### Help Support The Rocketry Forum:

#### 1974_Trident

##### Well-Known Member
Things were so simple when I was a kid building Estes kits. I just followed my father's advice, "Duco Cement is the best stuff for building models." Looking back I think he was on to something, certainly for the small balsa/cardboard models. Duco even bonds excellently with plastics.

Now that my kits are getting bigger (I just started an Aerotech G-Force) and the materials more substantial and varied in composition, I am looking for strong adhesives in large quantities that will stick well particularly to the body tubes and plastic fins.

I began using epoxy and I really like it. I like the way epoxy handles and how strong it cures. My only concern is that not all epoxies bond well to all materials. I am using Loctite epoxy because I can go to Home depot and score an eight ounce kit for $15. While reading the directions I noticed that the five minute epoxy (in the red and blue packaging) is not recommended for use on most plastics. No sweat, Loctite also sells a seven minute epoxy (in the blue and yellow packaging) which promises to be great for all plastics except for non-stick type stuff. I am not building cookware so that's ok. The problem is that the seven minute epoxy is only available locally in 0.85 ounce syringe kits for$5. That's roughly ten times as expensive by weight compared to the five minute epoxy.

Does anybody here know if the five minute epoxy bonds well to plastics we find in model rocket kits?

Are there any tried and true epoxies available that you could recommend?

Also, for the small rockets; I helped my son build an Estes Patriot Missile a few weeks ago and we used the Testor's Model Rocket Cement (in the red tube). It seemed to work well but after a dozen flight we have popped off two fins. The glue joint is cleanly separating from the body tube fillet and all. Our remedy so far has been to re-glue the joint back on maintaining the original fillet so we don't have to do any touch up painting. We use CA for this. For the rockets currently under construction we lightly sanded the body tubes and remarked the fin lines before gluing the fins on with CA. I am planning to use Elmer's Carpenter's Wood for the Fillets.

Any thoughts of what I should do differently or more/less of?

#### NjCo

##### Well-Known Member
Also, for the small rockets; I helped my son build an Estes Patriot Missile a few weeks ago and we used the Testor's Model Rocket Cement (in the red tube). It seemed to work well but after a dozen flight we have popped off two fins. The glue joint is cleanly separating from the body tube fillet and all. Our remedy so far has been to re-glue the joint back on maintaining the original fillet so we don't have to do any touch up painting. We use CA for this. For the rockets currently under construction we lightly sanded the body tubes and remarked the fin lines before gluing the fins on with CA. I am planning to use Elmer's Carpenter's Wood for the Fillets.
CA can get brittle over time so it's not a good choice for fins which take a lot of strain during flight. Yellow glue is a much better choice. Also, the recent Titebond Molding & Trim glue is really great. It's thicker than normal wood glue so it doesn't run and it dries slightly thicker as well so it's great for fillets.

For plastics I would recommend ditching the plastic model cement. The type of plastic that Estes uses doesn't work well with this type of cement and you will get fins popping off eventually. The best stuff to use is a plastic welder. The brand I use is Ambroid ProWeld but there a number of different brands. Check you local hobby store and they will likely have one. This stuff is essentially a plastic solvent. It dissolves the outer layer of plastic on the mated parts and bonds them together as if they were a single piece of plastic. This stuff makes rock solid joints! The only thing you have to watch out for is that the pieces have to perfectly align with each other without a lot of gaps for this stuff to work. It's also pretty toxic so you have to use it in a well ventilated area and I'd avoid having the kids around.

#### troj

##### Wielder Of the Skillet Of Harsh Discipline, Potent
Epoxy isn't a good choice for any of the plastics used in hobby rocketry.

I believe AeroTech recommends CA for their kits. I'd probably stick with that recommendation.

For wood & paper joints, I typically use Titebond II, up through I motors. That includes Estes-type kits.

Plastics are always a challenge, and some plastics moreso than others. I once built a rocket out of pill bottles, and had a hard time finding an adhesive that would work on that particular plastic. I found some that was \$150 an ounce, and specific designed for it, but that was a bit outrageous. I did finally find a LocTite product that worked acceptably, but it's not much use for other materials.

-Kevin

#### MarkII

##### Well-Known Member
Devcon makes an epoxy that they market as being for use with plastics. It comes in the regular 25 ml dual plunger tube and you might also be able to find it in squeeze tubes. If your local hardware store doesn't have it, you can find it at Walmart. Also Lowe's, and probably Home Depot, too.

