2001 Suburban Pop Top Conversion

sallf

Member
I've been thinking about doing this for a while and finally decided to kick the project off this weekend. I think my tipping point was reading through @boll_rig 's 2003 Suburban build, so much good information in there, and feel inspired to share with you all in hopes that my eventual success (or failure) can help someone else down the road. I think I'll do a lot of similar things to boll_rig's (cut off the roof in the back, x lift with actuators, fiberglass topper) but the big difference to start is I want to build a female mold. It seems like it'll be a little harder to build but hopefully it'll be easier to glass and reenforce the shape before I pop it out of the mold.

I do have a decent camper setup at the moment, but it is SEVERELY lacking in head room. With my current setup I have x2 four foot drawers and a full bed, which has been great for weekend trips but am wanting something that will be more comfortable for longer trips. I'll post some pictures below to document it before I start this new build.


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Full memory foam mattress fit nice in the back. You'll notice velcro tabs on the windows to hold up curtains. I would NOT recommend this as they inevitably peeled off with heat.

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X2 four foot drawers.

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Ended up using skateboard bearings and 1x1 aluminum square tube for a runner. Worked really well. Had 3 or 4 towards the back the sandwich the tube so it doesn't tip when you pull it out.

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Front piece hinges up so I can put up the two bucket seats and top is wrapped in felt.

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Drawers were sized around this folding table.

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The table pulls all the way out but ended up working pretty well cantilevered out like this as well.




Anyways, that's the old build. I'll make an update on the new build as soon as I make some significant progress.
 

rayra

Expedition Leader
Looking forward to it. Definitely talk with boll_rig about what he would do differently.
I put a very late idea in Boll_rig's topic about using a flat-bottomed boat as a multi-use pop-top.
 

heidiurs

Adventurer
I've been thinking about doing this for a while and finally decided to kick the project off this weekend. I think my tipping point was reading through @boll_rig 's 2003 Suburban build, so much good information in there, and feel inspired to share with you all in hopes that my eventual success (or failure) can help someone else down the road. I think I'll do a lot of similar things to boll_rig's (cut off the roof in the back, x lift with actuators, fiberglass topper) but the big difference to start is I want to build a female mold. It seems like it'll be a little harder to build but hopefully it'll be easier to glass and reenforce the shape before I pop it out of the mold.

I do have a decent camper setup at the moment, but it is SEVERELY lacking in head room. With my current setup I have x2 four foot drawers and a full bed, which has been great for weekend trips but am wanting something that will be more comfortable for longer trips. I'll post some pictures below to document it before I start this new build.


View attachment 441178
Full memory foam mattress fit nice in the back. You'll notice velcro tabs on the windows to hold up curtains. I would NOT recommend this as they inevitably peeled off with heat.

View attachment 441180

X2 four foot drawers.

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Ended up using skateboard bearings and 1x1 aluminum square tube for a runner. Worked really well. Had 3 or 4 towards the back the sandwich the tube so it doesn't tip when you pull it out.

View attachment 441184
Front piece hinges up so I can put up the two bucket seats and top is wrapped in felt.

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Drawers were sized around this folding table.

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The table pulls all the way out but ended up working pretty well cantilevered out like this as well.




Anyways, that's the old build. I'll make an update on the new build as soon as I make some significant progress.
Looking forward.It sounds interesting.Cant wait for you to start.Good luck and keep us updated please


Sent from my SM-G920I using Tapatalk
 

chilliwak

Expedition Leader
Nice looking set up in the back of your Burb Salif. You can do lots of things with a bBurb, as I can see you have done. Thanks for posting pics. Cheers, Chilli...:cool:
 

sallf

Member
Looking forward to it. Definitely talk with boll_rig about what he would do differently.
I put a very late idea in Boll_rig's topic about using a flat-bottomed boat as a multi-use pop-top.
@rayra thanks for sharing. That's definitely not a bad idea. I found a number of options but ultimately I'd have to work around the dimensions and they all seem to be a little taller than I want. Here were the best options I found:
http://directboats.com/amjonboat.html
https://www.homedepot.com/p/Sun-Dolphin-9-4-ft-Water-Tender-Boat-WT94CW/204690379

My roof is roughly 118" x 52" so one is too wide and one is too long. I think I'll keep that in mind for a potential plan B if the mold doesn't go well.

