nwadc10

I have no experience fiberglassing, well, anything. My next project is going to be the TFF4U Corsair. I never considered fiberglassing until Isaw photos of some glassed planes and was impressed with their appearance. I set off to research the process and products required as much as Icould. Now, I am very interested in glassing airplanes but throughout my research I couldn't find the answer to a couple of questions that Ihave.

First, why are so many using Bondo, in particular? Would a hobby balsa filler work just as well? Second, the seams from one section of fiberglass to another, say on the wing between the top and bottom of the wing, how are those removed? Are they removed by sanding after initial glassing, after the coat of filler, or do they never appear if the fiberglass is so thin to begin with?

Thanks,
Justin

KC36330

I've never used Bondo, it's just too heavy, talc powder works but there are lightweight fillers sold by West System and i've found them to work the best for me, easy to sand and light weight.

on the seams, you do bottom of wing first, use a T-bar sander to sand/cut the edge of the glass where it wraps around the edge, then do the same for the overlapping piece and there's hardly any seam at all, minimal filler and you're good to go.

if you've never glassed before, start with some scraps or small items till you get a feel for it.

good luck

nwadc10

Ah, yes, I've seen that T-Bar technique on a youtube video. I'll have to research your filler technique too. I did fail to mention that I will be testing the process/practicing on scrap balsa first as Ihaven't even purchased any items for the Corsair project yet. Thanks for the tips.

Justin

speedracerntrixie

My Feedback: (29)

Justin, glassing an airplane is actually easy to do, it just takes some time. First, get the airplane prepped as if you are going to use an iron on covering. The glass won't hide anything. Get the surface as dust free as possible. I lay out a piece of 3/4 oz cloth on a surface, pour out about a silver dollar size spot of resin and with a playing card squeegee the resin towards the outside. Work slowly and get the cloth wetted out but not soaking in resin. When the cloth is wetted and smoothed out, get some toilet paper and blot as much resin out of the cloth as possible. This will greatly reduce the amount of sanding required. When overlapping allow the first side to fully cure and feather edge before the next side. Now that the whole airplane is covered, I have a 6" sq peice of blue foam and use it as a sanding block with 220 grit. Very lightly sand and feather any seams being careful not to burn through the glass. Once smooth you will need to fill the weave some. There are lots of ways to do this from using a past filler to just start spraying primer. What Ido is saturate a paper towel with resin and wipe it on the surface. The resin will stick to itself better then any filler will and because it dosent have any clay is lighter. After a final sanding this surface will be ready for primer. I like the Klass Kote primer system. It is light, fills well and sands fantastic. It is also fuelproof. Pictured is the last airplane I painted using this system.

Bundubasher

Justin,
You get normal "fibreglass resin" that hardwarestores sell and you get epoxy resin. The latter is lighter and safer to work with, but it is a matter of choice. Then you can only "glass" sheeted surfaces", not open areas such as what you can do with i.e. Oratex or Solartex, speaking of which you can iron on and spraypaint. This will give you just as nice finish at the fraction of the sweat working with ",glass".

Cheers
Bundu

kenh3497

I add a bit of denatured alcohol to my epoxy mix to thin it a bit. This makes the epoxy a bit thinner and squeegees better. Use the above technique but look carefully at the surface. If the surface is shiny and looks "wet" you have to much resin. If a spot looks "dry" you need a bit more. If I have excess I try to squeegee it off the trailing edge if possible to get rid of it. I can't remember if I have ever soaked up excess with a paper towel like some do, but that's just my technique.

Good Luck on your project.[sm=thumbs_up.gif]

Ken

dreadnaut

My Feedback: (5)

You can mean two things when you say Bondo. First, it is a brand name, and is the brand I see most on polyester resins sold at home improvement stores. Second is a polyester based filler putty, often sold by Bondo. If you want light weight, and good sandability in a bondo (note the lack of capitalization), a company named Evercoat make some good polyester based fillers. These are used to fill bubbles and seams on layed up fiberglass parts like fuselages.

Epoxy resins do not smell as strong as polyester, and this leads many to believe they are less harmful. They are capable of producing allergic reactions in some people, so gloves and good ventilation are recommended.

Adding alcohol is a common practice for thinning epoxy, but if you use a high quality, lower viscosity resin like West System, it isn't necessary, and can weaken the layup. Polyester can be thinned with acetone. I always keep a can of denatured alcohol handy because it works great for cleaning up un-cured epoxy messes.

nwadc10

@speedracerntrixie: Great looking airplane! I love the shine and smoothness of the appearance. Using the blue foam as a sanding block sounds like a really good idea, I've added it to my notes.

@Bundubasher: I am planning on using the epoxy resin. At least for testing purposes (to test the process) I will likely get the Z-Poxy finishing resin but I'm not set hard and fast on that product for the actual application on the airplane. Throughout my research I found it fascinating that the preferred bonding agent is as varied as the those glassing. I've looked a number of things and to the novice (me) it seems that epoxy resin is the simplest procedure.

