Virgin Sand In Kaokoland (a post lockdown adventure)

[BoskakBruce]

Yoh - I hope that Slime didn't bite you in the butt. Excuse my frankness Bruce, but as far as I can see that was very wrong decision.

Slime makes tube unpatchable - not sure what it is but the chemicals would prevent the patches to stick. So what you have in effect done is you turned two perfectly patchable and hence reusable (many times) tubes into a throwaway once-off ones. I doubt that Slime would help anyway in the heat and distances & speeds you were doing and once you will get hole big enough, the tube is useless.

I would have just stocked up on patches and glue in Opuwo. Most probably you still had 3 x 21 inches tubes, that could be used at the rear in pinch anyway.

Your frankness is welcome.

The reason I was comfortable with the slime in the tube is that I'd already successfully patched a tube with it. I carry vulcanizing glue and big Slime (brand) motorcycle patches, not those flimsy bicycle patches. I can assure you, if you apply the vulcanizing glue to both the (cleaned) tube and the patch, leave it 15 minutes and then apply it with pressure, nothing is going to make that patch peel off.

One of these days, I'll make a video demonstrating this.

Personally, I believe (I don't know for sure) that the reason patches fail with slime is becasue often:

1) the patch is a flimsy bicycle patch made in China from a cheap bicycle repair kit.
2) The glue is contact cement instead of vulcanizing glue.
3) The rider is too impatient to wait 15 minutes for the glue to vulcanize.
4) The tube is a shitty Chinese tube with very little rubber in it's chemical makeup, so patches are less likely to stick. I've started using Michelin tubes recently which aparrently have more ruber in their chemical makeup (and are therefore more easily patched with vulcanizing glue).

Would love to hear your thoughts...

 

[Ian in Great Brak River]

Man what a story. We stopped over there some years ago but it was nowhere near as dry as it is now. Great RR!

 

[OomD]

Absolutely loving this!  :thumleft:

 

[Xpat]

....

Your frankness is welcome.

The reason we were comfortable with the slime is that we'd already successfully patched a tube with it. I carry vulcanizing glue and big Slime (brand) motorcycle patches, not those flimsy bicycle patches. I can assure you, if you apply the vulcanizing glue to both the (cleaned) tube and the patch, leave it 15 minutes and then apply it with pressure, nothing is going to make that patch peel off.

One of these days, I'll make a video demonstrating this.

Personally, I believe that the reason patches fail with slime is becasue often:

1) the patch is a flimsy bicycle patch made in China from a cheap bicycle repair kit.
2) The glue is contact cement instead of vulcanizing glue.
3) The rider is too impatient to wait 15 minutes for the glue to vulcanize.
4) The tube is a shitty Chinese tube with very little rubber in it's chemical makeup, so patches are less likely to stick. I've started using Michelin tubes recently which aparrently have more ruber in their chemical makeup (and are therefore more easily patched with vulcanizing glue).

Would love to hear your thoughts...

I stand corrected then. In the interest of research, I would still like to understand more details though - do you by any chance remember what tube it was you guys patched?

I still would stay clear off Slime or any similar product, unless as a last desperate resort - e.g. I run out of patches in middle of nowhere so will try to pour that stuff in to see if it can stop / limit air leak. I'm skeptical they really work with tubes as these stretch (I believe these product were intended for tubeless tyres, which do not flex much) - and the fact that you already had to patch tube with one in it seems to confirm this to an extent. Also they make proper mess of any future flat fixing with that goo messing up everything. They also do tend to block up the valve stem making pressure reading unreliable.

Patching the tube is topic that fascinates me as it is absolutely essential skill for trips like this and yet - even after years of reseach and trials - it still seems like an alchemy - or rather black magic - to me. I can patch a tube nowadays with reasonable success - i.e. I will usually manage to make it work but it takes sometimes multiple tries.

