raychem tubing back connectors

[rodorico83]

Hello guys.
Which raychem semi rigid double wall series you use for the back of your connectors ??
I was looking at the catalogue but so many...

The more suitable i see are:
SCT, SCL, ATUM, DWFR

However in the catalogue only the SCT is specified as semi-rigid.

[tlracer]

The type of heatshrink depends on the application, location, etc:

A semi-rigid would be ideal for a connector that is well-supported; however it would be no use for a connector that's in a tight corner where it may need to be flexed to mount/dismount.

There would be no point in using an adhesive-lined option if the connector may need to be re-entered at some future time.

Adhesive-lined heatshrink is excellent where there is the potential for moisture ingress.

SCT is specifically aimed at automotive applications, so would be a good 'go to' for most situations.

[lowside67]

What type of connector? Most quality connectors have anti-strain features built in, so the purpose of heatshrinking over the connector body is more for environmental sealing, and therefore using rigid SCL is less necessary.

With the caveat that it depends on the connector, but most times you are going to need a high ratio to allow the heatshrink to be large enough to slip over the end of the connector and yet to recover (shrink) enough to be tight to the cable as well.

I built a complete wiring harness for my car recently and almost exclusively used ATUM 4:1 to seal my Deutsch DTM/DTP connectors. Even with 4:1, sometimes you'll need to do a 2-step seal to allow it to get tight enough to grip the wires firmly.

Here is an example of a connector segment on my harness. If you look closely, there is a wire splice on the left side where it says branch - that's got a small segment of rigid SCL to support it, which will then be wrapped over with ATUM.

-Mark

[Rick Iverson]

X

What type of connector? Most quality connectors have anti-strain features built in, so the purpose of heatshrinking over the connector body is more for environmental sealing, and therefore using rigid SCL is less necessary.

With the caveat that it depends on the connector, but most times you are going to need a high ratio to allow the heatshrink to be large enough to slip over the end of the connector and yet to recover (shrink) enough to be tight to the cable as well.

I built a complete wiring harness for my car recently and almost exclusively used ATUM 4:1 to seal my Deutsch DTM/DTP connectors. Even with 4:1, sometimes you'll need to do a 2-step seal to allow it to get tight enough to grip the wires firmly.

Here is an example of a connector segment on my harness. If you look closely, there is a wire splice on the left side where it says branch - that's got a small segment of rigid SCL to support it, which will then be wrapped over with ATUM.

-Mark

And you Sir, are an artist

[rodorico83]

What type of connector? Most quality connectors have anti-strain features built in, so the purpose of heatshrinking over the connector body is more for environmental sealing, and therefore using rigid SCL is less necessary.

With the caveat that it depends on the connector, but most times you are going to need a high ratio to allow the heatshrink to be large enough to slip over the end of the connector and yet to recover (shrink) enough to be tight to the cable as well.

I built a complete wiring harness for my car recently and almost exclusively used ATUM 4:1 to seal my Deutsch DTM/DTP connectors. Even with 4:1, sometimes you'll need to do a 2-step seal to allow it to get tight enough to grip the wires firmly.

Here is an example of a connector segment on my harness. If you look closely, there is a wire splice on the left side where it says branch - that's got a small segment of rigid SCL to support it, which will then be wrapped over with ATUM.

-Mark

Actually is for some DT/DTP connectors and others, in this application im talking more about those that does not have anti-strain, or it does not look too strong. ATUM is semi flexible right ?

Well normally you place the heatshrink before placing the connector.
i guess to know if you need two step depends on diameter difference between back of connector and wires.
did you use any 12 or 4 pin DTM-DT connector ?

[lowside67]

Yes, ATUM is semi flexible but glue lined so If you get a good and tight seal over the connector body and it can shrink enough to tightly grip the wire bundle, the glue provides a fair bit of anti strain since the wires can’t effectively bend against the strength of the glue. My car uses only ATUM or SCL, I don't have any SCT and have never played with it.

When I say “2 step” boot - I mean 2 steps of ATUM plus the underlying heatshrink on the wire bundle (so I suppose 3 steps total if you include the wire covering itself). I think we are on the same page here but for the benefit of others:

Example, I have a 2 pin DTM connector that connects my starter trigger wire and ground to the harness: 2x 20awg wires. Even with 4:1 heat shrink, the smallest size (by memory - I think 1”) that goes over the connector body will not seal such a small wire bundle (1/8” DR25) So in this case, I would use the 1” 4:1 which shrinks down to 1/4”, then another segment of 1/2” 4:1 which will go over the loose 1/4” end of the connector boot and also tightly seal the other end against the heatshrink that covers the wires and goes to the next branch point. This way the whole thing is sealed from each end.

