You bet it's a beginner's forum and because of that it'd do us all some good to qualify as much as possible. To say that "it's ok" to do something isn't really what we ought to be doing here. We really ought to say it's ok but.... and fill in the "buts" every chance we get.

As for "belittling"..... sorry if you took anything I said as belittling because it wasn't meant to be anything other than clarification. I have noticed that the written word is really vulnerable to individual's own interpretations. And some people are really quick to read "with insight" words that aren't there. But I apologize if I offended you. And I wasn't belittling anyone. Whenever you don't agree and state your own side, that's not belittling, it's stating your own side. Adding happy faces and <grin> and <chuckles> are meant to lighten up the text. If you don't see them that way.... hey, chuckle.... far be it from me.... grin........

BTW, if you have any further personal advice, I'm just a pm away.

In my opinion this forum here has to be handled just a bit differently than a lot of the other forums on RCU. A beginner in the hobby can be a very fragile thing indeed. I've seen new people that were afraid to ask questions because they didn't want to bother anybody, or they didn't want to come off "looking like a beginner", or this didn't want to sound stupid, or a variety of other things. For these reasons I feel that beginners need to be handled a little differently. And because of the unique situation here on RCU the more experienced people here need to kind of "watch out" for the new people. One huge problem is "perceived experience". For example, a beginner will come on here (or even worse they will lurk in the forum) and they see somebody that has a "Joined RCU date" of 6 months to a year ago so in there mind they subconsciously think that person knows more because they have been in the hobby longer. When in reality the person with 6 months is still just learning themselves. This can be really bad if the person with 6 months starts giving out bad (or even dangerous) advice and the new person follows it because they think the other guy is more experienced because he's been here longer. Now some might think or say that this really doesn't happen, but some of the more experienced people here know for a fact that it does happen all them time. We've seen people here that will give very bad advice just because they want to "appear" to be an expert on the subject. And in some cases this advice can be downright dangerous to follow (I've seen some pretty big whoppers of bad advice given about running engines before that gave me cold shivers when I thought about what could happen). Sometimes these people giving the advice may just be trying to honestly help out but just don't know the correct answers yet. But in other cases there are people out there that have some serious "personality issues" and will throw out advice just so they "look" like an expert, whether the advice is correct or not. Heck, I've seen one or two that have said that they were trying to run up their post count so "they had more posts than the moderators because they wanted people to listen to them". There was even one person who created a second user account here on RCU (yes, a very big no-no by the RCU rules) just so they could ask questions and then answer those questions with their other "real" user account (I swear that this honestly has happened. There are other mods and people in this forum that can vouch for me that this has happened). Yes, very pathetic but absolutely true, it has happened here.

Anyway, I got a bit long winded there, but what I am trying to point out is that because of the very nature of beginners here we need to try and make sure that advice is as accurate as possible. Even with dangerous acts aside, we need to remember that a beginner is fragile. They are in a situation where everybody knows more than they do (at that moment because they are learning), everybody else can do something they can't do yet (take off and land), they have just spent a lot of money getting started (hey, we all know this isn't a cheap hobby), and are usually in a group of people they don't know. With all of that in mind it doesn't take much to upset somebody to the point that they just say "screw it" and give up on the hobby. Especially when advice ruins their plane, radio, or equipment. So this is why a lot of people on here are so quick to correct when advice is wrong (and I'm not saying anybody here is right or wrong at this moment, rather I'm just finishing to explain the point that Piper_chuck brought up). Nobody on here knows "everything", but between them all the "experienced" (a.k.a. "Old Farts") have a pretty impressive amount of "collective" knowledge. As I said, nobody knows it all, but most of us (at least I do) takes a lot of time researching something that we're not sure about before we post it in the forums to insure accuracy.

With all of that in mind I would like to thank all of those more experienced people that spend time here in this forum helping out the beginners. It's a lot of work at times, but do know that people to appreciate you. I can't speak for everybody as to why there are here to help, but I do know why I do it. Even with the amount of extra time it takes, the aggravations, and even the minor mishaps I love being an instructor. Why? Well, THE BEST feeling in RC flying is that solo flight you made, and the feeling you had for about 3 weeks after you did it. No matter what else you do in the hobby you'll never have a feeling better than that is (IMHO). When I instruct I get to relive a little bit of that feeling whenever a student solos. And I also instruct because I like seeing new people get into the hobby, and I like to help out when I can.


