What am I doing wrong?

[accooper]

I am new to CA, and I hate it, but I need it. I am trying to make some transitions using styrene plastic. But no mater what I do, CA will not stick to it.

I have tried the cheap stuff.

No go.

I went to the hobby shop and bought the good stuff.

No go.

I even bought some new styrene thinking that the other may have had some type of solvent on it.

Any ideas here. I am really getting frustrated.

Andrew From Texas

 

[tbzep]

Regular CA isn't all that good for styrene. You need to use something that's made for bonding styrene like Tenax 7R, Ambroid Pro Weld, Tamiya Super Thin, etc. I like Tenax 7R. A little bit goes a really long way. These are all better than the classic Testor's model cement, which doesn't have a good strong solvent like methylene chloride any more.

Some folks also like to use MEK, which can be found at your local hardware store.

 

[accooper]

I cannot tell you how crazy this is making me. From what I have been told CA is the end all in Glue!

It isn't.

I will try your suggestion.

Thanks For The Help.

Andrew From Texas

 

[tbzep]

Some CA's will bond some plastics, but the general varieties that I've used haven't done well with them.

 

[NjCo]

Yeah, CA just isn't what you're looking for. Plastics like styrene aren't porous enough for the CA to provide a good bond between two pieces. What you need is a solvent based adhesive that will essentially melt a thin layer of the styrene to allow the two pieces to be welded together. I've used Ambroid Pro Weld and it works great. You should be able to get it at any good hobby store. You won't see this stuff off the shelf in most stores because it's basically just methylene chloride which is pretty toxic stuff. It only takes a little bit of this stuff, hold the pieces together for about 10 seconds and the end result is the equivalent to one piece of plastic.

I have seen a bunch of people complaining that the styrene fins on their Estes D Region Tomahawk keep popping out of the styrene fin can. That's because they use CA or even plastic modeling cement which is what Estes recommends. Plastic modeling cement usually contains toluene which is another type of solvent. I put my fin can together with Pro Weld and the entire fin can is rock solid.

 

[accooper]

Will this glue work with me making transitions? Most are BT60 and below.

Andrew

 

[tbzep]

Will this glue work with me making transitions? Most are BT60 and below.

Andrew

CA will bond paper and balsa parts, so it will work for your transition sections. I like using yellow or white glue whenever I can, but I use CA when I need an instant bond, or to soak into paper/balsa parts to harden them.

Tenax 7R and the others I mention actually melt styrene parts together, welding them into one piece, as NjCo mentioned.

 

[accooper]

SOOOOOO, you are saying that I can't use the glues you suggest to make styrene transitions or are you saying I can?

I am so confused.

Andrew

 

[MarkII]

CA doesn't need a porous surface for bonding; in fact it does better if the surface is non-porous. (It works really well for bonding steel to steel or aluminum to aluminum, for instance.) Nevertheless, it is not the best adhesive for absolutely every material. Maxi Cure (or slow-setting, extra thick CA) can reportedly work well to bond styrene to styrene, but the other bonding agents that tbzep mentioned would be good choices.

I haven't used the others mentioned, but I have used Tenax-7R. This stuff is runny like water, but it is extremely volatile (it contains ether) so it dries almost instantly. To use it, have a small #1 synthetic bristle paint brush handy. Put the parts to be bonded together (they must mate perfectly, surface to surface) and clamp them, then use the paintbrush to paint a thin line of Tenax-7R down the seam. The Tenax (can't really call it a glue; more like a solvent and bonding agent) will wick into the joint and bond the two parts together without leaving behind any bead line. Remove the clamp after a couple of minutes. Just use enough Tenax to paint a thin line; if you use too much, it will melt the plastic. Keep your bottle of Tenax-7R tightly capped between uses, so that the solvent doesn't evaporate out of the bottle. (The hobby shop will probably also sell other Tenax adhesive products, too, but the one you want is the 7R, with the yellow label.)

Isn't there a sticky thread that deals with the whole matter of adhesives somewhere? The choice of which adhesive/bonding agent to use for a particular job is dependent upon what two materials are being bonded, how well they fit together, how strong of a bond is desired, and probably a few other factors. No single adhesive is ideal for everything.

MarkII

 

[NjCo]

Will this glue work with me making transitions? Most are BT60 and below.

Andrew

If it's plastic to plastic bonds then yes it will work. If it's plastic to paper or to balsa then I think I'd go with modeling cement which has a weaker solvent for the plastic but also an passable adhesive as well. This type of bond works OK with most low power rocket applications. The other option is an epoxy adhesive which has a strong adhesive that works well on a wide variety of materials but requires mixing and is a little harder to work with.

 

[JRThro]

SOOOOOO, you are saying that I can't use the glues you suggest to make styrene transitions or are you saying I can?

I am so confused.

Andrew

You can, if what you're doing is gluing styrene to styrene, or styrene to something else. Testor's also makes a liquid glue for styrene. The bottle of it that I have is a black plastic bottle, as seen here:
https://www.testors.com/product/136635/3507A/_/Liquid_Cement_1_Oz.

