8020 DIY pop top

Wisco150 · 09-13-2021, 10:04 AM

Hi Everyone,

I salvaged a fiberglass top out of the junk yard. I removed the metal roof and the pop top together to use the metal frame as a mock up for a home built pop top before I cut a hole in our vans roof. The fiberglass top had a reverse flange which was a beast to separate. My idea is to use 8020 as the frame work and either using 8020 components/gas struts for a vertical lift or a westfalia style hing but still using 8020 as the frame work. I reached out to a local 8020 distributor but I haven’t heard back after the initial contact. I’m wondering if anyone here has experience with using a program to design something out of 8020 and determine what kind of weight/load the 8020 can support to help determine what series of 8020 to use.

I’m more than willing to pay someone for their time if going the route of creating a computer aided design off of my sketches ideas.

Thanks in advance, any suggestions, tips or comments would be appreciated.

boywonder · 09-13-2021, 01:41 PM

Here are my suggestions:

I have no idea what your skill level is with mechanism design, tube bending/welding fabrication, fiberglass work, etc so please keep that in mind when reading my comments.

I'd maybe do some prototyping with 80/20 to kinematic studies/development but I wouldn't use it for the final design.....I would use DOM cro-mo seamless tubing. You can find folks who can bend and/or weld this for you, it just takes some effort.

6061-T6 aluminum has about 1/3 the yield strength of chrome moly so you will need a thick cross section to keep it from bending (you get a thick cross section with 80/20), but you don't have lots of space for fat tubes. Mild steel's yield strength is somewhere between AL and cro-mo.

Think about how you will fabricate the canvas........this project alone will likely be a challenge, especially if you want windows/screens and/or zippers, or double wall insulation.

I highly recommend studying both the SMB and CCV top mechanisms before you start. The SMB method is straightforward but bed width is limited if you want to sleep up top. The SMB method also suffers from needing lots of force right a the beginning of the lift travel due to the crossbar geometry.

Also think about what you have to attach the mechanism to the roof, do you need to fiberglass in some support/attachment areas?

Wisco150 · 09-13-2021, 05:14 PM

Hi boywonder, first off thank you for your very helpful response. I am amateur at best when it comes to designing projects for vans and beginner at best for metal skills. I designed a removable door for the e series along with the 3D printed parts for and that’s about the extent of my experience for van projects from start to finish.

That you for the recommendation of DOM cro-mo tuning.

I’ve worked a lot of sewing related projects and sailrite is probably my most frequently visited website next to sportsmobile fourm.

I’ve tried to save as many Colorado camper van mechanisms photos as I can to review and study. They would Ben my ideal top but due to cost, not an option at this time. For the components time and energy Colorado camper van has put in their tops and business I believe the price of their top is really fair but just more than I can afford. I expect to spend a good amount of money to construct my own top and even more time and effort but prefer to see what can be created.

I made up a very poor sketch of how I would attach the mechanism to the top.

To try to explain...

The drawing is a “cut” view of the fiberglass top I have from drivers to passenger side.

The Yakima style bracket idea is to have a bracket made similar t the Yakima wide body bracket for the 1A rack. I would have it made so the surface mounting to the fiberglass would be larger (wider and taller) for more contact surface and my thought would be to have four on each of the fiberglass top. Yakima wise body brackets say 220lb per pair of brackets. My thought if I had larger Yakima style bracket and four of them, it theoretically should be enough to support a fiberglass roof, the weight of the mechanism/frame and canvas. The Yakima brackets do have some pressed steel parts for strength which I don’t know if I could have duplicated but if I had made them out thicker steel or if chromoly plate is an option to have them made out of that.

The interior bracket, sandwiches the fiberglass in between the interior bracket and Yakima style bracket. If I were to have four Yakima style brackets on one side I would have four interior brackets Held with adhesive and bolts.

The upper square tube frame mounts to the four interior brackets on each side. The tube frame being like a picture frame with cross bars at the front and rear (not pictured)

The westflaia style hinge mounting to the upper square tube frame and lower square tube frame.

The Lowe square tube frame, similar to the upper square tube frame, it would be a picture frame with cross bars at the front and rear. The Lowe square tube frame mounts to the van supports found just below the outer roof sheet metal.

