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Here's the WHOLE (not "Holy") TRINITY of warbirds, patiently awaiting my application of cloth.
Well friends, I am still not caught up with the posting of my progress on this fabrication project, but it is very late, and I have to get up early so I can go out and practice tomorrow morning for Saturday's Big Kahuna Warbird Race. I have very few flights on my planes, yet I want to be at least semi-competitive. So I am calling it a night.
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By the way Steve, responding all the way back to post #9 . . .
I too, greatly admire your work. I feel honored to have received one of only 2 posts that you have made since 2003!(?) The hollow-core fuse construction methods you showed me on your latest project look incredible! Great job.
Hey, and that certainly is a nice picture you used for your avatar!
To my fellow modelers out there,
All good-natured ribbing aside, the relationship that Steve and I have is the whole point of this thread. We are both self-taught, experimenting with these techniques; and sharing with each other what we are learning along the way. I shared a great and relatively inexpensive primer that works exceptionally well for finish work on plugs; then he helps me by sharing a great spot filling putty that cuts my working time significantly because it dries fast, sands easily, is readily available, and doesn't have to be mixed like Bondo or microballoons and resin.
I could list multiple examples of how we help each other, but the point is . . . that the more of us that choose to dabble with this type of construction, the more we learn and can share. Thus, shortening the learning curve for us all and greatly improving the ease and quality of our methods and results!
(And "yes" I am supposed to be practicing for tomorrow's race right now, and then working on my molds; but these forums are getting addicting! Now I see why you so rarely post, Steve. They are like potato chips . . . once you start, you just can't seem to put the bag down!)
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quote:
ORIGINAL: Iron Dog
(And "yes" I am supposed to be practicing for tomorrow's race right now, and then working on my molds; but these forums are getting addicting! Now I see why you so rarely post, Steve. They are like potato chips . . . once you start, you just can't seem to put the bag down!)
So Steve,
As a follow-up, I'm thinking about how addicting these forums are while I'm eating breakfast ("yes", I'm a bum and was up too late last night; but I have an excuse . . . I'm on vacation) and I'm thinking about all my friends who are way too afflicted, too. I see Tommy Gun, Skids, and Leadfoot on the forums most every time I am on, and I'm thinking . . . "Hey, aren't you all at work, right now?!"
Tommy, if you spent less time on-the-clock, in the forums, maybe you wouldn't have to go into work tomorrow and miss the race! (So, does that comment finally put me on the 2010 Sh!@ list, too!? Sorry my friend, but I couldn't resist.)
And Leadfoot . . . aren't you driving right now? Hey buddy! Eyes off the I-phone, and back on the road! (And "no" Casey . . . I'm notsorry for that one.)
Okay, so now that I've successfully painted a bulls-eye on my back, unleashing the wrath of Tommy, Leadfoot, and Skids, I am going to go take refuge out at the flying site. Just know that it is just for fun, and it's only done out of love, guys. As my late grandfather used to say, "I'm sproutin' horns!"
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Hey everyone,
Note the response times from those two:
My comments weren't but 11 minutes old and I already had a response posted from Casey. And I know what a s-l-o-w typist you are, Mr. "Yeah, I'm driving through Vallejo right now . . . and I didn't know how to spell 'celebratory' (drinks), so I just said 'victory' instead." So you must have been on and trying to come up with a response immediately after I posted! Ya know its hard to concentrate on spelling when you are already multi-tasking driving with one hand while typing with the other.
And Tom . . . I was 2:40pm! Ya can't tell me you were on a lunch break!!! (Unless those 3-hour lunches are another symptom of the problem as to why you have to go into work tomorrow, instead of hang out with the rest of us.)
Way to prove my point, while simultaneously shootin' yourselves in the foot, gentlemen!
So my fellow racers out there, I think that at the June President's Cup Race, when Tommy can again join us (if he doesn't screw that one up, too) we need to schedule a little "INTERVENTION" for our addicted comrades!
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Okay, back to business for awhile . . .
I'm breaking some of my own rules. I was supposed to start this process when I had 3 - 4 relatively uninterupted days to complete this project, and that didn't happen! I have WAY to much going on to do this the "right" way. This is gonna be one of those "Do as I say, not as I do" kind of entries. Sorry guys! So, Step 9 really should be Step 1, and should have been done before I even started waxing my molds. By not following my own rules, and not anticipating just how much other conflicts are halting quick progression through the steps, I am letting my initial thinned epoxy coat cure way too long before adding cloth and I will not end up with a solid chemical bond. I'll talk more about this at the end.
Step 9:
Beings I didn't do this at the beginning like I am supposed to, It is time to start cutting my fabric. First, I pull out all my templates (pic 1); then, clean and prep my cloth cutting table (pic 2). I have a fabric cutting mat and Olfa fabric cutters that make life SO MUCH simpler than trying to cut fiberglass with scissors. These tools are VERY WELL WORTH THE MONEY! I have templates for all the wood parts (wing ribs, fuse formers, etc., that I make out of formica) to build other structures of the plane, and then I have fabric cutting templates. Fabric cutting templates can be made from just about anything that will not snag the fabric. The P-51 fabric templates show templates made from mostly paper and cardboard (pic 3); and the P-39 templates (in pic 2) are made from my favorite material . . . formica. I misplaced most of my old P-47 fabric templates (they were made from the blue plastic sheet that was a backing liner from some old 3/4 oz. FG cloth), and had to make new ones. Yet another reason why this should have been done before-hand! All these little delays really start to add up!
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Here I am laying the templates for the P-39 out on the fabric.
You might notice that I am trying to cut my parts at approximately a 45 degree bias. The fabric tends to take compound curves better when it has been cut at an angle to the weave. Following the weave horizontally or vertically doesn't seem to work quite as well, at times. Also, don't get carried away trying to put everything at exactly 45 degrees either. You'll have too much waste; and, from what I've read, the structure is supposed to be stronger if the weave patterns vary somewhat. The best analagy I could give is to think about how plywood is stronger when the grain patterns are alternated, as opposed to all running exactly the same direction.
Also, I'll bet you are thinking, "The dimensions of the fabric cutting templates look "off" somehow." They probably seem too tall to you, when compared to the horizontal axis. That is because they are a little taller than they are wide. Remember the sides of the fuse are not straight, they are curved, so it takes a little extra fabric vertically to compensate for this fact.
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Hi Iron Dog, Nice job explaining your fiberglass lay-up techniques! I'm looking forward to reading the rest of the process!!
Question #1 Where do you find the formica for your cloth cutting templates?
I like the idea of spraying (rather than brushing) on a thin surface coat of resin into the molds to reduce the pin holes....I have a few more questions.....#2 How much did you thin the sprayed epoxy if at all? #3 What kind of settings (pressures etc.) did you use on your spray equiptment? #4 What did you clean yor spray equiptment with after shooting the epoxy surface coat?
What do you think....Maybe you could keep the sprayed epoxy surface coat off of the mold flanges by covering "masking" the flanges of the molds with paper taped to the exterior (non-tooling part) of the molds. Just tryng to think of a way to avoid disturbing the PVA on the mold flanges and still spray on the surface coat
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Thanks for the feedback, Steve. It is good to know that someone is reading all this and finding something here to be useful!
To answer your questions:
1) I picked up the formica sheet at Lowes, back near the kitchen refinishing area. It comes in 4' x 8' sheets in many various colors. It is a little pricey, but to me it is the best material I have found, so far, to use as cutting templates (either for cloth or for balsa parts). When I take a sharp corner, or just stray into the template as I tend to do sometmes, I'll cut pieces clean off that are made from paper, plastic, or cardboard. Even with plywood I tend to shave the edges from time to time. This has the effect of changing the shape of the template gradually. But, of course the effects are cumulative and will eventually ruin all the time spent in making accurate templates. The formica is much more durable and more resistant to those occasional "boo-boos". Because the 4' x 8' sheets are a little awkward for me to store and handle, until they've been cut down, now you have me wondering if cabinet shops, kitchen refinishers, or similar businesses might sell scrap cheaply (or even give it away)? If someone out there knows a cheaper source, please let us know.
2) I thinned the epoxy with denatured alcohol, and merely thinned it until it "looked right". I was going for it to be the consistency of the PVA, beings the PVA flows together so smoothly, and I was hoping for the same effect. If I had to guess, it was less than a third alcohol.
3) The results spraying it on were less successful than I would have liked. If you look closely at some of the pictures where I was applying microballoons and resin to the wing fillets, you can see pitting from bubbles that I still got from the spraying application. I'm unsure if that is because I have the wrong viscosity of the thinned resin, or maybe too much air pressure. I realized after the fact, when I saw the bubbles, that I had my pressure setting rather high on my compressor. I had gotten used to the HVLP (high volume, low air pressure) gun that has a regulator on it, set for 40psi (this gun and setting is outstanding for applying PVA), and I was using my O-L-D, well worn and used basic detail gun for the thinned epoxy. Without its own regulator, I may have needed to adjust the air pressure lower (it was somewhere between 60 and 80psi . . . oops!) I picked these guns up (for cheap) at Harbor Freight Tools.
4) I used acetone for the cleanup, but wasn't completely thrilled with the clean-up. Things still felt a little sticky. I would bet that KlassKote's epoxy reducer would make short work of it, but that stuff is alot more expensive and not as readily available; and, as old as the detail gun was, I was kinda treating it as if it were expendable anyway.
As far as masking the flanges:
As you well know (but others totally new to this may not have considered), they do need to be PVA-ed because when we join the mold halves, there are places where the epoxy used at this stage will seep a little into the crack. If the flanges are unprotected, you may glue everything together well enough that the only way to separate it all will be to cause damage either to the molded part, or the molds themselves. I think your idea would probably work. The problem here is that making these paper flange covers to fit, takes up some of the additional time that would have been saved by the spraying process, versus just brushing it in, in the first place. I still think that for us guys doing one or two fuses in our garage at a time, that brushing on the coat still represents a "best practice." If doing multiples to keep ourselves and friends in race planes season after season, then taking the time to find the correct mix of thinned resin and the correct air pressue, and to make "flange cover templates" would likely be worth the time to make for your molds.
Everybody, please note Steve's comment to "tape it to the EXTERIOR (NON-tooling part of the molds," so you don't accidentally remove the PVA from where you need it.
If we were doing large scale production, perhaps a form-fitting, drop-in prefabricated lining to protect the mold halves while spraying PVA to the flanges would be worth making, but probably not what the average hobbyist wants to deal with. Just my opinion, for what it is worth.
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man this forum is just chalk full of information. My question is that how would you lay up the plug and old . Earlier in the forum you kinda glossed over how to get all of the imperfections out of the plug and mold but not how to make the actual plug and mold thats kinda what i want to know how to do so then i can go along with the rest of your wonderful instructions.
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Spencer,
Thanks for taking the time to let me know you find this helpful. That's the whole point of me trying to do this. Unfortunately this site is having problems. I have typed a very detailed response twice over the last hour, and lost it both times right as I tried to post it. It is late and I'd planned to be in bed long ago so I have time to complete the next steps in my current thread. So, please excuse the abbreviated version, but I'm exhausted and very frustrated with RCU for repeatedly dumping my posts, right now.
What you are asking for is a lengthy process worthy of a thread all its own; and I'm having enough trouble just trying to complete this one, right now! If there is enough interest in this thread, perhaps on my next vacation I can take everyone through that process during my next major project. However, that won't be until August/September at the earliest.
Beings I know you don't want to wait, the process I follow is much like the process detailed in the CST Sales tutorial. A link is posted below. Also, the guy that is documenting his copy of a Top Flite P-40 has an excellent set of tutorials that can be found at the second link below. I think there are nine videos in all. This is the intro. These should help you get started with what you are asking for, then perhaps I can help you more, later. I would suggest building your skill-set by copying an existing cowl following the CST Sales tutorial . . . that is how I started out. Start small, with something you don't have alot of time and resources invested in, and make your mistakes there. Afterwards, you'll have the skills so you'll be ready to successfully take on a bigger project, such as a fuse plug, when I can show you, later. As they say,"You gotta walk, before you can run."
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Earlier I posted a picture of all the P-51 cloth cut out and ready to go. Here's all the major cloth pieces for both the P-39 (on the left side) and the P-47 (on the right side), ready to go, too:
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Ollie, I got a ton of formica from a cabinet shop they were going to throw away. I offered them some money for it but they were so happy to get rid of it that they loaded the truck up and just gave me as much as I wanted. They even told me me if that wasn't enough to come back and get more.
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Thanks ollie for giving me that website. i just scanned through the tutorial on there and it looks pretty straight forward but i have some questions about some of the processes but the questions are to long and detailed so i'll just wait till i see you next.
