Help Support RocketryForum by donating using the link above or becoming a Supporting Member.


Results 1 to 11 of 11
  1. #1
    Join Date
    15th November 2015
    Posts
    10

    Epoxy Clay vs. Liquid Epoxy

    Hey guys so I am looking into building my Level 2 Certification rocket over the next couple of months and while trying to get a list of all possible building components I came across a very interesting question. The question is which is better Epoxy Clay which is a two part epoxy that you can mold with your hands or Liquid Epoxy that is also two part mix that you sort of pour on and leave to dry till the next day. I know that with the clay epoxy you wouldn't necessarily have to wait to epoxy all the fins on but are there any other differences to these two like strength or resistance to shattering?


  2. #2
    Join Date
    13th June 2014
    Location
    Cocoa Beach, FL
    Posts
    3,554
    Epoxy clay is brittle. I'd stick with Rocketpoxy or Proline 4500 for external filets and west system or aero poxy or US composites for internals.

    Tim
    L3 NAR 98225

  3. #3
    Join Date
    8th August 2014
    Location
    Rockford, IL
    Posts
    2,398
    Quote Originally Posted by timbucktoo View Post
    Epoxy clay is brittle. I'd stick with Rocketpoxy or Proline 4500 for external filets and west system or aero poxy or US composites for internals.
    +1. I use RocketPoxy on internals, too, depending on the build.
    Details on your build would help. However, I'm thinking there's a reason no one really uses epoxy clay for rockets. Having never tried it, I don't know, but this is one example of groupthink I'm quite happy to go along with.
    -CzTeacherMan
    TRA #15280 - QCRS, Tripoli Wisconsin, WOOSH
    Level 1 - 9/28/2014 Wildman Sport on CTI H163 White Thunder
    Level 2 - 5/23/2015 Wildman 3" Darkstar CTI J400 Smoky Sam
    First Mile+ & Mach+ - 9/25/2015 Wildman Punisher CTI J360 Skidmark
    Level 3 - 5/15/2016 Wildman Gizmo XL-DD-V CTI M1540 Imax

  4. #4
    Join Date
    13th October 2014
    Location
    SouthEastern, WA
    Posts
    5,707
    Use something other than epoxy clay, for the reasons others have listed. I use mostly US Composites 635 w/medium hardener for everything if the rocket is HPR, with a few inexpensive additives like milled fiber, mircoballoons, or Cabosil it will work in most any application. I do use JB Weld exclusively to bond motor retainers though. Rocketpoxy, Proline, West, Aeropoxy are truly the premier epoxies and their price show's it, they are the best, however other epoxies work for most of our applications and are less expensive.
    Rich

    NAR# 99154

    L3-4x upscale Estes Cherokee-D- AT M1297W 5/28/2016 http://www.rocketryforum.com/showthr...r-rharshberger

    TriCities Rocketeers NAR section# 736 http://www.tricitiesrocketeers.org/

  5. #5
    Join Date
    15th November 2015
    Posts
    10
    For details on the rocket itself I'm thinking of using blue tube for the air frame and maybe the same for the motor mount tube. However I might have some 54mm kraft phenolic lying around that I could use for the motor mount. For the motor range I want to stick with a J because I want to be able to recover this easily and not have to stare into the sky trying to locate my rocket. I used West Systems 105 & 205 for my level one and that worked great but I really just want to see if there was a more cost effective way to secure my centering rings and fins to the airframe.

  6. #6
    Join Date
    8th May 2012
    Location
    Southern, CA
    Posts
    6,191

    Awesome stuff epoxy clay

    I never had any issues with epoxy clay. You can do all your fillets and not have to worry about drips or dry time. I think the "FIX IT" epoxy clay has a 3 hour work time. Sets up over night and dries nice and hard. You can file and shape it and blend it. It actually offers a lot of advantages over the pour and pray epoxy that most rocket builder experts on here use and are partial to using. Because if you don't listen to the rocket experts on here then you are doing it all wrong.

    Hey give it try you might like it is all I'm saying

    Here's the link if you want it.

    https://www.avesstudio.com/fixit-category/fixit

    Click image for larger version. 

Name:	20151114_110301.jpg 
Views:	77 
Size:	120.2 KB 
ID:	276543Click image for larger version. 

Name:	20151114_110309.jpg 
Views:	88 
Size:	168.2 KB 
ID:	276544Click image for larger version. 

Name:	20151114_110322.jpg 
Views:	74 
Size:	165.3 KB 
ID:	276545


    I might add that it isn't as messy and no need to tape off your rocket. You can if you want for perfect fillets and just blend the edges with a moisten finger dipped in denatured alcohol. BTW see the picture of a MADCOW fiberglass Twitch done with epoxy clay. Pretty sweet!! This stuff is a fraction of what you would pay for pour and pray epoxies
    Last edited by AfterBurners; 23rd November 2015 at 12:10 AM.
    NAR # 89516
    HPR Cert Level 1

  7. #7
    Join Date
    15th July 2015
    Location
    Tidewater area of Virginia
    Posts
    1,397
    I'll offer a differing point of view.

    Having used Fixit clay (from apogee) on several MPR and HPR rockets, NEVER AGAIN. Unless you're routinely landing on very soft grass or plowed dirt, they're prone to cracking. Nearly 50% of my clay fillets have cracked on landing, even in the best of landings. Sometimes, if your rocket is spinning a little, even that slight side velocity is enough to crack it. Same landing scenario with my liquid epoxy fillets have all been 100%. I've found that even cheap epoxy (BSI) has been more resilient than clay fillets.

