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 It's The Way The Resin Crumbles
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Author Previous Topic: sound affects Topic Next Topic: Signs For Structures
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a440
Engine Wiper



Posted - 02/13/2015 :  12:44:46 PM  Show Profile  Reply with Quote
Help!!
I bought Micro Mark mold putty and casting resin, and followed with the directions, but every time I make a cast with the resin in the mold it crumbles when I take the dried cast from the mold. No matter what I do to follow directions, the result's always the same
"This skin reserved for Silver Fox Cape For Mrs. Van Dough."
--from Looney Tunes' Fox Pop

Country: USA | Posts: 205

fockewulf37
Crew Chief

Posted - 02/13/2015 :  1:39:51 PM  Show Profile  Visit fockewulf37's Homepage  Send fockewulf37 an AOL message  Reply with Quote
Not knowing the resin you have... Are to getting the right ratios. Some resins require a scale to get the correct ratio... Pt cast many parts a week and have not run into that problem...

Ty



Country: USA | Posts: 894 Go to Top of Page

n/a
deleted

Posted - 02/13/2015 :  1:42:59 PM  Show Profile  Reply with Quote
quote:
Originally posted by a440





- Could not enough hardener (by weight or by volume)
- contaminated mixing bowels, etc
- uncompatible colourant
- too many airbubbles in resin
- resin not compatible with mold or mold release
- wet or contaminated mold

These are some of the common reasons I know about.

marty


Marty

Country: | Posts: 78 Go to Top of Page

Pennman
Fireman

Premium Member


Posted - 02/15/2015 :  7:37:35 PM  Show Profile  Reply with Quote
You need to consult with forum member, Sgt Bob.
If it's information regarding resins or casting questions, he's your man. Either PM him or send him an email.

Rich



Country: USA | Posts: 4033 Go to Top of Page

Hodgdon scale models
New Hire

Posted - 02/17/2015 :  07:22:08 AM  Show Profile  Visit Hodgdon scale models's Homepage  Reply with Quote
I've found that humidity can cause this crumbling problem, also cold temperatures and not letting the mold release spray dry on the mold before casting. Don't let the resins become damp or contaminated by moisture, that seems to be the biggest cause I've found for the crumbling problem. Your resin may be contaminated and beyond recovery.

Jim

Country: USA | Posts: 18 Go to Top of Page

Coaltrain
Fireman

Posted - 02/17/2015 :  07:41:25 AM  Show Profile  Reply with Quote
What resin of theirs are you using. I have used a few different types of Micromark resin and never have that trouble, maybe your resin is bad. You can remove the part before the resin fully cures as long as you lay it on a flat surface. When the resin cures but is still pliable pull the part from the mold and lay in on some wax paper that is on a flat surface.

If you do have a lot of air bubbles in the resin your casting will be very fragile. Micromark makes a "water clear" risen that you can pour in your mold and see if there are trapped air bubbles, use a tooth pick to untrap the bubbles. Mix the resin in a small cup, use a flat stick and make sure you scrape the sides and bottom of the cup to fully mix the resin, then I like to pour the resin into a second cup, pour slowly and keep the cups far apart so you get a thin stream to help release trapped air from the mixing process. Also when pouring into the second cup keep the receiving cup tilted and pour onto the side of the receiving cup, like you are trying to keep a beer from foaming. Pour the same way into your mold, keep a thin pour stream and pour on a side so the resin flows into the mold. Only pour a small amount into the mold and poke the resin down into any deep holes so the air comes out, then pour the rest very slowly, check for more trapped air.

Micromark makes a slower setting resin that works better because you get more time to get rid of air. I know it seems tempting to get the fast cure resin because it will seem like you can make more parts faster, but you will just end up making more parts and taking longer because you will end up with too many bad parts and wasted resin with the fast cure stuff. It would be easier if you had a vacuum chamber to pull the air out, or many forum members have made pressure chambers from plumbing pipe. I am going to build a pressure chamber myself. The idea of the pressure chamber is that you pour your resin, place the part in the chamber, crank up the pressure and force the bubbles to shrink in size. Air bubbles are going to be your biggest issue with casting resin parts.



