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How do different glues work?

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  • Member since
    August, 2019
How do different glues work?
Posted by Josh_the_painter on Tuesday, August 06, 2019 6:18 PM

Ive been having an enjoyable read of everyones posts and learning a lot. Getting back into the hobby Im trying to learn about all the products available. 

20 years ago I used a revell glue that seemed to melt into the plastic to form a weld. 

Any modelling I've done since, which has been ultimately diorama or model railway based I have used super glue. But I dont know if that's a particularly good option. Super glue seems to just sit on top and not wick.

I see the Tamiya glues to be popular, then theres think and thick variants? Whats the purpose of each? How do the glues work, do they wick into the plastic to form a weld or simply adhere to the surface? 

Am I way off, is there something else more preferred?

Cheers,

Josh

  • Member since
    March, 2014
Posted by Graham Green on Thursday, August 08, 2019 4:22 PM

Very strange that nobody has answered your query, so here's something that was written about 25yrs ago, it is still relevant, even today.

 

Everybody has an opinion, there just like Ar$e#oles   ---   everybody has one, so if anybody disagrees with what is written, then they are welcome to add their two cents worth as well.

 

 

 

 

 

  • Member since
    September, 2012
Posted by GMorrison on Thursday, August 08, 2019 6:19 PM

That pretty well sums it up.

  • Member since
    February, 2016
Posted by lowfly on Thursday, August 08, 2019 8:20 PM
The Tamiya brand of thin glues are some of the best on the market. Easy to use, no odor and work quickly. They actually melt the plastic together or "Weld" the parts together. This is what you want. The thin cements are good for dry fitting parts and once you get the part where you want it you can brush the glue onto the closed joint and it will "wick" into the seam making a permanent bond. The tube type glues are good for large, surface area bonding. large, flat pieces that you can clamp or hold together with no issues. I wouldnt suggest this type of glue for small parts as it has a longer curing time
  • Member since
    March, 2014
Posted by Graham Green on Thursday, August 08, 2019 9:03 PM

Tamiya seems to be recommended a lot, now I have taken a sniff of this stuff and to my untrained nose, it smells suspiciously like Methyl Isobutyl Ketone which is what Testors has as the main ingrediant.

Here's a quick guide to what you will pay for Tamiya and notice the quantity of liquid for the cash that you will splash out for a lousy 40 mil.

Then have a look at the next link and notice the quantity ( 250 mil ) and the LOWER price as well, so which one is far more user friendly?

 

https://www.metrohobbies.com.au/products/tamiya-extra-thin-cement-quick-setting

 

 

https://www.bunnings.com.au/protek-250ml-clear-priming-fluid_p4750123

 

  • Member since
    March, 2014
Posted by Graham Green on Thursday, August 08, 2019 9:06 PM

A quick google snatched this little gem, so all who use Tamiya and reckon its "the ant's pant's " for glue, sorry to burst your bubble,  but you better highlite this link below and go have a look.

----------------------------------------------------------------------------------------------------

 

http://mackthemaker.com/macks-hacks-a-better-plastic-glue/

  • Member since
    September, 2012
Posted by GMorrison on Thursday, August 08, 2019 9:39 PM

This forum really frowns on the concept of saying sh*t as though if you spelled it out it’s crude but If you “disguise” it and yet it’s clear what’s meant, is ok. It’s juvenile.

You are extremely annoying when you call out others as being dense.

  • Member since
    April, 2003
  • From: USA
Posted by keavdog on Friday, August 09, 2019 5:51 AM
I do like Tamiya thin for some applications, but I like a bit hotter solution for things like fuselage assembly or wing joints.  Before Tamiya there was Weldon #4 - a bit hot and you have to be careful to not to let it run outside of joints but it's by far the best in terms of liquifying the plastic and producing a joint that is 'welded' together.   

Thanks,

John

  • Member since
    April, 2016
Posted by GlennH on Friday, August 09, 2019 9:27 AM

Graham Green

Tamiya seems to be recommended a lot, now I have taken a sniff of this stuff and to my untrained nose, it smells suspiciously like Methyl Isobutyl Ketone which is what Testors has as the main ingrediant.

Here's a quick guide to what you will pay for Tamiya and notice the quantity of liquid for the cash that you will splash out for a lousy 40 mil.

Then have a look at the next link and notice the quantity ( 250 mil ) and the LOWER price as well, so which one is far more user friendly?

