Now this is neat!

[Chaharly]

So I've been getting concerned with plastic welding on the old venture, because it has a many a crack in the plastic. I've been using the bondic, but I think I'd actually get a better bond with plastic welding. I've been looking up heat welding and friction welding and saw this video and thought it would've been worth a look. Its a little long winded, but its pretty cool! Check it out!

 

http://lifehacker.com/5972326/friction-weld-plastic-with-a-rotary-tool-and-plastic-rods

[Guest Jamsie]

i prefer to use this method for repairs as i have access to the tools needed

https://www.youtube.com/watch?v=j4RECGjEOnE

but i would recomend going in half way with repair , then when set , turn over and do the same on the other side , so that you have a full thickness repair

[M61A1MECH]

Another neat way to repair or join plastic is with ultrasonic welding, used a lot in production plastic fabrication, I suspect the cost of equipment would be out of range of the home hobbiest.

[Flyinfool]

Using a solvent based adhesive that melts the plastic together will give the strongest possible repair. Heat welding can equal or even exceed the strength of a solvent bond IF you add additional material to reinforce the joint so that the filler can make the joint stronger than the original material and you get a full penetration weld. Adhesives that do not melt into the original material require a lot of surface prep so that they can grip the surface to try to hold it together.

 

My favorite for cracks in ABS is to first use a thin solvent adhesive that will wick into the joint and melt the 2 parts together. If the original ABS was broken into two pieces, I use ABS pipe cement to glue then together. I let this dry completely so I now have a part that will retain its shape while I work on it. I then lay down a film of ABS pipe cement and into that I lay fiberglass cloth with another layer of the ABS pipe cement rubbed into the cloth. This softens the surface of the original ABS and actually embeds the glass cloth into the original ABS making it stronger than the day it was molded. Face it, if it cracked once that means it never was strong enough as designed. Adding in the glass cloth will make it stronger than designed and hopefully will not break there again.

[Chaharly]

Now what I'm wondering Jasmie is if that plasti-fix stuff is just sort of an epoxy used to bind them together, or does it break down the plastic on the fairing and bond the 2 together. I've been using bondic as my main source of plastic repair, but really all that does it use surface area friction to hold the pieces together. I usually drill several holes along the crack and fill it them in with bondic around it, essentially stitching it together.

 

And I think I could really get along well with one of those M61A1MECH, I tell ya what. How about you boys from the site help me go in on the investment for one of those, and after I take the proper classes to learn how to run it , I'll fab anything you guys want for just the cost of shipping Do you think you'd need ear-plugs to run that thing? It makes the weirdest noise on the video!

 

And I think I've heard you suggest using the solvent based adhesive before. Where do you pick up stuff like that? I also like your idea of using fiberglass matting and actually making it part of the plastic, it seems that would be really useful on the fairing where the two pouches hang off of. Is the price of the solvent pretty fair?

[dacheedah]

we made abs cement with acetone and shavings of abs, we make the shavings by drilling into abs pipe repeatedly. put equal parts in a sealed jar for 24 hours, shake the jar occasionally. It will dry very strong.

[Flyinfool]

The ABS pipe cement is at most any hardware store or other place that sells plumbing supplies. Some of the adhesives are for PVC and some are for ABS. They are slightly different. Make a strong effort to keep the cap on the can as much as possible, it will harden in the can pretty quick. It skins over very fast, dries very fast in thin layers, a but in a deep joint it can still take a day or 2 for full cure. You do not want to paint over it for a few days to be sure all of the solvents have evaporated. Stick your nose on it and if you can still smell the solvents, it ain't fully cured yet.

 

The glass cloth you can get at most hobby shops as it is used a lot on model airplanes, or get it at most marine stores that sell stuff for repairing boats, Even some places that sell auto paint and refinishing supplies.

 

Neither is expensive.

[Guest HdHtr]

we made abs cement with acetone and shavings of abs, we make the shavings by drilling into abs pipe repeatedly. put equal parts in a sealed jar for 24 hours, shake the jar occasionally. It will dry very strong.

 

Yes.

[Doug royal86]

I have used baking soda and super glue for a quick fix. Just don't breath the smoke. I put a small amount of baking soda in the crack then drop super glue on it. it will get hot and dry very fast.

[cowpuc]

I have used baking soda and super glue for a quick fix. Just don't breath the smoke. I put a small amount of baking soda in the crack then drop super glue on it. it will get hot and dry very fast.

 

Now there's one I have never heard of Doug!! Gonna have to get the baking soda and super glue and give it a shot!

[Doug royal86]

The smoke is poison so don't breath it.

[saddlebum]

Bondic is just an adhesive and unless the surface is properly prepped it just peels off. Plastifix and plastex are solvent based and melt the materials together. You can also embed fiberglass cloth into the repair for added strength. You can form or build up missing tabs etc as well.

[Chaharly]

Bondic is just an adhesive and unless the surface is properly prepped it just peels off. Plastifix and plastex are solvent based and melt the materials together. You can also embed fiberglass cloth into the repair for added strength. You can form or build up missing tabs etc as well.

 

What I liked about the bondic, and I should post pics up later. Is since its a plastic, I filled a hole in my lower fairing in by chasing the bead with the light making what was essentially rebar. But you're right, you have to sand down the area that you're applying the bondic and drill several holes, even as you're applying it. I basically use it to stitch the bondic to the plastic and to itself.