    My prep has always been to remove the glassine wrap and sand the wood to ensure tooth for the clay. It's NEVER come off of the tubes or the wood, but it's cracked down the clay itself.

    It's easy to work with, it's easily repeatable, and it sands nicely, but it's NOT the right material for fillets on most mid power or any high power rockets, based on my flights/landings this summer and fall. YMMV.

    For some assembly, some repairs, clay is OK, but I've relegated it to a LPR/MPR tool.

    Even my cheap, crappy BSI epoxy fillets proved tougher than my fixit clay fillets this weekend. 2 of 2 clay fillet rockets cracked at least 1 fillet. 2 of 2 BSI epoxy filleted rockets flew twice as much and didn't crack a single fillet. NONE of my RocketPoxy fillets have cracked.
    Last edited by Banzai88; 23rd November 2015 at 12:16 AM.
    ATCS(AW) Tom Keith, USN, ret. _____NAR 99781 L1_____MDRA 212
    SEVRA, NAR 621http://www.sevra.org/ Tripoli East North Carolina (Bayboro), TRA #65, http://ncrockets.org/, MDRA http://www.mdrocketry.org/
    LVL 1 24 October 2015, Leviathan, CTI H133, 2469 ft, Bayboro
    LVL 2 Soon, Super DX3, AT J420 Redline, est 3500 ft, Bayboro or MDRA

  8. #8
    Join Date
    15th November 2015
    Posts
    10
    AfterBurners first off I'd like to say nice job on the Madcow Twitch, your paint scheme is pretty awesome and the whole rocket looks really good! Also what I just realized is with the clay epoxy trying to epoxy the centering rings into the airframe might be a little hard. Did you use clay epoxy for the inside rings as well? If so how did you do them? Normally with the "pour and pray" epoxy I would do just that for the centering rings but this seems impossible to do with the clay.

  9. #9
    Join Date
    18th March 2012
    Location
    Huntsville, AL
    Posts
    9,084
    I always use US Composites 635 Medium with enough fumed silica to get a peanut butter consistency. Never have I cracked a fillet, even when a rocket came in drogueless from about 2K feet.
    Matt, Tripoli #14257
    L1 11/13/16
    L2 2/25/17
    L3 Spring 2018....
    Facebook Youtube



  10. #10
    Join Date
    8th May 2012
    Location
    Southern, CA
    Posts
    6,191
    Quote Originally Posted by JoshLewy32 View Post
    AfterBurners first off I'd like to say nice job on the Madcow Twitch, your paint scheme is pretty awesome and the whole rocket looks really good! Also what I just realized is with the clay epoxy trying to epoxy the centering rings into the airframe might be a little hard. Did you use clay epoxy for the inside rings as well? If so how did you do them? Normally with the "pour and pray" epoxy I would do just that for the centering rings but this seems impossible to do with the clay.
    I used the clay just for fillets. The pour and pray epoxy I use for assembly
    NAR # 89516
    HPR Cert Level 1

  11. #11
    Join Date
    4th August 2011
    Location
    Lincolnton NC
    Posts
    5,330
    Quote Originally Posted by AfterBurners View Post
    I never had any issues with epoxy clay. You can do all your fillets and not have to worry about drips or dry time. I think the "FIX IT" epoxy clay has a 3 hour work time. Sets up over night and dries nice and hard. You can file and shape it and blend it. It actually offers a lot of advantages over the pour and pray epoxy that most rocket builder experts on here use and are partial to using. Because if you don't listen to the rocket experts on here then you are doing it all wrong.

    Hey give it try you might like it is all I'm saying

    Here's the link if you want it.

    https://www.avesstudio.com/fixit-category/fixit
    Hay man, I just breezed by this company in one of my searches last night and wasn't sure if it was what I was looking for, so I continued my search. I wasn't about to pay "you know who" for their FIX IT brand with their always over inflated shipping charges and wound up finding this old thread instead. NOW, thanks to your posting, I ordered some from the AVES company you linked. It'll be my first time using clay epoxy for fillets but I have watched a few good vids and it looks fairly simple and not anywhere near as messy as "goo epoxy". (That stuff is a PIA to use on fillets) Has this stuff withheld the test of time pretty good for you?

    Thinking outside the box is normal for me. Went inside the box once and got claustrophobic.
    Can't never did!
    Inventions weren't created by skeptics.
    There's a bright side to every screwed up week.


Similar Threads

  1. Epoxy clay
    By Bohica in forum Techniques
    Replies: 12
    Last Post: 23rd December 2007, 07:31 AM
  2. Epoxy Clay
    By nomopbo in forum Product and Vendor Reviews
    Replies: 13
    Last Post: 5th February 2007, 06:38 PM
  3. Fix-It Clay Epoxy
    By Cougar93 in forum Techniques
    Replies: 13
    Last Post: 6th May 2006, 11:17 AM
  4. Clay Epoxy: Fix-It vs. Plumbers
    By BobCox in forum Techniques
    Replies: 26
    Last Post: 7th December 2005, 08:45 PM
  5. Replies: 5
    Last Post: 7th November 2005, 03:06 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •