DIY DOF adapter help (attaching the nikon ext. tube)
 

Hi,

I'm following some of the steps Daniel's tutorial (http://www.jetsetmodels.info/pics/basic_35mm_dof.pdf) but I'm having trouble finding a way to attach the nikon extension tube to the 72mm-58mm thread. The end of the extension tube is not quite 58mm and it's not quite 55mm.

Can anyone shed some light on this?

Get a filter and JB Weld
 

Rafael,

Your tube is probably 57mm threaded with a 54mm inner diameter. To solve this, buy the cheapest 58mm filter you can find. Then take out the glass and retainer. Afterwich, use a slow 2-part epoxy (JB Weld) to glue the 58mm filter.

For some hints, look at my blog: http;//yousillyman.blogspot.com

Thanks, Mike. This one was a true head scratcher. But my question is: can super glue hold the weight of a heavy lens?

What's a 2-part epoxy (JB Weld)?

Rafael,

I recommend a 2 part pioneer marine epoxy. I use this for making custom step down and up rings using the method described by Mike Dulay.

Ted

Thanks, Ted. I checked on the marine epoxy (visited their website) and it seems that this is some very powerful stuff used on CONSTRUCTION and BOATS! So, I'm pretty confident it'll handle the weight of a heavy lens. I only hope this stuff exists here in Barcelona.

P.S - It's not really a glue, is it? It's more like a resin that solidifies after some time, right?

welcome to the madness
 

Rafael, sorry confusing you with the word 'glue.' We often first think of superglue or elmer's glue when we hear this word.

In truth both superglue and epoxy are kinds of resin. The difference is how fast it sets and the kind of material is used.

Superglue/krazyglue/zap/etc is made of cyanoacrylate which is fast setting but brittle and produces fumes. It's the fumes that are dangerous to our optics. Forensic investigators actually use these fumes to lift fingerprints from evidence because the fumes attach to oils vigorously.

As for epoxy, its been around a long time so you shouldn't have much trouble finding one at a good hardware store anywhere in the world. You want the slowest curing kind (typically 15-30 minutes). These are typically the strongest ones and allow you time to position and align the filter to the macro tube. Because there's about a millimeter gap, you have to lay the epoxy on thick, twist on, then scrape the excess off with a blade or credit card. Keep the tube on a surface as you work since you won't be able to keep alignment if you hold it with your hands (it's soft to start with so the filter may protrude off to one side for a bit while you clean). Have a light behind it to help you see a misalignment (even if you do, it won't be massive but could be annoying).

Some hints for working with epoxy:

1) Open air -- some epoxy have a strong smell, most newer ones are almost odorless though
2) Clean the threaded parts with soapy water to remove any finger oils which won't bond
3) Don't get any on your threads, if you do have a wet cloth read to wipe it away (at worst, use your fingers -- don't forget to wash before eating!). This is another good reason to use a slow setting epoxy. It takes about 10 minutes to attach the filter if you take your time.

Hi, Mike. Very helpful info. Indeed I found something that should be the equivalent to epoxy in Spain. The guy actually told me that after it solidifies it gets as hard as steel (I found it very exaggerated but confident that it'll work for the purpose I'm using it for). I found it funny that the cover actually had a picture of a guy fixing a broken chain with it hahaha.
Anyway, it looks like some sort of "gum" on the outside with a different center. The guy told me a I should cut a piece and then mash it together with my hands until both materials were one, and then I should apply it to wherever I want to use it on. I have no idea about quantity though. Should I put a lot or just a little? I'm always afraid it won't hold and I'll end up with a broken lens. Another question is should I put it on the outside where both rings meet or on the inside (since you said DON'T put it on the threaded part, I figure it must be put on the outside).
Thanks again. The info you gave me is simply crucial.

Never mind. I just did it :D ...but I didn't notice it and now the adapter looks like the leaning tower of pizza hehehe no problem. All I need is to substitute the first tube on the nikon extension tube and the step down ring. I'll just keep trying.

Rafael,

LOL, welcome to DIY. What you bought is called 'epoxy putty' here in the states. Sounds like you bought steel putty epoxy. They're not kidding about the strength of that epoxy, you can fix broken engine blocks in pinch. I've used it to seal certain parts of pneumatic cannons. 8-)

And what I meant about not getting it on the threaded parts was, not to get it on the threaded parts that you'd use to attach your macro/other spacers in case you spill liquid epoxy. If you do this and forget to clean up then your filter/spacer would be useless if you can't screw them together.

The trick to putty is to use it like clay and knead it around the rear thread of the spacer and the front thread. Mash both pieces together and then put something heavy on top of them. Check the balance and alignment then let sit.

I've updated my blog with a picture of what the tube looks like when completed. Hope that helps you

Thanks again, Mike. It does help a lot. Your tutorial is the bomb. As soon as I have some non-leaning adapters I'll post some picts ;-)