Fast-setting epoxy (5 minute, 7 minute, etc.) is convenient, but it isn't as strong as slower-curing epoxies. When you are at the store buying the Devcon Platic Epoxy, do yourself a favor and also pick up some Devcon 2 Ton Epoxy. It's a very good general purpose epoxy.

As you are finding out, each type of adhesive is formulated to bond a certain set of materials, but there is no single adhesive that effectively bonds all materials. Plastics are particularly difficult to bond. Testor's plastic cement in the red tubes has been repeatedly reformulated over the years to make it safer and less likely to be abused, but these changes have reportedly (and ironically) also rendered it less effective as a plastic cement. It might be still OK for static models that won't be handled much, but I wouldn't trust it for anything that is going to undergo the stresses of being launched with a rocket motor.

To get a good overview of the range and variety of adhesives that work well for our hobby, visit a well-stocked hobby shop. Read labels; they will tell you what the product is formulated for.

Epoxy is a good, strong adhesive that is effective as a bonder for a wide range of materials. Depending upon what type and size of rocket you are building, it can either be mandatory, an option, or total overkill. It is dense and very hard (one of its beneficial qualities) and because of that, it can really add a lot of weight to a small model rocket. Depending on what the project actually requires, there are often lighter alternatives.

On my adhesives cart (yes, cart) in my rocket room, I have around two dozen different products. Some are very specific to a very narrow range of applications, while others have much broader uses. For bonding many types of plastics, I have heard that Plastruct Bondene Styrene & ABS Plastic Solvent Cement works quite well. You can usually find it in a hobby shop. I have a bottle of it (it is a liquid that comes in a 2 oz. glass bottle) but I haven't tried it yet because I haven't had any need to bond any plastic parts in awhile.

For bonding fins to body tubes, wood glue/carpenter's glue works extremely well, and it is by far the most popular adhesive for this purpose in model rocketry. Titebond (either II or III) and Gorilla Wood Glue are high quality, strong wood glues. CA's are a whole story in themselves. Do a search on the forum for threads relating to specific adhesives like CA, epoxy, wood glue and plastic cement. There have been really exhaustive discussions of all of them in the past 6 months.

MarkII

#### 1974_Trident

##### Well-Known Member
...To get a good overview of the range and variety of adhesives that work well for our hobby, visit a well-stocked hobby shop. Read labels; they will tell you what the product is formulated for...

For bonding fins to body tubes, wood glue/carpenter's glue works extremely well, and it is by far the most popular adhesive for this purpose in model rocketry. Titebond (either II or III) and Gorilla Wood Glue are high quality, strong wood glues. CA's are a whole story in themselves. Do a search on the forum for threads relating to specific adhesives like CA, epoxy, wood glue and plastic cement. There have been really exhaustive discussions of all of them in the past 6 months.

MarkII
I tried the hobby shop route. I looked in the yellow pages and even recognized the names of some huge hobby shops which I used to spend hours in during my youth just admiring all of the rockets and planes planning which one I would build next after mowing a few more lawns. I started making phone calls. Every single hobby shop listed in the book is out of business, without exception!!!

While I was in Big Orange yesterday I spent some time looking at their adhesive selection. They have the Titebond glues and Gorilla glues but I don't recall if they had Gorilla "Wood" glue, I know they had the foaming Gorilla Glue which doesn't seem very suitable for rocketry. I have been using the Gorilla CA with success. My favorite online retailer has a nice collection of CAs and epoxies. I'll buy a variety, if I decide that any aren't quite right for rocketry I will always find a use for them around the house. I used the Elmer's Carpenter's Wood Glue for filleting fins on the Big Bertha and Red Max and I an not pleased with the result. The glue skins over and as the glue dries and shrinks the skin tears and leaves random pits.

I'm not sure where on the spectrum of CA viscosity the Gorilla CA falls but it seems pretty thin, just like Crazy Glue. How much shrinkage should I expect as CA dries? The stuff I'm using shrinks quite a bit. Do the thick CAs shrink any less?

In regards to searching for threads about the various adhesives, can you recommend search terms? I tried searching for the various types of adhesives and almost all of my search results were threads where a type of adhesive was mentioned but overall the thread was irrelevant to discussion on adhesives.

