anything would change or happen to it, as my other jugs of resin and rubber are kept upstairs. Answer = nope. No difference or change.

I was just thinking why not use something that gives you the option of using pressure or not w/out having to worry about contamination (foaming) or not using pressure (foaming). You could pressure Alum. white if you wanted but do not have to in order to achieve very very nice results.

I do not know about Task9 resin, I'll take a look at it. Maybe Alum. white does not fit your application / requirements? But you can get outstanding results as well using other options.

[Longbox55]

I use Alumalite, too, and beleive me, when it gets some age on it, it WILL foam. Like Art stated, it is hygroscopic, meaning it absorbs moisture, just like brake fluid.

[shucky]

Thanks for the info. I know its not immune to getting contaminated, perhaps just not as sensitive as what the OP is using.

[Karmodeler2]

Hey Mike,

You are right. I mis-read your post, sorry. I thought you said there is a resin that does not foam and needs no pressure. You are saying that you can get results without pressure. Sorry about that.

I will say, that when you start doing 2 piece molds, car bodies and bigger pieces, you will need pressure. And when you see the difference, you will not go back to room "standard barometric" pressure. The parts I make are as smooth as molded injected plastic. I ensure that my master is ABSOLUTELY perfect, to the best of my ability, and all my off spring are the same way. I do not use mold release, but use baby powder lightly dusted in the mold. I use mold release only when making a two part rubber mold so the two halves will go together and separate when it's time to take out the master and start pouring resin. It is used only where the rubber touches the rubber for the two halves and never in the area where resin will be poured.

The Task9 is made by Smooth On and I have only found one problem with it. It is translucent, so your offspring are hard to tell how detailed they are, because of the translucent state of the part. You never leave parts in raw resin form, so as soon as you prime it, it looks like identical to the master (because it is). It's just hard to tell when you de-mold it because of it's translucent state.

The pro's you ask?

I can tap and die the resin.

I can throw my car bodies on the ground and they DO NOT break (yes, I know you don't go around throwing car bodies, but have you dropped one before?)

The tensile strength is about 7 times greater than the normal stuff (the Smooth On 320 which is what a lot of people use)

It's one of the toughest, hardest resins I have worked with and I love it. But everybody is different. My friends that cast has switched and love it but that is not saying you will like it. It does require pressure, but produces incredible results.

It's the same price (with in a few dollars) of the other stuff (like the 320).

Everybody has their techniques. That is how I have obtained mine. I take advice from others and form my own. (and then do a two piece mold....LOL)

These are just mine.

They also make an incredible clear that is UV stable and which can be tinted any color you desire. I use their tints, in future, to give my windshields a very subtle, but accurate color for the safety lamination. I use green for the older vehicles, and a blue/grey for newer ones. If you were not told it was there, you might not see it. But if you look across the vehicle, from left to right, while looking though the front windshield, you will see it. When I point it out, most people are surprised.

But, that is how the glass is on older (and newer) cars.

David

David

[jeffb]

very well said dave. the only problem i have with the task line is that its very very hard on the rtv molds. ive tried task 2 and i like the results, but it eats the molds faster than the 300 series.

[Karmodeler2]

very well said dave. the only problem i have with the task line is that its very very hard on the rtv molds. ive tried task 2 and i like the results, but it eats the molds faster than the 300 series.

Not sure of the mold material you are using, but I use a product from Silicones Inc out of NC and it's GI 1110. It is so flexible that I can turn my molds inside out and still have a good mold. Now, if I am doing production work, it might be a different story. You are probably trying for at least 50 pulls a mold and I'm not sure if I have ever done that many and if the 1110 would work. Most use the 1100, but I spoke to a tech there and he recommended the 1110 for the flexibility over the 1100. If you call them, talk to Nancy, she is very sweet and helpful with one of the most beautiful southern voices.

I know their product has been OUTSTANDING for me and it picks up finger prints on the masters, if you are not careful. The detail is amazing. I do vacuum the rubber and pressure the resin.

David

http://www.silicones-inc.com/siliconesdatasheets.html

[Karmodeler2]

My thoughts in reading through the posts were, "why use a resin that requires pressure, or risk foaming/does foam at all ...?"

Hey MIke,

I'll do a sample for you if you like at no charge to you except shipping to my house, and I will pay shipping back to you.. Send me one or two or your molds that you would like parts for (not car bodies, but say calipers, carbs, rims....something along those lines). I will pressure cast Task 9 in them and send the mold and the parts back to you. Then you cast a few with the same molds you sent me using your resin. Remove your parts, and take my parts and prime and paint them and tell me which one you think is A) the better looking part and took less time to prep before final stage. I take my parts from the molds, wash in bleach white, prime, paint and put on the model. There is no prep phase as I have no imperfections in the parts. Sometimes I skip the bleach and have had no problems. I will send you some calipers I just did and you can look at them and prime them the way they are because I have not washed them and can see for yourself.

It's a free test for you to see what the difference in a pressurized QUALITY resin and a non pressurized one.

You can PM me and I'll send you all the address info.

David

I can even do an unpressurized Task 9 batch to show you why I pressurize. The bubbles are unbelievable with the chemical reaction of the two liquids. Not to mention the heat that is formed.

[jeffb]

i use smooth on rtvs..and yes, i do try to get a lot per mold. missing link uses task 4 and loves it. i do use the task 2 on my slot car bodies because of the hardnest. the 305 works for general models since most guys dont whack their built display models against the wall.. i hope..

i use smooth on rtvs..and yes, i do try to get a lot per mold. missing link uses task 4 and loves it. i do use the task 2 on my slot car bodies because of the hardnest. the 305 works for general models since most guys dont whack their built display models against the wall.. i hope..

yea! i make ohana!

[Lownslow]

i use smooth on rtvs..and yes, i do try to get a lot per mold. missing link uses task 4 and loves it. i do use the task 2 on my slot car bodies because of the hardnest. the 305 works for general models since most guys dont whack their built display models against the wall.. i hope..

yea! i make ohana!

i used to use 305 but it was hard to spot the pinholes and flaws. i switched to 320 but im gonna get 321 because of the longer pot life. i got some new molding rubber its actually pretty nice way better than the oomoo series its great for high detail and undercuts

[RyanSilva]

I use320 and 321 for about a year and love it! Moldmax series is wonderfull stuff. I used Oomoo before and it didnt hold up well for me, so I use moldmax 10-30 exclusively.

Even if you're a hobby caster(casting for yourself) A pressure pot from harbor freight, a 1/4 and 3/8 plug fittings and you're set. It is enough to turn your world upside down and get beautiful casts.

I find the money spent is money saved in the long run with botched castings from foaming and humidity.

This summer was brutal, in the north east for casting, with all the humidity. Now I have a reason to break out the 2nd pot!

Edited September 15, 2010 by RyanSilva

[Lownslow]

I use320 and 321 for about a year and love it! Moldmax series is wonderfull stuff. I used Oomoo before and it didnt hold up well for me, so I use moldmax 10-30 exclusively.

Even if you're a hobby caster(casting for yourself) A pressure pot from harbor freight, a 1/4 and 3/8 plug fittings and you're set. It is enough to turn your world upside down and get beautiful casts.

I find the money spent is money saved in the long run with botched castings from foaming and humidity.

This summer was brutal, in the north east for casting, with all the humidity. Now I have a reason to break out the 2nd pot!

i got a pot i just gotta redo the fittings so that its vertical

[jeffb]

tried the oomo. its nice for beginners because its a 1;1 mix and you dont need to vacuum it, but it dosent hold up under production use. i do use the 300 resin for filling bubbles and i can use it in one part molds without pressure if the humiditys low. it cures very fast, in about 30-60 seconds depending on ambient temp

[shucky]

I use320 and 321 for about a year and love it! Moldmax series is wonderfull stuff. I used Oomoo before and it didnt hold up well for me, so I use moldmax 10-30 exclusively.

Even if you're a hobby caster(casting for yourself) A pressure pot from harbor freight, a 1/4 and 3/8 plug fittings and you're set. It is enough to turn your world upside down and get beautiful casts.

I find the money spent is money saved in the long run with botched castings from foaming and humidity.

This summer was brutal, in the north east for casting, with all the humidity. Now I have a reason to break out the 2nd pot!

Ryan, if I understood my research correctly, if you pressure cast your resin you would have needed to de-air (vacuum) your mold making material (rtv). If there are air pockets in your mold (from not being de-aired) and you pressure cast your resin you can cause / risk imperfections in your reproduced piece as these air pockets try to move around. Does this sound about right?

If so, what is the purpose of having a pressure pot if you do not own a vacuum pump/chamber?

This thread is a wealth of info so far. Thanks fella's.

[RyanSilva]

Hi Mike, you are correct.

However

the purpose for owning a pressure pot is you can pop all your airbubbles in your RTV to a microscopic level

You do not need to vacuum or degas your silicone if you have a pot. Not sure how it works for car bodies, but doing 1 and 2 piece molds for wheels, suspension parts and other items, pressure is wonderful.

My resin experience is a shot in the bucket compared to the guys who have been doing it for over 6 years, but in my years of casting, letting RTV cure under pressure has been amazing.

Make yours molds as usual, mix up your RTV, pour your mold..throw it in the pot and let it cure under pressure.

Mine will cure in less than 10 hours, then I'll bake the mold for a hour at 150 degrees to finish it off.

Edited September 15, 2010 by RyanSilva