Quantcast

Amazon build question

The Rocketry Forum

Help Support The Rocketry Forum:

CaptainVideo

Well-Known Member
Joined
Mar 13, 2017
Messages
95
Reaction score
25
I was watching a video on building the Amazon rocket, and part of it involved gluing a plastic coupler to the rocket tubes. The plastic base that the fins go on also goes to the paper tube. I went through a lot of glue threads and came out more confused than ever. For plastic parts I used to use the testors model glue that comes in a red tube. But that is rated for plastic, and to make things more confusing I read this in another post
Be leery when using Testor's model cement on plastic rocket parts. Testor's is formulated for styrene plastic and a lot of what's coming out of China these days isn’t styrene and Testor's won't hold.
So the testors might not even work for gluing the plastic fins to the plastic base? What should I use for gluing the plastic base and coupler to the paper rocket body tubes?
 

bradycros

Well-Known Member
Joined
Feb 13, 2009
Messages
4,284
Reaction score
5
The longer the epoxy takes to cure the stronger it gets. I would use 30 min. epoxy.
 

jpoehlman

Well-Known Member
Joined
Sep 29, 2014
Messages
219
Reaction score
9
Testor's plastic model cement has worked fine on all the Estes E2X kits I've done with kids. Use what suggested in the instructions, you will be fine.
 

TangoJuliet

Well-Known Member
Joined
Jun 26, 2016
Messages
1,239
Reaction score
9
On larger LPR and all MPR rockets I would use 30 minute epoxy. Be sure to scuff the plastic with some 320 grit sandpaper for added grip by the glue.
 

CaptainVideo

Well-Known Member
Joined
Mar 13, 2017
Messages
95
Reaction score
25
Wound up ordering the testors red off ebay for $5.20, which is what I used to use years ago for plastic rocket parts. From what I recall it stank but worked better than the non toxic version. The seller also threw in a small bottle of Testors CA, which I'm sure I can find a use for. Someone mentioned it is good for tacking on wood fins while the Elmers(or whatever other white glue is used) dries, so you don't have to sit there holding them to the tube.
The instructions just say "plastic cement", so I guess the testors red fills the bill. Between that and the sanding sealer(which also stinks), I'll probably wait till the end of April to start construction, as I want to have the window wide open.
 

T-Rex

Ordinary Average Guy
TRF Supporter
Joined
Jul 22, 2011
Messages
2,997
Reaction score
51
For non structural connections, I will usually gouge the surface of the plastic with a hobby knife (X's all the way around) and just use wood glue....
YMMV
 

bradycros

Well-Known Member
Joined
Feb 13, 2009
Messages
4,284
Reaction score
5
Wound up ordering the testors red off ebay for $5.20, which is what I used to use years ago for plastic rocket parts. From what I recall it stank but worked better than the non toxic version. The seller also threw in a small bottle of Testors CA, which I'm sure I can find a use for. Someone mentioned it is good for tacking on wood fins while the Elmers(or whatever other white glue is used) dries, so you don't have to sit there holding them to the tube.
The instructions just say "plastic cement", so I guess the testors red fills the bill. Between that and the sanding sealer(which also stinks), I'll probably wait till the end of April to start construction, as I want to have the window wide open.
"don't have to sit there holding them to the tube."

Make a fin guide out foam board, available at Wal Mart. It's cheap.

Nip off the corners where the guide will touch the fin/body tube joint so any oozing glue doesn't get on the guide.

Go to www.payloadbay.com to make your own custom template.

IMG_1569.jpg


IMG_1570.jpg


IMG_1571.jpg
 

Nytrunner

Pop lugs, not drugs
TRF Supporter
Joined
Oct 15, 2016
Messages
7,773
Reaction score
3,402
Location
Huntsville AL
Mine has 4 flights with Elmer's at the coupler lol.
Hasn't budged yet. I didn't worry too much about an E2X model
 

dr wogz

Fly caster
Joined
Feb 5, 2009
Messages
6,118
Reaction score
1,296
Location
Land of Poutine!
just a note here:

the older Testor model cement would soften / melt the plastics, and would result in a melty plastic to melty plastic bond. Kinda like using acetone to glue the parts, or for lack of a better work "weld" the parts together.

Epoxy doesn't always stick to plastics, ABS being one that it don't stick to. It will fill in the scratches, cracks & crannies and hold on by sheer will, like a nut holds onto a bolt..