@kenh3497: Thanks for the tips, I have come across that debate before, to thin or not to thin. LOL

@dreadnaut: I guess I meant Bondo brand name. The auto body filler is what Iwas thinking of. I've seen some mix resins with microballoons, another product Ihave yet to work with, for the purpose of a filler. What are your thoughts on that? The claim is that the microballoon mix is very easy to sand. I did notice my hobby shop has the West system on hand so I will have to research that in more depth.

I was hoping to limit my questions to the originals but invariably more questions pop into my head as Ilearn more. To that end, in everyones experience, what is a good paint? I've seen a lot of reference to auto paint with little reference to anything else. Is this the normal paint for this process? Whatever the paint is, how is it applied, by airbrush, byaerosol can, by some other means?

Thanks for the tips so far. My confidence is building with every tip and Iam very excited to glass my first airplane!

kenh3497

MY opinion on thinning epoxy....

If you are only using the thinned epoxy to apply light weight cloth (3/4 oz or lighter) the thinning agent will evaporate fast enough so the strength is not affected enough to matter. You are only "gluing" the cloth to the surface not using it as a structural component. If you are doing a layup of a fuselage or cowl, never thin the resin as the strength will be affected. The thinner has no chance to evaporate from the thick layup.


Have you looked at using the water based polyurethane varnishes to glass with? Never done it myself so I can't really comment. I'm told it is a bit lighter than epoxy, not quite as durable and less messy as it is water cleanup. I guess you need to watch the product soaking into the wood as it is water based? Some are using some sort of sealers as a first coat.


Ken

nwadc10

I plan on using 3/4 oz glass so this is applicable. What is "layup of fuselage"? I am glassing purely as a finishing process rather than iron on covering so in my application it is not intended to add strength.

I have read some posts about the water based polyurethane and while it does sound easier cleanup it also sounds more complicated. Until I get more experience I need to keep this simple.

Justin

Mk23socom

My Feedback: (7)

Justin, I did my first fiberglass job last summer and used the epoxy resin method. I thinned slightly with 91% isopropyl and finished accordingly. I found it to be easy to do, gave a great finish, and was easy to prime and eventually paint. My only advice is to make sure you do good wood work. I had a few spots that I said "screw it, good enough" and ended up having them look like the south end of a north bound mule.

By "layup of fuselage" he means if you are laying up fiberglass in a mold for a fuselage as opposed to building one out of wood. Same goes for a cowl. I would not pay any attention to that part as it won't pertain to you. But he is right, do not thin your resin when building parts that require built in strength.

Go ahead and go with the epoxy resin if you are most comfortable with that. I did and learned alot and was very happy in the end.

Also, you a 647 guy?.. if not, disregard..

nwadc10

Thanks for the tips Kirby. I too would have been a "screw it, good enough" kind of guy LOL. I've seen mostly references to automotive paint used to paint the plane. Is that what you used or something else? What was the method of application you used to apply the paint: airbrush, aerosol can, other?

Sorry, I can't figure out how Iwould fit into a "647"

Justin

Mk23socom

My Feedback: (7)

Justin, I used the Tamiya AS and TS line of paints in the aerosol cans. Great stuff, expensive as crap though for how much you get. If you are on a budget, there are lots of other options out there to choose from. I cannot recommend anything that I haven't used yet, just wouldn't be proper. The next project I am working on I am going to try to do in Warbird Colors waterbased paint. It can be applied a number of ways but I plan to use my HVLP gun to accomplish this task. Last time around I used automotive primer in the spray can form. I am currently looking at other, more productive methods that would potentially net me a better finish. The stuff I used didn't sand very well in the dry state and where I was working at the time was not a place that I could have gotten away with wet-sanding. I would be happy to answer any other questions you have as a first timer as I was in your shoes less than a year ago! Any mistake I made that I can steer you clear of would make your life easier. OH, and by the way, if you have any questions about what fillers to use, fire away, I have used 6 methods and have found my darling in the most recent one.

acerc

Latex house paint is a good alternative. If interested I'll give detail's.

MTK

Filling with balsa filler works fine IF you monokote.

If you want to paint, you may still use balsa filler except you have got to seal it with epoxy. Don't use thinner in the epoxy, it will bubble the filler after a month or two. Better yet, don't use balsa filler under paint, period. Sure there are some that will work okay but it's very inconsistent.

