andysaeed: ok...i bought foil for work.
is it just for separeting the dish (fiber) form mould? or it must be sticked at dish?

IT DEFINITELY MUST STICK TO THE DISH !!!,.. IT, AT THE SAME TIME, SEPARATES THE DISH FROM THE MOULD. IT IS YOUR REFLECTOR OF THE SIGNAL WAVES, WHICH SENDS THE REFLECTED WAVES TO THE FOCUS WHERE THE LNBF IS LOCATED IN A CONVERGED FORM.

ok..tanx..i got it full.
im in the way of doing that...im sure i will make it...and so gratefull of you..
1-about resin and foil ...
i have about 5 kilograms of resing...i dont know wether is it enough or not...
size is 1.60cm
and on what you said me last time...it seems that i must do resin 2 time.firs for foil and second time for fiber..
2- for holding lnb should i make dish hole?and stablish pipe into dish?

Is it possible to use WAX instead of resin for instaling fiber mate on the foil?

andysaaed how far have you gone with your dish.This is my 1m dish fibre though.

Can I get d size of my dish from d radius of the dish,I av a big off which I don't know d size,whether 1.8m,2m,3m etc

okoegualek: Can I get d size of my dish from d radius of the dish,I av a big off which I don't know d size,whether 1.8m,2m,3m etc

put a tape to the edge of your dish with the face up, (reflective surface).. you might need the assistance of a second person though, to hold the tape to the edge and you pull out the reel to take measurement at the opposite end.
Now, you need to move your hand that holds the tape to the dish edge left and right while the other guy remains stationary., during your movement you pick the highest value recorded as your dish size,

geometry:

put a tape to the edge of your dish with the face up, (reflective surface).. you might need the assistance of a second person though, to hold the tape to the edge and you pull out the reel to take measurement at the opposite end.
Now, you need to move your hand that holds the tape to the dish edge left and right while the other guy remains stationary., during your movement you pick the highest value recorded as your dish size,

TANKS MAN,HAILINGS

@ All,
This is just my contribution to a nobel man, a noble cause and a worthy thread. This is one fellow you might never meet in a very long time. GEOMETRY, thank you.

(Resource material for all who want to learn)
WHAT IS FIBERGLASS?

First of all, let me explain exactly what "fiberglass" is. It's a composite material, meaning that it's comprised of two (or more) different materials mixed together. Typically, fiberglass consists of a matrix of glass fiber, saturated with a polymer resin. The glass fiber has good tensile strength, but is flexible (like cloth). The resin locks the glass fibers in place, to keep them rigid. The end result is a strong, relatively lightweight compound, that is resistant to moisture and chemicals.


FIBERGLASS MOLDING

Making fiberglass involves just as much art as science. While science creates the high-tech materials that we use in fiberglass molding, it often takes the vision of an artist to form it into a beautiful shape. And while the directions on the can will tell you exactly how to mix the resin, making a plug or a mold will often be a "seat of the pants" venture. There is no set-in-stone formula for making a fiberglass mold, or a fiberglass part. So you have some freedom for artistic expression. However, there are some general guidelines you will need to follow.

Also keep in mind that the fiberglass layup is only a small part of the whole process. Most of the work involved in making a fiberglass part is actually in the prep work and finish work. I often tell people that making fiberglass is about 40% prep work, 20% fiberglass layup, and 40% finish work. Be prepared to do a lot of grinding and sanding.


FIBERGLASS RESIN

There are two main types of resins used in automotive applications: polyester and epoxy. Both have their advantages and disadvantages. See the list below.

POLYESTER RESIN

ADVANTAGES
Low priceAdjustable curing time
DISADVANTAGES
More brittle than epoxyShrinks when curingNot as resistant to water and chemicals as epoxyHorrible odor

EPOXY RESIN

ADVANTAGES
Doesn't shrink when curingNot as brittle as polyesterMore resistant to water and chemicals than polyesterVery little odor
DISADVANTAGES
High priceCuring Time isn't adjustable
I personally prefer epoxy resin, because of its superior qualities. In my opinion, it's worth the extra cost. But for automobile body parts, polyester resin will work too. My suggestion would be to try using both types of resin, and see which one you like better.