Cyanno Acrylic (CA) will also fill the voids, scratches etc.. and will hold as the epoxy, but at a much more molecular level.

I'd go CA on your application..


https://www.motherearthnews.com/~/m...for Choosing the Right Glue/198-088-02tab.jpg
 

Micromeister

Micro Craftman/ClusterNut
TRF Lifetime Supporter
TRF Supporter
Joined
Jan 19, 2009
Messages
15,074
Reaction score
47
Location
Washington DC
just a note here:

the older Testor model cement would soften / melt the plastics, and would result in a melty plastic to melty plastic bond. Kinda like using acetone to glue the parts, or for lack of a better work "weld" the parts together.

Epoxy doesn't always stick to plastics, ABS being one that it don't stick to. It will fill in the scratches, cracks & crannies and hold on by sheer will, like a nut holds onto a bolt..

Cyanno Acrylic (CA) will also fill the voids, scratches etc.. and will hold as the epoxy, but at a much more molecular level.

I'd go CA on your application..


https://www.motherearthnews.com/~/m...for Choosing the Right Glue/198-088-02tab.jpg
CA is the absolute Worst choice for bonding any plastic to anything! CA becomes Brittle very shortly after curing. it has NO molecular level bonding what so ever. It is ONLY a surface bonding agent.

Solvent Welding is the very BEST method of bonding Styrene, ABS, Acrylic and Modified Acrylic plastic. Acetone, MEK, and (MC) Methylene Chloride are the "Preferred" Solvent welders. MC Being the very best and (Hottest) Choice. Testors Liquid Cement is by far the Weakest of the Solvent weldering agents. Testors Tube type cement is a weaker solvent.

For hard to bond Plastics like Polycarbonate (Lexan), Polyproplene, and others 5 & 30minute epoxies are the best choice particularly when teamed up with "The Epoxy Rivet Method".

If you needd more information about what glues or adhesives work with which plastics, might I suggest a visit to www.narhams.org from the Left hand menu - Look for the Library section under Tech Tips-017 "Working with Plastics". It's a 12pg pdf with extra photos and in depth text.
A quick read from this Tech Tip will answer many of your misunderstood assumptions about what works with what plastic.
 
Last edited:

CaptainVideo

Well-Known Member
Joined
Mar 13, 2017
Messages
95
Reaction score
25
I'm a little leery of epoxy, it doesn't seem all that noob friendly. LOTS of posts on Amazon reviews with comments like "When arrived, hardener was rock solid, shelf life sucks, never hardened, said 30 min but was solid in under 2 min".
 

dhbarr

Amateur Professional
Joined
Jan 30, 2016
Messages
7,004
Reaction score
1,454
I'm a little leery of epoxy, it doesn't seem all that noob friendly. LOTS of posts on Amazon reviews with comments like "When arrived, hardener was rock solid, shelf life sucks, never hardened, said 30 min but was solid in under 2 min".
Grab some 10-15min at the hardware store and play with it on some spare junk ( cereal boxes, popsicle sticks, milk jug lids ). I mix it on a paper plate w/ a tongue depressor, newspaper in the dining room.

Not scary ( but do wear nitrile gloves ).
 

Micromeister

Micro Craftman/ClusterNut
TRF Lifetime Supporter
TRF Supporter
Joined
Jan 19, 2009
Messages
15,074
Reaction score
47
Location
Washington DC
I'm a little leery of epoxy, it doesn't seem all that noob friendly. LOTS of posts on Amazon reviews with comments like "When arrived, hardener was rock solid, shelf life sucks, never hardened, said 30 min but was solid in under 2 min".
Don't be to leery of most epoxies: One does have to pay attention to actual "Pot Life" which is stated clearly on the containers. Generally 5 minute 1 to 1 epoxies have a pot life of about 3 to 5 minutes but have a full cure strength of an hour or more. 30minute epoxies have a bit longer pot life setting in 7 to 15 minutes with a full cure usually of 24hours.
the Slower the epoxy takes to fully cure the Stronger it is. and will retain a bit more flexability then 5 minute or most other glues, cements or adhesives.
As stated above. Get yourself a 10-15 minute epoxy from the hardware or home improvement store and experiment with it. I personally perfer DEVCON 5 minute and 30minute (2-ton) epoxies for most of my building. There are many others out there that are just fine... Except J-B Weld which is a great Structural Epoxy but for most Model rocket use is Way Overkill and Heavy.
 
Top