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Old Oct 20, 2005, 02:04 AM
Warbird crazy!
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United States, CA, San Mateo
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Finishing Resin or glassing and resin?

I am putting together a plan and budget (I know that's a good one ) for my first scale kit build. At first I was resigned to using covering, but the subject I wish to pursue is a camo war bird so painting looks the way to go. I found Sig Finishing Resin Kit at Tower and wondered if any one had done a balsa build and sealed it with Resin but no fiberglass for painting. Also, how does the weight compare between covering and resin coated planes. It will be a Ron Daniels Tempest MK II 1/10.9 and I will sheet the wings. This is in the distant future as I have not even ordered the kit yet , but I want to have a grasp on what I will need for materials and even more, start learning what I need to know . Thanks for any help.

John and Christo
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Old Oct 21, 2005, 04:48 PM
FLYER spelled I-squared-R
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For electric scale, I would look for something lighter. You don't need the fuel-resistance of epoxy.
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Old Oct 21, 2005, 05:32 PM
hul
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Switzerland
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you can use acrylic automotive primer if you're only after a good surface, it's easier to apply and sand and probably lighter than epoxy. Epoxy is good for fuel resistance.
Glass adds a lot of strength and stiffness and doesn't add much weight if done properly. My well used glassed Mosquito (1 1/2 year old) doesn't have any cracks in its finish yet.
Consider water or oil based polyurethane to attach the glass and consider doping the balsa before the PU. I have not tried the dope yet, but think it will keep the PU from soaking into the balsa and save some weight.

Hans
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Old Oct 21, 2005, 06:21 PM
Electric Coolhunter
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United States, TX, Fort Worth
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Resin without the glass is not a good choice. The wood looks nice for a while, but tends to split later, along the grain, as the wood ages.

Especially in a crash...
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Old Oct 21, 2005, 08:00 PM
Trampling out the vintage
Joined Feb 2002
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The Sig polyester resin is way too heavy for finishing an airplane in that size range for electric. You want to use something like Z Poxy and .5 fiberglass cloth.

Finishing a model with fiberglass is a whole subject unto itself. Visit RCScalebuilder, do a web search, consider going to a well -stocked hobby shop and getting an article on how to do it. These are all sources for "how to".
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Old Oct 21, 2005, 08:41 PM
Electric Coolhunter
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Actually, done properly, with the removal of al excess liquid resin, the polyester is no heavier than epoxy and can be lighter.

The viscosity is greater, and more tends to remain behind, if you are not careful.
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Old Oct 21, 2005, 09:06 PM
Go get them Meg!
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Using resin without some sort of cloth (Glass, silk, nylon) gives you the worst of both worlds. It does not add strength, makes the balsa brittle, and is heavier than a traditional wood filler.
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Old Oct 21, 2005, 09:18 PM
Warbird crazy!
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Thanks for all the great info guys .

I will read more into the subject and it looks like using .5 cloth is the choice here. I wanted to go with an iron on covering, but to really do this right painting seems the way to go, just wasn't sure about the weight of using glass. Also, I am confused as to the weight of the glass as it is given. Is the .5 or 2 oz representing the actual weight of the fiberglass cloth per sq. yd. ? If that is the case, the cloth itself is very light compared to say Monokote, so the weight must come from the amount of resin used. Thanks for the help, you probably can't tell that I have never done this before .

John and Christo
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Old Oct 21, 2005, 10:32 PM
The Hun in the Sun
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Yes, the weight is per square yard. And you are 100% correct, the added weight comes from all the resin, filler, and paint. As others have said, done correctly, a glass finish doesn't need to be excessively heavy. But you need to be really careful with how much resin you use.
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Old Oct 21, 2005, 11:28 PM
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New Hampshire, USA
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These are a couple of informative discussions on glassing. Their good enough to make me believe that I can do it

http://www.rcgroups.com/forums/showt...96#post2940196

http://home.fuse.net/ryan/glassing.htm
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Old Oct 22, 2005, 12:29 AM
Warbird crazy!
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Thanks Doug and Von

Now I know enough to be just about dangerous . Looks like it may be a good idea to get a scrap piece maybe from a club member or my LHS to practice with. The nice thing with doing a glass finish is you can sort of build in the weathering even if it was not intended .

John and Christo
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Old Oct 22, 2005, 01:06 AM
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Peterborough, ON
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I visited Ron Daniels last weekend and had a very informative chat with him. He had one of his planes there that was glassed and it *does* make for a way more realistic finish than an iron on covering. I'm contemplating it for my Jim Ryan Bearcat. I have Ron's Super Chipmunk to build over the winter, but it doesn't lend itself well to 'glassing.
Good luck with whatever covering you choose (and post pix when it's done!).

Peter.

Quote:
Originally Posted by new2rc
Thanks Doug and Von

Now I know enough to be just about dangerous . Looks like it may be a good idea to get a scrap piece maybe from a club member or my LHS to practice with. The nice thing with doing a glass finish is you can sort of build in the weathering even if it was not intended .

John and Christo
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Old Oct 22, 2005, 10:19 AM
Big gov never Works
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Skunk Water, Rhode Island
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Quote:
Originally Posted by DougC
These are a couple of informative discussions on glassing. Their good enough to make me believe that I can do it

http://www.rcgroups.com/forums/showt...96#post2940196

http://home.fuse.net/ryan/glassing.htm

Thanx for the referal, Doug. And all it takes is to do it and get comfortable with the system. Everybody developes their own little "knacks", that makes it easier for them. It comes in time and effort.

Steve
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Old Oct 22, 2005, 12:01 PM
Trampling out the vintage
Joined Feb 2002
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Quote:
Originally Posted by Thomas B
Actually, done properly, with the removal of al excess liquid resin, the polyester is no heavier than epoxy and can be lighter.
While I imagine this is possible given the right technique and lots of experience, I don't think this is good advice for someone new to fiberglassing parts.

I don't know of any process that reliably produces a lighter finish using polyester vs. the dedicated finishing resins like Z-Poxy. I don't know how you can thin polyester. Z-Poxy thins well and therefore can be put on thinner/lighter. Plus, polyester has a terrific oder than many people find offensive and that is potentially toxic.

I'm glad someone posted Jim Ryan's directions. They are the best I have seen. Note that he also warns against using the products like the Sig polyester resin.
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Old Oct 22, 2005, 01:44 PM
Electric Coolhunter
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United States, TX, Fort Worth
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Quote:
Originally Posted by Greg Smith
While I imagine this is possible given the right technique and lots of experience, I don't think this is good advice for someone new to fiberglassing parts.

I don't know of any process that reliably produces a lighter finish using polyester vs. the dedicated finishing resins like Z-Poxy. I don't know how you can thin polyester. Z-Poxy thins well and therefore can be put on thinner/lighter. Plus, polyester has a terrific oder than many people find offensive and that is potentially toxic.

I'm glad someone posted Jim Ryan's directions. They are the best I have seen. Note that he also warns against using the products like the Sig polyester resin.
Polyester resin is easily thinned with styrene monomer.

As I recall from previous research, a fluid oz of cured Polyester resin is significantly lighter than a fluid oz of typical laminating resin, cured.

While polyester certainly has a more noticeable stink, it is actually not as bad for continued exposure in some ways as the epoxy resins are.

The prime reason I do not use polyester is that once in a while, the system does not work well, due to some issue with the age of the materials or contamination of the materials. A model covered with uncured or partially cured polyester resin is a real mess.

I do tend to agree that epoxy is the best choice for most, and for the beginner, but not because it is the lightest.
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