Ok, off the soapbox now, and one comment about the thread subject on thinning epoxy. I know that a lot of people say that "they have never had a problem" thinning out epoxy with alcohol. I used to say exactly the same thing myself, I had been using and thinning epoxy for years and never had a problem. And then I had the problem. I don't know if it was bad alcohol, or too much of it mixed in. But I got a batch that was messed up and when I sealed the engine compartment area with it the epoxy never set up. I left it for a week and tried everything I could think of to get set, to include heating it up with a heat gun (had it almost too hot to touch the epoxy ) but I couldn't get it set. It stayed a soft mess. It took me 2 days of work to get all of that mess off the engine compartment. After that I vowed that was the last time I would have that happen (yes, it was that bad). So now I do as others have said, I put down a small blob and heat it and spread it with an epoxy brush. When I do have to thin the epoxy with alcohol (there are some places you just can't get a heat gun on, especially in an ARF) I will add the alcohol ONE drop at a time from an eye dropper, and only thin it just enough so I can spread it. I'm not saying that others are wrong, or right, with the way that they do this, but rather I'm just sharing my experiences with this subject and hoping that I can help others out there.

Whew, what started out as a quick post sure turned into some good time on the soapbox. So I'll get down off of it now. Thanks for listening.

Ken

Heck, this is turning into a spitting fight....... sorry if anyone thinks I'm spitting, because I'm just sitting here grinning like the idiot I am.

I wanted to help the beginners. And I asked a question when I should have been dry as dirt and simply stated cold facts.

If you're thinning epoxy with drugstore alcohol, you're thinning it with water as well. How much water depends on the drugstore and how much they put into the alcohol. I have a WALGREENS bottle of 91% that says it is 91% isoproply and the rest is water. If you thin your epoxy with that, you're putting 9% water into the epoxy.

Glues do different things with different additives. Does water evaporate as fast as alcohol? Does the water bond with the epoxy? Does the alcohol bond with the epoxy? Does the water migrate into the wood? Do pigs fly? Who knows any of these answers? <grin>

whatever.........

BTW, I have a guarantee that I apply to my advice. All the guys at my field know it and use it often. If you're not entirely satisfied, there is no additional charge. chuckle.....

Darock,
Please don't think that I was directing any comments at you. I was merely pointing out why some people do things a certain way here in this thread. If you thought that I was talking about you, or directing my comments at you, I do apologize for that because it wasn't my intention. I just merely took the opportunity to explain why the "mood" of this forum is the way it sometimes. Piper_chuck broached the the subject so I just expanded on what he said.

Once again I am sorry if you thought I was talking about you. That was the furthest from my mind.

Ken

Hhhhhmmmm! I still wanna know, do I need to use the epoxy for the fuel & radio compartments? Or will the Aerogloss hot fuel-proof dope that I am planning to use suffice for those areas? I do intend to use epoxy(thinned by heat, not alcohol) on the firewall. It just seems to me that it would be much easier to get to these other areas with the fuel-proof dope which needs no thinning. So is this gonna be sufficient, yes or no? Thanks.


Mark

I always fuel proof (with epoxy thinned with heat) the firewall, engine compartment, and the fuel compartment too. Do this because I have lost a plane because of a fuel leak. Ultra Sport 60 that I didn't fuel proof the fuel compartment. It had a fuel leak from the tank that I didn't notice because the wood was soaking it up. The fuel weakened the glue joint for the F2 former, and this former held the dowels on the front of the wing and held the wing in place. During an outside loop the former pulled out, and of course the wing separated from the fuselage. Wing floated down and landed softly in the top of a mesquite tree, but the fuselage became a lawn dart and was totalled.

Hope this helps

Ken

Ok, Thanks Ken!


Mark

Hi All,
Thanks Ken for the insight on beginners. I have just started into RC flying and have not flown yet. What I want to do is get this baby ready for safe flying and hopefully for a long time, as you say this is not a cheap ( fun ) hobby.
When you guys say epoxy, is there a specific brand that is a favorite to use ?
Thanks in advance,
Wayne.

There's a fifty, fifty chance I'm right, and a 90% probability I'm wrong.

There are quite a few different brands available out there and as far as I know they are all pretty much the same. There are some really high dollar epoxies available for the full scale aircraft industry, but those are pretty much overkill for our hobby (unless you're into flying the giant scale planes) . I use the store brand at our local Hobby Lobby (craft store, not a hobby shop). I've been using it for 8 years and haven't had any problems. If you use a local store brand make sure you do a test on it before putting it on the airplane. If you can't find anything local here is a good source of epoxy online:
[link=http://www.anchorseal.com/products/abondprod.asp]Anchor Seal Products[/link]

I know of quite a few people here on RCU that use their products.

Hope this helps.