 

https://www.metrohobbies.com.au/products/tamiya-extra-thin-cement-quick-setting

 

 

https://www.bunnings.com.au/protek-250ml-clear-priming-fluid_p4750123

 

 

That is showing as a primer for plastic pipe. Primer is part one of the two steps to join PVC. You still need the glue after priming to weld the pipes together. I guess one day I can try some primer alone on some sprue scraps and see what happens.

A number Army Viet Nam scans from hundreds yet to be done:

https://www.flickr.com/photos/southwestdreams/albums/72157621855914355

Have had the great fortune to be on every side of the howitzers.

  • Member since
    March, 2014
Posted by Graham Green on Friday, August 09, 2019 4:14 PM

GlennH
 

That is showing as a primer for plastic pipe. Primer is part one of the two steps to join PVC. You still need the glue after priming to weld the pipes together. I guess one day I can try some primer alone on some sprue scraps and see what happens.

 

 

Somehow you have missed the point about this lot, if you have a look at what’s inside the Primer container/bottle, you will see that it’s just about the same stuff that is in the Tamiya bottles, only a heck of a lot more liquid/glue, for far less price and it does exactly the same job on polystrene as what Tamiya/Testors does.

 

  • Member since
    August, 2019
Posted by Josh_the_painter on Friday, August 09, 2019 4:31 PM

Thank you for the replies.

Interesting bit of reading there Graham. I can understand how the MIK melts into the styrene. Also interesting was the MEK/ accetone mix. There's liters of MEK sitting around at work we use for thinning composite materials. That may be a bit aggressive however. 

Ive got a wing to paint out at the airport today then a Hospital visit, but on my way home Ill swing through bunnings and grab some pipe primer for a play.

Interesting  how the make up differs in so many glues. I suppose there will be an agenda how specific manufacturers want the glue to perform and a chemist will create something around those parameters. Such as no smell etc. Perhaps there's a thought process for not permanently fixing things together incase of a mistake? 

  • Member since
    August, 2019
Posted by Josh_the_painter on Friday, August 09, 2019 4:38 PM

keavdog
I do like Tamiya thin for some applications, but I like a bit hotter solution for things like fuselage assembly or wing joints.  Before Tamiya there was Weldon #4 - a bit hot and you have to be careful to not to let it run outside of joints but it's by far the best in terms of liquifying the plastic and producing a joint that is 'welded' together.   
 

So I wonder what the chemical make up of this was? I imagine a good acetone content would extract the solvents quickly allowing a quick drying glue.

  • Member since
    April, 2003
  • From: USA
Posted by keavdog on Friday, August 09, 2019 7:22 PM

From the weldon website

Methylene Chloride * #

 (dichloromethane) 

Trichloroethylene * #

Methyl Methacrylate Monomer

And at $20 a pint,  very cost effective. 

Thanks,

John

  • Member since
    August, 2019
Posted by Josh_the_painter on Saturday, August 10, 2019 2:07 PM

keavdog

From the weldon website

Methylene Chloride * #

 (dichloromethane) 

Trichloroethylene * #

Methyl Methacrylate Monomer

And at $20 a pint,  very cost effective. 

 

 

Yes most definitely. Also interesting reading that methacrylates are used in the production of poly products so again the glue is, in essence, making up part of the structure of the plastic and I assume cross links the molecules giving you that welded bond. 

Josh 

  • Member since
    March, 2014
Posted by Graham Green on Saturday, August 10, 2019 9:58 PM

Josh_the_painter

Thank you for the replies.

Interesting bit of reading there Graham. I can understand how the MIK melts into the styrene. Also interesting was the MEK/ accetone mix. There's liters of MEK sitting around at work we use for thinning composite materials. That may be a bit aggressive however. 

 

 

This stuff is about as agressive as Tamiya or Testors, all you have to do is paint some onto each bit and press together, then when it's taken, dip the brush into this MEK once again and "wick it" along the seam being glued.

 

Done correctly, you may not even see where the join was before you started, like every other glue, if it's done wrong, then it's a stuff-up.

  • Member since
    July, 2013
Posted by steve5 on Sunday, August 11, 2019 11:33 PM

Josh_the_painter
Ive got a wing to paint out at the airport today then a Hospital visit, but on my way home Ill swing through bunnings and grab some pipe primer for a play.