#### MarkII

##### Well-Known Member
The reason that I suggested going to a hobby shop was so that you could browse around and read labels. A hobby shop will also have stuff that you can't find anywhere else.

Do you have an arts and crafts store, like Michael's? That would be another good place to browse around in.

I found my Gorilla Wood Glue at Lowe's. Gorilla Polyurethane adhesive (the stuff that foams up) does have its uses in rocket building, though; you'd be surprised. I haven't used Gorilla CA. Cyanoacrylic adhesive does not shrink. The water-thin variety is readily absorbed into anything porous, though, and when it cures, the bulk of the liquid evaporates. The cured CA that remains and creates the bond is in a very thin layer. For thin CA to work as an adhesive, the parts that are to be bonded must fit together perfectly (tightly), with no gaps. If there are any gaps between the parts that you are bonding, or you are bonding porous materials, then you can use medium viscosity (gap-filling) CA or slow-curing (thick viscosity) CA. You have other choices as far as adhesives for rocket building, though.

I haven't read too many posts that praise Elmer's Carpenter's Glue. The preferred brand around here seems to be Titebond (either II or III). Gorilla's wood glue is a new product; I bought some when I couldn't find any Titebond in anything smaller than half-gallon jugs at the Lowe's that I happened to be in, and I like it so far.

There are a couple of popular ways to make fin fillets. One is to use 30-minute epoxy that has been thinned with microballoons. Another way that is starting to catch on is to use a brand-new product, Titebond Molding and Trim Glue. I have used both, and can attest that each method produces smooth, even and bubble-free fillets. (Epoxy mixed with microballoons can be sanded after it has cured in order to enhance the evenness and smoothness of the fillets.)

MarkII

#### dixontj93060

##### Well-Known Member
I have seen some use the Gorilla poly glue for attaching bulkheads within nosecones (traditionally a tough thing for epoxies)--anyone have some specific experiences they can share in this application?

#### MarkII

##### Well-Known Member
I have seen some use the Gorilla poly glue for attaching bulkheads within nosecones (traditionally a tough thing for epoxies)--anyone have some specific experiences they can share in this application?
I used it to secure the motor mount in a cone rocket. The thick, foamy bead of cured glue essentially formed a thick fillet around the base of the mount, filling the space between the sides of the mount and the inside tip of the cone. I have also used it to secure weight inside of a plastic nose cone. Like I said, it has its uses. The bond it creates is very strong and shock-resistant.

MarkII

#### Micromeister

##### Micro Craftman/ClusterNut
TRF Supporter
As with everything in this hobby there are a ton of different methods and materials at our disposal.
Plastics are a particually prickly subject as the adhesive and method varies with the material. Styrene and acrylics can be jointed by solvent welding with anyone of a number of very good products on the market. Ambroid Proweld, Plastistruct Plastiweld, & Tenax-7r are 3 decent "solvent welding products". Testors Liquid cement is the weakest of these solvent welding products but works well with styrene nosecones. other more agressive solvents like MC(Methylene Chloride) MEK or even Actone can be used on Styrene and acrylics with great efficency. MC being the best choice.
All that side if you don't know what "type" plastic your dealing with there are time other adhesives come into play along with alternative joining methods.

Generally epoxies 5 or 30 minute are not recommeded for "plastics" but can be combined with a joining method called "epoxy riveting" that has been proven to permanently join some of the most difficult to attach plastics to just about any other mateial. this method has been used to join, Polycarbonate(Lexan), Polypropylene, butyrates and polyethyene to themselves and just about every other type meterial. This method is used exclusively on all my Odd-Rocs to join Fins and motor mounts to all the about
This method required the drilling of a couple lines of 1/16" holes down both side of the area around the fin attachment location prior to running the line of epoxy then attaching the fin.
Someone mentioned Gorilla glue. I have to say as a wood worker I love this stuff IF the parts can be securely clamped together or it's in an area noone will ever see as this stuff foams uncontrollably and will leave gaps an weak spots if not tightly clamped. With so many MUCH better choices of ahesives and glues for joining materials Gorilla glue (or any Polyurethane glue) should be left for the Wood working guys as it's really not very useful in this
hobby
I'm in the process of writhing a new Tech-Tip for my club which should be up on the narhams.org library website sometime before the first of the year. it may be of help as it deals with many of the Plastics we run into and adhesives and glues along with working methods of joining them for our use.
the Article is written and has been submitted for posting, Look for Tech-Tip-017-Working with Plastics.
hope this helps.

