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Guide 2 - Electronics Tube Endcaps

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  • Author: OpenROV
  • Time estimate: 2 hours
  • Difficulty: Moderate

You should have a good understanding of how acrylic cement works at this point. We are now going to introduce the use of epoxy. The epoxy acts as a barrier to the water and allows wires to "pass through" the endcaps.

Edit Step 1 Syringe Preparation  ¶ 

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Edit Step 1 Syringe Preparation  ¶ 

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5 Edit Step 2  ¶ 

Image 1/1: The cut on the left needs to be to the left of the end point of the syringe so it will have a place to seal underwater.

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  • Cut just past the plunger stopping point and at the 2.0 mL mark.

  • The cut on the left needs to be to the left of the end point of the syringe so it will have a place to seal underwater.

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  • Save the plunger. You will need it later.

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  • Cut the syringe tube with a thin hacksaw blade.

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Edit Step 6  ¶ 

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  • Make sure to sand both ends.

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Edit Step 8  ¶ 

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  • Use a paper towel to clean out the inside.

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Edit Step 10  ¶ 

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Edit Step 11 Cementing Large Surfaces  ¶ 

Image 1/1: The best method of cementing the endcap parts together is as follows:

Edit Step 11 Cementing Large Surfaces  ¶ 

  • The endcaps have a large surface area that needs to be cemented together.

  • The best method of cementing the endcap parts together is as follows:

    • Note: These pieces are for demonstration purposes only. While holding one side, place the needle of the applicator between the two surfaces to be cemented.

    • Add a liberal amount of cement. The goal is to have cement completely filling the gap between the surfaces. Any excess or spills will evaporate quickly or can be wiped away.

    • Apply slight pressure with both hands while the cement cures.

    • Add acrylic cement around the entire edge of the newly cemented parts to ensure that they are completely joined.

    • Clean any excess off with a paper towel or cloth.

  • When working with acrylic cement it is recommended that you wear gloves, safety glasses, and work in a ventilated area.

Edit Step 12  ¶ 

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  • You are not going to use this piece right now.

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Edit Step 15  ¶ 

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  • The hole is on the left side of the rectangular opening

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  • When working with acrylic cement it is recommended that you wear gloves, safety glasses, and work in a ventilated area.

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  • Make sure the holes are lined up.

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Edit Step 19  ¶ 

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  • Make sure the opening is to the right side.

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  • Make sure the opening is to the right side.

Edit Step 21 Non-Pass-Through Endcap Acrylic  ¶ 

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Edit Step 21 Non-Pass-Through Endcap Acrylic  ¶ 

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Edit Step 26  ¶ 

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  • Closed side of syringe down and flush with 3mm piece.

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  • Open side of syringe up.

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Image 1/1: The disk should be centered with the syringe.

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  • Angled part is to the right.

  • The disk should be centered with the syringe.

Edit Step 33  ¶ 

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Edit Step 35  ¶ 

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2 Edit Step 36 Pass-Through Endcap Epoxy  ¶ 

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2 Edit Step 36 Pass-Through Endcap Epoxy  ¶ 

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Edit Step 37  ¶ 

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  • The DB-25 connector connects all the electrical components to the controller board.

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Edit Step 40  ¶ 

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Edit Step 41  ¶ 

Image 1/1: When working with cyanoacrylate (super glue) it is recommended that you wear gloves, safety glasses, and work in a ventilated area.

Edit Step 41  ¶ 

  • Use superglue to connect the DB-25 to the acrylic. This bond will also help the epoxy flow in a later step.

  • When working with cyanoacrylate (super glue) it is recommended that you wear gloves, safety glasses, and work in a ventilated area.

Edit Step 42  ¶ 

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Edit Step 43  ¶ 

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  • Do not get glue in this hole.

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  • It is very important that the DB-25 is completely flat.

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  • Wait until the superglue has completely dried before completing this step.

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  • These wires need to be flat and not protrude past the top piece.

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  • Double check that the wires are flat.