My current understanding is as follows (and I invite and appreciate comments from fundis who know what they talk about as I would like to get to the bottom of this - it really is essential skill for this kind of riding that I am not able to master 100% for some reason): The root of the problem is that the compounds used for tubes have changed over the years.
- In old days mostly natural rubber was used for tubew, which responds well to the traditional vulcanizing process you described Bruce
- Currently most of the tubes are made of butyl rubber (synthetic one) - including Michelin ones at least according to this post: https://www.bobsbmw.com/store/product/michelin-tube-17-rear. The main reason is cost - they are significantly cheaper than natural rubber ones. They have some functional advantages (do not leak air like natural rubber) as well as disadvantages (more prone to catastrophic blowouts). I think it is pretty safe bet, that - unless you specifically seek and order specialized natural rubber ones - most tubes you will buy on the shelves in the bike / HW shops are butyl rubber, especially here in Africa.

And here lies the problem IMHO: the butyl rubber doesn't respond to vulcanizing as the natural rubber does. It actually works exactly other way around - you should not use vulcanizing glue on butyl rubber, but have to use rubber cement.

Here is my understanding of it now after many frustrating hours in various bushes in Africa (Bruce, you might recall my struggle not far away from Epupa Falls on our trip: https://wilddog.net.za/forum/index.php?topic=222953.msg4039508#msg4039508):

Natural rubber: follow the vulcanization process Bruce described

Butyl rubber: In many ways the process is exact opposite of the natural rubber:
- use Rubber cement, not vulcanizing glue
- use cement very sparingly - a lesson I have learned in the link above. Ignorantly (or rather being used to vulcanization) I have spread cement generously over clean tube as well as patch, and even after letting it dry for 10 minutes or so, it will always come off. Justin finally explained on satellite phone that I have to use only minimal amount on the tube itself and not on patch at all and after letting it dry up I would press it on with the round end of my wheel spanner.

With this approach I was able to fix even heavy duty tubes, which before were abslutely unfixable for me (and even some shops that tried).

I welcome any feedback on this as I would like to get to the bottom of what the right approach is. It is annoying that one needs to know compound of the tube to be able to apply right solution.

 

[Xpat]

I guess the situation is further complicated by the fact that most tubes today are probably mix of natural an butyl rubber and it is impossible to find out at what ratio. I guess that is what you were alluding to Bruce when you said Michelin has higher natural rubber content and that cheap Chinese tubes are probably mostly butyl.

So the question then is what to bring on the trip. Vulcanizing glue or rubber cemment and how to decide with to apply as I believe vulcanizing glue is not going to work on Butyl tubes.

I carry rubber cemment (preferrable Rema Tip) and RemaTip patches and once I have learned about the need to apply minimum glue and let it dry, that did resolve most of the woes I run into before. The question is, if by any chance I come across natural rubber tube - will this work or will I be screwed without the vulcanising glue?

 

[JustBendIt]

I believe that proper preparation of the area to be patched is vital to the patch actually sticking - the area around the puncture must be roughened up / sanded down and lekker clean - you have to carry and use rough sandpaper - forget about that crap metal tab they include in puncture repair kit

Once puncture area is properly prepared then the glue can be applied sparingly - note as Xpat says above that more glue is not better

Once glue has dried a bit and is tacky to the touch then the patch can be applied with pressure ...a roller stitcher is the best tool to use to make sure the patch sticks to teh tube

Let it cure for a good 10 minutes before refitting the repaired tube inside the wheel

 

[BoskakBruce]

I guess the situation is further complicated by the fact that most tubes today are probably mix of natural an butyl rubber and it is impossible to find out at what ratio. I guess that is what you were alluding to Bruce when you said Michelin has higher natural rubber content and that cheap Chinese tubes are probably mostly butyl.

So the question then is what to bring on the trip. Vulcanizing glue or rubber cemment and how to decide with to apply as I believe vulcanizing glue is not going to work on Butyl tubes.

I carry rubber cemment (preferrable Rema Tip) and RemaTip patches and once I have learned about the need to apply minimum glue and let it dry, that did resolve most of the woes I run into before. The question is, if by any chance I come across natural rubber tube - will this work or will I be screwed without the vulcanising glue?

