PVC roof rack?

[ArtHummer]

Alright, I got one stupid idea that is stock in my head and I just HAVE to get it out of me. It might be absolutely ridiculous and stupid but, give me your thoughts on it...

The other day I was reading a post about building roof rack and one of the concerns was to keep the weight down (some roof racks are heavy). there was a discussion about making it partially out of aluminum to bring the wight even lower...
All that got me thinking and searching for lighter and cheaper materials. And the material I stopped on is PVC. As inspiration I remembered a video on YT about making a bow out of PVC (https://www.youtube.com/watch?v=3zyV8tZGJtE) In it, the guy used 3/4" and 1/5" pvc pipes. He inserted 3/4 in to the 1/5 for extra rigidity.

So here is what I came up with...
The idea will be to make it look kind of like a roof rack on Nissan Xterra. I've seen one fit on TAPDH3T's rig and it looks pretty good(http://www.hummer4x4offroad.com/for...6-Looking-for-a-H3-roof-rack&highlight=nissan).
To give more extra rigidity to PVC pipe and good connection of pieces together, I was thinking using the 1.5" and 1.25" pipe. The 1.25" will have to be inserted in to the 1.5" (like it is done on video for the bow). The 1.25" will have to be a bit longer to have room for the connection peaces.
Something like that...

Then you can connect this peaces with regular PVC couplings. There are straight couplings, T couplings and 90, 45 and 30 degree elbows. When you will connect the 1.25" coupling it will be almost flash with the outside 1.5" pipe. That way the connection will not stick out and will not be visible.

You can also go from 1.5" outside pipe to a smaller diameter for the smaller rails.

Using this method you can connect it any shape or form possible. You can build it small and slick as a Xterra's rack or go all out and build a basket type rack.
To finish it off and NOT to make it look like you have some kind of a plumbing system installed on your roof, it will have to painted with sprayed on bed-liner. It will make it look rigid, give it extra strength and hide all the connection lines.

The PVC is much lighter then aluminum and with inserting 1.25" in to 1.5" will make it much stronger also. Price wise it will be very cheap too. 10' for the 1.5" PVC cost is less then 3$ in home depot. Plus connecting couplings, PVC cement and bed-liner and this project will run you in less then 100$


So what do you think? Is it possible or am I going nuts??? Any pluses and minuses?
Your comments and sarcastic remarks are welcome!!!:emb:

 

[skeptic]

Just for looks or do you plan to use it? I suppose in theory you might be able to make it look good, but if you were to try to use it... Think highway speed wind, the load bouncing up and down (cause it will never be rigid like steel or aluminum), lack of strength... Trying to take it offroad would be even worse. Might get the desired results if you were to help move your mother-in-law's stuff, but probably not a good idea to carry anything you want to keep.

 

[ArtHummer]

If you will make a some king of a spoiler on the front to deflect the wind, highway speed will not be a problem at all. And function wise I think it will be able to hold a medium size loads. I think the spare tire, jack, shovel and few water canteens will sit on it just fine without any damage. You will surprised how strong the PVC is. It has a little flex but don't brake that easily. And with 2 pipes in one will make it even stronger.

Found this video on YT. It is test for the 2" pvc pipe. I don't understand all the numbers but it looks like they put more than 1000lb on it. Can you imagine it 2 time thicker?

[video=youtube;9TWixGNQQk0]https://www.youtube.com/watch?v=9TWixGNQQk0[/video]

 

[abearden]

Problem is the flex. Bouncing weight will fatigue the PVC. Worth a try, but I wouldn't put anything heavy on it or have any long sections of unsupported pipe.

 

[ArtHummer]

Can't really find any concrete information about PVC strength. Found this on the PVC website (http://www.pvc.org/en/p/pvc-strength)

Bending strength
Fig.3 shows the bending strength of PVC products in comparison with other plastics. It is expressed in terms of the maximum stress upon break of the test piece, where the test piece is supported at two points apart and a vertical stress load is applied at the centre. (An index to show the magnitude of force at break, when the test piece is bent).

Bending strength of various plastics

From the chart it looks like the "Bending strength" (whatever that means) is 69 - 114 MPa. This is 10007 - 16534 psi

 

[alrock]

I dunno, maybe it will work but I'd be concerned about strength and the finish. How will you finish the rack? Could be difficult to give it a good, durable coat of paint.

 

[TAPDH3T]

It is an interesting concept!!

 

[Steve #1]

I had considered this somewhat a while back. I have eye bolts that I installed in my rails and considered running PVC between them for cross bars. I then determined that strapping my cooler to my spare tire, while just a red neck, was easier.

 

[TAPDH3T]

U know ur a redneck when....... Lol

 

[ArtHummer]

I dunno, maybe it will work but I'd be concerned about strength and the finish. How will you finish the rack? Could be difficult to give it a good, durable coat of paint.

