Wood type

[dmmd01]

I've been reading Kriege and Berry's "The Dobsonian Telescope" in anticipation of building a 17.5" scope. With my recent purchase of a 16" Starfinder, I'm now pushing forward in figuring out how to do both so that I can actually transport and utilize these beauties without a personal assistant. I've hit my first serious roadblock: finding the correct wood. The book recommends Appleply or Baltic Birch, but after calling a dozen different lumber yards, woodshops, and cabinet makers, nobody knows where to get these. One person said that they have a supplier that makes something similar to Appleply, but that it costs around $185 per 5x5 sheet. I'm wondering where others have purchased the wood for their scopes in the 16"-17.5" range, and if other woods have been used. Of course the results are important. I'd really like to do this right, so I'm willing to put out some money, but I'd like to know that I'm getting the right product for the job. Thank you in advance for your help with this. (I love these forums!)

[roverich]

Hi dmmd01 ...Try these guys [Registered users can see links. ] ...I found apple ply for 94 dollars a sheet plus shipping from wisconsen...You could do another road trip and save the shipping costs ..

[Tom Clark]

For the last 25 years I have been using Oak plywood with good results. It's available from plywood distributers, and even HD and Lowes for around $45 per sheet. It works and looks great.

[dmmd01]

Rover and Tom, Thank you both for your input. While I would love to drive back to the land where cheese flows like water, I think I'd have to pass right now. And as to oak, I'm glad to hear that you are able to use it effectively on larger dobs. The picture of your fleet is beautiful. Actually, I saw your website a few months ago before I knew I was going to be building, and now I need to get back there... Your design is exactly what I've been looking for!

[star drop]

Originally Posted by dmmd01

Rover and Tom, Thank you both for your input. While I would love to drive back to the land where cheese flows like water, I think I'd have to pass right now. And as to oak, I'm glad to hear that you are able to use it effectively on larger dobs. The picture of your fleet is beautiful. Actually, I saw your website a few months ago before I knew I was going to be building, and now I need to get back there... Your design is exactly what I've been looking for!

I have a telescope that I purchased from Tom almost twenty years ago and have had no problems with the oak plywood whatsoever.

[dmmd01]

Gotta love the testimonials!

[roverich]

Hi dmmd01 ...The only drawback from using plywood or particle board is moisture getting inside and delaminating or swelling of the wood ...As long as the wood is well protected with a varnish or polyurethane and waxed regularly you should be alright ... Some viewing areas are more prone to scopes dewing up and moisture is a enemy of wood ... Especially plywoods ....Another alternative to oak plywood is Baltic birch ...Oak has great grain structure but Baltic birch is a great looking wood also and not as expensive but just as strong ...

[dmmd01]

Rover, thanks for the insight - we went to Lowes and HD yesterday after calling a few more places and not being able to find BB. The 3/4 oak came in at 47.88, and the 5/8 at $21. I'm worried that the 5/8 won't be thick enough for the rings, but the 3/4 will be excessive. This project is truly a learning experience! The especially nice part though is that my wife loves designing, and has been drawing numerous possible configurations.

[roverich]

If it were me ...I would go with the thicker wood ...I always over engineer something when i build it ...If i am not mistaken 3/4 has thicker wood slices as opposed to 5/8 ...The same amount of wood layers but thicker layers ...Make sense ? .....Also , you can get "end tape" for the edges that is made of real oak .....You iron it on the edges of the wood panels for a nice cosmetic finish .... Its just cosmetic but it makes for a beautiful finished project when using plywoods ...

[Tom Clark]

The Kriege book is getting rather dated in scope design. His scopes were all quite heavy compared to the norm today. About 15 years ago we started experimenting with building lighter scopes, and today everything up to my 24" is almost all 1/2" material. Our old 25" weighed 250 pounds, and the newer model 24" weighs only 160. That's quite a weight savings. I used to build 18" f/5s and they weighed 104#. On my [Registered users can see links. ] you will see many scopes built with the lighter material.

Yes, the scopes are still very solid and have almost no vibration. Give the 24" a good rap to the diagonal cage and it dampens in less than 1/2 second.