I also found this cheap big truck bed topper on Craigslist, which I thought might work, but ultimately decided that I'd rather work harder to get the dimensions right (and a better look).

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sallf

Member
Made some good progress this weekend on the mold. Hardest part was definitely getting all the curves of the roof. After trying a couple things I ended up basically building a big frame and then used thin plywood to make the curve.

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Draft angles on the front and back were easy since I could just cut the ends of the frame with the correct angle. To get a draft angle on the sides I ended up gluing in some shims. I probably could have ripped some 2/4s but this seemed easier initially.


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Then pieced in the sides.

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Screwed on some feet so I could flip it over.

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Next step is getting the top on and cleaning up all the corners. I'm thinking instead of trying to round out some of my sharper corners, I might go for more of a fractal look. Below is a rough sketch, anyone have experience making a form like this? My first thought was drawing it out with tape and then filling in the tape with cardboard, and then transferring that to plywood, but it was hard to be exact with the thick tape...plus I kept peeling it off. My second thought is to draw the lines with dowels and hot glue them together. Seems a little crafty, but it's my best idea so far.

Anyone have other thoughts ? It seems like one of those decisions I might regret in about 40 hours.


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rayra

Expedition Leader
Look up the woodworking technique of scribing. Build a simple 4-sided box out of 1/2" plywood in 12" tall strips. One sheet should provide enough material. Build the box, shore the inside corners with 2x2. Set the box on the roof and stabilize it. Shore the box so the top edge looks level with the vehicle - the roof is not level, it's crowned from front to back and side to side. Then use a circle-drawing compass or similar tool as a scribe, set / spaced to the highest gap between the frame and the vehicle roof, at either the front or back corners. And then simply run the scribe down the front, back and one side, drawing the matching curve on the plywood box. Then cut your marked line (doubling the side pieces to make a mirror-match) and you should have a snug fit for your pattern frame.
Figure out the slopes you want before you frame the panels.
The resulting frame can become the interior buck for your fiberglassing work. I wouldn't suggest leavinf the plywood in, it would add 35-40lbs to your pop-top.

Shore that box frame with cross sections, skin the top with 1/8" pressboard or something similar. Reinforce the inside ends and corners with 1x2, something that will fill the joints. And when that is set up attack the outside sharp edges to round things, round the corners etc.
When that's done, that's your buck. From there you make your fiberglass shell as thick and pretty as you want. Make it 2-3 layers. When the shell is done you flip it and glass in a supporting framework. I'd suggest something like EMT conduit for weight and rigidity. And with a little pre-planning you can set bolts thru it at the inside corners or wherever your liftign frame attachmetns need to go.
 

sallf

Member
Look up the woodworking technique of scribing. Build a simple 4-sided box out of 1/2" plywood in 12" tall strips. One sheet should provide enough material. Build the box, shore the inside corners with 2x2. Set the box on the roof and stabilize it. Shore the box so the top edge looks level with the vehicle - the roof is not level, it's crowned from front to back and side to side. Then use a circle-drawing compass or similar tool as a scribe, set / spaced to the highest gap between the frame and the vehicle roof, at either the front or back corners. And then simply run the scribe down the front, back and one side, drawing the matching curve on the plywood box. Then cut your marked line (doubling the side pieces to make a mirror-match) and you should have a snug fit for your pattern frame.
Figure out the slopes you want before you frame the panels.
The resulting frame can become the interior buck for your fiberglassing work. I wouldn't suggest leavinf the plywood in, it would add 35-40lbs to your pop-top.
Thanks for the info @rayra! Building the frame high and then running the plywood down to the edges of the suburban would have been a better method than what I did, which was build the frame resting on the suburban and then run plywood up. I did use a compass to get my lines (didn't know that was called scribing) but with my method I had to make cuts sheet by sheet and then attach to the frame. The draft angles made it especially hard since I wasn't 100% sure where the lines were actually going to be.

I am planning on just doing firberglass, but am not planning on having a male buck. The female mold (would you still call that a buck?) seemed like it would be easier to reenforce before I popped it out. I also have a friend who says he has a vacuum bag big enough, so might try that method.