WORKING WITH RESIN

Polyester and epoxy resin are fundamentally different in the way they are mixed and applied. Polyester resin uses a catalyst to harden it (called MEKP), which is mixed in a very low ratio (a few drops per ounce). But with epoxy resin, the hardener is mixed at a much higer ratio (which could be 1:1, 3:1, 4:1, etc depending on the type of epoxy). It's also important to note that while you can vary the curing time of polyester resin by increasing or reducing the amount of hardener, you cannot do that with epoxy. You must mix the epoxy and hardener at a predetermined ratio. Otherwise, the epoxy will not properly cure.

Also, most polyester resins have a little bit of wax mixed in. As the resin is curing, the wax rises to the top and seals out the air (to help it cure). This causes two "gotchas". First is the fact that the wax rises. This means that the exposed surface needs to be facing up. If the exposed surface is facing down, the wax won't come to the surface. And the resin won't properly cure. Secondly, you will need to remove the waxy film after the resin cures. Otherwise, subsequent layers of fiberglass, or paint, will not adhere to the resin.

Another thing to keep in mind is that resin is exothermic, meaning that it creates heat as it cures. The heat aids in the curing process. This means that the temperature of your working environment will affect the curing time of the resin. This also means that you can use heat (or cold) to control the curing time. For example, I will sometimes use a cold pack to slow down the curing of my epoxy resin. And when I want something to cure quickly, I will let it sit in direct sunlight. Heat lamps can also be useful.


GLASS FIBER

Glass fiber is the heart of any fiberglass project. There are two main types, cloth and mat. The glass fiber cloth is quite literally a cloth made of woven glass fibers. The glass fibers are typically woven in a cross-hatch pattern. This makes the glass fiber cloth relatively dense, which increases the strength and reduces the amount of resin needed to fill the voids. Glass fiber mat, on the other hand, is basically just a bunch of short strands piled up at random. They are not woven together. As a result, the mat is not as strong as the cloth. And there is more open space between the strands, requiring more resin to fill the voids.



The bottom line is that glass fiber cloth will yield stronger, lighter parts than glass fiber mat. And since the glass cloth needs less resin, it will also be less brittle. In my opinion, glass mat is really only suitable for building up thickness, or for parts where expediency is more important than strength or weight.

One more thing: if you're using glass fiber mat with epoxy resin, make sure the mat you use is compatible with epoxy resin. While almost all glass fiber cloth is compatible with either epoxy or polyester, glass fiber mat is often formulated specifically for use with polyester resin. Check the packaging to be sure.


THE IMPORTANCE OF MOLDS

The resin and glass fiber are not solid until after the resin cures. When you mix the resin, it's a liquid. And the glass fiber is flexible. The wet fiberglass will sag, or even collapse, under its own weight. For small jobs (patching cracks and holes, filling gaps and seams), this isn't much of an issue. But for anything bigger, the fiberglass will need to be supported. This is where molds come in. The mold gives the fiberglass something to rest on, and a shape to conform to, until the resin hardens.

When building a fiberglass mold, there are several things to take into consideration. Some examples:

-- Will the mold be used only once, or to make several parts? If it's a single-use mold, it only needs to hold together long enough for the fiberglass to harden. But if it will be used to make several parts, it must be sturdy enough to withstand the rigors of having fiberglass parts pried out of it several times.

-- How will I remove the fiberglass from the mold after it hardens? For simple shapes, this is pretty easy. But for complex or convoluted shapes, it is quite possible to get the fiberglass trapped in the mold, or vice versa. In order to avoid that, you will need to either make a multi-piece mold that can be pulled from the fiberglass part piece by piece, or make several smaller fiberglass parts that can later be joined together to form the complete structure.

