gosk8ing

Hey,

I have never fiberglassed a plane before and need help. I have already read as many "how to"s as i can, but still have some questions.
I was looking at these two resins.

One is: Epoxy Bond Fiberglassing Resin 430 (750ml - should be enough for TF P47 .60, yea?)
This Epoxy resin has 68min pot life at 25 degrees C which i think is good because it will give me more time to work with it as a beginner and would be good to mix with micro ballons.

http://www.solidsolutions.com.au/vie...y%20fibreglass


The other one: Polyester Fiberglassing Resin 475 (1 litre)
This Polyester resin has 20min pot life at 20 degrees C, which i think is a bit fast, and probably way to fast for mixing with micro ballons.


http://www.solidsolutions.com.au/vie...0fibreglassing

The only other thing is, the MEKP Catalyst only has a shelf life of 3 months, which means each plane i done, ill have to buy more MEKP - its only $7, so its not much. How long is the life sheft for epoxy resins????
What are the advantages/disadvantages of Polyester over Epoxy and Epoxy over Polyester?
Are there any other products that i will need for glassing?

Cheers,
Daniel

gosk8ing

Hey,

Just been looking at the following website:
http://www.airfieldmodels.com/inform..._finish/03.htm

At the bottom he recommends only doing one coat to tac down the fiberglass cloth. Then he stated not to do a second coat with resin, but instead, using primer to fill the weave. Has anyone done this because this is the first time i have heard this???
Also he recommends not using 1 hour epoxy because it will soak into the balsa to much. What about using a wood sealer before applying the fiberglass. I think this will help but will it reduce the bonding to the balsa???

Cheers

Ed Smith

Do not use polyester resin. It is a dangerous material to have around the house. It will stink the house out for weeks after it is used.

Always use epoxy resin. I am not famailair with the product you mention. It seems as if it will be suitable. Can you tell how thick it is? If it is too thick it is difficult to spead over the surface and will drag the cloth up with it. I assume you are using a 3/4oz max weight cloth. 68 minute cure time is not very slow. you will be surprised how fast that time goes when the resin is curing. I use a much slower cure epoxy when glassing. It gives me some time if I need to make some adjustment. The larger batch mixed will speed up the cure time. With the cure time you mention I would not mix up much more than 70 grams at any one time. I say grams because I mix mine by weight. Never thin epoxy resin. I will not argue about this. Thinning reduces the strength of the resin, in this case probably not an issue. Thinning can also affect the curing of the resin. In some cases the resin will not cure "Hard" it stays knd of "Gummy". This is usually discovered when it is too late.

When glassing have everything ready before the resin is mixed. Lay the cloth out on the DRY surface to be glassed and smooth it out. Pour some resin in the centre of the glass covered surface and with a spatula work the resin towards the edges. When the cloth is saturated scrape off as much resin as you can. If the resin is left too thick the cloth will "Float" in the resin and not be down on the wood. Too much resin will result in a very heavy airplane.

Your second post is correct. I do not apply a second coat of resin. When the first coat has cured I lightly sand the surface and trim off any excess cloth around the edges. Do not sand through the weave. The first coat of primer shold go on fairly thick to ensure the weave is filled. Sand the primer until the weave just starts to show through.

Ed S

daven

My Feedback: (1)

I fiberglass exactly as Ed's post. Works well for me also.

saramos

I too use this method. I do give the balsa a coat of sanding sealer and a final 320-400 grit sanding before glassing. I place the glass on the surface (.5 -.75 oz), brush it with a drafting brush, then apply the epoxy with a small disposable brush working in 1 oz batches. Once the epoxy is applied, I use a small squeegee (phony credit cards work well) and squeegee off the excess epoxy. I then use a roll of toilet paper to blot off that last little bit (some don't think this is necessary, but it's cheap and easy). Once cured, I use a high build auto primer in a rattle can. I apply a coat, let dry and wet sand most of it off with 320-400 grit. Rinse and repeat as needed to fill the weave. For small dings, I use auto spot putty, for larger dips an low spots, I use epoxy/microballoons. I prefer the redish phenolic microballoons. They're lighter and easier to sand than the white glass microballoons.

Scott

j.duncker

My Feedback: (2)

Tried credit cards tried brushes hated both.

Use a foam roller 2 to 3 inches wide you can really work the epoxy [ never polyester ] resin in even using the lightest cloth.

It is also MUCH FASTER. I find I use two coats the first laminating resin the second finishing resin and still need to fill pinholes.

If you have thick resin do not be afraid to warm it up after mixing it will thin out and flow better. N.B. It also sets faster. You can use an alcohol thinner or meths but I have had problems so I use thin warm resin.

ALWAYS wear protective gloves and ALWAYS wet sand epoxy and dispose of the contaminated water and cloth or tissue carefully. Never blow off or allow the dust to dry out. The dust is nasty stuff and is a cumulative allergic irritant.

gosk8ing

Hey,

Thanks for all the help!!!
Im going to be glassing a TF .60 P47. How much epoxy resin should i buy, 750ml or 1.5 litres?? How long is the shelf life of epoxy resins??
Now going on the scale detailing and painting.
When do you apply panel lines and rivets??? - after applying the filling primer to fill the weave???
I thought that using primer to fill the weave would make the top coat paint crack after a couple of months of aerodynamic loads. Eg. Same effect when you apply paint to thick
What about using a mix of micro ballons and epoxy to fill the weave. Anyone tried that????
Now onto the paints. I dont have an air compressor and an air brush, so i was wondering how well spray cans work???
Can you please list what type of filling primers and primers i should use??
Also, can you please list what type of topcoat paints i should use??? - ones that are fuel resistant
When do you sand in between paint coats, if at all???

