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Newbie - Questions on glues?

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  • Member since
    March 2020
Newbie - Questions on glues?
Posted by richiev on Tuesday, March 24, 2020 10:01 AM

Just finished my 1st model in ... well we wont give it years but lets just say there was a peanut farmer in the white house.  

It was a massive learning experince and i dove into it with a iwata neo and aircompressor to start buidilng airbrushing skills.  Overall it came out so-so - but thats what i exepected out a 1st model - most importantly I learned a ton and am already onto my next model a Tamiya P-47D Razorback. 

Question to the group:

I am kinda confused at the amouont of glues out there.  I dont really understand exactly when to use each one.  Right now i have Tamiya Extra Thin Cement (i guess for overall parts build where i can get capilary action), a canopy glue and testors cement.  But ive seen all sorts of other glues people are using including CA (thin and gel) , PVA, solvents etc.  

Can people tell me what kinds of glues (types and brands) they are using, and for what use cases ?  It will really help me out if i can hear what situations different glues help solve and why you decide to use one over the others.  

Thanks,

 

RichieV

 

Tags: glues , newbie
  • Member since
    August 2005
  • From: Mansfield, TX
Posted by EdGrune on Tuesday, March 24, 2020 2:47 PM

The whole modeling scene has changed since you last did this in your teens

Tube glue -- the old red Testors stuff, or the similar stuff in the black bottle with the long metal tube spout.   This is a mild solvent mixed with a plasticizer material which keeps it from evaporating so quickly.  It laso leads to stringing.    The two parts are sort of imbedded in a crystaline structure.   Age or freezing may break the bonds.  I have some of this on the bech that I use for long seams where liquid glues would evaporate before you get to the end.    I will tack these parts together then finish welding with liquid

Liquid glue -- a watery "hot" solvent ;  Methyl Ethyl Ketone (MEK), Tenax, Tamiya green top, etc.   These glues quickly melt the plastic then evaporate.   Since they are so thin they will flow by capillary action.   Hold the pieces together and touch a brush with the glue to the joint.  The glue flows.   Give it a few seconds then press the parts together and some glue beads may squeeze out.  Like welding metal the two parts are one piece.   Generally only used on polystyrene, but there are some solvents available for specialty plastics such as PVC or ABS.

Canopy glues.   These are white "Elmers type glues,  often called polyvinyl acetate (PVA).   There are many brands with varying drying times.   Generally go on white and evaporate to clear.   Since they are water based they do not craze or melt clear plastics.  They have a gap filling property.  They dry generally clear/translucent.  They are water cleanup

Super Glue/Cyano Acrylate (CA) is a glue which bonds the parts via a crystalline structure.    Good in tension strength.   Poor in shear strength.  Used on resin materials where solvent glues do not melt the parts (epoxy may also be used).  Used on dissimilar materials - plastic & resin, resin & metal.   Can be used as a filler if sanded soon after setting.  Wait until tomorrow and the glue will be harder than the surrounding plastic.  CA reacts wit the humidity in the air to harden.  CA gives off fumes as it hardens.   These fumes will often discolor clear canopu parts.  That is why CA is not widely used for canopies.  (That being said there are some who are able to treat the clear plastic with Future floor polish to avoid the CA fuming.   But that is for another post.)

A couple weeks ago the folks at Squadron Mail Order had a program on their Youtube channel on glues.   Jef Verswyvel, their resident pattern-maker - the guy in the hat - is good.   The other guy is a local "expert".   Take his comments about the glues thermally melting the parts together with an appropriately sized grain of salt.  An overall summary of glues showing different types & labels

https://youtu.be/nzlBwOUx_qQ

 

  • Member since
    September 2012
Posted by GMorrison on Tuesday, March 24, 2020 3:05 PM

To that excellent list I would add two part epoxy. It is useful in instances where you have dissimilar materials like resin, metal, etc. and you need to have a strong bond. It's kind of clumsy stuff but I use it for things like large resin hull pieces or wing to fuselage joins. It usually has a pretty slow cure time, and can be messy. But it doesn't fog clear styrene like CA will, and if you can clamp the parts together until cured, makes a strong bond.

An old sign maker told me a trick to remove the hardened epoxy; good old fashioned spirit turpentine.

  • Member since
    March 2020
  • From: South Florida
Posted by Having-fun on Thursday, March 26, 2020 9:03 PM

The explanation of the different types of glue is welcome info from a newbie like me, but, as I read the article, I realized that I have no idea of the material I am working with. How can I tell what type of plastic or resign I am working with?