-- Is my mold material compatible with my fiberglass resin? I'm sure you've heard that polyester resin melts styrofoam. It also attacks some types of plastics. However, it does not affect urethane foam. Epoxy resin doesn't affect any type of plastic, that I know of. Also, keep in mind that fiberglass resin can get pretty warm as it hardens. So make sure to avoid using mold materials that are susceptible to heat. Fiberglass curing in the sun can get hot enough to hurt if you touch it. And I've occasionally seen resin get hot enough to melt the bottom out of a plastic cup.


MAKING A PLUG

Sometimes, you can't just build a mold and start making your fiberglass parts. You may want to copy an existing part. Or maybe making the mold from scratch would be problematic in some way. In these cases, you would use what's called a "plug". A plug is a mock-up of the part you want build from fiberglass. After you build the plug, you make a casting of it. The casting becomes your fiberglass mold.

You can build a plug out of just about anything. Use whatever works to get the desired shape... scrap wood, styrofoam, plaster of paris, sheet metal, whatever. I've even used my car as a plug.

Once you finish building the plug, you need to prepare it for the casting of the mold. This means that if you used foam or wood (or any porous material, for that matter), you need to seal it. I've used packing tape, duct tape, and garbage bags to good effect. Some people like to use aluminum foil. I've also used polyurethane and even epoxy resin on occasion. The idea is to make the surface as smooth as possible. Then you use a mold release agent to be sure the casting won't permanently bond to your plug.

It's pretty common to cast the mold from fiberglass. The process is pretty similar to making a fiberglass part in a mold. However, you want the casting to be much stronger than the fiberglass parts it will be used to make. This means that your casting will be much thicker than the fiberglass parts you plan to make with it. You might also need to incorporate a reinforcing structure into the casting. If you do decide to reinforce your mold, it's best to do this before removing the mold from the plug. That way, you can be sure the mold retains the correct shape.


CONCLUSION

Hopefully, now you will have a basic understanding of what fiberglass is and how to work with it. As with any skill, you will need hands-on experience. With experience will come increased skill and confidence. In the meantime, here is some more valuable reading material.

What is Fiberglass?Fiberglass 101Fiberglass for NewbiesFiberglass FAQFiber Glast Learning CenterDo-It-Yourself Guide to Polyester Plug and Mold Building
If you find any factual errors in this article, please send me an email or PM. Thanks.[/list]

FerociousGTO:
8 part Step By Step Guide To Molding Fiberglass. A simple introduction to fiberglass mold construction; explained using a model aircraft cowling. From plug, to mold, to finished fiberglass part.


How To Mold Fiberglass. 1 of 8


How To Mold Fiberglass. 2 of 8


How To Mold Fiberglass. 3 of 8


How To Mold Fiberglass. 4 of 8


How To Mold Fiberglass. 5 of 8


How To Mold Fiberglass. 6 of 8


How To Mold Fiberglass. 7 of 8


How To Mold Fiberglass. 8 of 8

FerociousGTO:
IMO pretty go videos!

How To Fiberglass - Two Part Mold Construction - #1 Flanging

How To Fiberglass - Two Part Mold Construction - #1 Flanging

How To Fiberglass - Two Part Mold Constuction - #2

How To Fiberglass - Two Part Mold Constuction - #2

Source:http://centralfloridafieros.com/forum/index.php?topic=149.0;wap2

lengthy informative and well put together....thanks

@Swordswifter...

..really,... I feel highly honored and good,... we are looking forward to your big bombshell you are about to drop... don't say I am letting the cat out of the bag... lol !,... I will have up the explanation as regards the analysis of the DEVELOPMENT drawing for your sectionalised ANTENNA ... ''in the oven'',...I have being trying to see how to break it down for easy assimilation for all,... don't worry,.. it is going to be pretty soon,.. I must confess,. I feel proud to see you gone that far...

geometry: @Swordswifter...