If front of the westfalia style hinge would be gas struts (not pictured) just like westfalia style roofs.

The pink being the van body.

Wisco150 · 09-25-2021, 07:44 AM

No longer thinking or planning to use 8020 but going the route of a Westfalia style pop top. Thank you to members Shenrie for information and pictures from his DIY CCV pop top install which helped me figure out mounting to the van and to the roof.

Yesterday I was able to go to the local makers space and cnc cut pieces of the hinge assembly. I mocked it up with some extra bolts I had from a L track floor system I’m working on and the top and bottom pieces I glued together and need them to dry yet but the picture shows the general idea. I plan to double the lower arms sandwiching the upper arms in between.

Once I get a mock up finalized and the cad drawings adjusted if needed I plan to cut the pieces out of either 3/16 or 1/4 steel. I’m concerned of the weight but want to make sure the hinges are heavy duty enough so I’m really unsure on what thickness of steel to use.

Wondering if anyone has recommendations on bolts/fasteners to use. My plan/idea is to use shoulde bolts, steel washers or steel spacers and nylon washers in between the steel washers or steel spacers. Any input on what might be best or what has worked for others would be awesome!

boywonder · 09-25-2021, 08:23 AM

Excellent mock up.....

I would use shoulder screws and nylon spacers. Think about larger shoulder diameters..maybe 3/8" or more.

Mcmaster sells all kinds of spacers including hat shaped ones if needed.

Consider where you may be able to use angle or channel to increase lateral stiffness. .....and consider increasing the overall size of the mechanism proportional to the roof size.

*EDIT...I see that you are doubling up some of the links...that will help with lateral stiffness....further apart is better.

I suspect the SMB PH is significantly heavier than a westfalia.......never played with the VW version so I'm guessing here.

It would be pretty slick if you can incorporate a gas spring in the mech as well, in addition to a couple others that you will likely need.

boywonder · 09-25-2021, 10:13 AM

gas springs.....

https://www.mcmaster.com/gas-struts/

Shoulder screws......

https://www.mcmaster.com/shoulder-screws/

Nylon Spacers......

https://www.mcmaster.com/spacers/nyl...eaded-spacers/

https://www.mcmaster.com/spacers/

boywonder · 09-25-2021, 10:21 AM

Here's another idea......Perhaps modify a tilting garage door mech.....weights and size are similar.

https://www.homedepot.com/p/E900-HAR...00-R/205510959

campism · 09-25-2021, 04:27 PM

Since you're using Westy hinges, why not a Westy latch?

Pictured below is the roof latch from a VW Westy. You're looking up through the front of the roof opening. The small prong is mounted to the flat metal of the roof while the larger piece is attached to the poptop. Very secure and probably available on the Samba classifieds for a reasonable price.

Here's one in NC.
https://www.thesamba.com/vw/classifi...php?id=2481600

Wisco150 · 09-25-2021, 04:59 PM

Hey boywonder,

Thank you for your response and links that is super helpful.

My plan right now is to use angle iron as a rectangular frame to mount to the two roof supports (like Shenrie shows on his diy CCV) and mount the hinge mechanism directly to the angle iron. Since the base and the top pieces of the hinge mechanism I’m working on is a U channel my thought is to have a piece of steel welded to angle iron where the lift mechanism attaches to create a channel in that portion with one channel section being on the drivers side and one on the passenger side.

I will have to also figure out a size of the hinge mechanism as a whole in comparison to the fiberglass top to avoid having too small of a hinge

I’m designing the hinge to use 0.5” shoulder bolts.

I’m planning to use at least one gas strut on each side but will need to
figure out a weight estimate once I get a little bit further along. My goal is to take the fiberglass top to the local scrap metal yard and weigh it

Do you have a recommendation on what thickness steel to make the hinge pieces out of? I was thinking 3/16”

boywonder · 09-25-2021, 07:28 PM

You can probably weigh the top using a couple of bathroom scales...one on each end.

Designing with gas springs can be challenging, but you can always just trial and error it along. You need an extended length that will be constrained by the compressed length and usually you will need to mount at an angle to meet those constraints, and then you need to do some trig if you want a reasonably smooth motion.