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  1. #1

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    Advice on producing Fiberglass fuse from mold.

    Hello , I was not sure if I should post on another area of RCU but decided on this forum I should get the advice I need. I purchased a set of molds of the Jerry Bates 82"Seafuryl which are in great condition and have nice panel lines and hatch details. I have experience in glassing but have not done a fuse of this size before and am looking for tips and advice that may help. I have wax and mold release and wish to use e[pxy gelcoat, epoxy resin and woven cloth. The previous owner has worked in the composite industry his entire working life and he gave lots of useful advice but he only used polyester resin and non- woven chopped glass cloth. I am wanting to know what weight cloth and how many layers to do a warbird fuse of this size. I appreciate any advice and tips that poeple may have. The previous owner did say that he always did it in 2 halves and joined with a 1" strip while the whole fuse was stil wet , which I think is called a wet joint.....I think. Cheers Guys Trent.
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    \'\'THINK BIG\'\'

  2. #2

    RE: Advice on producing Fiberglass fuse from mold.

    I have always wondered, when I see a set of molds for sale are they the original production molds and why has the producer sold them off?
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  3. #3

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    RE: Advice on producing Fiberglass fuse from mold.

    Trent - Caution with polyester resin. fumes are terrible and with extensive use can cause liver damage. Easy to work with, but only in a well ventalated area. I am just a rookie and have only done one fuse (polyester resin) and one cowl (epoxy resin). The best advice that I have found is from reading the build treads from Slow-Low and SCALECRAFT in RCU (I'm sure there are others too). http://www.rcuniverse.com/forum/m_10441461/tm.htm they have given me very helpful advise in this build tread.
    Hope this helps
    Leroy

  4. #4
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    RE: Advice on producing Fiberglass fuse from mold.

    Trent, there are going to be a great many ways of going about this. As far as materials go, wax and PVA is the best way to go for mold prep. Be cautious, not all waxes are compatable with PVA. I would never do a project like this with polyester. I would go with a good quality laminating epoxy and use a hardener that will give you about an hour pot life. I would wax, PVA the molds and then spray in a coat of epoxy primer and do the layup within 24 hrs of the primer being touch dry. As far as the cloth weight and how many layers is going to be a difficult thing for anyone to figure out online. I use alot of 4 oz cloth because it is readily available, easy to work with and 3 layers of 4 oz is going to be lighter and stronger then a single layer of 12 oz. You will most likely have to lay up a few before you get it figured out. Depending on what your expectations are and the size of the project you may want to consider some core materials and vacuum bagging. If you can gain access to inspecting a Comp ARF airplane you may learn a great deal.

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    RE: Advice on producing Fiberglass fuse from mold.

    I would never do a project like this with polyester.
    You have to educate me on this one. Like, why not?

    Except for the Epoxy junk that comes out of China, I'll bet there's been more Polyester resin fuselages, and after market product parts made for plans, over the years, than any other resin.

    Nothing wrong with Polyester resin.

    Charles
    Owner: CFC Graphics. "Model Airplane Graphics from a Model Airplane Builder." cfcgraphics.com

  6. #6
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    RE: Advice on producing Fiberglass fuse from mold.


    ORIGINAL: Avaiojet

    I would never do a project like this with polyester.
    You have to educate me on this one. Like, why not?

    Except for the Epoxy junk that comes out of China, I'll bet there's been more Polyester resin fuselages, and after market product parts made for plans, over the years, than any other resin.

    Nothing wrong with Polyester resin.

    Charles

    OK If you are open to learning.............


    Polyester is:

    Heavier, brittle, expands and contracts more with temp changes. Inconsistant from batch to batch. Not compatable with many core materials. Not compatable with CF. More toxic. Has adhision issues with some paints. Smells. Has shorter pot life.


    The " Junk " out of China you are refering to is polyester not epoxy. They do this because of lower cost and polyester parts cure a little faster so they can get more parts per week out of of the molds. Yes, lots of manufacturing is done in polyester. Boats, bathtubs, showers, sinks, the corvette body panels are a type of ester based resin. However, all full scale aircraft parts are epoxy based. All aircraft structures we produce at my work are epoxy as it is a more stable product. For finishing an airplane it works just fine if you work around it downfalls as I have assumed you have but to make layups with it would be more headaches then it is worth. The old Byron kits were polyerster but because they did other manufacturing with the same staff and same processes. When I works at a shop that sold the Byron line I had to deal with alot of customer issues that resulted from the polyester layups.


  7. #7

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    RE: Advice on producing Fiberglass fuse from mold.

    OK If you are open to learning.............
    Of course I'm into learning.

    I didn't get five aviation ratings by being a "closed book." Two of those ratings are commercial.