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  • Make sure to press down on the white piece directly over where the wires are during the entire time that the cement is drying.

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Image 1/1: The epoxy has two parts that mix in the nozzle to get an even distribution.

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  • You will use epoxy to create permanent waterproofing for the endcaps. There are a few things you want to keep in mind:

    • The epoxy has two parts that mix in the nozzle to get an even distribution.

    • Before you open the tube hold it upside down to allow the air bubble to travel to the top. Air mixed in the epoxy can cause issues.

    • Remove the cap, as well as the tip and then install the mixing nozzle.

    • The first part of the epoxy might not be properly mixed so squirt out a little to make sure that the epoxy you do use is evenly mixed.

  • Wear gloves when handling epoxy and have paper towels on hand to clean any surfaces that it happens to drip on.

Edit Step 52  ¶ 

Image 1/1: When working with epoxy it is recommended that you wear gloves, safety glasses, and work in a ventilated area.

Edit Step 52  ¶ 

  • Now we are going to use the epoxy.

  • When working with epoxy it is recommended that you wear gloves, safety glasses, and work in a ventilated area.

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Image 1/1: The epoxy will settle after a while and the level in the hole will go down. Check back after 30 minutes and fill with more epoxy in this hole.

Edit Step 57  ¶ 

  • You will fill the wire cavity with epoxy through this hole. It is designed to allow the epoxy to flow through.

  • The epoxy will settle after a while and the level in the hole will go down. Check back after 30 minutes and fill with more epoxy in this hole.

Edit Step 58  ¶ 

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  • The epoxy will flow around all the wires. Make sure to wiggle the wires around so the epoxy gets in between them all.

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  • If epoxy leaks from around the metal part of this connector, use a paper towel to wipe it up before it hardens.

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Edit Step 61 Non-Pass-Through Endcap Epoxy  ¶ 

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4 Edit Step 63  ¶ 

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Edit Step 64 Front Battery Tube Endcap Epoxy  ¶ 

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Edit Step 64 Front Battery Tube Endcap Epoxy  ¶ 

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Edit Step 66  ¶ 

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  • Fill until epoxy comes out this end.

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Edit Step 69  ¶ 

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Edit Step 70  ¶ 

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Edit Step 71 Continue Your Build  ¶ 

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Edit Step 71 Continue Your Build  ¶ 

  • Continue your build by progressing to Guide 3.

You're Done!

33 Comments

HELP!!!! STEP 11 is confusing me!!! We don't have any endcap pieces that look like the ones in that picture. I'm starting to think that the illustrations from STEP 11 are from an earlier (maybe a 2.6???) version of the OpenROV. Can someone please confirm this?

We don't want to continue if we are missing pieces needed for our build

Joey Maier - Reply

Those pieces in Step 11 are for demonstration purposes only to explain the concept. Starting at Step 12 you should have all of those parts (yours will be clear though instead of smoked colored). -Brian G.

OpenROV -

I had to do some tipping to get theair bubbles out of the wire wet port. By taping off the connector side hole and tipping the air bubble to the wire side I was able to inject a second time which pushed all the air out. Next time I would inject from the bottom with the angular side upwards.

cmacphee - Reply

Thank you for the feedback! -Brian G.

OpenROV -

Step 32 Is there a good technique to assure these pieces are centered on the syringe? The previous section used the motor shaft to assure alignment, but that isn't an option here. The hole diameter on the larger pieces is much bigger than the syringe, so using the syringe as an alignment jig won't work either.

Josh Stein - Reply

How much bigger is the piece that you are seeing. They should be pretty close. If you send a picture to support@openrov.com we can help you out. - Brian G.

OpenROV -

To what extent do the DB-25 & the Acrylic Plastic handle heat?

I seem to have gotten extra epoxy drips on the nozzle in steps 57~60, and while removing the nozzle a droplet of epoxy got into one of the ports of the DB-25. I am planning on using the heat gun to melt/weaken the epoxy and then remove it. If this is going to damage it please let me know, I'll try to figure another alternative.

