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26th Aug 2021, 7:38 pm | #1 |
Octode
Join Date: Jul 2004
Location: Evesham, Worcestershire, UK.
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Plastic glue
I'm working on a perdio portarama at the moment and have a couple of broken plastic lugs to deal with, can anyone recommend a suitable glue that actually welds the plastic?.
Greg.
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26th Aug 2021, 8:05 pm | #2 |
Dekatron
Join Date: Aug 2016
Location: Colchester, Essex, UK.
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Re: Plastic glue
-What type of plastic is it?
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26th Aug 2021, 8:36 pm | #3 |
Octode
Join Date: Jul 2004
Location: Evesham, Worcestershire, UK.
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Re: Plastic glue
Hi phil
Dunno!, typical hard plastic used in the sixties for trannies etc. Greg.
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26th Aug 2021, 10:18 pm | #4 |
Heptode
Join Date: Feb 2006
Location: Marlborough, Wiltshire, UK.
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Re: Plastic glue
Plasticweld, made by EMA and available from model shops etc is the best bet. Acetone or chloroform (!) might work too.
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27th Aug 2021, 12:52 am | #5 |
Heptode
Join Date: Jan 2008
Location: Ashhurst, Manawatu, New Zealand
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Re: Plastic glue
What Ambientnoise said....Polystyrene? Model aircraft glue - make sure you position the parts tightly together so that there is maximum contact and make sure the faces are perfectly clean - isopropyl alcohol does well.
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27th Aug 2021, 10:05 am | #6 |
Dekatron
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Re: Plastic glue
Does Plasticweld or similar attack the plastic surface ? i.e. if any glue gets on the upper or lower surface not being glued will it mark ?
David |
27th Aug 2021, 10:56 am | #7 |
Dekatron
Join Date: Sep 2011
Location: Rugeley, Staffordshire, UK.
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Re: Plastic glue
I used Loctite Vinyl, Fabric & Plastic Glue Transparent Flexible Adhesive to repair the flexible plastic handle on my Pye M78F. Here's the story: https://www.vintage-radio.net/forum/...d.php?t=176395
TBH, I think it's probably more suitable for repairing 'bendy' plastics and vinyls, but it worked for me, and maybe someone might be looking at this thread who needs such a 'bendy' glue.
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27th Aug 2021, 10:57 am | #8 |
Dekatron
Join Date: Jun 2013
Location: East Sussex, UK.
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Re: Plastic glue
Polystyrene glue (solvent) will probably work but if the lugs are fixing points then I would beef them up with Araldite or similar.
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27th Aug 2021, 10:58 am | #9 |
Dekatron
Join Date: Jan 2012
Location: Brentwood, Essex, UK.
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Re: Plastic glue
Another vote for the EMA stuff (methylene chloride). I get my supplies from a local shop that sells model railway stuff. Methyl Ethyl Ketone (MEK) is also sometimes available in small bottles from the same sources. If there is room, and visual appearance is unimportant, flat lugs can be strengthened by splicing small pieces of polystyrene sheet or girder section (from the same sources) of an appropriate thickness across the break. Plastic car body fillers like Plastic Padding can be used to strengthen round lugs and bosses . Plastic Padding has been hard to find recently, but Ronson High Performance wood filler seems the be the same as Plastic Padding type soft under a different name and works well with polystyrene. Araldite is better but runny, whereas the stiffer car body filler can often be used without having to make a mould to stop the Araldite from running before it sets.
Last edited by emeritus; 27th Aug 2021 at 11:12 am. Reason: typos |
27th Aug 2021, 11:55 am | #10 |
Heptode
Join Date: Feb 2006
Location: Marlborough, Wiltshire, UK.
Posts: 915
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Re: Plastic glue
Re post #6, plasticweld or any glue which softens/dissolves the material will leave a mark on a surface. It’s the nature of the beast so take care. If not too bad, marks can be polished out but far better not to get them.
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27th Aug 2021, 12:44 pm | #11 |
Octode
Join Date: Jul 2004
Location: Evesham, Worcestershire, UK.
Posts: 1,415
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Re: Plastic glue
Thank you all, I'll investigate some MEK based adhesive, fortunately the break is on an inner part where the eye doesn't see, plenty of other work on this little set meantime..
Greg.
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27th Aug 2021, 1:19 pm | #12 | |
Dekatron
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Re: Plastic glue
Quote:
David |
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27th Aug 2021, 2:48 pm | #13 |
Dekatron
Join Date: Jan 2012
Location: Brentwood, Essex, UK.
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Re: Plastic glue
The EMA solvent is highly volatile, which is why it is preferred over glue for assembling plastic model kits that incude transparent windows. I use a small artists' paint brush to carefully apply the solvent to both edges before pressing together. Sometimes it is necessary to apply solvent twice, the first time to soften up the plastic, and the second time to ensure it will flow into the other plastic part on pressing together while still visibly wet. You can in principle apply solvent after pressing the parts together by relying on capilliary action to ensure that the solvent penetrates, but this can mean flooding the edge. Although the solvent does evaporate rapidy, it does leave a slighty dulled surface finish. I did manage to reassemble the plastic window over the tuning scale of one of my transistor radios after something hard and pointed fell on it and shattered it to several pieces, but the cracks are still visible.
Last edited by emeritus; 27th Aug 2021 at 2:48 pm. Reason: typos |
27th Aug 2021, 4:20 pm | #14 |
Dekatron
Join Date: Apr 2019
Location: Worthing, West Sussex, UK.
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Re: Plastic glue
Have now got some Plasticweld from local Model centre, will try it out, first time I have been in the model centre, loads of interesting items there.
David |
27th Aug 2021, 6:09 pm | #15 | |
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Re: Plastic glue
When using plastic weld for a broken lug or similar, hold lug in tweezers, practice putting it in place, dunk end in the solvent and then put in place. Then leave it for an hour or so, overnight is better. It evaporates very quickly from a surface but takes ages to escape from the join.
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27th Aug 2021, 10:25 pm | #16 |
Octode
Join Date: Jul 2004
Location: Evesham, Worcestershire, UK.
Posts: 1,415
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Re: Plastic glue
Thanks folks, ema solvent it is, and it's on its way, let you know how it goes.
Greg.
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28th Aug 2021, 12:57 pm | #17 |
Octode
Join Date: Aug 2006
Location: Rye, East Sussex, UK.
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Re: Plastic glue
Methylene solvents are about the best you'll find but if the fracture is stress related, don't expect the repair to last long without additional support.
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28th Aug 2021, 4:46 pm | #18 | ||
Dekatron
Join Date: Apr 2019
Location: Worthing, West Sussex, UK.
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Re: Plastic glue
Quote:
David |
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28th Aug 2021, 6:08 pm | #19 |
Octode
Join Date: Jul 2004
Location: Evesham, Worcestershire, UK.
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Re: Plastic glue
Sounds like heaven, I'd just want everything!.
Greg.
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29th Aug 2021, 12:29 am | #20 |
Heptode
Join Date: Jan 2008
Location: Ashhurst, Manawatu, New Zealand
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Re: Plastic glue
Just watch out for the MEK - it's nasty stuff - plenty of ventilation or outdoors even better.
Our stores would dish out small quantities in plastic or foam cups - it goes straight through the bottom!
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