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Hi everyone, they are Emiliano, 40 years, amateur practitioner from 2003 and passionate for a lifetime.
I was always just an astro deepsky (my works go under the pseudonym ulisse031) but from a month I bought used a Dobsonian 10″ the gso (he delux) e… It is another world is opened!Around '98 I had the idea to scratch a 150mm f6 (at the time it seemed huge) reading for me legendary “amateur astronomer” photocopied 3rd hand from the library of’ ITIS by a friend.
Unfortunately, want the lack of internet, want the lack of a real need have stopped me at first hurdle (the then irrepreibilità for me of silicon carbide)“Today”, I will try again, I read a lot, dream day and night mirrors, and I think it is within my reach.
The carborundum is now easy to find, 2 its 3 phone calls, After careful research on the Internet were positive, and they are already in 3kg trip 80 and 2 kg of 120 (other grains purchase if the arrival perform cutting and roughing)
Even ceria now is good, but I will buy later.The first project (my dream is to be able to get to a 20 molar″) is the construction of a 300mm f5 or f6 we will see during processing, obtained with common glass 20mm (I'm struggling to find the glass…)
We'll see, for now I just wanted to greet you and tell you that there am I..
hello Emiliano, welcome among Grattavetro !
A 300 mm focal those with common glass is fine and it is definitely within the reach, It is a good project that will give you much satisfaction, Also when an idea has matured and desired for so long can not do anything but make its implementation more engaging and exciting.
It will be a pleasure to read you and your part in this realization.
Maximum.Hello and welcome Emiliano between scratchers!
You were probably abundant in the request for carborundum……A little bad: the limit you will remain for the Toggle Next Mirror
If you are looking glass 20mm, making a round of phone calls between the glassworks in your area we will definitely find.
Of course, remember to point out that should NOT be tempered glass, possibly, made cutting discs from a plate not too young.
We have published some articles in the workplace: if you have not already done, I invite you to read them. If you do not have much time and you already know that appoint it several months, Do not underestimate the location you choose, to be at your disposal.
For the first phases of the work, Here you can find all the tips to start off on the right foot.
My advice in general at work are those already mentioned here and there:
1) if you're too tired, not to work on the mirror;
2) if you hurry, not to work on the mirror;
3) If you can not wait to indulge in the mirror and you have fun to scratch, what is a good time to scratch.
good job!
Thanks to both of you for the welcome.
I bought 3 kg of 80 because I'm going to make the cut in the house of discs, costruendomi a cup and working abrasive… I do not know how it goes away in the cut, but given the low cost of large grits I did not want to skimp… and then… of course, my intention this will be just the first in a long series
I have a lot of irons in the fire, currently many of my employees are engaged in the creation of an observatory to remote control (here in Romagna the sky is very poor), percu only towards the end of July I will proceed expeditiously with other projects.
Luckily the person with whom I carry on the project of’ observatory is extremely interested him also to the scraping of the mirrors percu spalleggiandoci each other should be able to do it without getting bogged down in the street.
Luckily the space I do not miss, me I have to study well anyway.
Meanwhile, thanks again.hello Emiliano, a big welcome from my…
As always here you will find people who will try to try to resolve with you the inevitable glitches that will surely arise, but they are almost always solvable…
The only warning I give is: be very careful with grattavetrite because it can become a disease (in a good way of course)…
Hello and good luck for your projects… hello Mirco, thanks for the welcome.
Last night I realized the cup to carry out the cutting of the glass cylinder.
Unfortunately my drill press has a distance between the axis of the mandrel and the support column of just 110mm … so I'm losing some’ of time to build up an adequate support to cut a disk from 300mmI also write to ask your advice…
But where the glass plates purchased?
I finished the glass of Ravenna, up to 8mm all have something, one also has some leftovers from 15mm but no for greater thicknesses, They can order plates by two square meters with 19mm thickness… but they cost a drain and not knowing if you'll get to the bottom of the first mirror are reluctant to invest so much.sopperplesso…
hello Emiliano, personally discs have always taken them from my glassmaker , which cuts and refines the 19 mm with CNC machines ( or if necessary make them cut with the waterjet:
https://www.grattavetro.it/forums/topic/primario-cassegrain-rc-300/page/2/#post-5512 )If you can not find them by the glass in your area, keep in mind that, if you want, I can be cut from my glassmaker ( which it is also quite cheap ) and spedirteli, I work with a e.commerce and have an agreement with a reduced cost and expeditions are accustomed to packaging to “Courier Test”.
hello Massimar, thank you.