    With all due respect, and I know this Epoxy VS. Polyester thing has been going on for a long while.

    I've always been lead to believe that Epoxy is heavier. And lead by some informed individuals. I cannot change my mind on this. Well, maybe.

    Polyester, the ratio mix is more forgiving than that of Epoxy. By far. This you know is true.

    I know the Byron kits well, having had a few and don't forget Mr. G's kits. I had two of them. Issues were developed because builders used glue products that wouldn't stick that well. Even today, that problem still exists. It's the builder, not the material.

    Brittle / Flexible. Well, read this.

    1997, Fiberglass Specialities catalog. Says right on the cover, "New FLEXIBLE epoxy." I could photograph it.

    Not that I don't want to learn, to the contrary.

    I'll stay with my winning game, Polyester.

    Although, this I must say. Years ago, I purchased a set of Gee Bee Z wheel pants from Stan's Fiberglass. Epoxy they are. And they are excellent!

    Charles





    Owner: CFC Graphics. "Model Airplane Graphics from a Model Airplane Builder." cfcgraphics.com

  8. #8
    speedracerntrixie's Avatar
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    RE: Advice on producing Fiberglass fuse from mold.


    ORIGINAL: Avaiojet

    OK If you are open to learning.............
    Of course I'm into learning.

    I didn't get five aviation ratings by being a "closed book." Two of those ratings are commercial.

    With all due respect, and I know this Epoxy VS. Polyester thing has been going on for a long while.

    I've always been lead to believe that Epoxy is heavier. And lead by some informed individuals. I cannot change my mind on this. Well, maybe.

    Polyester, the ratio mix is more forgiving than that of Epoxy. By far. This you know is true.

    Yes, as long as the minimum amount of MEKP is added you can go 3 or 4 times the amount and all you do is shrorten pot life. That being said, you must still measure out the MEKP so you get the same ratio throughout the layup. If not you have differnt expansion/contraction rates. Imagine a fuse with this happening differently on each side.

    I know the Byron kits well, having had a few and don't forget Mr. G's kits. I had two of them. Issues were developed because builders used glue products that wouldn't stick that well. Even today, that problem still exists. It's the builder, not the material.

    Byron was suggesting epoxy to bond in formers and such and not instructing on how to properly prep the surface. Once instructed to scuff with 100 grit, clean with acetone and bond in with polyester and 1" glass tape problem was solved. Until some thought it was OK to glass wings with the same resin.

    Brittle / Flexible. Well, read this.

    1997, Fiberglass Specialities catalog. Says right on the cover, "New FLEXIBLE epoxy." I could photograph it.

    There are all types of hardeners that modify the finished product. If bonding in a high vibration enviroment, this would be a good way of going. Dosen't really apply to this topic as it is not laminating resin

    Not that I don't want to learn, to the contrary.

    I'll stay with my winning game, Polyester.


    If you are happy with the results you are getting why change. Different people have different expectations. Building composite components for a DOD company have raised my expectations and it has helped me build better models.

    Although, this I must say. Years ago, I purchased a set of Gee Bee Z wheel pants from Stan's Fiberglass. Epoxy they are. And they are excellent!

    Charles






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    RE: Advice on producing Fiberglass fuse from mold.

    Trent- I don't consider myself an expert on molding but I have been fairly successfull in my first attempt at a fuselage. See my work at: http://www.sidgates.us/HOBBIES/F-94C/F94C%20PROJECT.htm

    You are getting very good advice to stick with epoxy resin. Looking at your molds I am concerned about the flexibilty. You may want to back them some how for more rigidity. I went with fairly light weight molds and backed them with cheap blue foam. I lay the molds on an absolute flat surface when the parts are curing. I have pictures of my fuse molds on my web site. I would consider some extra glass cloth layer from the wing forward to the fire wall. You probably need nose weight any way and extra strength up front is good with a gas engine.

    I highly recommend you check out my glass covered foam bulkheads to get the fuse ridgid and keeping it light. The firewall and any bulkheads that mount the wing should be stronger than foam. I like end grain balsa covered with carbon fiber instead of glass cloth.

    If you have any specific questions PM me or on this thread.
    SidGates
    Web: http://www.sidgates.us

  10. #10

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    RE: Advice on producing Fiberglass fuse from mold.

    Speed,

    Thanks for that information AND for taking the time to explain.

    I do believe I've learned something, and, I'll probably be asking you for other related information in the future.

    You do write with confidence.

    Thanks again,

    Charles
    Owner: CFC Graphics. "Model Airplane Graphics from a Model Airplane Builder." cfcgraphics.com

  11. #11

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    RE: Advice on producing Fiberglass fuse from mold.