I'm very interested josh , did you get any primer , if so how did it go ?

steve5

 

  • Member since
    August, 2019
Posted by Josh_the_painter on Monday, August 12, 2019 6:57 AM

steve5

 

 
Josh_the_painter
Ive got a wing to paint out at the airport today then a Hospital visit, but on my way home Ill swing through bunnings and grab some pipe primer for a play.

 

I'm very interested josh , did you get any primer , if so how did it go ?

steve5

 

 

Hi Steve, 

Yes I picked some up and painted a few cockpit pieces this morning on an airfix p-40 B. Im going to experiment with the primer tonight or tomorrow morning so I will be sure to let you know the results!

Josh

  • Member since
    August, 2019
Posted by Josh_the_painter on Monday, August 12, 2019 3:53 PM

So, I didnt get a chance to glue my cockpit pieces together as I wasnt ready.

However in the interests of science I cut off two 2" long strips of sprue, held them together parallel and applied the pipe primer, a small amount on a fine tip brush. What do you know! After 30 seconds they were joined. I began to try and roll them apart and as the solvents in the primer hadn't evaporated yet, as I separated the two pieces there was a web of plastic between them where they were melting together and cross linking. 

Further pipe primer re-softened the glue allowing them to come apart. I pushed them back together and when home from work looking foward to seeing a nice solid bond. It works!

Josh

  • Member since
    March, 2014
Posted by Graham Green on Monday, August 12, 2019 4:09 PM

Josh_the_painter

 

Hi Steve, 

Yes I picked some up and painted a few cockpit pieces this morning on an airfix p-40 B. Im going to experiment with the primer tonight or tomorrow morning so I will be sure to let you know the results!

Josh

 

 

Whoa there Bullock,------ DO NOT paint any items first and then attempt to glue them together properly. You will need to scrape of the paint where you expect the glue to take, then you will melt the paint along the joining seam as well.

Your joining seams will look terrible, if you go ahead with this idea.

 

Why not do the sensible thing, glue all the bits together that will be painted the one colour, this now allows you to clean up anything that needs cleaning up, then and only then, will you paint it.

 

DO NOT use any glue that will melt the styrene, anywhere near 'clear' moulded bit's, or you will have one hell of a foggy mess all over the clear bits.

 

Choice is your's alone to make, but you have been told what will happen -----

  • Member since
    May, 2009
  • From: Poland
Posted by Pawel on Monday, August 12, 2019 4:16 PM

Hello!

Two things:

First: one glue that Graham didn't mention in his write up, and that is getting more and more popular recently for building really small detail is the UV-hardening resin that allows you to line up small parts, clean up excess and start the hardening using Ultraviolet light. Some time ago it could only be had in dental supply shops, today Revell starts marketing it for modellers. Graham will surely point out that you can have it cheaper somewhere else.

Second: I've been using lacquer thinner for glue for more than 20 years now, and while I agree that it's a great alternative to overpriced "modeller's" "thin" glues, it's not as easy to do as Graham wants to have it. After I have used up my bottle of lacquer thinner, and it took me ovet ten years, I have found the environmental laws changed and I can't find easy replacement for it. I tried using pure acetone and MEK, and a mixture of them, but those didn't give me the good characteristics I've had before - a glue that would stay on plastic long enough to allow for handling and aligning the parts, and melt the plastic enough to make a strong weld. MEK and acetone evaporate too fast. Other lacquer thinners consist of xylene and toluene, and those don't melt the styrene enough.

The breakthrough came when I have found stuff called "acrylics thinner" that contains xylene and butyl acetate - that was a hit. This stuff stays long enough to let you handle and align the parts, and melts the styrene very effectively.

Hope this helps - thanks for reading and have a nice day

Paweł

All comments and critique welcomed. Thanks for your honest opinions!

www.vietnam.net.pl

  • Member since
    August, 2019
Posted by Josh_the_painter on Monday, August 12, 2019 8:11 PM

Graham Green

 

 
Josh_the_painter

 

Hi Steve, 

Yes I picked some up and painted a few cockpit pieces this morning on an airfix p-40 B. Im going to experiment with the primer tonight or tomorrow morning so I will be sure to let you know the results!

Josh

 

 

 

 

Whoa there Bullock,------ DO NOT paint any items first and then attempt to glue them together properly. You will need to scrape of the paint where you expect the glue to take, then you will melt the paint along the joining seam as well.