These are all such good questions and I have many of them myself. I'll just share my experience and I'm not saying that I do it correctly or the "right" way, but I've had no issues with the products I use so far. All my patches stick on and stay on.

For the last few years, I've only used Slime Patch Kit #2033. You can see pics on it here: https://www.amazon.com/Slime-2033-Patches-Rubber-Cement

It contains thicker patches that the bicycle kits. I use the Slime Rubber Cement that come with it, which I believe to be the same as vulcanizing cement. I say "believe" becasue the label is unclear and I read online to apply it to both the tube and the patch, wait 10-15 minutes and then apply. That is what I've been doing or 3 years and that has been working very well for me so far, including having patched UHD tubes successfully (I use the massive rectangular Slime patches on UHD tubes).

Sitting on the table in front of my now, I have a tube of Tip Top SVS Vulc cement (which I have never used and am going to test out). This is definitely vulcanizing (as the name suggests and the website confirms), but the name is confusing becasue it's also called cement. Here's a link: https://www.amazon.com/Tubes-Rema-SVS-Vulc-Vulcanizing-Cement/dp/B07GD3P434

To add the the confusion, there's contact cement, which I believe is not vucanizing.

In my glue experiece with the Slime brand, RUBBER cement is the same as VULCANIZING cement.
CONTACT cement is not.

I don't know what the "right" glue to use is for my tubes becasue I don't know what the tubes are made of. All I know is that Slime patches and Rubber Cement have worked on every tube I've patched, from cheapies to expensive UHD ones.

Then, I read this: https://advrider.com/tubes-tubeless-or-mousses-for-adventure-riding/

Lyndon Poskitt claims that Michelin tubes have more natural rubber in them than other tubes. So, I bought a set of Michelin Standard enduro tubes and have them in my bike now. When I get a puncture on them, I'll report back.

The tube that I successfully patched with slime (the liquid) inside of it was a Mitas UHD tube patched with an enormous Slime (the brand) patch and Slime (the brand) glue.

Lastly, I learned a great tip from Marc. Wrap your cememnt tubes in duct tape. That way if they get crushed in your tool kit (as mine regularly do), they won't leak and you won't be stuck without cement when you most need it.

 

[BoskakBruce]

I believe that proper preparation of the area to be patched is vital to the patch actually sticking - the area around the puncture must be roughened up / sanded down and lekker clean - you have to carry and use rough sandpaper - forget about that crap metal tab they include in puncture repair kit

I agree 100%.

 

[Amsterdam]

Bruce, this is a very nice report and it is lekker to relive our adventure. Because it truly was an adventure.

On the tube repair story I side with the no slime crowd. We discussed it before the trip and I decided not to use it.  The reason was that I have not found it effective before and have had it become a big ball of muck in the tube that throws the balance off. But after Marc needing 7 patches for his back tube and 4 for the front I relented. And a good thing it was too as we had no more punctures afterwards. Either the  slime worked or Marc and Bruce finally got sed my riding philosophy: “don’t be unlucky “.  Simple yet effective.

I have had to patch tubes with slime before and it is no big deal. I clean up the area around the hole with a bit of petrol to get the mess off. After that I sandpaper, glue and put a patch on. Never been an issue for me.  But maybe I just wasn’t unlucky.

 

[Xpat]

This is very usefull - at least for me. So we can conclude based on the real world experience that:

- tubes with Slime in it can be actually patched (I still wouldn't use Slime, but now its just personal preference).

- rubber cemment and vulcanizng glue are the same thing (not 100% conclusive - weird that in this age of google it is so difficult to confirm), but all indications I have seen are in the same direction. This is actually great, as it means you just need to carry any glue that is designated either of those things (and the tip on duct tape is great - I battle with tubes getting destroyed in my luggage and spreadin glue all over).

So now its just question to figure out correct technique:

- clean up and roughin up of tube is pretty clear - never point of contention.