#### NjCo

##### Well-Known Member
Styrene and acrylics can be jointed by solvent welding with anyone of a number of very good products on the market. Ambroid Proweld, Plastistruct Plastiweld, & Tenax-7r are 3 decent "solvent welding products". Testors Liquid cement is the weakest of these solvent welding products but works well with styrene nosecones. other more agressive solvents like MC(Methylene Chloride) MEK or even Actone can be used on Styrene and acrylics with great efficency. MC being the best choice.
Not sure about the other products you mentioned but ProWeld is basically just Methylene Chloride. And it also says right on the bottle the types of plastic it will work with. Styrene, butyrate, ABS and acrylic. It will also work with lucite and plexiglass but not as well. That's why it's best to see the bottles in person if possible so you can read the labels. If you don't have a hobby store in your area then a craft store is often a good choice. Hobby Lobby usually has a good selection of adhesives and modeling products. Micheal's will also work occasionally but they tend to have the more usual stuff and not as many specialty products.

#### MarkII

##### Well-Known Member
In regards to searching for threads about the various adhesives, can you recommend search terms? I tried searching for the various types of adhesives and almost all of my search results were threads where a type of adhesive was mentioned but overall the thread was irrelevant to discussion on adhesives.
This thread contains some useful information on glues:

Chris Michielssen (hcmbanjo) has a site with useful information for beginners, including a section on adhesives:
https://www.howtobuildmodelrockets.20m.com/

Sirius Rocketry's web site has an article by BSI about their CA:
https://www.siriusrocketry.biz/isho...pter=1&zenid=a7a1809c2437c95048284d762e62e4fb

and another one about their epoxy:
https://www.siriusrocketry.biz/ishop/index.php?main_page=page&id=6

along with an FAQ:
https://www.siriusrocketry.biz/ishop/index.php?main_page=page&id=7

MarkII

#### MarkII

##### Well-Known Member
The "Techniques" section of TRF is a gold mine of information about adhesives.

Here's YAET (Yet Another Epoxy Thread):

and EYAET (Even Yet...):

YACAT:

Launch lug fillets sans air bubbles:

YALLFT:

YAFT:

This barely scratches the surface. There is much more, but you get the idea.

MarkII

#### Micromeister

##### Micro Craftman/ClusterNut
TRF Supporter
Not sure about the other products you mentioned but ProWeld is basically just Methylene Chloride. And it also says right on the bottle the types of plastic it will work with. Styrene, butyrate, ABS and acrylic. It will also work with lucite and plexiglass but not as well. That's why it's best to see the bottles in person if possible so you can read the labels. If you don't have a hobby store in your area then a craft store is often a good choice. Hobby Lobby usually has a good selection of adhesives and modeling products. Micheal's will also work occasionally but they tend to have the more usual stuff and not as many specialty products.
Plexiglass is a Brand Name Acrylic plastic, Lucite is a Brand Name for modified acrylic, actually Acrylic with a cross-linked polysilicate surface treatment. MC is the preferred solvent welding agent for both When we start taking about Brand names it simple confuses the subject. Ambriod Pro-weld is a fine product but you'd have just much luck with MEK from the home improvement store and it'll cost a ton less.
The way to Learn what solvent or adhesive works with what "Plastic" is to study the various Types of plastic materials rather then other way around. Lots of great stuff on-line, in the industrial catalogs under the Plastic TYPE rather then brand name.. ie don't look for LEXAN or PLEXIGLASS but Polycarbonate and Acrylic This is exactly why I'm writing the article and doing a demo for the club next month.
Hope this helps.

Last edited:

#### grafgulch

##### Well-Known Member
This maybe old news, but I just heard the TENAX-7R adhesive company is going out of business. I thiught that stuff was great!

Paul

#### Stymye

##### Well-Known Member
adhesives---- chemical based like cya ,epoxy..ect

glues-----made from natural substances like the old hyde glue and some white glues,pastes and resins..ect

#### Rocketeer41

##### Well-Known Member
Ok, now I understand what are adhesives.:boat: