bstanley72
Member
Is this in place of the polycrylic? Or used as a finishing coat?
Fiberglass + Foam: A Tutorial and Discussion
- Thread starter willsonman
- Start date
You can use it in place of it. I have found that it dries faster and tends to seal the weave of the fabric better in fewer coats. You can still mix it with baby powder. If you plan to use it with FT airplanes it will be flexible enough to use as hinge points as well, unlike epoxy.
I'm thinking of glassing a more complex fuselage, like the Sea Duck I want to make next. I want to glass the fuselage after assembly so it seals the whole thing from water (no seams). Question about the paper: would I assemble it first, then remove external paper and glass it?
I'm thinking of doing the same thing with my PBY but I'd prefer to leave the paper on. Removing it would not work out well for structural integrity. The duck may be the same.
I'm afraid that covering all my curves and such might not be possible, and am wondering if I could accomplish something similar by coating the competed plane with an epoxy/BP mixture without fiber sheets.
The problem with glassing assembled parts is the seams. Once you remove the paper you have paper stuck to those seams and it makes for bad glass adhesion/sealing. If you remove all the paper from the part and glass it before assembly you will have a better product. Using SS will help keep the foam more flexible for construction and then after assembly of a part you can coat again, fill weave, paint, etc.
HilldaFlyer
Well-known member
I've coated the paper with epoxy resin and it stiffens up just fine. See the article Adams vs Ross the graph
last two point are paper left on and "painted" with Polycrylic or Epoxy Resin. Both are a bit stronger than the paper alone. I should note that this was done with Ross foam core and not Readi-Board. Since Readi-Board peels so easy, I did not perform the Polycrylic or Epoxy resin on it.
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HilldaFlyer
Well-known member
Maybe I didn't get the question??? Are you wanting to leave the paper on? There is very little to gain by adding polycrylic or epoxy to the bare foam... very weak, but adds a smooth surface.
Using fiberglass cloth is pretty easy, and the lighter weight cloth (0.65 to 0.73 oz/yd) contours pretty nicely. Heavier weight cloth has a tendency to lay flat so tight corners and compound curves are hard to do without relief cuts.
My first planes skinned in fiberglass were done by building the plane, removing the paper and then adding fiberglass cloth and resin. I'm now skinning whole sheets of foam and then cutting and building.
and ^this guy^ knows what he is saying. LOVED his planes at FF this year. He's done the research and readily provided it to us. What more can you ask for?
HilldaFlyer
Well-known member
The planes to fly - Maybe?
David's going to build them for us too? But.... but... that'll be like keeping all the fun for himself!
Loved meeting you David, for the first time... although, I do find it funny we both live about 45 minutes to an hour from each other, yet we drive 10+ hours to Ohio to meet up. We're a bit off, eh?
Yeah, I'm wanting to leave the paper on, as removing it would destroy the plane, and fiber-glassing beforehand would probably end badly with the way some of my curves run. The air frame is quite strong as is, mostly I'm wanting to glass it so that I can get a smooth even surface, fill seems, etc. Essentially I want a good bondo for airplanes, and it would be great if it added a bit of exterior hardness to protect against hanger rash.
Maybe kevlar fiber or similar mixed into the goop.This will also be over the top of water resistant foamboard, as it seems much less likely to peel away than redi-board if it's floating on the water. Ross foamboard would be an option if the paper wasn't so hard to remove. It can be done, but it's hard to get a good curve afterward.
I think I just need to do some testing. I'll probably build a set of floats, and then try a few different coatings, and maybe even see what I can do with actual fiberglass sheets.
HilldaFlyer
Well-known member
Well, we could have met... Friendly jab - I wasn't the one who didn't come to the Mini- FliteFest Northeast in April!
I enjoyed meeting you to and a 10 hour drive is totally worth meeting everyone.
On a side note, we are going to do the Mini-FliteFest Northeast again this Fall. I'm trying to get club officers on board so they are more inviting than the past one. You will be more than welcome to come.
HilldaFlyer
Well-known member
Yeah, I'm wanting to leave the paper on, as removing it would destroy the plane, and fiber-glassing beforehand would probably end badly with the way some of my curves run. The air frame is quite strong as is, mostly I'm wanting to glass it so that I can get a smooth even surface, fill seems, etc. Essentially I want a good bondo for airplanes, and it would be great if it added a bit of exterior hardness to protect against hanger rash.
This will also be over the top of water resistant foamboard, as it seems much less likely to peel away than redi-board if it's floating on the water. Ross foamboard would be an option if the paper wasn't so hard to remove. It can be done, but it's hard to get a good curve afterward.
I think I just need to do some testing. I'll probably build a set of floats, and then try a few different coatings, and maybe even see what I can do with actual fiberglass sheets.
Hi localfiend,
I think it is going to be hard coming up with a "bondo" that is clear to use for smoothing surfaces. To smooth things out before paint, I use Q beads and epoxy which makes a white paste. This will cover your paper so I don't think it is an option for you. Maybe someone else has a better option than painting several layers of polycrylic.
If you're going to put kevlar or glass into the mix, it is my advice to just get a really light fiberglass cloth and skin the plane. I us 0.73 oz/yd cloth (Thayercraft) and epoxy resin (The stuff I use is totally clear) and with a little sanding with some 600 grit paper, it will be smooth! I just discovered the best (so far) outlet for epoxy resin - check out Resin Research and get the Kwik Kick. It is so clear that a few coats will not be seen, but each coat adds weight, of course.
I've gotten some really nice gentle curves using foam that is fiberglassed on one side. You can actually roll it into a tube if you want to. Floats would be a really good thing to practice with. Glass one side of the foam, cut out the parts, glue together and then glass the seams. I think you'll be surprised how easy and gratifying it is.
I used to live in Pullman, we could have built together,...
I don't need the coating to be clear, as I'll be painting after the fiberglass, that's one of the goals. Clear would be cool if it would work over the top of decals/skins. Is that what you were thinking I was after?
My fiberglass musings are directed mostly towards a large 100" PBY. I can add a lot of weight to the design before it becomes detrimental. Actually, as the design stands, it's probably a bit too light. More wind penetration would be good.
I'll order some stuff and start playing with it. Didn't realize fiberglass would bend, guess I'll see how far I can push it. Wonder if you could cut the foamboard with a CNC after fiberglass had been applied... That's the other thing I'm after, speed and quality. If I can coat a quick easy to build foamboard plane with something that makes it stronger, and smooth for paint, without adding significantly to build time, I'll declare victory.
Small world, Pullman isn't that far away.
HilldaFlyer
Well-known member
Yes - I thought that was your goal and yes, it will work very nicely. Peel the foam board paper, adhere the printed paper with decals, panel lines and rivits, overlay with fiberglass and build away.
For a point of reference, removing paper and skinning with 0.75 oz/yd glass comes in lighter than leaving the paper on. If you're after structure, using 1.42 or 3.22 oz/yd cloth will do nicely but are a bit heavier than the paper. Oh, and I note that once epoxy resin is applied (penetrates) to paper, it becomes waterproof. I have tissue covered wings overlaid with fiberglass and they are tougher than nails.
Fiberglass is pretty flexible. After skinning sheets of foam, I have been able to cut out the troughs for A or B folds and bend it to 90 degrees on the corner. You can only do it once, but it will bend. There are epoxy resins that are more pliable than others (I'm testing 4 different types now) The cloth will bend, the resin is the stiff part. Willsonman uses polycrylic or sanding sealer with fiberglass cloth and it is more pliable than epoxy, but it is not as strong.
Fiberglass foam sheets can be cut with CNC. I use a hobby blade and it zips right through. It doesn't even need to be as sharp as the ones used for cutting paper. Be aware that the fiberglass dulls the blade really fast and the same will be true of CNC machine. Having said that, once the fiberglass foam sandwiches are made (I make full sheets) it builds as fast as the paper foam board. I use Gorilla Glue all joints that I want permanent and hot glue for the ones I may want to remove... a little alcohol and the fiberglass/hot glue interface part ways. For Gorilla Glue joints, I lay a very thin bead down the joint, hold the joint in place and tack it down in a couple of spots with hot glue to hold it until the Gorilla Glue cures.
I like the stuff you have built and flown off the water (what are those, like pumping ponds?)
bstanley72
Member
And I just placed an order for some Z-Poxy yesterday! I'm going to give Wilson Man's Bloody Ripper a go using 1.4 cloth and the Z-Poxy. Maybe I'll try the Kwick Kick at some point as well. I read through your testing article the other day, so if you say it's good stuff, that's good enough for me!
When I do use epoxy, I use Fibreglast and it will break if you try to bend it. The stuff is crazy strong.
HilldaFlyer
Well-known member
Thanks for the reference Willsonman - I read through their web page and watched their videos. I'm completely amazed every time I look into different epoxy resins, the more I learn the more I want to try new things. Looks like Fiberglast has a great line of products. I'm sure for the stuff we're doing, it really doesn't matter what we use, but I think it is cool that there is such a wide verity of choices - sometimes too many choices can make decisions making tough.
Resin Research appears to have a similar system and range of resins. Resin Research provide 4 different resins (1980, 2000, 2020 & 2040) that have differing modulus from high to low (from very stiff to very flexible) that are all compatible with and can be mixed with three different hardeners that determines pot life (fast, medium and slow cure times). I'm testing these resins now looking at flexibility/stiffness with the hopes of determining the one that I like using for models. I have only used their Kwik Kick product (see below) and it is really excellent for what I do.
In the past I have been almost exclusively using System 635 Thin epoxy from US Composites with Medium and Fast hardeners (summer and winter curing). The biggest reason for searching out a new supplier was the 635 Thin has a propensity to blush leaving an orange/brown residue on the surface when cured in humid conditions or when it gets wet after curing.
The color of the hardener on the right is the color of the blushing that actually bleeds through paint causing discoloration and who want a plane that bleeds/oozes orange/brown? Not me... My next Blue Angel is going to have a metallic blue paint that costs more than the plane.
The other product I have used is from C&J Composites.
When I wrote to them earlier this year and started asking some technical chemistry questions, they promptly referred me to their supplier -> Resins Research. This is how I learned of Resin Research and all the different kinds of resin they offer. The C&J product above has the same color as the Kwik Kick, so I assume it is the same.
Sorry for the length - hopefully it is helpful.
Somewhat on-topic, but also off-topic, here's a great video / ad of a fiberglass tape product that I just love for a number of reasons:
1) It's funny
2) It seems like a cool product and the funny message didn't overshadow it
3) At the end of it, you can hear their aerial video platform flying as they show raw footage
Now, could this be a good "tape and fly" solution for fiberglassed airframes? I could see this being useful in the multirotor world too for field expedient repairs.
1) It's funny
2) It seems like a cool product and the funny message didn't overshadow it
3) At the end of it, you can hear their aerial video platform flying as they show raw footage
Now, could this be a good "tape and fly" solution for fiberglassed airframes? I could see this being useful in the multirotor world too for field expedient repairs.