- applying glue is not clear to me. Should the glue be applied generously on both tube and patch for proper vulcanisation to occure (seems to make sense with tubes with high natural rubber content), or should it be applied very sparingly (probably if it is mostly Butyl tube)?

I have tried generous application of glue many times and it basically always failed. Now I didn't always wait 10 - 15 minutes before applying the patch, but on many times I did and still usually ended up in tears. On the other hand application of very little glue on the tube only (though if I would put it sparingly on patch it probably wouldn' make difference apart for potentially endin up with too much glue) and letting it dry before applying patch does seem to work for me in most cases.

In other words, does the vulcanisation actually still takes place with modern tubes (especially Butyl ones) or not. What is you glue application protocol [member=7804]Amsterdam[/member] ?

 

[BoskakBruce]

I’m up at 5am. I want to soak in the last moments of this spectacular place while sipping my morning coffee.

I know that a great adventure awaits today. I’ve been looking forward to this second half of the trip for months.

Why?

Because it’s going to be a little more technical and (if the photos I’ve seen online are anything to go by) stunningly beautiful. Plus, there’s the sand on the Marienfluss – miles and miles of beautiful sand that I can’t wait to dig my tires into.

All three bikes are full of fuel. Today I have 26 liters on my bike – 6 of them strapped to my front fender. And my radiator fan works! Woohoo (thanks Jan Lucas)!

We wolf down some oats, pack the bikes and hit the road.

I pull out at 8am before the other to visit the viewpoint above Epupa (which they have already visited). The morning air is refreshingly cool and the view breathtaking. This is a good way to start the day.

 

[BoskakBruce]

We’re on our way to Okangwati first. That’s where we’ll buy our last fuel.

My good spirits are short lived.

Something happens on the way that rocks all of us a little.

Marc has an unfortunate collision with a goat. I wish that I could say that nobody got hurt, but that’s not the case…

The goat doesn’t make it.

There’s nothing that we can do. It was nobody’s fault and accidents happen. A few years ago, my wife also hit a goat running across the road and it almost knocked her off her bike. Goats run across roads and humans ride bikes and shit happens.

But still, killing an animal makes me feel bad, but I feel bad killing cockroaches too.

We’re not going to stop and bury the goat, giving it a funeral. In this environment, it will probably make a healthy meal for one of the area’s human or animal inhabitants.

We talked about trying to see if we could find the farmer who owns the goat and compensate him, but we wouldn’t know where to even start looking because these goats just roam freely and graze wherever they want. Plus we’re in the most sparsely populated country on planet earth. Plus, we can’t speak the language.

We decide to ride on.

Call me a nutjob, but I can’t help thinking, “This will be paid for in karma later on in the trip.”

We take a detour via another dry riverbed. Jan Lucas warns me to look out for deep holes in the riverbed that can swallow a motorcycle whole.

“Ride carefully and slowly” he advises us. I listen, because he’s been right a few times already. Sure enough, he’s right again. They are not small.

 

[BoskakBruce]

We arrive in Okangwati and bump into the Swiss family from last night.

It’s great to see them again. They’ve rented two trucks, each with a rooftop tent. Mom and Dad in one truck. Son and daughter in the other. We don’t stick around to chat, because we’ve got a long ride ahead today and want to get going before it gets too hot.

We say goodbye to the Swiss family and head straight to the fuel place, which is basically someone’s back yard with a drum of fuel and some women serving it in 5 liter water bottles.
 
I am very glad that I have a Guglatech fuel sock in my tank, as this place doesn’t exactly look like the owner values cleanliness. The fuel sock was expensive, but it actually filters water from fuel – that’s how fine the filter mesh is. There are Youtube videos demonstrating this that sold me on the idea.
Marc had filled up here several years ago and taken a photo (see below) of one of the young girls.

He’s delighted when the same girl comes out of the owner’s house. He whips out his phone and shows her the picture of him and her that he took some years before.
She’s also delighted. They bond and take another photo (see below). It’s cute.

