Wood Stain - Can you dilute it to make it lighter in colour

[CoombellKid]

Originally Posted by nightstalker

Are you going to allow for a 10 " mirror on the next one rob ?

Hmmmmm... I have been thinking about it since yesterday. But for me
in the end $400 is $400 not going towards a 16" maybe... hopefully... eventually...

Still it is tempting too tempting no if I was going to spend a bit
of cash at present it would definately be on a 2" OIII filter.

regards,CS

[Orion]

Originally Posted by CoombellKid

Well I went to Bunnings this afternoon, as usual most of the ply was the
usual standard. I picked through the 9mm but couldn't find a useable
piece. So I decided to go another route and got a sheet of 3mm and a
sheet of 7mm. I think I was lucky with the 3mm it doesn't appear to
have any noticable voids. The only difference is the 7mm made of pine
and the 3mm outer veneer looks like some sort of hardwood. Anyways
they're now in the press being laminated with the good sides out.
So I've rebounded and jumped back on the horse . After the painful
death of my first effort with the SC , and the workshop disasters that
followed . I'm not going to try and copy the original, I'll only make mistakes
and I have ali tube for the struts. But I'm still going with the slimeline SC
style to keep the weight down.
So I have a Q, is Shelly's exterior PVA ok to use to glue the ali tube into
the plywood rings? as they intend to be permanent. Or is there a better
alternative addhesive.

regards,CS

You could try Mister Ply and Wood. The hoop pine is reasonably priced and good to work with.

Rob did you do some sort of drawing to calculate the angle of the truss blocks? It will be a shame to do the same mistake again.

I usually use an epoxy for the truss tube blocks but for the ply wood rings PVA will suffice.

Originally Posted by CoombellKid

Hmmmmm... I have been thinking about it since yesterday. But for me
in the end $400 is $400 not going towards a 16" maybe... hopefully... eventually...

Still it is tempting too tempting no if I was going to spend a bit
of cash at present it would definately be on a 2" OIII filter.

regards,CS

In the future you might want to sell the telescope and it would be nice to sell it with the option to fit a bigger size mirror. If you are going to build the cage again making it 2 inches wider should'nt be a problem.

[CoombellKid]

Originally when I built the SC the angles were correct for the truss pole
connecter on the SC. It was later when I changed the size of the mirror
box the angle on the SC were now incorrect. The split blocks on the mirror
box look good, I had taken some measurements and calculated the angle.

We dont have a Mr Plywood up here, not that I know of. Although I have
dicovered Lismore Timber and Plywood. I haven't been there yet but intend
to next time I'm in Lismore during the week.

What about Araldite? can you use it to glue ali and wood together? I may
just go with some very thin booker rod and a couple of fancy nuts on
the ends.

Too late I didn't allow for making the SC bigger for a bigger mirror.

regards,CS

[Orion]

If you want a good bond I would use the 12 hour Araldite.

[CoombellKid]

Originally Posted by Orion

If you want a good bond I would use the 12 hour Araldite.

Ed,

I have to go over to Ballina in the morning, so I'll drop back into Bunnings.
I'm tossing up whether to glue them or use threaded rod. I know there is
more weight in the threaded rod, but you can get some pretty thin stuff
and they only need to be 55mm long.

I cut the new set of rings this afternoon. I'm going to steal your lots of
holes drill around the rings look. It should counter the threaded rod maybe.
Anyways it looks kinda neat. The old focuser borad is still a perfect fit.
but I have changed it's location, and it also needs to perform another
function, supporting a spider arm. So I will probably need to make another.

regards,CS

[Orion]

Remember Rob that the focuser board and the thin ply that goes around the cage will give it plenty of strength.

I don't see any reason for using the threaded rod it will only add weight.

[CoombellKid]

Originally Posted by Orion

Remember Rob that the focuser board and the thin ply that goes around the cage will give it plenty of strength.

Yup I'm going to use that as an advantage. The first version was very
solid, even with a bit missing

Originally Posted by Orion

I don't see any reason for using the threaded rod it will only add weight.

Dear I say it, it was/is more for cosmetic reasons than purposeful reasons.
When I counter sink the 16mm SC struts the wood drill bit breaks through
the other side leaving a hole which has to be filled. So I was thinking of
replacing the filled hole look with one of those fancy helmet looking end
bolts. I have to go over to Ballina this morning so I'll drop back into Bunnings
while I'm passing through Lismore.


Also I've been trying to track down Teflon, where can I get it? does it sell
under another name?

regards,CS

[CoombellKid]

Finished drilling the holes. At first when I was marking them out they seemed
to far apart, then when I cut the rings the markings looked to many. So I
checked back on Ed's thread and saw he has 7 per 90 degrees raidi I have 8
also my circumference is alot smaller, but since they were marked I went with
it. Now I like the look of all the holes drilled through the rings.