..really,... I feel highly honored and good,... we are looking forward to your big bombshell you are about to drop... don't say I am letting the cat out of the bag... lol !,... I will have up the explanation as regards the analysis of the DEVELOPMENT drawing for your sectionalised ANTENNA ... ''in the oven'',...I have being trying to see how to break it down for easy assimilation for all,... don't worry,.. it is going to be pretty soon,.. I must confess,. I feel proud to see you gone that far...

@ Geometry,
I'm also very proud to have had a good teacher such as yourself to have guided my steps every step of the way. God bless you.

now that my people is the spirit,im equally honoured to be a humble student...so much. to learn 'eish' -to qoute my good friend ilish.

...It is a new dawn, hello, people!,HERE WE GO;





Development Drawing for a Sectional Paraboloidal Surface.
GENERAL;
The concept of development drawing explains how we have a plane representation [2-D] of yet a somewhat complex GEOMETRY of figures or shapes in engineering. It is what we have employed in cutting out metal sheets before stamping/forging into whatever shapes in AUTO and CLADDING/CONSTRUCTION industries, to mention a few of its applications.

SCOPE;
Development Drawing for a Section of a Paraboloid.
We need to get familiar with some terms, a lot of which we have come across at one time or the other;
Parabola – 2-D geometrical representation with standard mathematical equation; y^2=4ax.
Paraboloid – 3-D Geometrical representation of parabola. Paraboloid is generated from parabola.

PREAMBLE;
We need a quick journey to our high school day geometry class, specifically MENSURATION under which several shapes were thoroughly addressed. In this discussion, we shall make mention of shapes like; Cone, Sector, Triangle, Parabola and Paraboloid. In actual fact, the two later shapes were not extensively dealt with during high school day but, let us see how we can play around these shapes and figures that describe them and come up with something tangible that can be useful to us.
Before i proceed, I am going to take a hypothetical example of a project undertaken by a DIYer, on this tread, the terms. I promise, are going to be those we are familiar with, perhaps, a few strange terminologies but, I bet they could be linked with what we are familiar with, especially, if we had been part of DIY on Nairaland.
We are going to look into a parabola of 250cm in diameter with F/D ratio of 0.4, we remember the
equation of parabola to be y^2=4ax ---- (1), a and 4 are constants of the equation. And a being the focal length of the parabola, usually denoted by F.
Then, we can write; x=y^2/4a
Hence, x=y^2/4F ---- (2).
Remember x is the depth our parabola;
F/D ratio IS 0.4,
Hence, F/D = 0.4 ---- (3).
We can therefore obtain a value for x;
F = 0.4*D.
= 0.4D
= 0.4 multiplied by 250
= 100cm.
What this translates to is that the distance from the center of our parabola to a point 250cm equidistant from the edge or circumference of the paraboloid.
Alright, let us see what x is in value;
From equation 2,
X = y^2/4F,
Therefore; x = y^2/4*100.
Y = radius of the parabola; = D/2 = 250/2 = 125.
Y = 125cm.
Hence; x = 125^2/4*100 or 125^2/400.
= 39.0625cm.
So, our parabola is 39.0625cm deep.
That is that about our parabola.
Now let us discuss making a development drawing for a section of this parabola:
First of all we need to know how many division we are going, also, we should know that the derived development has its effectiveness hung on two main factors;
(1) The number (n) of divisions - The more the number (n) the better the resulted obtained.
(2) The depth - The shallower the parabola, the better as well.

MY ADVICE;
*adopt as many divisions (n) as possible.
*Chose a higher value of F/D ratio.

At any rate, we are sticking to our hypothetical example.
Thus;
F = 100cm
X = 39.0625cm
D = 250cm
Y = 125cm.

Reasons for Conception of Development Drawing Technique.

