Go Back  RCU Forums > RC Boats > RC Boats General Discussion
Reload this Page >

Science experiment with resins

Notices
RC Boats General Discussion Discuss general rc boating topics here.

Science experiment with resins

Old 08-02-2009, 10:43 AM
  #1  
Dreamin Hemi
Thread Starter
 
Dreamin Hemi's Avatar
 
Join Date: Nov 2004
Location: Milton, DE
Posts: 2,638
Likes: 0
Received 0 Likes on 0 Posts
Default Science experiment with resins

Here in the United States we're in the middle of what is typically the hottest month of summer. Lately it's been in the 90's consistantly. This creates a rather large problem in working with fiberglass resins. Here's what I'm playing with. Typically you are given about 20-22 minutes of work time before resin begins to turn into jelly and is no longer usable when mixed with MEKP (catalyst) at 1% at 70 degrees. There have been times where Ihave to frantically mix a quick batch of resin to finish a hull because it "goes off" too early on me. With it being 90 degrees out, Ihave only about 12-15 minutes before it kicks, sometimes less.

Using a new brand of resin that I'm not too familiar with yet, I've set up an experiment using two different types of catalyst. Catalyst has different oxygen contents depending on the type. In this series of pictures, you see a sort of reddish mixture (#1), a brown mixture (#2) and a blue (#3), the control resin that has no catalyst in it. With it being 82 degrees outside, I've lowered the hardener concentration to about .75% where typically 1% would be used. Too low and it will begin to harden, but stay sort of "rubbery".

Two of these mixing cups have been catalyzed with different types of hardener. The red or #1 was catalyzed with the same type of resin I use when building full size boats using a chopper gun (the resin is sprayed into the molds along with the catalyst, mixed in the gun and air before it hits the mold). This reddish resin has a 3-4% oxygen content. The brown sort of color or #2 was catalyzed with the same amount of hardener with standard clear MEKP with an oxygen content of about 9% to 10%. The blue or #3 is straight resin out of the bucket, uncatalyzed. Placed there to see the color differences as the catalyst does it's work. The catalyst is altering the colors due the chemical reaction that takes place. The hardener is a peroxide that dues have some bleaching properties to it.

I've been checking frequently noting the time and viscosity every 3-4 minutes and stirring around just as I would in making a hull.

So far it's been 25 minutes and still looking fluid.

You don't want it going too long since wet resin may effect the gelcoat layer below and could tripe (wrinkle) the layer.

Keep checking back as I'll update fast as I can

Attached Thumbnails Click image for larger version

Name:	Jh15530.jpg
Views:	23
Size:	54.8 KB
ID:	1248532   Click image for larger version

Name:	Ni24814.jpg
Views:	16
Size:	54.1 KB
ID:	1248533   Click image for larger version

Name:	In26521.jpg
Views:	15
Size:	51.1 KB
ID:	1248534   Click image for larger version

Name:	Ys48765.jpg
Views:	23
Size:	49.8 KB
ID:	1248535  
Old 08-02-2009, 10:56 AM
  #2  
Dreamin Hemi
Thread Starter
 
Dreamin Hemi's Avatar
 
Join Date: Nov 2004
Location: Milton, DE
Posts: 2,638
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Science experiment with resins

40 minutes later.....the middle or #2 resin suddenly and quickly turned into jelly and is heating up very hot as it kicks off. Still, lowering the MEKP amount makes it go off, and yielded me an extra 20 minutes or so of work time. I think that may be a little too much fluid time and the gel COULD be affected. Will keep experimentating with different mixtures and post results. It's about 84 degrees now and VERYhumid. A strong thunderstorm is fast approaching. Humidity also plays a factor.
Attached Thumbnails Click image for larger version

Name:	Nk28114.jpg
Views:	16
Size:	44.3 KB
ID:	1248540   Click image for larger version

Name:	Oj28026.jpg
Views:	14
Size:	52.0 KB
ID:	1248541  
Old 08-02-2009, 11:12 AM
  #3  
Dreamin Hemi
Thread Starter
 
Dreamin Hemi's Avatar
 
Join Date: Nov 2004
Location: Milton, DE
Posts: 2,638
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Science experiment with resins

58 minutes from start and finally the red or #1 cup of resin has kicked off and also quickly hardened. Both tubs are impossible to hold due to the extreme heat that is generated while this chemical process does it's job.

#2 or what was once the brown color has now turned into a deep purple.
Attached Thumbnails Click image for larger version

Name:	Zx72571.jpg
Views:	21
Size:	50.1 KB
ID:	1248555   Click image for larger version

Name:	Xs59420.jpg
Views:	17
Size:	59.2 KB
ID:	1248556  

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.