Your joining seams will look terrible, if you go ahead with this idea.

 

Why not do the sensible thing, glue all the bits together that will be painted the one colour, this now allows you to clean up anything that needs cleaning up, then and only then, will you paint it.

 

DO NOT use any glue that will melt the styrene, anywhere near 'clear' moulded bit's, or you will have one hell of a foggy mess all over the clear bits.

 

Choice is your's alone to make, but you have been told what will happen -----

 

 

You make a good point Graham and appreciate the advice. 

I wasnt sure how to approach building the interior in regards to painting. My intial thought was to do exactly as you suggested and assemble then paint the interior green as the large majority of the interior is green. A quick hit with an airbrush would make short work of it. The problem I saw was once assembled the interior is basically a box awaiting fitment to the fuselage. I figured I would never be able to neatly paint the interior this way so opted for in parts. To then , as you have pointed out, clean up any paint and carefully glue. I planned to use white glue for the canopy. 

Would you consider this still to be a misguided approach and for future reference be better off trying painting once assembled? 

 

Josh

  • Member since
    August, 2019
Posted by Josh_the_painter on Monday, August 12, 2019 9:18 PM

Pawel

Hello!

Two things:

First: one glue that Graham didn't mention in his write up, and that is getting more and more popular recently for building really small detail is the UV-hardening resin that allows you to line up small parts, clean up excess and start the hardening using Ultraviolet light. Some time ago it could only be had in dental supply shops, today Revell starts marketing it for modellers. Graham will surely point out that you can have it cheaper somewhere else.

Second: I've been using lacquer thinner for glue for more than 20 years now, and while I agree that it's a great alternative to overpriced "modeller's" "thin" glues, it's not as easy to do as Graham wants to have it. After I have used up my bottle of lacquer thinner, and it took me ovet ten years, I have found the environmental laws changed and I can't find easy replacement for it. I tried using pure acetone and MEK, and a mixture of them, but those didn't give me the good characteristics I've had before - a glue that would stay on plastic long enough to allow for handling and aligning the parts, and melt the plastic enough to make a strong weld. MEK and acetone evaporate too fast. Other lacquer thinners consist of xylene and toluene, and those don't melt the styrene enough.

The breakthrough came when I have found stuff called "acrylics thinner" that contains xylene and butyl acetate - that was a hit. This stuff stays long enough to let you handle and align the parts, and melts the styrene very effectively.

Hope this helps - thanks for reading and have a nice day

Paweł

 

 

Thanks Pawel. 

I had seen the ultraviolet glues now you mention it. I use ultraviolet primers quite regularly at work so I am familiar with the processes. 

The idea of laquer thinner is an interesting one. I have about 5 different reducers/ thinners here I could have a play with, at varying drying rates. The pipe primer is definitely working however. Almost all thinners are a brew of a number of chemicals so I guess its just landing on that right mix to be A) aggressive enough and B) slow enough. 

You did mention using the laquer approach not so easy. What challenges did you find with it? How did you overcome them? 

My trial this morning was succesful in applying a very controlled amount via a brush although I can understand how too much would fast lead into trouble.

  • Member since
    November, 2009
  • From: Twin Cities of Minnesota
Posted by Don Stauffer on Thursday, August 15, 2019 9:22 AM

Josh_the_painter

Ive been having an enjoyable read of everyones posts and learning a lot. Getting back into the hobby Im trying to learn about all the products available. 

20 years ago I used a revell glue that seemed to melt into the plastic to form a weld. 

Any modelling I've done since, which has been ultimately diorama or model railway based I have used super glue. But I dont know if that's a particularly good option. Super glue seems to just sit on top and not wick.

...

Josh

 

I find most thin CA glue does wick into seam.  I also use the thicker gel CA.  Because of its higher viscosity, it does not wick, but does fill small gaps.  So I keep both types on hand.  When the seam does not close real well, I use the gel.  But if the seam is a good tight fit I use the thin stuff for its ability to wick.

BTW, I also use the Tamiya stuff, as well as the new laser hardening stuff (for transparencies- it does not fog the surface like solvent and CA glues do.

I believe each type of glue/cement has its uses, and keep some of each on hand.