    Some other info about polyester vs. epoxy...

    One of the big issues is the shrinkage of the resin. Resin shrinkage causes fabric print-thru (surface blemish), warping of molds and parts, and internal stress within the laminate the can lead to micro-fracturing and reduction in toughness. The shrinkage of epoxy is significantly lower than polyester.

    Most of my parts pop out of the mold painted and ready to go. I spend a lot of time creating molds with stellar finishes so the painted parts come out of the mold with stellar surfaces. This is a big time and money savings. If the resin shrinks too much the fabric will print through to the surface of the part or mold and ruin that finish. This is a very common occurrence with polyester resins (and epoxies if you pop the part out of the mold too soon or cure it too quickly with heat). This really stinks if you've made a mold and end up with the fiber backing telegraphing through to the mold surface. Now you have to polish the thing if you want to remove it. If you're painting your parts after molding then may not be such a big deal since you can sand the blemish out of the surface.

    Who likes molds that warp and don't line up properly? This is a pretty common occurrence with molds made from polyester due to it's higher degree of shrinkage. Again, if you're painting after the part is produced then these irregularities can be repaired. If you want to get pristine parts out of the mold then the mold must hold it's shape. Using a low shrinkage resin like epoxy can make a significant difference stability of the mold (if the mold is constructed properly).

    Thin flying surface parts made with polyester are also much more prone to warping over time. A razor thin racing foil with a warp is now worse than the Clark Y. If the part is thin, epoxy will make a more stable part.

    The shrinkage of the resin will also create internal stress which can promote micro-fracturing when the composite is flexed. Ever seen a gel coat, which is polyester based, all full of cracks after an impact....or just from sitting around? Laminates made with epoxy are simply tougher. They can be stressed much further before these micro internal cracks form. For this reason epoxy laminates will fatigue much more favorably than polyester resins and have a higher impact strength.

    I also like my internal organs. The off-gassing of curing polyester isn't good for you. Most manufactures recommend the use of a respirator while using polyester, while most epoxy manufacturers state that a respirator isn't necessary if the ventilation is adequate. Almost all modern epoxies are also VOC free. Skin contact with either resin isn't good and using solvents to clean it from your skin will carry it right into your blood stream. Bad news.

    There are also other reason like increased HDT, Tg, exothermic reactions during mold construction (generated heat), shelf life, bonding strength, extended cure times, and inter-laminar strength that make epoxy a favorable choice for me.

    Ohhhh...and my wife hates the smell of polyester.

    That all being said, polester resin works, is cheap, and arrives at physical properties much sooner in the cure than epoxy. If you can't afford epoxy then using polyester to make a part or mold is better than not having a mold or part at all.

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  12. #12

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    RE: Advice on producing Fiberglass fuse from mold.

    Thanks guys for all your responses, its been a great read and I am learning a lot. Keep it coming guys. Cheers Trent.
    \'\'THINK BIG\'\'

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    RE: Advice on producing Fiberglass fuse from mold.

    On the poly is heavier than epoxy statement. If one has 1 oz by weight of both resins and is applied to the same cloth, viscosity being equal along with coverage, would the weight not be the same??

    (Note that some glass fabrics are treated to bond with epoxy rather than poly. You will come across terms like Volane and Silane (spelling?) these are coatings on the glass fibers to aid in the bonding of resins. Also, fabrics that have no coatings are only washed of the lubricant use to stretch the glass into fiber.)

    Back to my original issue.

    If the weight is not the same, then the difference would be measured in a few grams. For us and our composite models, the weight of the resins has never been an issue. One can make either resin heavier or lighter by method of application and follow up.

    Also, poly resins fuses, if one has one in storage for some time, it will be much like a pane of window glass. I have an epoxy BVM F-16 from 1991 and a poly 1990's Yellow F-16 (today made from epoxy) from the same year. When I pick up the Yellow, it always fractures a little every time I handle it. Not the BVM. Time is not poly's friend, at all. Again, today the Yellow is made from epoxy. Far more durable if you don't crash very often and keep models for awhile.

    A good site to get technical info is Thaylorcraft. in the US, pricing can't be beat.

    I posted a few notes on the warbird form of your topic.

    Steve

  14. #14
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    RE: Advice on producing Fiberglass fuse from mold.


    ORIGINAL: SCALECRAFT

    On the poly is heavier than epoxy statement. If one has 1 oz by weight of both resins and is applied to the same cloth, viscosity being equal along with coverage, would the weight not be the same??

    (Note that some glass fabrics are treated to bond with epoxy rather than poly. You will come across terms like Volane and Silane (spelling?) these are coatings on the glass fibers to aid in the bonding of resins. Also, fabrics that have no coatings are only washed of the lubricant use to stretch the glass into fiber.)