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Spencer,
I'm glad it was helpful. Waiting on the questions would be good. I want to be able to answer them, however typing them out (such as this) takes alot of time for me to complete. I'd like to get more posted on the procedures I've been taking in the lay-ups of the Trinity Build, but there is so much work involved, and still way too many other distractions and conflicts, that all I can do right now is take pictures to document it, and I'll post the steps and pictures as soon as I can.
But, here is a sneek peek at some of the work on the P-39 (left)and the P-47 (right).
Ollie
< Message edited by Iron Dog -- 4/21/2010 11:34 AM >
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I decided to start laying up the P-47 first. (Probably because I was so happy with the prototype's performance during the "Big Kahuna" SAM Warbird Race, and expect this one to be lighter, and therefore better.)
Here are shots of me getting everything I need laid out:
fuse halves
major sections of cut cloth (I used a 3 oz. tight weave, followed by a 6 oz. loose weave)
scrap cardboard to protect my work table and gloves to protect my hands (that epoxy gets messy and can be troublesome!)
flux brush
1-1/2" disposable trim roller
1" brush (the roller worked so well, that I never ended up needing this)
Also pulled to the workstation before starting, so it would be handy, was my scrap FG cloth, Olfa rotary cutter, a trash can, and a couple of paper towels.
Once you start mixing epoxy, it is like a race; and, as I said earlier: "Life revolves around cure times."
By the way, the light spots on the top nose section and just below the "razorback" are from me sanding out some minor imperfections that I couldn't remove from my original plug. That is where I sanded through my original "tooling coat" that had graphite powder mixed into it . . . thus the black finish to the rest of the mold surface, yet some light spots. This variation would be similar to that caused by sanding through the primer on a primered surface. That taught me to do two black tooling coats, ever since. (But that is a topic for another thread.)
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Another new method I am trying out with this build is to apply most of my epoxy using a small trim paint roller, rather than a 1" brush. My hope is that it will:
speed up the process of wetting out the cloth
more evenly distribute the epoxy to the surface of the mold
help me to use less epoxy and save on weight. This is important beings hand lay-ups supposedly use 30% more epoxy than vacuum bagging, and I don't have any vacuum bagging equipment, yet.
by largely eliminating (or at leat minimizing) the use of the 1-1/2" bristle brush I hope to eliminate or minimize the snagging of the bristles on the cloth, and therefore the deforming of the weave of my cloth.
I take the REALLY small pieces that most people might normally throw away and keep them in an old microballoons container to be chopped up for use as "chopped fiberglass."I also found a really cool mini paint roller pan at Lowes (left of the picture).
Other materials pre-pulled to the workstation and at the ready, not mentioned in the prior post, are:
chopped fiberglass
mixing cups and popsicle stick for mixing epoxy
mini paint pan
denatured alcohol
composite rollers (the metal rollers with blue handles at the top of the 2nd pic)
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I have not been pleased with the commercially available chopped fiberglass. I stays too rigid (like mixing in uncooked long grain rice) and does not smoothly conform to the surface it is being applied to. (See pic. #1) That makes it nearly impossible to get the cloth to lie down and conform to the mold surface adequately. In turn, this weakens the strenth of the layup, which is counter to the point of adding it in the first place.
Therefore I take the really small pieces of my scrap FG cloth and put it in a small Tupperware container. I then stick the tips of sharp scissors inside the container and cut repeatedly. I want the cloth to be mainly in individual strands, but don't overdo it or you won't have much strength being added (usually about the time my hand starts getting tired, anyway). In my opinion this is a filler material that adds at least a little bit of strength, as opposed to microballoons, and also helps to hide the weave of the cloth being applied. And by using the scrap, it is essentially free (I was going to throw it away, anyway), while working better for my needs than the commercially available option.
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Using the pump dispensers, I mix some epoxy into a shallow cup (pictured is a Cozy Shack Pudding conainer). As before, mix epoxy thoroughly before adding filler.
Add chopped FG strand and mix.
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I use this "slurry" to help partially fill in the still-too-tight-for-cloth areas of the wing fillets. This gives me more strength . . . certainly less brittleness . . . than microballoons.
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All Forums >> RC Airplanes >> Pylon Universe - RC Pylon Racing >> Scale Racing >> RE: Warbird Racer Trinity-build 
RE: Warbird Racer Trinity-build - 
The hollow-core fuse construction methods you showed me on your latest project look incredible! Great job. 
