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General Category => General Discussion => Topic started by: ribbert on December 08, 2020, 04:01:17 AM

Title: It never fails to crack me up.
Post by: ribbert on December 08, 2020, 04:01:17 AM
Much has been written here over the years on plastic welding and some of our members have achieved near black belt status in it but I don't recall anything being written about the methods used to strengthen the join once it's been welded.

Noel
Title: Re: It never fails to crack me up.
Post by: Old Rider on December 08, 2020, 05:41:54 AM
Quote from: ribbert on December 08, 2020, 04:01:17 AM
Much has been written here over the years on plastic welding and some of our members have achieved near black belt status in it but I don't recall anything being written about the methods used to strengthen the join once it's been welded.

Noel

I have tried this method :
https://www.youtube.com/watch?v=gRCMIDILfEI (https://www.youtube.com/watch?v=gRCMIDILfEI)

But my experience is that it just cracks open again on the
old brittle plastic on the FJ . I use to make a reinforcement with epoxy putty on the backside after first welded and
scratched the surface .
Title: Re: It never fails to crack me up.
Post by: ZOA NOM on December 08, 2020, 08:53:06 AM
That's the beauty of Plastifix. It replaces the plastic and chemically bonds it. It's as strong as new.
Title: Re: It never fails to crack me up.
Post by: Waiex191 on December 08, 2020, 08:56:42 AM
My lower fairing has one of the parts cracked off at the aft mount bolt and is only held on by the heat shield.  I was going to fiberglass it on the inside.
Title: Re: It never fails to crack me up.
Post by: ZOA NOM on December 08, 2020, 09:08:38 AM
Quote from: Waiex191 on December 08, 2020, 08:56:42 AM
My lower fairing has one of the parts cracked off at the aft mount bolt and is only held on by the heat shield.  I was going to fiberglass it on the inside.

Definitely investigate PlastiFix

(https://d29y7fsthxbb26.cloudfront.net/cache/400-400-/catalog/graphics/1/01-00543.jpg)

Title: Re: It never fails to crack me up.
Post by: fj1289 on December 08, 2020, 07:42:59 PM
Didn't I see something a good while back about paper clips bent and used with a large soldering iron?  A DIY version of Fred's incredible garage sale find?  Seems the imbedded metal would be a good reinforcement.
Title: Re: It never fails to crack me up.
Post by: red on December 08, 2020, 08:00:44 PM
Quote from: ribbert on December 08, 2020, 04:01:17 AMMuch has been written here over the years on plastic welding and some of our members have achieved near black belt status in it but I don't recall anything being written about the methods used to strengthen the join once it's been welded.
Noel
Noel,

Wire screen-door screening material is good, too; just make sure it's really metal screening (a sample does not burn).  Bend as needed and trim to a good fit with tinsnips or heavy scissors, so there is no metal coming out of the patched area.  You can tack the screen patch into place with a hot soldering iron, of course.
.
Title: Re: It never fails to crack me up.
Post by: aviationfred on December 08, 2020, 10:04:59 PM
Plastex/Plastifix can't be beat for the simplicity of use and the ability to actually form missing parts. https://www.aerostich.com/plastex-repair-kit.html?___SID=U (https://www.aerostich.com/plastex-repair-kit.html?___SID=U)

I still have good luck with the old tried and true Black ABS cement. I had a broken tab on the rear seat cowling for my VFR. I mixed the ABS cement with loose fiberglass fibers. This has held fast with no signs of failing.

As Chris mentions.... the Hot stapler machine is a game changer. When I had to make main fairing repairs after the attempted theft of my 95. The fairing was presentable with about an hours worth of work.

1st photo is the VFR cowling tab
2nd photo is the inner side VFR tab, ugly but functional
3nd photo is the Main fairing damage
4rd photo are the Hot staples
5th is the finished repair.
6th photo is enlarged from a 10 foot away shot.