In my opinion, the design of the Deutsch connectors are sufficiently strain relieved for any reasonably supported application. In theory they are also weather sealed as well - the addition of an extra layer of ATUM improves both functions and for me, is sufficient. You will notice that a lot of professionally built harnesses also do the same.

I only have a handful of DTP connectors on my car - rad fan for example. Since the wire is a lot stronger (in my case 16awg), I am actually even less worried about strain relief - the design of how much longer the connector is really reduces the stress on the stripped section of wire in the crimped pin.

I've attached a photo of the completed harness segment that I photographed above. It uses rigid SCL at the branch point (along with a zip tie which is 100% for strain relief) but ATUM at the connector. I have 2,3,8 pin DTM connections on my car and 2,4 pin DTP connectors. I am ordering a 12 pin DTM to redo a switch connection though, shortly. Hope that helps!

-Mark

[lowside67]

Here is a good graphic to check out:
https://www.fischermotorsports.com/w...337-scaled.jpg

If you zoom in closely you can look around at different connector types - I am 99% sure those Deutsch DT* connectors in the foreground of the image are sealed with ATUM 4:1 given how much they shrink around the connector body.

-Mark

[rodorico83]

Here is a good graphic to check out:
https://www.fischermotorsports.com/w...337-scaled.jpg

If you zoom in closely you can look around at different connector types - I am 99% sure those Deutsch DT* connectors in the foreground of the image are sealed with ATUM 4:1 given how much they shrink around the connector body.

-Mark

looks like as it looks flexible. However i would prefer to use a semi rigid instead like the use for those MIL connectors.

[rodorico83]

Yes, ATUM is semi flexible but glue lined so If you get a good and tight seal over the connector body and it can shrink enough to tightly grip the wire bundle, the glue provides a fair bit of anti strain since the wires can’t effectively bend against the strength of the glue. My car uses only ATUM or SCL, I don't have any SCT and have never played with it.

When I say “2 step” boot - I mean 2 steps of ATUM plus the underlying heatshrink on the wire bundle (so I suppose 3 steps total if you include the wire covering itself). I think we are on the same page here but for the benefit of others:

Example, I have a 2 pin DTM connector that connects my starter trigger wire and ground to the harness: 2x 20awg wires. Even with 4:1 heat shrink, the smallest size (by memory - I think 1”) that goes over the connector body will not seal such a small wire bundle (1/8” DR25) So in this case, I would use the 1” 4:1 which shrinks down to 1/4”, then another segment of 1/2” 4:1 which will go over the loose 1/4” end of the connector boot and also tightly seal the other end against the heatshrink that covers the wires and goes to the next branch point. This way the whole thing is sealed from each end.

In my opinion, the design of the Deutsch connectors are sufficiently strain relieved for any reasonably supported application. In theory they are also weather sealed as well - the addition of an extra layer of ATUM improves both functions and for me, is sufficient. You will notice that a lot of professionally built harnesses also do the same.

I only have a handful of DTP connectors on my car - rad fan for example. Since the wire is a lot stronger (in my case 16awg), I am actually even less worried about strain relief - the design of how much longer the connector is really reduces the stress on the stripped section of wire in the crimped pin.

I've attached a photo of the completed harness segment that I photographed above. It uses rigid SCL at the branch point (along with a zip tie which is 100% for strain relief) but ATUM at the connector. I have 2,3,8 pin DTM connections on my car and 2,4 pin DTP connectors. I am ordering a 12 pin DTM to redo a switch connection though, shortly. Hope that helps!

-Mark

Ok i got your 3 step process

mmm the original wiring loom i have from lola and from SolutionF uses DR25 all around, and semi rigid line adhesive with good bonding in all or most of back connectors

I still have to received these DTP connectors, but TE dont supply heatshrink support for this series only for DT or DTM...

[lowside67]

Ok i got your 3 step process

mmm the original wiring loom i have from lola and from SolutionF uses DR25 all around, and semi rigid line adhesive with good bonding in all or most of back connectors

I still have to received these DTP connectors, but TE dont supply heatshrink support for this series only for DT or DTM...

You can still use a glue lined heat shrink on the regular DTP series - they just don't have a "lip". This will still work just fine since the glue will adhere to the connector body.

I still think using semi-rigid is not going to work like you think it will. As far as I know, it is 2:1 similar to the fully rigid SCL I have... if that's the case, it's going to take many sizes of "stepping down" to actually get all the way from the connector body to the wire.

The systems of how the Deutsch connectors use the rubber weather sealing at the end that also serves to "separate" the wires from each other will work as effective strain relief as long as you can keep the wires from moving against each other - in the same way that plywood works by taking multiple thin layers with no real strength (in this case, the wires) but by immobilizing them against each other, the whole thing can no longer bend.

-Mark

[lowside67]

I managed to find this - this is an example of the "3 step sealing" that I referenced above.