    Back to my original issue.

    If the weight is not the same, then the difference would be measured in a few grams. For us and our composite models, the weight of the resins has never been an issue. One can make either resin heavier or lighter by method of application and follow up.

    Also, poly resins fuses, if one has one in storage for some time, it will be much like a pane of window glass. I have an epoxy BVM F-16 from 1991 and a poly 1990's Yellow F-16 (today made from epoxy) from the same year. When I pick up the Yellow, it always fractures a little every time I handle it. Not the BVM. Time is not poly's friend, at all. Again, today the Yellow is made from epoxy. Far more durable if you don't crash very often and keep models for awhile.

    A good site to get technical info is Thaylorcraft. in the US, pricing can't be beat.

    Epoxy resin. Nitro high rpm engine, lot of vibration, not a problem. Ever.

    Steve
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  15. #15
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    RE: Advice on producing Fiberglass fuse from mold.

    Did I mention I don't know how to get a quote right from a previous post.

    Steve

  16. #16
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    RE: Advice on producing Fiberglass fuse from mold.

    The guy that taught me how to work with fibreglass andpoly resin many years ago, told me then that you can add a few drops of castor oil to the poly resin when you mix it with the catalyst. He said it helps a bit for shrinkage and makes the final item a little bit more elastic (stronger).
    I never tried it and actually forgot about it for about30 years or sountil I read this thread.

    Does anybody have experience with this - can this be verified or not? Was just wondering

    I'm spoilt with the types of epoxy resins one can get these days - they are just so much easier than the old smelly poly stuff.

    Cheers
    Bundu
    My experience is that continental drift sometimes causes the Earth to jump up and knock a plane out of the sky......

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    RE: Advice on producing Fiberglass fuse from mold.

    I can't find "Thaylorcraft" except for some Spanish web sites. Any help?
    SidGates
    Web: http://www.sidgates.us

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    RE: Advice on producing Fiberglass fuse from mold.

    It would be Thayercraft.com

    Adam

  19. #19

    RE: Advice on producing Fiberglass fuse from mold.



    THIS IS A NOTICE HELP WANTED
    VAMODELBUILDERS IS GOING TO BE PRODUCING AIRCRAFT IN THE GOOD OLD USA. AT THIS TIME WE AR SEEKING OUT A COMPANY TO PRODUCE OUR FIBERGLASS AND COMPOSITE FUSELAGES, COWLS ETC.
    ALL PRODUCTION WOULD BE EPOXY RESIN.
    wE THANK YOU ALL FOR ANY HELP IN THIS SEARCH.

    VAMODELBUILDERS
    http://vamodelbuilders.com/
    vamodelbuilders@yahoo.com
    Glen Allen, VA

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    RE: Advice on producing Fiberglass fuse from mold.

    Adam - I really appreciate you sharing your source and you expertise. I found Thayercraft and will be ordering from them next time. I have been using 3.2oz, 5oz and 9 oz. cloth. Can you recommend Thayer part numbers suitable for RC models close to these weights? I see finishes of Silane and Volan, do you have a preferance?

    Sid Gates
    SidGates
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  21. #21
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    RE: Advice on producing Fiberglass fuse from mold.

    Spelling, not my strong point.

    Steve

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    RE: Advice on producing Fiberglass fuse from mold.


    That's not flying, that's just falling with style!

  23. #23

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    RE: Advice on producing Fiberglass fuse from mold.

    Hello Guys, well I put all the advice I have obtained from this thread and one on the warbird forum an pulled 2 cowls , 1 hatch and a fuselage. Lots of hard work in doing the fuse but I am very happy with the results. Many thanks to all who chimed in with advice and I hope others got some helpful hints as well. Cheers Trent.
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    \'\'THINK BIG\'\'

  24. #24
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    RE: Advice on producing Fiberglass fuse from mold.

    Pretty clean layup. And true, very labor intensive.

    Steve

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    RE: Advice on producing Fiberglass fuse from mold.

    Very nice work, now the hard part..... building the wing. However your half way there from a built model. What motor are you going to use?

    Here is my naked Seafury ... and the enjoyment of a fly bye.... I seem to never get around to weathering my planes and adding other details cuz most likely on to another warbird project...

    The fly bye picture was taken by Scot Heaths... awesome cameraman, he can take nice pics of things going fast.

    The fuse in the back is the one that took some of my life away... about 3-4 months of making a nice plug. Its really not the mold or what comes out of the mold, if you have a nice plug you will have nice parts from it.

    BTW the Seafury is a great flying warbird, I rank it with the P47 as far as ease of flying.
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    Happy Flying!


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