How to properly pin a part! (Say that three times fast!)

ionic1000 · Post by **ionic1000** » Mon Dec 15, 2008 11:23 pm

I was wanting some suggestions and maybe some tips of the trade on how to pin parts (particularly resin) together. Example I'm working on Starcraft's Enterprise A in 1/1400 scale and I want to pin the neck and pylons.

Kylwell · Post by **Kylwell** » Mon Dec 15, 2008 11:42 pm

Drill out a hole, or two, a bit larger than the pin you plan on using. I've switched over to carbon fiber rod but even paperclip material will do. 1/4 inch deep s fine but that all depends on the part(s) being pinned. The reason for the larger diameter hole is so you have some slop incase you didn't get the two holes (one in each part) exactly opposite of each other. The marking & drilling of holes is about the toughest part, especially if you're doing more than one pin.

Then, glop some epoxy or thick CA into the holes, drop in the pins and clamp into place. For larger parts you might want to use Aves or some similar heavy 2 part epoxy putty.

Andrew Gorman · Post by **Andrew Gorman** » Mon Dec 15, 2008 11:58 pm

Or just glue the part in place where you want it. then drill a hole with a small bit in a pin vise, add a bit of rod stock, glue, and fill the tiny hole. Once you have the parts where you want them to be, pin them in place. For me this beats the frustration of predicting where you want them to be once pinned.

Pat Amaral · Post by **Pat Amaral** » Tue Dec 16, 2008 1:42 am

Here's what I do:

Get the mating surfaces of the two parts to be joined as smooth and gap free as you can. Then place a generous drop of paint in the spots where you want the pins to go on one of the two mating surfaces. Next, carefully dry-fit the two parts together, making sure the drop of paint on the one side transfers to the other without too much smudging. Once you have both sides marked, you can separate the two an drill pilot holes into the paint spots on both parts. The depth of the holes should be at least half the length of the pin you plan to use. Once you drop the pin in, stuff the surrounding hole and the joint surface with apoxy putty to lock the pin down and seat the parts.

Marco Scheloske · Post by **Marco Scheloske** » Tue Dec 16, 2008 3:41 am

Andrew Gorman wrote:Or just glue the part in place where you want it. then drill a hole with a small bit in a pin vise, add a bit of rod stock, glue, and fill the tiny hole. Once you have the parts where you want them to be, pin them in place. For me this beats the frustration of predicting where you want them to be once pinned.

Do you mean ro drill through the whole part, from the backside, completely? Ouch...

Andrew Gorman · Post by **Andrew Gorman** » Tue Dec 16, 2008 9:13 am

Yep, through the whole part or assembly of parts, from whatever side is most accessible. A #70 pinhole is easy to fill.

Post by **TER-OR** » Tue Dec 16, 2008 9:14 pm

This has been covered in another thread somewhere...

I use one hole exactly the size of the pin. On the other part I drill a larger hole and place a little bit of epoxy putty (Aves) in it. Then, mate the parts and use just a little bit of CA adhesive or, if it's plastic, Tenax to meld them. The Aves will cure in a few hours. You don't even need to go that far if you you're reinforcing a relatively good joint. You can drilll two larger holes and use a smaller pin with Apoxie on either side.

Scotaidh · Post by **Scotaidh** » Sat Dec 20, 2008 1:33 pm

Flat the mating surfaces, as Kylwell said. Place the parts together as they will be once assembled. With the finest-pointed marker/pencil you can find, mark a line across the join where you want the pins to be.

Separate the pieces and decide which will have the pins. Drill one hole for the pin, and glue the pin in place. Once the glue is dry, you either a)load the end of the pin with marker ink, or b) sharpen the end of the pin. Put the parts together, once you're happy with the alignment, press them them together with a decent amount of pressure. Then either look for the ink mark or the scratch/dimple according to whether you inked or sharpened, and that's where you put your receiver holes. Easy-peasy.