Fred
Title: Re: It never fails to crack me up.
Post by: Bones on December 09, 2020, 03:42:22 AM
On one of my chin fairings I used a soldering iron to weld the joints together, then cut a piece out of an old spare I have and using the soldering iron welded the two pieces together. The place where it cracked is now twice the thickness and so far on last inspection is still holding up.
Title: Re: It never fails to crack me up.
Post by: X-Ray on December 09, 2020, 03:46:25 AM
As previously mentioned, I have used Plastex on some horrible breaks, and it really does work. Have not had a repair break yet as it actually fuses to the original ABS material
Title: Re: It never fails to crack me up.
Post by: JMR on December 09, 2020, 11:25:50 AM
Quote from: ZOA NOM on December 08, 2020, 08:53:06 AM
That's the beauty of Plastifix. It replaces the plastic and chemically bonds it. It's as strong as new.
It is a great product. Not cheap but I have repaired many plastic parts with it.
Title: Re: It never fails to crack me up.
Post by: Millietant on December 10, 2020, 09:53:07 AM
I love that kit that Fred uses - I used a paper clip, held in needle nosed pliers and heated with a gas torch, to strengthen the joint where I re-attached the piece of my belly pan that got damaged cornering at the Nurburgring many years ago. It was fiddly but so far seems to holding up really well.

I've just read about a plastic welding kit which was used/reviewed in a bike magazine for repairing bike plastics. They gave it a 10 out of 10 rating  :good2:.

(http://fjowners.com/gallery/12/6213_10_12_20_9_51_23.jpeg)
Title: Re: It never fails to crack me up.
Post by: red on December 10, 2020, 10:16:08 AM
Quote from: Millietant on December 10, 2020, 09:53:07 AMI love that kit that Fred uses - I used a paper clip, held in needle nosed pliers and heated with a gas torch, to strengthen the joint where I re-attached the piece of my belly pan that got damaged cornering at the Nurburgring many years ago. It was fiddly but so far seems to holding up really well.
I've just read about a plastic welding kit which was used/reviewed in a bike magazine for repairing bike plastics. They gave it a 10 out of 10 rating 
http://fjowners.com/gallery/12/6213_10_12_20_9_51_23.jpeg (http://fjowners.com/gallery/12/6213_10_12_20_9_51_23.jpeg)
Millietant,

Kinda pricey at US$104 (at the exchange rate on this date), but I'd like to hear if anybody uses it, and for what item, and the results.

The kit is a butane torch with plastic welding rods, for four different flavors of plastic (including ABS).  A local source of more ABS welding rods would be good, here.
I have no pressing need for the kit right now, but it's got a bookmark here.  Thanks for the tip.

https://www.machinemart.co.uk/p/power-tec-plastic-welding-kit-92418/ (https://www.machinemart.co.uk/p/power-tec-plastic-welding-kit-92418/)
.
Title: Re: It never fails to crack me up.
Post by: giantkiller on December 10, 2020, 12:35:16 PM
I've used plastex many times. Have had no failures so far. Comes with molding bars. Can be reused. Can buy individual components from the company.
Here is a  scoop that was missing the entire coner. Took a mold from a good  piece. Molded in new piece. Put  fine fiberglass cloth on the back. Put  plastex powder on the  fiberglass and  whet with solution. Fiberglass embedded plastic. Sand primer. Done. SUPER EASY.
Title: Re: It never fails to crack me up.
Post by: Charlie-brm on December 12, 2020, 09:33:04 AM
Quote from: Old Rider on December 08, 2020, 05:41:54 AM
Quote from: ribbert on December 08, 2020, 04:01:17 AM
Much has been written here over the years on plastic welding and some of our members have achieved near black belt status in it but I don't recall anything being written about the methods used to strengthen the join once it's been welded.

Noel

I have tried this method :
https://www.youtube.com/watch?v=gRCMIDILfEI (https://www.youtube.com/watch?v=gRCMIDILfEI)

But my experience is that it just cracks open again on the
old brittle plastic on the FJ . I use to make a reinforcement with epoxy putty on the backside after first welded and
scratched the surface .

I've seen that lad before but on this one I had to stop watching within a minute. If he thinks a dollar store paint tray is 1/ injection molded and 2/ nylon based, I'm out of here.