Ken

Hi All,
Once I have the engine area sealed with epoxy should I check the C of G ? According to the Alpha 40 instruction manual the C of G is 2 3/4 to 3 inch from the leading edge.
Question: should the airplane be straight and level or have a slight nose down. Also is this done with an empty fuel tank or a full one, it doesn't say in the manual.
Wayne

There's a fifty, fifty chance I'm right, and a 90% probability I'm wrong.

You want to balance the plane with the fuel tank empty. With a full tank of fuel when you take off the plane is going to be a bit nose heavy, but this is no big deal. A nose heavy plane is ok to fly with, it's tail heavy you want to avoid. If you balance with the tank full, then when you are flying and the fuel tank is empty, or low, you will now be tail heavy. And tail heavy is a recipe for disaster, so you want to avoid that. Tail heavy planes usually don't last too long before they are re-kitted.

As for the balance, you want the plane to be level when you balance it. A little nose down is ok, but try to shoot for the plane being level. And while you are balancing the plane don't forget to check the lateral balance of the plane. This is to check to see if the plane leans to one side when in the air. The best way to check that (in my opinion at least) is to get some heavy fishing line (twine will work too) and tie one end around the motor in the front of the plane and the other end around the fuselage at the tail of the plane. Now lift the plane up by the line and see if one wingtip drops. If it does then you'll need to get some weight on the opposite wingtip to level out the plane.

Hope this helps

Ken

elenasgrumpy,
I'd like to add something about your question.

Any paint or glue that's fuel proof works to fuel proof engine compartments. Just as RCKen said.

But there is reason to the madness that goes a bit deeper and that is....

If you have any concerns about the strength of an area that needs fuel proofing, glues add measurably more strength than paint. So if you have an ARF with a firewall that looks a bit suspect to you concerning it's glue joints or the quality of it's wood, glue is a good choice to do two tasks at once. And obviously, epoxy is one heck of a glue.

But if the area you want to fuel proof obviously doesn't need strengthening, paint is lots less trouble. Or if you're building a model and you need to keep the weight as light as possible, paint is usually lighter, although that's not always a given. However, one coat of paint very often doesn't do a very good fuelproofing job. Depends on the paint. Aerogloss or Sig dopes don't do a very good job with just one coat. And they don't do a very good job of lasting right where they're needed most, at the joints. And they won't cover well over some of the hotglues the ARF factories are using. You really need to make doubly sure to get a good wetting with paint around the joints and around those rubbery glues. Make sure you look closely after the paint has dried to see if you might not need another coat. and..... after that coat.....

And if you have a hard to get at area, epoxy is a pain to try to apply inside small spaces and doubly hard to apply only as much as you need. It's also really hard to insure total coverage if you can't see everywhere it's going. However, there is a trick that's helpful. Leather work requires dying sometimes. And that craft has neat "wool daubers" that're dead cheap and do an excellent application job with epoxy in hard to reach places. They have a blob of wool at the end of a twisted wire handle. You can bend that handle to make the blob go wherever you need it to go. If the handle isn't long enough, twist another handle together with that, and hold one of the blobs, and you got a twice-as-long handle.

So the choice is like a lot of things we do in this hobby, it's not a simple, single reason choice.

Hey, satisfaction guaranteed..... if you're not satisfied, there is no additional charge.

(btw, I maidened my WM.46 ULTIMATE an hour or so ago!!! BIG GRIN)

elenasgrumpy,

I go along with Ken on the heat thinned epoxy. I started doing this years ago when trying to get the fiberglass reinforcement fabric as smooth as possible on wing center joints. A really experienced builder put me on to the thinning with heat scheme. Now when I'm using epoxy for what you are talking about or for wing joints, I mix the epoxy and set the mixing container in a shallow pan of hot water. If it takes too long of course you have to keep replacing the hot water but this works like a charm. Once applied, specifically to the fiberglass joint, I squeege the excess off with a putty knife and let it set up. As for a firewall and fuse interior, this works well with a brush too.

Cheers,
Andy

Hi Ken,
Thanks for the advice. I used epoxy and spread it around with a small brush with the use of heat. Once it cooled down and set overnight I reinstalled the engine. Then I made a balancing stand with 3/8" wood dowel and a flat board. I drilled a hole on each top end and installed an eraser tips from pencils and then mounted them in drilled holes in the board. Then marked under the wing where the c of g should be. WOW was it ever nose heavy. So I placed lead inside at the end of the tail till the plane was just level, slight nose down, and fastened the lead in with a small bolt with washers and a locking nut. I also applied a little amount of epoxy to hold it firm. Thanks for the advice on checking the lateral balance. I would never have thought of it. I did as you said to and found out that the right wing was real heavy, so I had to cut open the left wing tip skin and installed lead till the wings were straight and level. Once I had the right amount of lead for balance I used epoxy to fasten the lead into place. Used krazy glue to reseal the wing tip skin.
I rechecked the nose balance, and everything seems to be ok. I'm guessing now it should fly alot better without much trim.
Once again thanks so much for your help. It should make my first attempt of flight with an instructor that much easier.
Wayne

There's a fifty, fifty chance I'm right and a 90% probability I'm wrong.