 

[Gus]

AC,

Adhesives are like fasteners. You've got bolts, you've got screws, you've got nails. What fastener works best depends on what you want to attach to what.

For styrene to styrene superglue gel will work, but you need to use a very thin layer, and accelerator will help. How well it, or any other adhesive, will hold depends on how much surface area you are able to join and how much tension the joint is under.

Adhesives like Tenax and Ambroid Pro-Weld (my favorite) work by actually melting the surface of the styrene and allowing it to bond to the adjacent piece. Again, surface area and joint tension play a big role in how well it will hold.

Perhaps if you post a picture of what you are trying to glue together we could help a bit more.

 

[tbzep]

SOOOOOO, you are saying that I can't use the glues you suggest to make styrene transitions or are you saying I can?

I am so confused.

Andrew

I forgot you were talking about plastic transitions. I'm used to making my own transitions. Yes, the stuff I was talking about will work on them as long as the parts fit together. Tenax is available by itself, or with a kit that has an applicator. I really like the Touch-n-flow applicator. I can apply tiny amounts of the stuff with it.

It's available at several places. This is one of the first sites that came up in a search. Tenax

 

[accooper]

Here are some pictures that I have of the few transitions I have made. These four I did get to stick after, my wife says, twenty tries. I don't know if you can see in the picture one of the larger ones is coming apart.

My largest transition is a BT55 to a BT60. The smallest is a BT20 to a BT50.

Thanks for all your help. This is really frustrating.

Andrew (Who Is Not Happy) From Texas

 

[Micromeister]

Here are some pictures that I have of the few transitions I have made. These four I did get to stick after, my wife says, twenty tries. I don't know if you can see in the picture one of the larger ones is coming apart.

My largest transition is a BT55 to a BT60. The smallest is a BT20 to a BT50.

Thanks for all your help. This is really frustrating.

Andrew (Who Is Not Happy) From Texas

AC:
PM sent hope it helps

 

[accooper]

I think we have hit on something here guys. I just made a transition using Testors Liquid Cement (my wife uses it for some of her scrap booking stuff. It ain't perfect but it is sticking together.

I will keep y'all informed on how it goes. My wife said that maybe my fat little fingers won't be able to make really small transisitions.

Andrew From Texas

 

[luke strawwalker]

I cannot tell you how crazy this is making me. From what I have been told CA is the end all in Glue!

It isn't.

I will try your suggestion.

Thanks For The Help.

Andrew From Texas

Whoever told you that led you down the garden path-- THERE IS NO BE-ALL END-ALL GLUE, though of course nearly everybody advertises their product that way.

I keep some CA on hand, the pink ultra thin stuff and the yellow medium/thick stuff from Hobby Lobby, but honestly I don't use it much at all for actual building. The thing I REALLY like CA for is hardening balsa nosecones, transitions, and occassionally fins, and for repairing cracked fins or stuff like that where the pieces will fit PRECISELY back together again. CA is also TERRIFIC for turning simple paper transitions into something almost akin to plastic-- tough and smooth!

Every adhesive has it's benefits and drawbacks, or strengths or weaknesses as the case may be. Wood (yellow) glue is best on wood/wood or wood/paper joints. White glue is best on paper/paper. Epoxy is probably THE most versatile, but also a PITA to mix, handle, and work with, and heavy, and usually overkill on LPR rockets for most things. The thickened white glues (Titebond Moulding and Trim Glue, Aileene's, etc) are great for fillets but I'd still use yellow glue to actually attach the fin to the tube, then fillet with the thickened white glues. Even urethane (gorilla) glue has some uses, though it's 'foaming' characteristics can be problematical. Rubber cement and contact cements even have their place, as does spray adhesives like Super 77.

For plastics, you need PLASTIC GLUES... and the exact brand or formulation depends on the type of plastic you're working with-- some are VERY hard to glue up. For styrene, get styrene glue-- the suggestions in the other responses are excellent. STAY AWAY from the tube-type "model airplane glues" (ESPECIALLY the 'environementally friendly (non-huffable) kinds, as they're basically just citric acid that doesn't work worth a darn).

The reason I don't use more CA is that I haven't found ANYTHING that needs doing that CA does a better job at than yellow or white glues, in rocketry anyway, other than quick repairs and hardening balsa and paper parts. Want fins attached 'nearly instantly'?? Use a double glue joint-- the speed of CA with the strength of yellow glue!

Anyway, the point to remember is, THERE AIN'T NO MAGIC BULLET glue that does EVERYTHING...

Good luck! OL JR

 

[luke strawwalker]

AC, lemme give you another tip that is EXTREMELY helpful for those of us with 'fat fingers'...

Get yourself a mess of those little 'hemostat' clamps from the hardware store, or better yet, when one of those big 'Homier' or "Cummings Tools" truck tool sales come to town. Don't buy them at the hobby shop; they're REALLY screw you on the price, though the hardware store is often fairly inexpensive on them. They look like little bitty long-handled scissors, and they make PERFECT clamps for this sort of work, ESPECIALLY making paper (and by extension plastic) transitions from sheet materials.