  • Member since
    September 2012
Posted by GMorrison on Thursday, March 26, 2020 9:56 PM

Most, by far, are styrene plastic.

As for the rest, search "kit" review. You'll get info.

 

  • Member since
    March 2020
Posted by richiev on Friday, March 27, 2020 9:12 AM

Thank you everyone for replies.  So let me ask a couple more follow ups.  

  1. So in general would the 'liquid glue' be your primary goto for most parts where they can be used on a 'standard' model?
  2. Once you get the aircraft painted and are ready to add the landing gear and guns and ...  For some of these parts im thinking a PVA/ Canopy type glue might be easiest since it will dry clear and shouldnt screw up the paint around it?  

 

Thanks,

 

RichieV

  • Member since
    August 2005
  • From: Mansfield, TX
Posted by EdGrune on Friday, March 27, 2020 9:29 AM

richiev
    1. So in general would the 'liquid glue' be your primary goto for most parts where they can be used on a 'standard' model?
    2. Once you get the aircraft painted and are ready to add the landing gear and guns and ...  For some of these parts im thinking a PVA/ Canopy type glue might be easiest since it will dry clear and shouldnt screw up the paint around it?  

1)  For general assembly, Tamiya Extra Thin (Green top) is my first choice.   As indicated, I may go with a tube glue to tack long seams

2)  For landing gear on a mostly complete model I will go with a super glue, perhaps hitting with it with an accelerator.    Same with guns, bombs, fuel tanks, etc.   PVA-type glues, even the quick grab types dry over a longer period and will not provide for structural strength during this time.   Wing stores are a problem with gravity, either upright or inverted since there is a small glue surface area

PVA will work on a canopy as a last step on a model that is upright on its legs since you generally have gravity working for you

  • Member since
    September 2012
Posted by GMorrison on Friday, March 27, 2020 10:00 AM

When I'm finisging up a model I'll go over it with my optivisor on and touch up little glue spots, bright brass etc. with a fine tipped brush.

  • Member since
    March 2020
Posted by richiev on Friday, March 27, 2020 12:07 PM

Thank you.  This is kinda what i needed.  Ive been trying to fifure out the best way to build and paint and then put it all together.  

 

How do you use a super glue and accelerator?  What are the steps?

 

RichieV

  • Member since
    September 2006
  • From: Bethlehem PA
Posted by the Baron on Friday, March 27, 2020 1:22 PM

I've got some of each, because each has a different use. 

I ask first, "What material am I gluing?"

For styrene-to-styrene bonds, I use styrene glues, because they create a bond by melting the material, basically forming a weld. 

As has been mentioned above, there are tube glues-Testor's is the one I use-and liquid glues.  Testor makes some, Tamiya, and there are others.  Again, as mentioned above, the liquid glues flow into joints and seams by capillary action, and they evaporate quickly.  So I use them for things like gluing two airplane fuselage halves together, or the upper and lower parts of the wings.  I can hold the parts and flow the glue along the seam.

Another advantage of using this method is that I can apply a little pressure to the seam and extrude a bead of melted plastic along it.  When the plastic cures, I can use a knife to scrape away that bead.  This makes it easier to conceal the seam when finishing.

I use tube glue for styrene, but in cases where I want to make adjustments while the glue cures.  Not too often, but that tube still has its place on my bench.

I don't use CA glue or 2-part epoxy, to glue two pieces of styrene together.  As Ed noted, those glues hold the parts, but they don't melt and weld.  I prefer to have that bond, for plastic parts.

I do use CA to glue unlike materials together, like metal to styrene, resin to styrene, or metal to resin.

For metal to metal or resin to resin, as with my metal and resin figures, I do prefer to use a 2-part epoxy.  As someone else noted, CA glue can give a good bond, but it doesn't have good shear strength, and I don't want to knock a piece off once it's attached.  2-part epoxies provide a good, strong bond, and are very good for assembling resin kits or metal kits.  A 5-minute epoxy will give you time to make adjustments.  Also, in the case of an all-metal or -resin kit, it's a good idea to pin the joints for additional strength, especially if there are no locating pins or lugs molded onto the parts.

For clear parts, I use white glue most of the time-Elmer's is the brand I use.  I do sometimes use styrene glue to attach a styrene canopy to a styrene fuselage.  But it's too easy to get some where I don't want it, and mar the part.  White glue won't do that, it cleans up easily, and it can also fill gaps around ill-fitting clear parts.

