Plastic repair

AV8r Tue Feb 15, 2022 8:09 pm

Good evening all,
Looking for information on anyone who is restoring broken or warped Cox, Wen Mac models. Considering setting up part of my shop for just this purpose. Looking for info on needed equipment and knowledge that might streamline this process.

Marleysky Tue Feb 15, 2022 10:42 pm

There are a number of ways to "fix" broken plastic parts. I think Testors Red Glue is the most common. JB Weld, epoxy are also in the mix. Heat guns and Hot Water can be used to reshape or un-warp plastic wings/tails/elevators. If it's been broken BOB ( RSV1cox) has probably fixed it. If you want to do some reading before he jumps in, you can use the "search" function and find a number of good threads try "Plastic" "repair" to see what turns up.
Or, post what you're trying to fix and the remedys will be given.

Here you go: https://www.coxengineforum.com/search?search_keywords=plastic&typerecherche=interne&show_results=topics

rsv1cox Wed Feb 16, 2022 7:21 am

My go-to's for plastic and other repairs. But I always find myself going back to common every-day Testors red tube cement. Most effective that I can find for repairing the types of plastic used in model airplanes.

But these get the most use.

Instructions say to "Apply sparingly to one surface, join and let cure for two hours." I do but ensure that all the surface is covered before joining and I don't move it for at least twelve hours or over-night. To join flat surfaces, I use waxed paper laying the recipient piece flat, then coat the mating surface and join angling down to avoid smearing.

No plastic repair is going to be perfect; you just try to make the best of a bad situation.

aspeed Wed Feb 16, 2022 10:45 pm

You could look up plastic welding on utube if you want to buy some stuff. Just a soldering iron to melt stainless steel screen for reinforcement. Mostly just a soldering iron with a spade/flat tip. Takes a bit of practise and a scrap piece of matching plastic filler sometimes.

cmulder Thu Feb 17, 2022 4:54 am

Using a temperature controlled soldering iron makes "welding" a lot easier.
For example a "ts100" can be set to temperatures much lower then used for soldering.
Each type of plastic has it own melting temperature and has a range where it is starting to get soft but not yet fully liquid.
What worked for me is to set the iron to 150c , poke a test sample of plastic , increase the temp by 10c and try again until the plastic becomes soft enough to melt th 2 sides of the joint in a controlled way.

Single temperature irons become to hot and that degrades (overheats) the plastic making good "welds" much more dificult.

rsv1cox Thu Feb 17, 2022 6:18 am

I bought one a couple of weeks ago, but I haven't tried it yet. Temperature controlled with a series of tips, a flat angled one looks most promising. I have tried using a soldering iron before with mixed results. They do make a mess restricted to hidden repairs, not really appropriate for something like this.