Thanks!

Ahmed Al Hameli - Reply

Sorry which kind of syringe do you use? The diameter is too much different! the plexi hole is about 9,4 mm the syringe is 6,5mm, so it dance inside!

SERGIO GIUSTI - Reply

Are you using the syringe that came in a kit or are you building from scratch. The syringe that we use has an outside diameter of ~9.25mm so it is a nice fit with the acrylic parts. You can find the part number and a link in the Bill of Materials

https://docs.google.com/spreadsheets/d/1...

Link http://www.amazon.com/Luer-Lok-Disposabl...

If this was built from a kit please email our support team (https://openrov.zendesk.com/hc/en-us/req...)

-Brian G.

OpenROV -

Hi Brian sorry I didn't see the syringe! was hide by the other components in the bag. Now I find it thanks for help reply

SERGIO GIUSTI - Reply

Glad to hear that everything was in the kit. Have fun with the rest of your build :)

OpenROV -

is it a problem ,and how is it corrected if the order of disc is onto the seringe is: 3mm then 1.5mm then 6mm, being the 3mm piece is flush with the closed end of the seringe. Is there a way to separtate the disc once glued ? or do i have to purchus another set of acrylic pieces and start again ?

James Milne - Reply

What is the point of cutting off this part of the syringe

Dan Britton - Reply

The syringe is a vent port for the air. If it was not there then when you put the endcaps on the air inside the tube would compress and cause the endcaps to want to pop off. With the syringe, after you put the endcaps on then you put the plunger in to keep water out during your dive and the pressure on the inside of the tube matches the pressure on the outside.

-Brian G.

OpenROV -

It goes through the non-pass through end.

david - Reply

Is there a way to align the "slits" of the disc perfectly. Or is eyeballing enough?

Maneesha Pandey - Reply

Eyeballing is as close as you can is the easiest way. - Brian G.

OpenROV -

Is there a good way to align the center of these larger pieces on the syringe center?

Josh Stein - Reply

The syringe should do a pretty good job of aligning the parts to be concentric. If you are having issues, please email support@openrov.com -Brian G.

OpenROV -

@ Brian G - Josh Stein is right. When you get to the 3rd layer (3 mm)/4th layer (6 mm) joint, the ID increases to form an eventual CBore with the syringe. Is visual alignment here good enough?

Ben - Reply

How long should I wait from when I cement this part before I do the superglue or epoxy steps? Minutes or should it cure overnight? Thanks!

teds - Reply

It depends on what type of cement you are using. Worst case, you should wait on the order of minutes for all of the acrylic cement to cure before moving on. -Brian G.

OpenROV -

By pulling the wires through in groups, working from one side to the other, I was able to keep the wire paths parallel, and thus it was easier to make this fit neatly.

teds - Reply

Thanks for the feedback. -Brian G.

OpenROV -

Can I use a grey epoxy, or does it need to be transparent? Also, should I be worried about the viscosity of my epoxy being different than the recommended one?

I'm considering using jb weld - 3960 psi, Set time 20-25 minutes, Cure time 15-24 hours. Provided I mix correctly without the mix injector, would that work well for this purpose?

Felipe Adachi - Reply

It looks like your question was already answered on our Forum. https://forum.openrov.com/t/epoxy-requir...

OpenROV -

Is this electrical tape? If so what is the point of it?

Ethan Lane - Reply

I think it is just to prevent the epoxy from flowing elsewhere

Fe3C -

Ethan - Yes it is electrical tape. It is used to keep the epoxy from flowing out as it is curing.

OpenROV -

A good way to do this is spin the endcap while applying the epoxy...

OpenROV - Reply

It's not completely clear from this picture.... I think the hole is not supposed to be filled, is that correct?

Adrian Cotter - Reply

I had the same question about this step.

Rick Fritsch -

The hole should not be filled. Sorry for the confusion. -Brian G.

OpenROV -

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