Bondo should be reserved for car repair...much too heavy and there are much better alternatives for model planes.

saramos

I strongly recommend denatured alcohol over isopropyl as it contains water which can aversly affect the cure. My preference is West Systems, but there are lots of people who have great results using other epoxies, polyester, polyurethane and even a product called liquid sheeting without glass. For prep work, I like a product from Minwax, their stainable wood filler. It's fairly lightweight. West System also has a lightweight filler that can be mixed in to epoxy. If you can find phenolic microballoons (it's a dark red), they are lighter and sand easier than the white glass microballoons. I also use auto spot filler for smaller fills. It sands beautifuly but is heavy. After glassing, I like to use Duplicolor High Build Sandable Primer to fill the weave and get a smooth surface. I use it in two colors in alternating coats, sanding back to just the top of the glass weave. The two colors really help to identify low spots. If I fill anything after glassing, I prefer a lightweight spackle. Once I get a good smooth even surface, I use the high build primer for panel lines and flush rivets. for butt joint panels, I use 1/64" chart tape. Lay the tape on the panel lines, spray with primer, let dry and pull up the tape. I use a small brass tube attached to a soldering iron to melt rings into the primer to simulate flush rivets. For overlapping panel joints, I lay masking tape on the edge of the panel line covering the lower panel. I spray the primer on the high panel feathering it away from the panel line. Pull up the masking tape and the primer creates a raised panel seam.

nwadc10

Thanks for the tips. The paint sounds more expensive than I'd like.Are mostusing a clear coat as the final layer(s) for protection?

I appreciate your willingness to help out with questions, no doubt I will be tapping into that in the near and distant future. Next week I will be getting small amounts of the products and testing the process. Like I mentioned before I plan on getting the Z-Poxy simply because the hobby shop has it and it's cheaper than the West System which is the only other finishing epoxy they have. From what I can gather, many have moved away from Z-Poxy I presume because better/cheaper epoxies have been found. Once I am ready to glass the real plane I expect to have to order the products online. Since I'm only in the playing around stage I'd rather not have to pay for either shipping or mass amounts of epoxy or fiberglass.

So, what is your method of filling?

nwadc10

Ah, understood. I will omit balsa filler from consideration. Thanks.

nwadc10

Yes, Ihave seen denatured alcohol mentioned a lot and thanks for the note on isopropyl. Isopropyl is what I have in the shop right now and I could have ended up using that...denatured is on the shopping list. I did come across posts on the other methods you mention and for now I have selected epoxy because, although I am as far from expert as you can get, it appears that epoxy is the simplest process (and there are a few videos on youtube, not so much for the other methods.)

I am intrigued by the microballon filler method. From what I've read it seems that it's one of the easiest to sand.

Savvy tip on alternating primer coats, I like it. In fact, I'm going to print this for future reference because your tips on adding scale details are excellent although when taking on a big change in how I do something I take baby steps so the scale details likely won't make it into this plane.

Regarding the specific epoxy, I've seen some use USComposites 635 Thin Epoxy Resin. Has anyone got any experience with this? The price is reasonable and you get a lot of it.

raptureboy

There are many options. I have used polyester resin before and it is very smelly and you want to be careful where you buy it from. I bought some from a home center and it was old and the catalyst did not kick off the resin all the way and it stayed sticky, never getting quite hard. Ended up sanding off and redoing[:@] Same goes for epoxy, make sure it's fresh. Here is a link for another tecnique http://www.youtube.com/watch?v=1rcKyCMDBJE
This guy is quite the scale builder and he posts on here alot. He did a heck of a job on this Hellcat http://www.rcuniverse.com/forum/m_25..._1/key_/tm.htm

wingspar

My Feedback: (3)

Rapture, sound more like you used laminating resin instead of finishing resin. Thus sticky and not hard.

Dave N

speedracerntrixie

My Feedback: (29)

Could also have been a lack of temp as both products should cure above 65 degrees. Epoxy is mix sensitive as well. 5% off on the ratio one way or another can result in an incomplete cure.

rgburrill

If you haven't built it yet you might want to look at Fliteskin. They have fiberglass sheets that can be used in place of sheeting. They also have a very thin (.007) sheet that can be used in place of a covering. These sheets can cover open areas and provide some strenght as well. But they are expensive.

Also, you can use Solartex or Worldtex (I haven't tried Oratex) white covering. Using a primer such as Rust-Oleum and sanding it well gives a metal like finish. It is a little heavy so you should look at other ways to lighten the build first. But it also adds a lot of strength. I did this Royal Corsair this way.

rgburrill

Sorry, can't get the bigger picture here. Please check My Models for a bigger image.

Mk23socom

My Feedback: (7)

Justin, I use the 91% because I have it around and I have never had a problem with it thus far. When I am out, I will go get the Denatured. I haven't used the microballoon/epoxy mix for filler because I haven't seen a need yet. I have used balsarite and Elmers wood putty for wood filler and was mostly satisfired with the results. I have recently found the featherweight spackle to be the most user friendly.

For the clear coating, I found some Krylon matte clear that was compatible with my undercoat and one can was able to coat my entire .60 size TFP-47. i think the can was like $5.75