When that's done, that's your buck. From there you make your fiberglass shell as thick and pretty as you want. Make it 2-3 layers. When the shell is done you flip it and glass in a supporting framework. I'd suggest something like EMT conduit for weight and rigidity. And with a little pre-planning you can set bolts thru it at the inside corners or wherever your liftign frame attachmetns need to go.
How many layers would you recommend in total? My thought was to do 3 layers of mat. Let that set, add my internal reinforcements and then do a layer to cloth to lock it all in. Then I was going to pull it from the mold, flip it, add some metal strips to the top edges where I'll bolt my rack through and then do one more layer of cloth to seal that all in.

Conduit seems like a good idea for reinforcement on the inside. I've also heard of people using high density foam. Anyone have experience using that for stringers or reinforcements?


I made a little more progress last night adding my fractal shapes to the front. Ended up making my shapes with thin balsa strips and then transferring that to plywood. Once I remembered how geometry works, it ended up being a pretty good process.

Everything is cut at this point, just need to glue them in, double check the fit on the suburban and then cut a top.

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rayra

Expedition Leader
You're right about working with an exterior mold making in easier to keep the piece supported while you lay in framing etc.
I'd go with a pretty thick gel goat then three layers and probably two when glassing in your supports. The round tubing would be a bit easier to bend to suit, due to the dual curves. Otherwise some square tubing would do.

There's no escaping the labor of making the exterior pretty, no matter which mold method you use. I've done a few small glass projects years ago. I found it easier to shape when I could run the glass over an interior mold. But I wasn't that great at fiberglassing.
 

sallf

Member
@rayra ya the subtractive method of an interior mold (sanding down corners) does seem much easier than the additive method (building up corners) but I'm hoping that the initial hard work will pay off when I start to glass...we'll see.

I'd go with a pretty thick gel goat then three layers and probably two when glassing in your supports.
I'm thinking I'll finish the exterior with Monstaliner. boll_rig seemed to have good success with it and the textured surface will cover up my (sure to be) many imperfections. With that in mind, would you still recommend a gel coat first?
 

rayra

Expedition Leader
Dunno. Not sure how well Monstaliner sticks to fiberglass? Then again there's no real point in a gelcoat if you are going with Monstaliner. Might even be lighter if you leave out the gelcoat. I was mostly think the gelcoat to give more room to work to make the surface pretty. Liner coat sorta makes that moot.
 

DAlgozine

New member
I don't mean to Hi-jack your thread, but some of the info I have may be of interest to you and your project. Bye the way, very cool project.

I've been kicking around the idea of a similar project for some time now. I too was inspired by @boll_rig 's 2003 Suburban build . I've searched for some type of existing top that could be modified, and have come up with a few reasonable candidates.

Go Fast campers has a design for pick up trucks https://www.gofastcampers.com/

What I like about this design is the heavier aluminum frame, which is strong and allows a simple plat roof (ideally minimal arch to shed water)
Of course attaching it to the Suburban will take some engineering. I contacted this company and asked if they sell this for large SUV's or if they will sell just the top, but I have not heard back yet.
Another very similar design is made by Snap Outfitters, called the Treehouse. Same pick up truck design, but also seems easily adaptable to large SUV.

Found this https://www.discountvantruck.com/vantopsraisedroofs/SuburbanTVvantopsCA.htm

But its for the older square body Suburbans. I called to try and get some info about what it might take to modify it for an 00-06, and I was simply told, don't bother, not worth it. But, I'm sure it could be done. I asked for some photos of the interior and some dimensions, but got nothing yet. Modifying this might be easier then starting from scratch.


I personally like the idea of solid sides, so I started working thru a couple different ideas. Then I stumbled on this DYI build
http://www.doityourselfrv.com/adventure-truck-diy/

The link has a brief photo coverage of the build and a video.
My plan is to fabricate and use structural sandwich walls made with plastic sheet inside, closed cell inside and aluminum sheet exterior, instead of the aluminum frame shown in this project. and I also plan to use the extruded aluminum pieces for the frame with an aluminum top. I like the bi-folding sides and exterior mounted gas struts. And I, like you plan to use my Suburban. Mine is an 06 2500. However, Im still in the dreaming / research and planning stage.
Great project. Keep us updated.
 

sallf

Member
@DAlgozine thanks for sharing! The last one is particularly cool. I like that they were able to get solid walls all the way around and that they don't need an actuator to lift. That's a clever build. I considered a beefier frame for mine, but don't have enough metal working tools to do it out of aluminum and didn't want to do it out of wood.