Here are the stats for the fiberglassing epoxy resin i was looking at.

Typical Physical Properties of
Epoxy Bond Fibreglassing Resin 430
cured at room temperature
Mixing Ratio 2.3 : 1 by weight 2 : 1 by volume
Pot Life At 25°C 68 minutes (100g mass using Tecam Gelation Timer)
Exotherm Max temp 98°C after 80 minutes (50g sample)
Barcol Hardness
GYZJ 935 unite
Time of cure 1 day 36
2 days 42
7 days 62
21 days 65
Heat Deflection Temperatures
(ISOR 75) 42°C after 7 days at 25°C
50°C after 7 days at 25°C and 1 hour at 100°C
Ultimate Flexural Strength
(ISOR 178 KPa) 64120
Maximum force applied to the sample at a fibre strain of 5%. Note sample did not break during the test.
0.2% offset flexural yield strength KPa 45510
Flexural Modulus (ISOR 178) KPa x 105 21.4
Ultimate Compressive Strength
(ASTM.D,695) KPa 48260
Ultimate Tensile Strength (ISOR 527 KPa) 29650
Compressive Modulus KPa x 105 12.4
Elongation at Strength (ISOR 527) % 4.4

Cheers

saramos

Filling the weave with epoxy/microballoons can be done, but it's a lot harder to sand and in the end, may be heavier. After filling the weave and sanding back down, and you have a nice smooth surface, you'll be ready to start adding surface details. For panel lines, I use 1/64" chart tape. I draw out all the panel lines, then lay out the tape. Then I apply a few coats of primer over the tape, feathering out toward the center of the panels. Once dry, pull the tape up and it leaves a chanel in the primer. often, the adhesive stays in the channel and needs to be picked or washed out. I break the tip off a #11 blade and grind a slight hook on the back side, then use it to scrape the adhesive out. Give a light sanding to get rid of any ragged edges and you're ready to burn (flush) or drop (button) rivets. I use a 1/16" brass tube on a soldering iron. I first mark out all the rivets to make sure I have proper placement and spacing, then melt the rivets into the primer. Once done, I again give a light sanding to knock off any rough edges. Now it's ready to paint.

Scott

gosk8ing

Hey,

Thanks saramos!! Just one question, whats chart tape and where did u get it from???

Cheers

saramos

Chart tape comes from the graphic arts industry before the advent of computers. It came in a variety of widths, colors, and styles and was used for making lines and charts. It used to be common in art supply stores, but is now much harder to find. I get mine here:

http://www.grafsticktapeandlabel.com/index.htm

Working with the 1/64" tape takes some patience as it tends to always want to flip adhesive side up[:@]

Scott

gosk8ing

Hey

Now onto the paints. I dont have an air compressor and an air brush, so i was wondering how well spray cans work???
Can you please list what type of filling primers and primers i should use??
Also, can you please list what type of topcoat paints that are in spray cans??? - ones that are fuel resistant
When do you sand in between paint coats, if at all???

Cheers

Ed Smith

To put it bluntly, very bluntly, the only advice I offer on spray cans is do not use them. Sure they will do a sort of a paint job but you will not be satisfied the colour choice is limited.. Having gone through the glassing process why ruin it all with a poor paint job. Look upon it as a long term investment and purchase a High Volume Low Pressure (HVLP) spray unit. There are moderately priced units available. For airbrush work purchase a small compressor and airbrush. The colour choice then is unlimited. A decent scale airplane such as the one you are building with engine, radio gear and finishing materials cost a certain amount of money. All of the aforementioned spray equipment can be purchased for about the same price as one complete airplane and will last forever. So, sacrifice one airplane, you will not be sorry.

Ed S

gosk8ing

Hey,

I have just been on modelflight and am looking at this airbrush. Paasche EZ Starter Set. What do you guys think?? What airbrush do you recommend??? By the way, i have never sprayed with an airbrush before.
http://www.modelflight.com.au/rc_mod...tarter_set.htm

http://www.modelflight.com.au/accessories_airbrush.htm

Cheers

saramos

I painted my TF Spitfire entirely using my Testors Aztec airbrush. This is the only brush I've had, so I cannot give comparisons. The brush was about $100 us with 6 or so tips. I already had an air compressor which I picked up for another $100. I got a better regulator than what came with the compressor, and got a couple of disposable inline filters. I used exterior latex house paint for the major colors. I took color samples down to the paint shop and had a quart of each color mixed. It took a little trial and error to thin the paint to the right point, but once mixed, it went on quick and smooth in a couple of coats. The markings and weathering were done with Model Masters and Humbrol paints. The nomenclature was done with ink jet decals. Latex is not fuel proof, so after letting the latex thoroughly cure for about 2 weeks, I clear coated the plane with waterbased polyurethane. I used rattle can satin wb poly. Next time, I'll not use the rattle can but use my airbrush or hvlp gun as the rattle can leaves a bit of an orange peel texture. It's not real noticable unless pointed out, but I'm sure an airbrush or hvlp gun will give better results.
Here's a couple of shots before and after weathering.

Scott