I bought about 8 or 10 of the little buggars for about $1 each at various sales and stuff, and they are EXTREMELY handy! The only thing I didn't like about them was the serrated jaws-- they would emboss a rather ugly serration mark into softened glued paper, but I fixed that easy enough-- I took mine to the shop and gingerly ground down the serrations until the jaws were smooth. One could accomplish the same thing with a Dremel tool with a cutoff disk or sanding drum installed, or even a good file and some elbow grease.

Last tool sale I went to I picked up a set of dinky plastic clamps in various sizes/shapes, a package for like $6 for 10 clamps, something like that. I also LOVE regular old spring clothespins-- pick up a pack next time your in the hardware store-- they're very handy too.

I've been building a LOT of Dr. Zooch kits and virtually ALL of his kits use paper transitions for things like capsule wraps, stage transitions, and engine bells, antenna canisters, etc. Once you get used to working with the stuff and choose the right glue (NOT CA) and have the clamps to help you 'hold things together' til the glue sets, you'll be amazed at how much you'll like paper transitions. Sounds like you've had some problems with paper transitions and switched to styrene thinking it would solve all your problems, when actually FMPOV the styrene is probably actually making them much worse! Thing is, when you're making transitions out of flat sheets of material, no matter what the material is, you're having to fight the natural tendancy of the material to 'lay flat'-- you HAVE to use some sort of clamp (even your fingers count if you're not using anything else) until the glue 'grabs' and can hold the pieces together against the innate strains inside the material trying to spring apart and 'lay flat' again...

I use white glue on paper transitions if they're less than about 2-3 inches long (as most are) and then when the glue is dry, I HARDEN the transition with CA, which soaks into the paper and bonds all the fibers together much like fiberglass, making the transition VERY smooth and tough compared to regular paper (be warned though, do this outside as the fumes STINK! and also, don't do it to paper wraps-- the CA turns the paper a bit 'translucent' and it's fine for painting over but will ruin pre-printed graphics on the paper.)

For longer transitions, you really have to use rubber cement or contact cement to bond the seam, because the white glue tends to make the paper 'wavy' and warped from the water in the glue swelling and softening the paper. Tim Van Milligan produced an EXCELLENT tutorial video on YouTube awhile back dealing with paper transitions-- go to www.apogeerockets.com and look for the links to the video tutorials.

Good luck! OL JR

 

[accooper]

My wife will never believe it. I actually made a decent Transition for BT50-BT20. I didn't think my fat fingers could handle it. Going to Liquid Plastic Cement has changed everything.

Thanks for all the help and advice!

Andrew (One happy old rocket builder!)

 

[accooper]

Why CA works sometimes and others it doesn't.
(as explained by my know everything freshman son and his room mate)

It all comes down to shear strength and gluing area.

The reason that Mr. Rocket could easily make a transition was how large it was. According to geometry( I guess) shear strength increases as size decreases as long as the material remains the same.

CA has lousy shear strength, and that according to these to experts was causing my problems. They tell me that is why companies who advertise Super Glue are very careful what they show.

So although Mr. Rocket's technique was great it only works on LARGE transitions. SOOOO, that would not work on what I am doing which is small, nothing larger than BT-60, and really not work on anything like a BT-5.

These two guys, one is into high power, suggest that:

1. Not use CA

2. Not use a butt joint

3. Use a glue made for styrene

4. Use the Estes lap(?) joint.

This is what I have been doing and gotten great results.

I have enclosed a couple of pictures so you can see the results.

One other thing I have learned. Never use a sharpie to mark styrene. It won't even sand off! On the white transition that is not a crack. That is Sharpie that won't even sand off. Primer does cover it up thou.

Andrew From Texas

 

[NjCo]

That is Sharpie that won't even sand off. Primer does cover it up thou.

Be careful with Sharpies and other markers. They have a tendency to bleed through paints. It's best to stick with pencil when marking your rockets.

 

[luke strawwalker]

Looking good AC... Those are nice transitions.

Quite right about CA's weakness in shear strength... CA is VERY strong in TENSION, but it's shear strength is rather pitiful, especially in shear planes exposed to shock loads (like fin tips hitting the ground and transferring that shock up to the fin/tube seam...)

Goes back to what I said about every different glue having a different job it excels at... OL JR

 

[accooper]

OK folks I did it. Take a look at these pictures. This is the transition I just made for a rocket I am designing called the Devils In The Details. This is just the transition but I will upload pictures as they become available in a new thread. Once again, thanks for the help.

Andrew From Texas

 

[foose4string]

Looks like you've found a solution, and have done a nice job.

For those sizes, I think you might have an easier time making paper(cardstock) transitions. I use plain ol' white glue to the tab and splice the ends, then hold for a minute or two with tweezers until the glue sets(or use clamps like Luke suggested). Cardstock holds up fine in my experience. Soak cardstock with CA once they are formed if you are worried about toughness. Sand smooth. They'll come out looking as good as styrene. Also, you may want to make the transition diameters match the OD of the tube exactly so you get a nice, flush fit that won't require any filling. Glue tube couplings at the top and bottom of the transition for a solid fit. Build a bulkhead inside the bottom coupler if it is a separation point for the rocket recovery.