Another thing you might consider, if you're trying to stay away from having to build a mold, is starting with a truck topper and then building a box to fit it. You'll see in my second post that I picker up a big Leer off craigslist that could have worked if you trim down the sides, but ultimately I would have lost a couple feet on the length and I wasn't willing to give that up. I also like the look of just having a single molded piece.

Keep me updated on your progress.
 

sallf

Member
Finished my mold this weekend and was able to get it mostly covered with mylar and packing tape. There are a couple loose strips on top and I have a couple wrinkles to straighten out, but overall I think it looks pretty good.

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I've been thinking about trying to vacuum bag it and an aerospace friend who had some materials came over and helped me setup a test. We did some rough resin and fiberglass layups, then sealed the bag to the floor, added some release paper and breather cloth and then used my shop vac to pull pressure. Didn't spend a lot of time on the setup and you can see we didn't leave enough material to pull down on all the sides properly but overall it seemed to work pretty well.

However, after discussing it further we decided that to get adequate suction on the real thing, I might need a couple more vacuums (looked into renting a vacuum pump that's made for this sort of thing but couldn't find one) and ultimately I think I'm going to go back to my original thought of just doing layup by layup.

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Polyester Resin vs Epoxy Resin
Quick side note. It took me an embarrassingly long amount of time to realize there was a difference between these two resins. For anyone who doesn't know this, let me point out a couple things:
  • Both can be used for fiberglass molding
  • Polyester Resin is also known as General Purpose Resin and Laminating Resin
  • 105 Epoxy Resin (from West System) is what my friend recommended if you take the epoxy approach
  • Epoxy Resin is about 5X MORE EXPENSIVE than Polyester Resin (Polyester was about $30/gal for me)
  • Both have similar "gel" times (working time) at around 15 - 20 min (though this is VERY dependent on temperature and how much catalyst/hardener you add)
  • Both us a catalyst/hardener to activate
  • Polyester Resin fumes are TERRIBLE (like to the point that I was worried about my neighbors). You definitely want a mask with organic vapor protection.
  • Epoxy Resin apparently doesn't have nearly as terrible fumes, though I can't vouch for this.
  • With Polyester Resin you can always add a new layer, no matter how cured the previous layer is. If it fully cures you can still add another layer and get a good chemical bond without sanding.
  • With Epoxy Resin if the resin cures, you need to sand the part before adding another layer to ensure a good bond.
  • Here's a good comparison chart I found: https://www.tapplastics.com/uploads/pdf/Resin_Chart_Front-Rev711.pdf
I had a surprisingly hard time finding good information on that!

Back to the build.

I ended up getting 8 gallons of Polyester Resin, which is hopefully enough for 5 mat layers and 1 cloth layer of my roughly 115" x 50" x 12" part. For our test piece above, I added less than 1% hardener which ended up taking over an hour to harden. It definitely could have used more. I found a video that recommended 1.5% - 2%. If you have something to measure cc's, 10cc's = 1% of a quart. So next time I mix I'm thinking I'll do 15cc's for a quart and see how long that takes.

My main concern is a lot of resin seemed to build up on the bottom of the mold. We'd push it up the walls and gravity would pull it back down and inevitably the test piece ended up with a pretty thick base. Anyone know how to best keep this from happening?

Other Questions
  1. I'm still thinking I'll coat the exterior with Monstaliner. Does anyone know if I should coat the inside with something? I'll inevitably coat the inside with fabric and/or veneer for aesthetic purposes, but don't know if I need to do anything else to keep it from smelling and allow it to fully cure.
  2. Does anyone know if I should add a release agent before I layup my first layer? Or will the mylar and packing tape release easy enough by themselves?
  3. Can anyone recommend an epoxy for attaching things like wood veneer to the cured polyester resin?
  4. The terrible polyester resin odor will go away, right?
Really appreciate everyone's feedback. I'm hoping to start laying glass this week, will keep you all posted!
 

rayra

Expedition Leader
But a good 3M organic vapor mask, not just particulate masks

weeks, for the odor. You'll want to let it air out as long as possible before you put any sort of finish lining on the interior.

yes on the release agent. Expect the resin / layup to stick to anything and everything. Including all of your clothing, shoes, hair.... it's like working with roofing asphalt emulsions, that stuff gets on EVERYTHING and comes off of NOTHING.
 
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