Well, some of us might be wondering why the worries about the Development Drawing Technique, is it really worth the trouble? My reaction would be; yes! If you have ever been in the trade, you would have, at one time or the other, given the idea a thought, considering the effort required in making a whole MOLD and transporting a fabricated whole PARABOLOID, (BUD).
Reasons;
(1) We can by-pass making a whole MOLD if we can work hard on Development Drawing Technique to achieve good result.
(2) We can achieve petalized paraboloidal sections which can be coupled together to form a whole Paraboloid.
(3) We can safe on cost during transportation, since petals would not require hiring big truck for delivery. Especially, when dealing with BIG BUD.

CONCEPT/PROCEDURE
HINT;
I need to mention that the concept is more of an analytical process than drawing, we need to know why our points are where they are and there must be basis for all comparisons. There for we support all our argument with simple mathematical analyses.

The first thing to do is to imagine a CONE in our PARABOLOID, inscribed, having the same height and base properties. For simplification, I have adopted the usage of colours to distinguish sketches for CONE and PARABOLOID; red for CONE and green for PARABOLOID.
In 2-D representation, we see a RED triangle inside a GREEN parabola, both having equal height and base. Therefore, same base circumference.
Next, we need to remind ourselves that a cone is derived from a sector of a circle.
Now, let us find out what our sector looks like that gives us the CONE inside our PARABOLOID.

In FIG. 1 and FIG. 2,
The slant side of the CONE is indicated by, l, its height by, h and its radius by, r.
HINT:
The arc length of the sector that forms this CONE is equal to the circumference of the base of the CONE, and this is same value as that of the circumference of the base of the PARABOLOID.
Let us see what we have;
Arc of the sector = base circumference of the CONE and that of the PARABOLOID.
Therefore,
2[PIE]r = base circumference.
= [PIE]D
= 250[PIE]
HINT;
The slant side of the cone has equal value as the radius of the sector, l = r’
Apparently, we figure out a circle of radius l, from which the sector that forms our CONE was cut.
This sector would subtend an angle called Theta.
Theta/360 = arc of the sector/circumference of the circle with radius r’
Theta/360 = 250[PIE]/2r’[PIE]
Theta = 360*250[PIE]/2l[PIE]
Remember r’ = l.
Theta = 360*250/2l
From FIG. 1,
(AO)^2 = (OO’)^2 + (O’A)^2, Pythagoras; right angled triangle.
AOl,
Therefore, l^2 = (OO’)^2 + (O’A)^2,
= h^2 + r^2,
= 32.0625^2 + 125^2,
= 1028.0039 + 15625,
= 16653.003,
l = \/16653.003, i.e, (square root of 16653.003),
= 129.045651cm.
and Theta = 360*250/2l,
= 360*250/2*129.04651,
= 348.71151
= 348.7 deg. ~ Approximately.
As indicated in FIG. 3, If we draw a circle of radius 129.05cm and measure an angle of 348.7 deg. The sector that subtends this angle would form the CONE that we earlier inscribed in the paraboloid.
And we ought to remind ourselves that we have a number (n) of division. We will later discuss how it is relevant to our Development Drawing.
As earlier mentioned, if we cut off the smaller sector that subtends an angle of 11.7deg. the bigger sector left behind would form a CONE, when its radii lines are brought together. This cone is our CONE, having an height of h, which is equal to x and base circumference of (Theta/360)*2l*[PIE].
= 348.7/360*[PIE]*2*129.05
= 785.7096
= 785.71cm.
Comparing this value with the circumference of the paraboloid;
2[PIE]r
= 2*[PIE]*125,
= 250*[PIE],
= 785.7142,
= 785.71cm. QED.

EVIDENTLY, THESE TWO VALUES ARE PRACTICALLY THE SAME.

I apologise to keep typing Theta, I could not find on my key board the key that gives me the appropriate symbol for angle, so also, some of my spellings, lol.

....................TO BE CONTINUED....................









-

I SENT THIS WITH THE PICTURE, OBVIOUSLY,, I HAVE DONE IT THE WRONG WAY, MIGHT HAVE TO TRY AGAIN TO UPLOAD THE ILLUSTRATED DIAGRAMS,
THANKS.