I'm going to paint the SC wall black and stain the rings the same as the first.
Should look ok with the ali struts, I hope.

regards,CS

[Orion]

WooHoo!...Looking good.

You got some sanding to do. Take your time the finish look depends on the prep. It might get a bit tedious after sanding the first five holes but it is worth it in the end.

What is the thickness of the ring?

[CoombellKid]

Originally Posted by Orion

WooHoo!...Looking good.

You got some sanding to do. Take your time the finish look depends on the prep. It might get a bit tedious after sanding the first five holes but it is worth it in the end.

What is the thickness of the ring?

When I got to about half way through drilling those holes I realised I had
a lot of sanding to do.

The ring thickness is 10mm, made from 7mm ply and 3mm ply laminated
with the good side out. To minimise sanding would you believe, shame
about all them holes

I'm happy with the way they have turned out. They will look nice stain
and with the SC wall painted black instead of stained.

regards,CS

[CoombellKid]

Well after a couple of nights wrecking my left hand little finger sanding all
them holes, I stained the rings and then yesterday afternoon I spayed them
with clear spray. Unfortunately while leaving them to dry and taking a drive
to town last night to pick up my son. A massive storm cell developed and
hit Coombell, I could see it as I was driving home. There was hail all over
the ground when I got here. One of the rings had blown free from the hook
it was drying on and landed on the ground. I didn't realise until later that
it had snapped through one section. I was going to start over again but on
further inspection this morning it looks like I will be able to glue it and you will
never notice.

Also finished spraying the bearings they just need the formica glued on
and then they ready to bolt onto the mirror box. I've stained and sprayed
the mirror box too. The are a few wood bleamishes not of my doing and
weren't seen until the stain was applied... but it to is looking quite nice
now that it looks semi finished.


Q, for Graham,

what size teflon squares/circles? did you used for your side bearing?

regards,CS

[Orion]

Did you make the bearings Rob and what color did you spray them?
Looks like 'Gunmetal Grey' one of my favorite colors.

[CoombellKid]

Yes I made them with a router, sprayed them gray as in the picture
posted above, to simulate forged steel lol. Each one is made from
12mm ply laminated to 24mm.

regards,CS

[Orion]

Originally Posted by CoombellKid

posted above, to simulate forged steel lol.

regards,CS

You achieved that they look good.

[GrahamL]

looks nice rob

1" round h/d felt.. not sure I'll need teflon on the alt bearings yet... its moveing nicely with just a little resistance atm
I read of a few having problems with teflon as the scopes get smaller it can be TO slippery for the small weight its carrying.

[CoombellKid]

Graham,

The original John Dobson style mount the scope was in had teflon on PVC
bearings. I still have the teflon but they are only 1cm x 2cm x 4mm pieces.
Teflon seems to be rear as hens teeth up here.

I'm cutting the veneer for the focuser board today, I think I have just enough
veneer left over from the first one. Along with the formica for the side bearings.
I think the easiest way to cut it will be attaching it to a piece of 3mm ply and
running it through the bench saw. I tried yesterday but the formica is too thin
to run through by it self.

regards,CS

[CoombellKid]

Graham,

Did you put that formica on your side bearings?
what did you use PVA or Contact, Kriege's book
say's use Contact, but would PVA be better?

regards,CS

[GrahamL]

just ply for now rob.. If i have to i'll do change things around ..
going to mount primary this weekend with a little luck and see
how it balances

[Orion]

Originally Posted by CoombellKid

Graham,

Did you put that formica on your side bearings?
what did you use PVA or Contact, Kriege's book
say's use Contact, but would PVA be better?

regards,CS

Use Contact to glue the Formica.

[CoombellKid]

Ed,

I tried to use contact glue, but the stuff I had here had been sitting on the
shelf for 4-5 years lol. Although I could still squeeze it out of the tube, trying
to spread the stuff was another story. So I went with PVA it worked
alright just a lil tricky holding it there until it set.


Anyways here is a few pics of more things I've done. I been working on the
split block bolts in the evenings of last week I was going to leave them
square. But I thought oh well trim the corners off and make them look
hexagonal and gave myself a nice big sanding job to boot . Put the rocker
box together yesterday, feels as solid as an Ox. Just filling the holes and it
will be ready for??? you guessed it more bloody sanding my poor arthritic
hands . I'm looking forward to those cheap GMC bench sanders to come
back into the shops... they were everywhere a couple of months back,
they should be back in stores by the end of November. I threw together a
jig to weld the tailgate together which will get done at a mates place this
morning.

Oh Yeah! pulled the new focuser board out of the press. Trimmed and poked
some holes into it and stained it. I'm really please how that has come out it
fits perfectly in thickness into the cut on the rings, not bad I thought as it
a bit of a guess. I've had to soak and bend another wall as I was just going
to tie it into the sides of the focuser board. The new wall will will lay right
across the board help secure it better plus it wont look like a piece of SC
wall is missing.

regards,CS