Country: | Posts: 1284 Go to Top of Page

Bernd
Fireman



Posted - 02/17/2015 :  07:59:12 AM  Show Profile  Visit Bernd's Homepage  Reply with Quote
I cut my teeth on using Micro Mark resin for casting. When I pressure cast the parts I found the castings to be very brittle and broke easily.

Micro Mark resins are ratio mixed. The better casting suppliers such as Smooth On and them are mixed by weight. The Micro Mark stuff is pretty forgiving as far as a ratio mix is concerned. Those are my findings with Micro Mark.

Bernd



Country: USA | Posts: 3100 Go to Top of Page

n/a
deleted

Posted - 02/17/2015 :  5:22:03 PM  Show Profile  Reply with Quote
Which of the Smooth On resins do you think are best for small detailed parts?

Marty


Marty

Country: | Posts: 78 Go to Top of Page

Bernd
Fireman



Posted - 02/17/2015 :  10:01:16 PM  Show Profile  Visit Bernd's Homepage  Reply with Quote
quote:
Originally posted by Ojaste

Which of the Smooth On resins do you think are best for small detailed parts?

Marty



I've only worked with the Smooth Cast 300 so far. Have had any problems. I haven't tried pressure casting the Smooth On though.

Bernd



Country: USA | Posts: 3100 Go to Top of Page

closetguy
Fireman

Premium Member


Posted - 02/18/2015 :  07:58:14 AM  Show Profile  Visit closetguy's Homepage  Reply with Quote
I know this sounds like a really oddquestion, but did you call Micro Mark? Seems like thats the first place you ask for advice and help?
Mike M



Country: USA | Posts: 1855 Go to Top of Page

Bernd
Fireman



Posted - 02/18/2015 :  08:39:54 AM  Show Profile  Visit Bernd's Homepage  Reply with Quote
Re-reading the original post I noticed he said he was using "mold putty". What I'm thinking he's trying to use this. Link:http://www.micromark.com/composimold-heat-and-pour-mold-rubber-10-oz,10894.html

Bernd



Country: USA | Posts: 3100 Go to Top of Page

mabloodhound
Fireman



Posted - 02/18/2015 :  10:28:55 AM  Show Profile  Reply with Quote
5 days and the OP hasn't responded. I wonder if he's interested in the answers?


Country: USA | Posts: 6680 Go to Top of Page

Bernd
Fireman



Posted - 02/18/2015 :  12:48:54 PM  Show Profile  Visit Bernd's Homepage  Reply with Quote
quote:
Originally posted by mabloodhound

5 days and the OP hasn't responded. I wonder if he's interested in the answers?



I was thinking the same. Or he just plain gave up.

According to his account he's only 17.

Bernd



Edited by - Bernd on 02/18/2015 12:51:01 PM

Country: USA | Posts: 3100 Go to Top of Page

a440
Engine Wiper



Posted - 02/18/2015 :  2:38:58 PM  Show Profile  Reply with Quote
quote:
Originally posted by mabloodhound

5 days and the OP hasn't responded. I wonder if he's interested in the answers?

No.I use a two part putty one white one violet.
Also, the reason I haven't replied is because I was busy with family matters, sorry
Anyhoo, thanks for the advice, I'll look into these and maybe buy a new batch of resin, maybe that may help


"This skin reserved for Silver Fox Cape For Mrs. Van Dough."
--from Looney Tunes' Fox Pop

Edited by - a440 on 02/18/2015 2:41:21 PM

Country: USA | Posts: 205 Go to Top of Page

Bernd
Fireman



Posted - 02/19/2015 :  3:33:43 PM  Show Profile  Visit Bernd's Homepage  Reply with Quote
In my search to fine more information on resin casting I came across this web site posting on the FineScalerr.com forum.

http://www.finescalerr.com/smf/index.php?topic=1024.0

It goes into quite a bit of detail on making thin resin castings. Found some great ideas to use once I get back into casting.

Bernd



Country: USA | Posts: 3100 Go to Top of Page

n/a
deleted

Posted - 02/19/2015 :  4:13:04 PM  Show Profile  Reply with Quote
I've used smooth on 300 and it was good for general things without deep and thin edges. I did lots of castings with Task 4 and it was better. I now have Task 2 and will be trying sometime soon to see how it does.

Marty


Marty

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