 

Don Stauffer in Minnesota

  • Member since
    July, 2014
  • From: Franklin Wi
Posted by Bakster on Saturday, August 17, 2019 9:49 AM

When I first got into this hobby I thought one or two glues should do it. Boy, was I wrong. I use white glue, Tamiya Thin, tube glue, epoxy, CA (both thick and thin), sprue-goo, UV glue, hot glue, and not in that order. They all have their place in my processes.

I will tell you though that I have not had a good experiences with UV glue. In my experience the bond was pretty weak, and the stuff stinks to high heaven, so much so, I moved the tube away from my work area. Just recently I noticed a strong odor in the room I kept it and in searching I had come to find that the UV tube had basicly expanded and broke its seal. Glue had oozed out, and into the garbage it went. I bought that glue at Walgreens, so maybe there is better stuff out there. For me, I gave it a go and I am moving on. I have other glues in my arsenol that will take care of business.

Interesting discussions.

  • Member since
    September, 2012
Posted by GMorrison on Saturday, August 17, 2019 9:53 AM

Josh_the_painter

 Would you consider this still to be a misguided approach and for future reference be better off trying painting once assembled? 

 

Josh

 

It isn't misguided. Just remove paint from the joining surfaces.

  • Member since
    March, 2015
Posted by JohnnyK on Thursday, August 22, 2019 4:17 PM

I have a question regarding glue. I will be gluing a brass rod to the wing of an aircraft. Should I use Super Glue, or Epoxy? 

  • Member since
    May, 2009
  • From: Poland
Posted by Pawel on Thursday, August 22, 2019 4:44 PM

Hello!

Basically, if you are able to make the two parts fit tight without glue, take CA. It holds best, when the glue layer is very thin. If the fit is loose, it might be better to use epoxy, this works better than CA if the glue layer is thick.

Josh - as for your question, I said "not so easy" in reference to replacing specialized plastic glues with a single component solvent. But if you get an idea what to look for and, roughly, how to mix it, you really can cut cost on plastic glue (this isn't really much), but also you can get around without mail-ordering such glue or without a hobby shop around - you just go to the hardware store...

Problem with pure MEK or acetone is they don't really solve all plastics well, but worst thing about them is that they evaporate too fast to let you work on anything but the smallest parts. The only way is to put the parts together and let the solvent wick into the seam - but this is not always possible/practical/desirable. But glues with some acetate mixed in solve plastics a lot better and linger a lot longer, allowing you to apply the glue to both surfaces and join the parts afterwards.

I hope that explains it - thanks for reading and have a nice day

Paweł

All comments and critique welcomed. Thanks for your honest opinions!

www.vietnam.net.pl

  • Member since
    March, 2015
Posted by JohnnyK on Friday, August 23, 2019 3:23 PM

Pawel,

Thanks. The fit will be loose so I'll use epoxy.

  • Member since
    August, 2019
Posted by Josh_the_painter on Sunday, August 25, 2019 6:54 AM

Pawel

Hello!

Basically, if you are able to make the two parts fit tight without glue, take CA. It holds best, when the glue layer is very thin. If the fit is loose, it might be better to use epoxy, this works better than CA if the glue layer is thick.

Josh - as for your question, I said "not so easy" in reference to replacing specialized plastic glues with a single component solvent. But if you get an idea what to look for and, roughly, how to mix it, you really can cut cost on plastic glue (this isn't really much), but also you can get around without mail-ordering such glue or without a hobby shop around - you just go to the hardware store...

Problem with pure MEK or acetone is they don't really solve all plastics well, but worst thing about them is that they evaporate too fast to let you work on anything but the smallest parts. The only way is to put the parts together and let the solvent wick into the seam - but this is not always possible/practical/desirable. But glues with some acetate mixed in solve plastics a lot better and linger a lot longer, allowing you to apply the glue to both surfaces and join the parts afterwards.

I hope that explains it - thanks for reading and have a nice day

Paweł

 

 

Interesting you mention the timing Pawel. Ive been using this pipe primer which I actually bothered to read and seems to be MEK. It doesnt dry quickly either. Ive been able to achieve mostly what you just said by test fitting, then applying to both sides and putting together. Anywhere I had a slight gap ( say on a corner where I may have just over sanded for fitment) a drop of the pipe primer has allowed the plastic components to I guess run into each other and fill the gap. At least for this project has worked ok. 

Ill post some pictures soon of my progress but while overall I think I have made a reasonable effort for my first model in so many years, there is lots of room for improvement. On a plus Im learning as I go so future efforts will benefit! 

Josh

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