Well, your proposal interests me greatly.
Can you tell me the cost of 2 or 4 discs 300mm 19mm thickness including the sending?
Although now I'm ready for cutting at home with cup, I would not mind to limit the difficulties least initially… and then I find the raw material….Welcome Emiliano also from me
..The more one is, the better you get to your destination.The glassmakers working strong thicknesses are those best equipped to produce objects for the furniture and construction (tables, chairs, stands espositivi, walkable floors etc.), where the thicknesses currently come to 20, but also to 30mm.
But I think it is already not so straightforward to find one of those glass, it becomes very difficult to get clippings of those sheets so thick…..and if instead of the cutouts, it is necessary to provide the slab derived clips, might as well have them cut into round, because those who work those thick slabs, It is always able to cut round.
The exact cost can I ask the glassmaker Monday, considers that my two discs 300/19 I have paid him sip year 50 Euros each, I think we are there roughly…
The National Shipping ( with these dimensions and weight ) we can do it at a cost of 8,50 Euro ( + 3 EUR optional insurance ) although for four records I would not do a single shipment, personally I would not put more than two disks in a single package, with only two discs, the pack would weigh approximately 8 Kg and would travel in complete safety, with glasses wrapped in generous layers of bubble wrap.If you then want to cut yourself glazing, I can also inform on the cost of a square plate e.g.. 400x400x19. definitely will have a lower price compared to the shaped disc with the machines cnc.
I confirm the orientation of the price.
In my case I paid it 100 euro for two round cut discs Ø305×20, acquired by a glazier of Asti that I have provided them as required, with the edge derived from cutting not worked, but chamfers 2mm had been polished (the machine probably smooths and polishes automatically).I heard the glazier, He said that the cost is 60 € disc 300/19, below that price for him is “a throw”
( nowadays, who would want on my conscience the “failure” of a noble master glassmaker )
Consequently, the asking price for the footage 400 x 400 x 19, is an undefined “will be on 20-30 Euro…”.
Thank you for your availability.
I'll tell you compared to what they did to me, (in quiesti days I received 3 estimates by large glassworks) the offer of your glassmaker is a good 30% lower.
Not to mention that if you use them too the quality of the cut should be well good.
I'm trying to figure out if they are able to cut glass or less, Unfortunately, many family commitments are slowing me greatly.
The difference between the plate and rim is remarkable, and well worth a few hours of work in more, also because in my dreams I'd be filled with self-built Dobsonian friends…I hope for tomorrow night to have certainty.
Ah, for that matter, the cutting quality is very good, the shape is precise to 1/10 mm and the shear walls are… lucid ! this is the 120/12 mm that I have cut off recently for the secondary ( 30 euri ), undoubtedly the machines using them well…
http://s26.postimg.cc/yg9l3vbtl/P3151152.jpg
p.s. color “green bottle” It is the result of the flash, in fact the color is much more clear and neutral
Bel secondary, really nice glass!
I am on the high seas, I'm still trying to cut the first glass disc.
At least I am understanding and correcting some errors.
Unfortunately I make a loud noise and I must relegate shear tests in the few moments when I'm at home with the children still awake but busy…Initially I had the plate insecure and without my knowing it came from one side while cutting, Luckily, vetraccio is recycled from an old shelf.
Surely the speed (about 300rpm) I'm using cutting (the lowest allowed by my drill) It is too high and shoot me off the abrasive.
I have to find a solution, also because glass and knife at the contact points become very hot even with very little pressure.Tomorrow after work I try again, staring better the plate and putting a better splashguard, The Dido My daughter's not good.
PS I know that the images are rotated, but originally they are not… godhttp://s13.postimg.cc/qyyx95arr/20150514_152430.jpg
http://s28.postimg.cc/dg2he7si5/20150514_162718.jpg
http://s1.postimg.cc/o3zfy5in3/20150514_205354.jpg
http://s21.postimg.cc/3qnczzasn/20150515_212008.jpg
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