Hope that helps!

Best regards,

Brad

The bigger the government, the smaller the citizen.

 

 

  • Member since
    August 2005
  • From: Mansfield, TX
Posted by EdGrune on Friday, March 27, 2020 1:56 PM

richiev

How do you use a super glue and accelerator?  What are the steps?

 

 
Broadly there are three viscosities of Superglue: thin & watery, medium gel, and thick gel.   The thin will set very quickly and the others in progresively longer times.   Superglues harden by chemical reaction with humidity in the air.  There are some additional chemical which can "kick" the reaction.   Even though superglues may set rapidly they will continue to harden over a period of time.
 
To use, such as for a set of landing gear as mentioned above,  put a small drop of glue in each of the landing gear locating holes .   Insert the landing gear leg pins into each of the locating holes, align, and hold.   Count to 30.   Most likely you are done.   If you have a slower glue an applicator of accelerator will set up the glue.   Mine is a spray, some come in bottles, a brush tip on the glue spot will set it up.   Be neat spraying.  Over spray from the left wing before getting to the right wing may contaminate the area and make the next drop of glue set up before you can insert the parts
 
Superglue is good in tension, but poor in sheer.  That means you cannot pull the parts apart but if you knock them sideways the joint may break.   The landing gear leg pins in the locating holes provide structure.   If you attempt to butt join two pieces by superglue the joint may be weak.   You may need a positive location material such as a pin or scarph joint.
 
Superglue can be used as a filler material.  A small bead of glue in a joint, then sanded immediately once set.  Wait until tomorrow and the glue may be harder than the surrounding plastic and hard to sand flush.   You can also dust a bit of baking soda in a larger gap/joint before hitting it with the superglue.    The glue/soad mixture can provide structure.    
 
One of the problems with superglues is that they fume as they set.  Hit that puddle of glue with the accelerator and you may see a puff of smoke (actually steam) and a strong vinegar smell.    The fumes carry the glue molecules and they are depositied on surfaces where they may not be wanted.   The fuming can be good.   Police crime labs will use superglue to collect fingerprints.   It can also be bad if your fuming supeglue raises fingerprints you left on your model.   Be cautious and judicious in your use of superglues.
  • Member since
    November 2009
  • From: Twin Cities of Minnesota
Posted by Don Stauffer on Friday, March 27, 2020 2:01 PM

To what has already been said, I will add;

White glue-(Elmers).  I use it not just for canopies, but any time I want a temporary glue that I will want to seperate later.

CA- there are two different versions of CA.  The normal type is the thin, fast drying kind.  The joints must be clean and closefitting with this- no gap filling ability.  There is the gel type CA which does do some gap filling. It is also slower setting, so I use it either for parts that are not a perfect fit, or for places I want slower setting.  There is accelerator available that then causes the glue to dry instantly when you apply the accelerator to the joint.

UV Laser-hardening resin- (seen on TV, but also available in hardware stores.  It is quite strong, and only hardens when you shine the laser on it. It is a bit more expensive than other glues, so I only use it to glue transparent parts that can fog with other glues.

Epoxy-  Very strong, but more work to use.  I only use it when I need really high strength. It is also good for glueing two parts of different materials.  I use it frequently when gluing plastic to wood or metal.

I also use the liquid solvent glue.  I especially use it for the long setting time- for things like long fuselage joints that take me several minutes for positioning and clamping.  I love the Tamiya stuff for that.

 

Don Stauffer in Minnesota

  • Member since
    September 2012
Posted by GMorrison on Saturday, March 28, 2020 10:18 AM

CA is good for putting together pre-painted parts.

  • Member since
    March 2020
Posted by richiev on Sunday, March 29, 2020 3:55 PM

Thank you for this reply.  Detailing the steps to take and the 'whys' are exactly what i need as i am still learning and coming up to speed.

 

RichieV

  • Member since
    March 2020
Posted by richiev on Sunday, March 29, 2020 3:56 PM

Ive picked up some of the fast and accelerator ones.  Will test them out here before doing the landing gear on my current model.

  • Member since
    September 2012
Posted by GMorrison on Sunday, March 29, 2020 4:23 PM

Just my two bits. I have used accelerator and finally got fed up with it.

It smells like h3ll and you need to be very sparing with it as it will leave crusty deposits.

I get similar results AFA accelerator with a little water, like a drop on the end of a toothpick. I used to use spit until I superglued a toothpick to my tongue!

But it works.

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