350 newt project

[paul11]

Last layer on

[irishbloke]

How many layers are involved? And how strong is that carbon fibre stuff? Is it stiff enough to hold a massive mirror like you've made for yourself on a GEM?

It's a brillant project and i'm enjoying reading about it.

Thanks

Brian

[paul11]

Hi Brian I’m glad you like the project, the tube Is made up from 1st layer of C/F then a layer of 1mm coremat and then 2 more layers of C/F. The mirror weighs 12lb and it’s going in tomorrow for a coat of paint, the mirror cell will be next and I will post images of that and yes it should be strong enough and it will be going on an EQ6,,,Paul.

[paul11]

All the coats of E/P are on now, I’ve done 4 hours sanding on this today and I’m only half way done, I will try and finish sanding tomorrow if my arm will take it,,,Paul.

[FraserClarke]

Hi Paul, Tube is looking nice. Out of interest, did you vacuum pack the CF while the resin was curing? I assume it cured at room temperature and you don't have a massive oven in the back of the garage

[paul11]

No i did not vacume pack and it was left to dry at room temp and i am giving my arms a rest today,,,Paul.

[paul11]

Well it’s all sanded with 1000 wet and dry and cut to length as you can see in the images, I have also removed the cardboard tube (images to follow). I still think this thing is to big.

[Starblazer]

Cut it and make it a truss??

Looks like a cracking project and if anything like your last one, should be interesting to see how it pans out

[paul11]

As you can see I have removed the cardboard tube, I have also cut the tube back with wet and dry, all It needs now is a coat of the shinny stuff. As you can also see in the image it’s a lot bigger than my first one in fact the other one fits inside it rings finder and all.

[irishbloke]

how does the carbon fibre compare to metal ones weight wise? Brian

[irishbloke]

also will there be much flex in it when fully put together?

[paul11]

Hi Brian a metal tube with this strength would weigh a lot more than Carbon Fibre. This tube is 3mm thick and weighs approx 10lb, using quite a lot effort I can flex the tube about 2mm on the end. I can’t flex the middle at all. When the tube rings, mirror cell and spider are fitted I don’t think the tube will show any flex at all. It’s more luck than judgement but I think I got the strength to weight ratio just right,,,,Paul.

[paul11]

A couple more images, here I am making the 10mm Carbon/coremat flat panels for the mirror cell.

[paul11]

I put this one on hold for a few weeks while I built my observatory, images of that are here http://stargazerslounge.com/diy-observatories/116254-started-my-observatory.html. I went down to Galvoptics tonight had a cup of tea with Roger and picked up my 14” F4.5 mirror so now I can get this scope finished. The first image is the back of the mirror and the other 2 are the face.

[Tim]

That looks a bit tasty Paul

Are you going to do any imaging with it?

[paul11]

Yes I am making this to do imaging with, lets hope it does a good job of it,,Paul.

[Astrokev]

Just seen this thread for the first time. Wow, fantastic project Paul. I'm really impressed with your skill, patience and dedication to the cause! This will look awesome in your new obsy. Look forward to seeing it mounted on your EQ6.

Kev

[paul11]

Thanks Kev if the weather plays ball i hope get this together for testing in a couple of weeks.

[Astrokev]

Hi Paul,

Also just noticed that you make guitars. Is this a main line of work or another "hobby". I don't make guitars, but am a keen player - I like mainly acoustic blues and rags and a bit of folky stuff, 'though I wouldn't rate myself as performance class by a long chalk (my wife would agree on this point!). Do you play??

[paul11]

Hi Paul,

Also just noticed that you make guitars. Is this a main line of work or another "hobby". I don't make guitars, but am a keen player - I like mainly acoustic blues and rags and a bit of folky stuff, 'though I wouldn't rate myself as performance class by a long chalk (my wife would agree on this point!). Do you play??

Hi Kev I found Luthiery to be the next step up to Joinery, I’m a lot better at making guitars than I am at playing them. I enjoy playing rock and I also like to play classical and it’s classical guitars I make as a hobby. I will start a new thread somewhere else on the site and post a few images if you are interested.

[FraserClarke]

picked up my 14” F4.5 mirror

oooh, shiny

good luck with assembly

[rabbithutch]

This is a fascinating thread. I've always harbored the ambition to be smart enough and proficient enough to grind a mirror and make a scope. It would surely make one proud to use a scope made with one's own hands (if done well, of course).

If one were to attempt to grind a blank - and it were the first he'd ever done - is there a size and focal ratio that would be best for a first try at it? I think an 8" dob mount newt would be the ideal scope for me, but the size seems daunting. On the other hand, a large mirror might be more forgiving of tyro errors than a smaller one would.

TIA

[Astrokev]

Hi Kev I found Luthiery to be the next step up to Joinery, I’m a lot better at making guitars than I am at playing them. I enjoy playing rock and I also like to play classical and it’s classical guitars I make as a hobby. I will start a new thread somewhere else on the site and post a few images if you are interested.

Not sure how well this fits with the astro theme of the forum, but yeh, that would be really interesting!

[yesyes]

Paul, I hope that new 14" scope fits in your new obs.. ;-)

[Astrokev]

This is a fascinating thread. I've always harbored the ambition to be smart enough and proficient enough to grind a mirror and make a scope. It would surely make one proud to use a scope made with one's own hands (if done well, of course).

If one were to attempt to grind a blank - and it were the first he'd ever done - is there a size and focal ratio that would be best for a first try at it?

TIA

Agree wholeheartedly with your comments Hutch. The satisfaction gained from standing back and proudly saying "I made that" must be hard to equal.

I've been tempted several times over the years but have never bitten the bullet. I'm therefore no expert, but from what I've read and gleaned, I believe starting with 6 or 8" is around the optimal size for a novice. Not sure it holds that larger mirrors are more forgiving.

For the smaller sizes, I think it's also probably a labour of love rather than a financial driver, although the cost benefits almost certainly increase with size (providing it turns out well, of course!).

I'm sure Paul or Glasspusher will offer their expert guidance on this, as I'm certainly no authority.

Kev