We’ve only used 4 liters of fuel by this point, so we don’t need much. Just a top up. It costs more than double what we’d pay in Windhoek, but that’s understandable.
This is the last fuel stop and you can never have too much fuel out here. Plus, remember Johan and Johan? Well, they’ve dropped 15 liters of fuel for us at the school ahead.

 

[BoskakBruce]

It feels like we are prepared for anything.

We have food for camping the next few nights and Marc and I are both carrying 6 liters of water. I have two 3-liter water bladders in my backpack and Mark has 6 liters in his (brand new) fuel bladder.

Speaking of water carrying, I’ve been loving my Klim Nac-pac, which is a backpack designed for dirt bikers. I’m carrying 6kg of water in it and some spares, and it doesn’t hurt my shoulders while I ride, nor does it flap around on my back in “attack” position.

Also, it rests nicely on my Giant Loop bad when I’m sitting. It’s been a great buy.

 

[BoskakBruce]

We head out of Okangwati in the direction of Van Zyl’s Pass. The track is unpredictable. - sandy in places and then rocky.

We pass the Swiss Family on the way, who have made a lot more progress that we had expected them to in 4x4s.

I pass a Himba village with a graveyard along the way… and some abandoned Himba huts.
 
Actually, I’m not sure is these huts are abandoned, or if they are used by nomadic herdsmen when they’re far away from home.

 

[BoskakBruce]

I meet a sweet Himba girl and her children as we take a rest under a shade tree in a riverbed. She keeps her distance, so I approach and practice my Otjiherero. 

“E-naranje a mi Bruce” I say.

Her face lights up with surprise that this white guy is speaking her language (or at least trying to).

We attempt to communicate, but it’s difficult without speaking her language.

Instead I ask her if I can take photos and entertain her kids by showing them pictues of themselves on my phone.

After a while, I say goodbye and give her another of my granola bars. I wish I had bought more of them with me, because they make great small gifts for the Himba.

 

[BoskakBruce]

Eventually, we arrive at Heartbreak Hill – a hill that must have been named after the number of cars it’s destroyed. I forgot to take a photo, so I stole this one from another ride report just to give you a sense of it.

Jan Lucas is obviously exhausted from the heat and the rock riding we’ve just done.

He makes it up the hill without smiling and I’m just hoping that he doesn’t lose so much energy that he can’t continue (or can continue but can't enjoy it).

 

[BoskakBruce]

We arrive at Otjitanda and discover a hundred Himba milling about under the trees, chatting, smoking pipes or drinking beer. It’s a Sunday and they are chilling, but I suspect this is what they’d do on any day of the week.

We head straight to the school to pick up our fuel. The principal of the school comes out of his house and leads us to the fuel.
 
Jan Lucas says something about needing rest. The last time he as exhausted, I saw him raised from the dead by a can of Coke. So I offer to ride back towards Heartbreak Hill where I saw a small shop as we had driven by.

He nods gratefully and I’m happy for the opportunity to help out, ride more sand and meet more locals. I return with the Coke and within minutes Jan Lucas is looking much better.

We make a donation to the school and head off towards Van Zyl’s Pass.

 

[BoskakBruce]

Van Zyl’s Pass is a bucket list pass for many bikers. It’s notorious for a little steep section that can catch you off guard. I’m excited to ride it and practice my hard-enduro balance skills.

The road continues to entertain us… rocky hills, sandy tracks.
 
At one point, I realize that we are miles off track. We’ve taken a wrong turn, but haven’t had time to look at the GPS because all of our concentration is on staying upright.
I blast past Marc trying to catch Jan Lucas so that I can alert him that we’ve missed a turnoff.

Just as I catch up to him, he stops having figured out that we are lost. I slam on my brakes so as not to collide with him and promptly fall over!

Shortly afterwards, we arrive at the top of Van Zyl’s Pass. It’s spectacular. 

I spot a Himba hut on the hillside and go check it out.

Marc gets to work with his tarp and sets up some shade for us to rest and cook soup under!

For the most part, it wasn’t that hard to ride – just steep.

 

[BoskakBruce]

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