I see a lot of build threads going on but I am wondering if any of you Pros (RCKen, Minnflyer, PiperChuck, Bruce, et al) want to start a repair post, I believe it will also help a lot of us newbies; for example I recently learned that you can at times mix CA and baking soda during the repair process. If you need a crashed plane for the post let me know

ca & baking soda???

ive used epoxy and cotton flux.. but ive never heard of ca and baking soda.. whats its used for... wood? foam?

I use microbaloons. They work with either CA or you can mix them into epoxy. It's a handy way to add a fillet to make a stronger joint or to fill gaps.

CA and baking soda is used to fill in where the modeler should have put wood. Not ideal, but better than nothing I guess.

The most important things to consider when repairing are alignment, strength and weight. Alignment should be obvious. Strength and weight tend to compete with each other. Make your repairs adequate, but try not to add any additional weight. A little extra weight is often hard to avoid, but if you have a 5lbs plane and after repair you weight 5.5lbs… you did something very wrong. Too often I see globs of epoxy, tons of extra wood, etc. I even saw one post a while back where someone was using construction adhesive to build with… why not just use brick and mortar? Sarcasm aside, I think I made the point.

When repairing, unless there is a terrible flaw in the design, keep in mind the planes that fly best often can’t handle rough ground treatment. If you strengthen (i.e. add weight) such that things don’t break as easily, you often end up with a worse flying plane that is actually more likely to crash, and when it does, the new failure point will move to some location that is an even larger pain to fix. For example, landing gear blocks, pilot doinks landing and tears them out. Easy fix, but pilot globs in a bunch of epoxy to be sure they don’t come out again. Next doinked landing, blocks hold, but wing spar breaks just past the epoxy globs, which is a difficult repair.

For us cheapskates you can use corn starch instead of microbaloons. Two reasons to mix with your epoxy. 1) it keeps the epoxy from "flowing" out of the gap you're filling. 2) it makes the epoxy very sandable and easy to finish out. One note is that you should never use epoxy to "fill" a structural joint. You should always go for wood-to-wood contact when you are building as it gives the strongest joints.

Hope this helps

Ken

Another thought to keep, is to make sure that you pick up all the broken wood parts from the wreck. You can often bring them home and glue them back together again and use them as a template for the new part's. Another much used repair tool is carbon fiber strips. This is an excelent choice to repair cracks in an ABS cowl. Good thread, lets see what other ideas come up. Good Luck, Dave

Great input guys, if you have pics to add to your comments even better[sm=thumbup.gif]

Edit: videos are welcome as well

I just may make a plane soly of CA and industial Adhiesive.

As DavidAgar said, pick up ALL of the pieces from a crash. If the crash was really bad put them in a bag when you get home, and then put it away for a week or so. Human nature, you're going to be really bummed out after a crash and you're first thoughts may be to just throw in the trash. At first it may not look repairable. But wait a week or so and then look at it again, you'll be totally shocked at just how easy the repairs actually are. The guys that get totally PO'ed and throw the plane in the trash barrel at the field are great. I'll fish the plane out and take it home to repair. So far I've gotten 5 airplanes like that!!!

Another great friend of the repairer are popsicle sticks..... uh, I mean craft stick!!!! You can find them at in the craft section at Wal-mart. You can usually get them by the 100/500/1000 pack. They are great for reinforcing after you put the parts back together.

Another great material for repair, fiberglass. When you're at the LHS pick up some lightweight fiberglass cloth.

Hope this helps

Ken

Or you can get popsicles and eat them first, Its tastier and the bottom of the stick is colourful.

Simplest thing to do... Stop crashing

I did a "How to" on sheeting repair once that has a few useful tips. Here's the link:

http://www.rcuniverse.com/magazine/a...?article_id=98