There is base DR-25 on the wires, then two sizes of 4:1 to deal with the difference in size between the connector and the thin wire bundle (2x 20 awg).

-Mark

[rodorico83]

Hi Mark, i had some time to take a pic of the Solution F world series wiring loom, all those connectors except the deutsch AS... ones, have in the back a semi rigid with nice bonding adhesive, all of them are in one step.
The SCT i mentioned before is 4:1 ratio with bonding, that's why i think it can work
It might be that those in the pic is not really tubing but rather this molded ones series (special for back of connectors) which i believe are semi rigid as well., but obviously going for that it will quite more expensive than using tubing.

In the meantime ive been drawing down the complete wiring loom except a couple of wires like gps, included master switch circuit alternator, starter, batt and all components.

I wanted to be sure of all what i need in terms of connectors and wires to tailor the solution f wiring with the aim datalogger, shifting valves, compressors, paddles , car sensors...

i was looking for a free or torrent available to do it, Solidworks it was goona take a lot time as i never did wiring with it so after some seeking i came with wireviz software (python program) which allows to draw as code in text file. it gave me most of the features i want and do the placing for you which did it quite well, showing clearly the alignment of connections from the rear to the front of the car, from the left to the right in the drawing.

https://github.com/formatc1702/WireViz

define all connector, define all the wires as cables with its colors, length and awg, and do the wiring mapping connector pins, it allows to define multi wires good for common lines like gnd. It was a bit tricky in the sense that you can not declare 2 cables for example when one splits in 2, so not easy to show this split in the drawing.
another drawback is that you can not define cables with wires with different awg, i ended using the notes field of the cable to describe wires awg variation.

Anyway im happy with the result it help a lot to understand what i need, have to do, and how everything connects

[lowside67]

Nice wiring harness mockup! I had the same challenge for mine and ultimately I opted to draw the physical harness segments but not do a diagram like that with each individual wire since there are relatively few on my car.

I think you are right that a number of those connectors have specific boots on them (definitely all the autosport stuff) but I agree that it's expensive and overkill for Deutsch DT* connectors. I have only used SCL and ATUM plus DR25 - look forward to your report on how the SCT works!

You have probably seen, but this is a great resource:
https://www.rbracing-rsr.com/wiring_ecu.html

I took some guidance from them:
"To provide additional sealing and strain relief, either Raychem molded shapes (boots), or adhesive heat shrink like ATUM (3-1 or 4-1 shrink ratios) can be used on Deutsch DTM Connectors. The lip diagonal dimensions above allow you to decide on the proper sealing boot or shrink tubing."

-Mark

[rodorico83]

Nice wiring harness mockup! I had the same challenge for mine and ultimately I opted to draw the physical harness segments but not do a diagram like that with each individual wire since there are relatively few on my car.

I think you are right that a number of those connectors have specific boots on them (definitely all the autosport stuff) but I agree that it's expensive and overkill for Deutsch DT* connectors. I have only used SCL and ATUM plus DR25 - look forward to your report on how the SCT works!

You have probably seen, but this is a great resource:
https://www.rbracing-rsr.com/wiring_ecu.html

I took some guidance from them:
"To provide additional sealing and strain relief, either Raychem molded shapes (boots), or adhesive heat shrink like ATUM (3-1 or 4-1 shrink ratios) can be used on Deutsch DTM Connectors. The lip diagonal dimensions above allow you to decide on the proper sealing boot or shrink tubing."

-Mark

I did not know that link, a lot info..., added to my bookmarks.
ill post some pics when is done

[rodorico83]

As promise, some pics of the result.
I made 3 modules, engine bay, cockpit and front.
Material used Raychem DR-25, SCT, ATUM & RS-PRO 3:1 Mil spec tubing, not as temp resistant as DR-25 but quite better price, and being 3:1 was more easy to pass though the wires.

[Joefisherff]

Great work and thank you for sharing the info.

[lowside67]

Apparently you and I have been on the same wave length!

Since posting last year, I actually sold my car and started over with a new one - building a complete wiring harness for the data, operations, and engine. I just finished testing the new wiring harness I built for my S1000RR BMW engine last night.

I used a variety of different booting methods that we talked about. The main harness connector is a molded Raychem boot, the "branch points" where a single trunk of harness splits into multiple branches uses Raychem SCL 3:1 semi-rigid tubing, and the connectors use Raychem ATUM 4:1 glue lined, sometimes 2 sizes, to get from the larger connector size down to a tight and weather sealed connection.

-Mark

[rodorico83]

I see you dont waste your time, me still working on the project almost 2 years already...

beutiful harness
Yep i follow similar approach but instead of SCL i used SCT 4:1 in branching and ATUM when i need some flexibility