There are sprayed on bed liners that are very durable. I never had a need to use one so I don't know much about brands or their quality. But you can ruff the PVC with some send paper for better bonding and cover it with few coats of some nice bed liner. This thing is thick and will cover all cracks on the connection points. You will not be able to see where the peaces are connected. And bed liner is durable, you will not be able to scrape it off easily.

The only thing i haven't thought of is how to mount it on the roof. Maybe the end peaces can be borrowed from Xterra rack.


There are lots of bed liners on the market and I don't know anything about it. Any insides would be appreciated. What all of you used before and how can you rate it?

 

[ArtHummer]

Here is a pic of how i think it could be build. But extra support can be added



Basket type and front spoiler

 

[58Bisc]

There are sprayed on bed liners that are very durable. I never had a need to use one so I don't know much about brands or their quality. But you can ruff the PVC with some send paper for better bonding and cover it with few coats of some nice bed liner. This thing is thick and will cover all cracks on the connection points. You will not be able to see where the peaces are connected. And bed liner is durable, you will not be able to scrape it off easily.

The only thing i haven't thought of is how to mount it on the roof. Maybe the end peaces can be borrowed from Xterra rack.


There are lots of bed liners on the market and I don't know anything about it. Any insides would be appreciated. What all of you used before and how can you rate it?

I would prime it with plastic primer to allow the bed liner to bond to the PVC. It should provide a little flex to the bed liner and stop it from peeling off when you use it.

If you are going to run into any issues I would think it would be on the cross bows. The long runs without any coupler support will more likely be your sag points. Some type of flat lattice work glued in may help tie the cross tubes together and help disperse the load. Not sure any of this will work, but I always like the thought of pushing the status quo.

 

[TAPDH3T]

I don't know how much lighter that's going to be!!! Mine is extremely light and i can stand on it!! I weigh 210 lbs!!! I would say each bar on mine weighs 5lbs or less!

 

[Beachbum]

No offence but not a very good idea. Not to mention dangerous to others on the road. I live in a high tourist area and quite frequently see travelers with similar set ups (be supprised at how many), beach chairs luggage etc. attached to some rigged (some even well done looking with an obviously large amount of time put into it) PVC roof racks. I have also seen these, little thought out when it comes to the safety of others, racks fail. Over time they become brittle, factor in wind speed, wind sheer on the highway from other traffic, vibrations, flexing, UV rays, load etc. Roof racks endure a descent amount of stress thus are made out of strong materials for that reason or you would be able to find tons of plastic PVC like racks on the market. Not any out there last I checked. Something fails and causes damage or injury to others the police and lawyers won't care what PVC strength charts say, how much PVC cement/glue you used, how many supports you used, extra tubing inside of the tubing etc. They'll just ask "Did you make this yourself?" The police around here hate these things with a passion and I know a policeman and a firefighter/EMT personally that have seen the consequences of "Redneck PVC Roof Rack" failures on more that one occasion and both have language about these set ups AND their fabricators that I don't think I will repeat on here. I also have seen quite a few 2x4 wood roof racks too (loaded, spare tire and all), don't know what some people are thinking half the time. My advice, save for a descent rack, it will be cheaper in the long run with no worries. You might be trying to save on weight but you are also reducing greatly the amount of weight you can load. On another note, you put one on even painted, coated you will get a fair amount of negative comments from other offroaders and maybe even some laughs. Hummers have enough haters on the trail as it is, I wouldn't give them anything else to pick at lol. Using it for VERY light loads, a small light item or two for offroading or camping is one thing but for highway use..not me, wouldn't suggest it. Just my two cents, go for it if you like, not something I would take the chance of myself though, just me. Glad tourist season is over for while lol.

 

[Can007]

I love the attempt for innovation, all invention started somewhere!!! Please tell me u r going to make a prototype???

 

[ArtHummer]

Well, the whole idea is kind of shady. Plastic is plastic and prone for bending and cracking. Personally I think the best solution still will be the all aluminum rack but it will cost allot. Aluminum is soft and you will have to use allot of it to make it durable.
I'm not planning on making a prototype anytime soon. I don't have budget and time right now with all the holidays. But maybe some time next year, just for the fun of it, I will make the test prototype of the cross member(since it will be the weakest point) for testing. I just want to see how much it will flex and if it will be able to hold any weight. At least if it will brake, next time, someone will come up with stupid idea like this one, I can say, I did it and it did not work.

 

[OIF Marinex3]

I figured that I would add some pictures to the conversation

 

[OIF Marinex3]

it looks pretty sketchy to me, not at all Hummer qualified :bc3:

 

[ArtHummer]

It does look like a plumbing on top of the roof. :giggle: That's where my pipe in pipe solution should cover it, hopefully.
Here are some more pics that others did

This one is out of 3/4"

 

[ArtHummer]

If only I could get my hands on those Xterra mounts... Will have to hit some junkyards.