After ll this arguing over thinning epoxy ... I can't understand why no-one has mentioned polyurethane varnish. You can use it straight out of the can, it's oil resistant, and if you REALLY feel the urge to thin it you can use ordinary paint thinner!!!

The reason I don't use poly is it takes too long to dry and too long between coats. With the Balsarite I use I can put 3 or 4 coats on one right after the other, let it dry for an hour or so, and I'm ready for the next step. I usually use a disposable brush so I don't have to bother cleaning it.

Chuck,

Thanks so much for this valuable information. Thanks for taking the time to find this article and post it.

My conclusions, after reading the article, would be to gently warm the wood, then apply a longer setting epoxy. This will not alter the chemisty of the epoxy, will aid in the penetration of the wood, and give longer working times.

Now, armed with this new info, I am planning to join to two wing halfs together on a new ARF project. The instructions call for 30 min epoxy, I'll simply switch to 60 min and that should solve my working time problems.

Thats why I peruse this website so frequently. I am so greatful that guys like you take the time to pass on such valuable information.

Jim

Jim, you're quite welcome. Glad that I occasionally have a tidbit of knowledge that someone else might find valuable.

I still havent seen anyone give a definite "yes" or "no" on using the Aerogloss fuel proof dope for fuel proofing. I was at my local Hobby Lobby last night, and they have a bunch of the clear, at a good price. Thinkin' I might use it if it's alright.

OK, how's this? Aerogloss is fuel proof up to 20 to 25% nitro fuels. It is dust free in 5-10 minutes, ok to handle after about 30 minutes, can be recoated after an hour, and requires up to 3 days to reach maximum fuel resistance.

Here's the rest of the text I got the above from:
"Flammable: Contains toluol and methyl ethyl keytone.
As with any type of painting procedure, always test for compatibility of materials on a scrap piece before attempting to paint model.
For best results: Fill and seal wood with Sanding Sealer, Balsa Fillercoat Primer or Prep Primer. Sand smooth and clean surface.
Use at 70 to 80 degrees (F), brushing or airbrushing with several
thin coats instead of one heavy coat. To thin for airbrushing, use
only Aero-Gloss Thinner. Dries ready-to-handle in 30 minutes;
recoat in 1 hour for brushing, and any time for spraying.
Tape free in 30-60 minutes before sanding and 24 hours or overnight before masking with vinyl electrical tape for trim painting. After
painting trim, dry at least 15 minutes before removing tape.
Cures to maximum fuel resistance in 3 days under normal drying conditions. Dust free in 5-10 minutes.
Allow 72 hours dry time if Formula-U is to be applied as a topcoat.
Tissue Models: Final applications of 1 part dope to 1 part Aero-Gloss thinner provides the smoothest finish."

I think I'll be sticking to Balsarite or epoxy.

Hi All,
Did a little surfing on the net and found epoxy paint, it's called Klass Kote.
They can be found at:
http://www.klasskote.ca/fags.html
Hope this may help some of you.
Wayne

LowlevlFlyer,

In one of my original posts I said that I use that quite a bit......a hangon from my old control line days. I use the Aero Gloss Fuel Proofer........yes it is a seperate product.......and then go over it
with Aero Gloss Hot Fuel Proof Dope. It's easy to use, dries really fast and does the job. A bottle of each and a bottle of thinner goes a very long way.

Cheers,
Andy

Ah, sorry Andy, I guess I overlooked that in your other posts.

Chuck, thanks for the info. Think I'll stick with epoxy, also.

I happened to be rereading the article I sited, looking for something different, when I happened across the following statement: "Water resistance of a piece of wood is not enhanced by deep penetration. Wrapping wood in plastic makes a pretty good waterproof seal without any penetration at all. Likewise, an epoxy coating on the surface is more water-resistant than a thinned epoxy coating that has penetrated deeply into the wood because, in most instances, the epoxy thinned with solvent is porous." The people at West Systems have concluded that thinned epoxy is porous. That seems to be a pretty compelling argument against thinning epoxy being used for fuel proofing.

Hmm, never thought of that, but it makes sense.