Magnets to secure a tarp

[Umnak]

I hate drilling holes in vans, and I love tarps. So, I want to use our 10x12 70 denier Tarp on the van using rare earth magnets. I know tarps, I don't know magnets. I've found some magnets that have eye hooks (https://www.kjmagnetics.com/products.asp?cat=180) and would like suggestions as to how much pull force or what size magnet to purchase. I figure three will do, but don't know if they should be 125lb (1 3/4") or 173lb (2") or even larger.

Any help would be appreciated.

Thanks,

 

[Hilldweller]

I don't know magnets well but I tried what you're saying and had mixed results.
They worked most of the time; I used magnets that hold pieces to be welded.
When it got windy they would wander. The scratches weren't terrible but they happened.

Just a caveat to consider.

 

[JackW]

vacuum cups...

http://www.toolup.com/woods-powr-gr...scplp3182322&gclid=CK6aovC3kcQCFW0V7Aodo2YA-Q

 

[doug720]

I have used magnets on my LandCruiser to hold a tarp for long time and found they work great.

I purchased mine from the same source listed above. Don't recall the rating on them, but I use the round button magnets about 1.25" dia. with a threaded hole in the center. I use a screw and nut as a handle to make them easy to remove. I place a magnet every 12-18" across the roof and about the same on the side if i need to offset the tarp as a wind block. These have held well in some sever winds, much better than ropes in my experience.

I also use slotted magnets to hold my lantern to my lift gate and many other uses.

I say go for it.

Sorry I don't have any pictures of my set up, but you should get the idea.

 

[AlbanyTom]

I think it'll work, but I also think that you have an excellent chance of scratching the paint. The reason is, it's very difficult to remove a magnet from a surface without either sliding it a little bit, or leveraging it off by tilting it. The former will scratch the paint if there is any dirt at all between the surfaces or if the magnet bottom isn't completely polished smooth. The latter will scratch the paint unless the magnet has smooth sides that are either soft or rounded...a square sharp edge is a problem. For once in a while use I'm sure it wouldn't be a big deal. But if you camp every weekend, I believe you'd end up with a bunch of scratches after a season.

I can understand not wanting to drill holes in the roof, though.

 

[CSG]

Small c-clamps with a bit of pad works fine on my Econoline based Traverse. Clamp to the drip rail.

 

[Umnak]

Thanks for all of your responses.
doug720 It is nice to know it works with the 1.25" magnets, though I would get by with three or four and use the ties on the tarp.

JackW I tried some heavy duty tile suction cups and they just don't work on the area where I want the tarp, there is a bit of a curve to the van there and the suction failed.

AlbanyTom I've thought about the scratches and wonder if I can use a thin piece of material between the magnet and the body of the van.

CSG C clamps on the drip rail is something I've considered, but have not found any that are small enough and yet strong enough to be effective.

 

[doug720]

For clarification, I place the magnets on the tarp, so it acts as an isolator to protect the paint. I also flat tow my 60 behind our motor home and use magnetic base trailer lights. These are supplied with small plastic discs to protect the paint and seem to work well. My 60 has a fair amount of "Natures Pin Stripping", and using magnets has not hurt the paint. Just use a little thought and no problems

The reason I use so many magnets is wind, getting up in the middle of the night to secure a loose tarp is not my idea of fun.

 

[robgendreau]

The problem is that the tarp will get a bit dirty, and then there's grit and you've got the scratch problem. I tried this a bit and either the material was too thick for the magnet, or thin and allowed grit in. I also used the magnetic trailer lights on flat tow, and got scratches once with those too. Best material underneath I came up with was doubled over duct tape. Kept it from sliding.

On my van I use powerful clamps on the rain gutter now. Sounds like you don't have that option though.

 

[JackW]

Thanks for all of your responses.

JackW I tried some heavy duty tile suction cups and they just don't work on the area where I want the tarp, there is a bit of a curve to the van there and the suction failed.

These smaller diameter ones are used on the roof of VW buses which have a contour to them - you might give them a try

http://www.toolup.com/woods-powr-gr...vacuum-cup-w-acc-mount-14-20-x-1-14-stud.aspx

•Attaches to flat or curved, smooth, nonporous surfaces.

 

[Umnak]

These smaller diameter ones are used on the roof of VW buses which have a contour to them - you might give them a try

http://www.toolup.com/woods-powr-gr...vacuum-cup-w-acc-mount-14-20-x-1-14-stud.aspx

•Attaches to flat or curved, smooth, nonporous surfaces.

Might work. Thanks,

 

[AlbanyTom]

The problem is that the tarp will get a bit dirty, and then there's grit and you've got the scratch problem. I tried this a bit and either the material was too thick for the magnet, or thin and allowed grit in. I also used the magnetic trailer lights on flat tow, and got scratches once with those too. Best material underneath I came up with was doubled over duct tape. Kept it from sliding.

On my van I use powerful clamps on the rain gutter now. Sounds like you don't have that option though.

That's exactly it. If you can keep the plastic scrupulously (spelling?) clean, it shouldn't scratch. But if you're like me, every time you're camping there's dirt/grit everywhere. The grit gets embedded in the plastic, because the grit is harder than the plastic, and it turns it into homemade sandpaper.

Putting tape on the car before the magnet goes on would keep the dust away, but I would worry about that hurting the finish long term - that is if it's a nice new truck. If this is something that you drive through the brush all the time anyway, then none of this matters.

My experience has been with magnetic mount antennas on various vehicles over the years, mine and others. For a one shot use, you can get away without scratches. But if you do it all the time, you're going to have a ring wherever the magnet was.

My current truck has a roof rack, so I'd use that. And I find that handy enough that if it didn't have one, I'd add one. Another option might be to mount some kind of low profile hard points on the roof, that have threaded holes in them. Then you could bolt rings or a rack to the top of the truck when you wanted one, and leave it off when you wanted a plain top. I planned on doing that to a Bronco I used to have, but never got around to it. I was going to use 3/8" or so stainless squares around 2x2", with a 1/4-20 threaded hole.

 

[CSG]

Umnak, check the 2" C clamps at Home Depot or Lowes. I think they're strong enough. I use four when I bother to put up a tarp awning. Alternatively, you can clamp them to the drip rail and tie the tarp to them if the tarp's got grommets.

I think magnets are gonna be a pain no matter what you use.

 

[Umnak]

That's exactly it. If you can keep the plastic scrupulously (spelling?) clean, it shouldn't scratch. But if you're like me, every time you're camping there's dirt/grit everywhere. The grit gets embedded in the plastic, because the grit is harder than the plastic, and it turns it into homemade sandpaper.

The van is a new-to-us 2006 Sprinter with just over 15000 miles on it. We drove it from Austin to Seattle this December and will bring it north in the spring. From there it's a year-long road trip around Canada and the US. Part of that time living in the Sprinter. We live in a rain forest so tarps are second nature for us. There is no rack on the van, but there is an AC unit and solar panels. Unfortunately they are hard to tie anything off of, and I don't want to be crawling on the roof in the rain.

Is there any downside to mounting the magnets in the proper position and simply leaving them on the van? If they have a substantial pull force, say over 200lbs, they may just stay put.

The van and the trip can be seen here and here [URL="https://www.flickr.com/photos/umnak/sets/72157645682662186/"]https://www.flickr.com/photos/umnak/sets/72157645682662186/






CSG "check the 2" C clamps at Home Depot or Lowes."

I will look at clamps when we head south again and find a place that has more than two options.

Thanks,

 

[FJR Colorado]

Ace hardware sells nice 90 # magnets with a convenient hole in the center for mounting hooks, QuikFists, whatever...