What a calculus class .
Am happy you are back and active.

lol @ Geometry,

Was wondering where all the figures had passed.
Anyway you can bet i will go through every inch of your first write-up so i can ask all the right questions.

@Obnelly,
I tried as much as possible to steer away from INTEGRATION & DIFFERENTIATION,..I am aware of the fact that not everyone on the thread are from engineering background, lol. this is just a mare high school MATHEMATICS,..I put in serious effort to come up with such simplification,... CALCULUS would have been the best tool, but might be quite difficult for non engineers to handle... yeah!

[img][/img]

sorry this came late,..

FIG 4;

FIG 4, AGAIN in Jpeg

sorry for the repetition, i am trying hard to get a clearer diagram for better viewing ,.. lol

Does that mean we can make 5 different dishes of various sizes from that last diagram?Also in fig3 i think we would need something like a protractor for us to get the best of that angle.

obnelly: Does that mean we can make 5 different dishes of various sizes from that last diagram?Also in fig3 i think we would need something like a protractor for us to get the best of that angle.

sure we could but not advisable in the orientation the set of triangles, the diagram above is for the procedure in making a development for PETAL in ''sectionalized'' dish. I will go further in the explanation of it as soon as I have the time to do so.

REMEMBER, THE DEVELOPMENT CONCEPT IS MORE FOR BOYCOTTING THE CONCRETE MOULD CONSTRUCTION,..and having sectional dishes.

obnelly: Does that mean we can make 5 different dishes of various sizes from that last diagram?Also in fig3 i think we would need something like a protractor for us to get the best of that angle.

...and also, on the protractor stuff,.. we are going to need one !,.. we can improvise, i.e make solid length of light square pipe and wear a bigger sleeve square pipe on it with an arrangement that can hold a scribber;.. that could be a maker, pencil, pen etc. I will try and sketch something out as an example of what I have always been using in case i need to do something like that.... then you can determine your radii... REMEMBER; FIGURES 3 IS A TRIANGLAR REPRESENTATION (AS REPRESENTED IN 2-D)OF CONE FROM THE RED SHAPE INDICATED IN FIG 2,.. BUT AS A SECTOR IN FIG 3...

WELL,.. ALL ALONG I HAVE BEEN DESCRIBING IMPROVISED ADJUSTABLE COMPASS, YOU WOULD NEED A PROTRACTOR TO GET YOUR CALCULATED ANGLES FROM THE CENTER MARKED BY THE SHARP POINT OF THE COMPASS,(PIVOT),....THE REST ARE STRAIGHT EDGE AND MAKERS,.... lol

Still a good sketch.In Engineering the only means of communication is through sketches/engineering drawing.its universally accepted for people in that field.Ride on.

@geometry

Pls I am working on the design of a triple lnb dish for my final year project. After going through your work here, I wanted to know if you could put me through the designing of this kind of dish.
Cheers!

cleverdiva: @geometry

Pls I am working on the design of a triple lnb dish for my final year project. After going through your work here, I wanted to know if you could put me through the designing of this kind of dish.
Cheers!

Well, I have not extensively have a serious practical input into that aspect of satellite signal tracking, I can explain how it works, but practical aspect is another experience entirely,.... theory would only guide you of doing it right even when your efforts have not yielded result... but, somehow I have seen people here recording sound success on the multi_lnb stuff, ..just search further on Nairaland ,...sorry,...just can't remember where....

geometry: sorry for the repetition, i am trying hard to get a clearer diagram for better viewing ,.. lol

pls how can i meet you cos i like u put tru on how to construct mold

Adewunmis: pls how can i meet you cos i like u put tru on how to construct mold

...please, read through the tread, its all encompassing as regards making molds,... all questions are entertained though. Pick one or two things from what was previously discussed then see how it is applicable to what you intend doing , design as in dish fabrication.... we can all learn from you too,....