Yep, that's what I am learning. Thanks for the input!
Converting a factory JK/JKU hardtop to modular
- Thread starter jscherb
- Start date
Yep, that's what I am learning. Thanks for the input!
02rangeredge
Adventurer
also, after looking into bedliner for the lower quarter of my truck I learned that it holds onto dirt hard, so if you ever want the top to look clean again, it more than likely isn't what you're looking for
What I have done with other projects is once it is completely dry, get some satin marine grade polyurethane spray cans and stand back a bit then spray to let it adhere and provide the "less porous" finish. It works. What you don't want is overspray buildup sag...
Looking back on your instructions with the build of the bolt flanges lay in with fiberglass, as an alternative, do you think a piece of steel or aluminum 90 degree angle bracket could be scuffed then shaped to the "slight" lines of the top angles and fastened into place using some 3M 5200, 3M Panel Bond or other SMC-compatible adhesive? This way I could prep the top local area for the angle bracket, position and affix both the panel and top angle brackets in-place before cutting to assure exact alignment. I would also use t-bolts on one bracket and assure alignment and use wax on the bolt threads as you suggest. Seems like it will suit the purpose and hold the weight of either a factory window and your slider windows. 
jscherb
Expedition Leader
Looking back on your instructions with the build of the bolt flanges lay in with fiberglass, as an alternative, do you think a piece of steel or aluminum 90 degree angle bracket could be scuffed then shaped to the "slight" lines of the top angles and fastened into place using some 3M 5200, 3M Panel Bond or other SMC-compatible adhesive? This way I could prep the top local area for the angle bracket, position and affix both the panel and top angle brackets in-place before cutting to assure exact alignment. I would also use t-bolts on one bracket and assure alignment and use wax on the bolt threads as you suggest. Seems like it will suit the purpose and hold the weight of either a factory window and your slider windows.
In my experience, and I've experimented with this a number of times with a range of adhesives, getting reliable structural bonds between metal and fiberglass is extremely difficult. I've tried 3M Panel Bond, Norton Speedgrip and others, and the result has never been something I'd trust on a structural joint, such as the bolt flanges that hold a modular hardtop together.
The one time I have been successful bonding metal to fiberglass I added large tabs (roughly 3" square) to the metal at intervals around the perimeter to provide more surface area for the adhesive. Tabs like that probably wouldn't work out too well on a JK hardtop modular conversion - there really isn't room for them in the joints between the panels, and they'd also be visible on the inside of the top. Simply bonding strips of metal to the SMC parts of the factory hardtop is unlikely to be successful.
The web page for 3M Panel Bond (http://3mcollision.com/3m-panel-bonding-adhesive-08116.html) says "This product is not intended to bond structural components of a vehicle..."
One reason structural joints between fiberglass and metal aren't usually successful is due to the different flex properties of the materials. With a fiberglass-fiberglass joint, both sides can flex together but with metal-fiberglass, different flex rates stress the adhesive and can lead to joint failure.
It really isn't that hard to do the flanges as I've described in the how-to section of this thread; it's the best way and as far as I know from my testing and experience, there isn't a "short cut" that will provide results as good as what I've described using fiberglass.
jscherb
Expedition Leader
The best practice in bonding metal to fiberglass includes bonding the metal to the fiberglass with epoxy or some other structural adhesive, encapsulating the metal in fiberglass and putting holes in the metal to allow for fiberglass-fiberglass bonding through the holes.
But if you're thinking about using metal angles for the flanges, there are a number of complications with that:
- You'll only be able to encapsulate one leg of the angle, you won't be able to encapsulate it properly on both sides.
- The joints are curved, and some of them are compound curves, so getting a metal angle to conform the the curves without stress will involve shrinking the metal to comply to the curves. Just bending a metal angle without shrinking will cause it to buckle slightly, which will likely cause the mating flanges not to mate perfectly, leading to leaks.
- Some of the angles of the flanges to the hardtop aren't 90 degrees - for example, the flange on the top of the side panels is roughly 90, but the angle of the corresponding flange on the bottom of the roof panel is maybe 70 degrees due to the curvature of the roof above the joint. So not only will you have to curve the metal angle, you'll have to change it from 90 degrees to something less so that it matches the flange below.
Trying to do the flanges in metal like you're suggesting will be more work, more expensive, and more difficult to make accurate joints than just doing them in fiberglass from the beginning.
jscherb
Expedition Leader
Update on the Freedom Panel Skylight kit...
Update 1: I've found a source for the latches in the photo below in black and at what should end up being an affordable price.
Update 2: A few weeks ago I sent drawings of the hinges I designed for the kit to a company that can manufacture them; a few days ago I got preproduction samples in the mail. The production hinges will be powder coated black, I told the company not to bother powder coating these samples because I just needed these first ones to verify the fit. Following current automotive engineering practice, each hinge is a simple piece of bent metal designed to flex when the skylight opens and flex back when it closes (I think the automotive industry did away with hinges with actual hinge pins for flip-out windows back in the 90's.)
In this photo the new hinge is sitting on side of the skylight because the original test hinges from the F150 are still installed.
The hinge fits very well but I'll make a few small tweaks to the dimensions for a perfect fit. Also these preliminary samples are made from stainless steel, which isn't suitable - the plan is to make them from spring steel, which is the next step in the development process.
Update 1: I've found a source for the latches in the photo below in black and at what should end up being an affordable price.
Update 2: A few weeks ago I sent drawings of the hinges I designed for the kit to a company that can manufacture them; a few days ago I got preproduction samples in the mail. The production hinges will be powder coated black, I told the company not to bother powder coating these samples because I just needed these first ones to verify the fit. Following current automotive engineering practice, each hinge is a simple piece of bent metal designed to flex when the skylight opens and flex back when it closes (I think the automotive industry did away with hinges with actual hinge pins for flip-out windows back in the 90's.)
In this photo the new hinge is sitting on side of the skylight because the original test hinges from the F150 are still installed.
The hinge fits very well but I'll make a few small tweaks to the dimensions for a perfect fit. Also these preliminary samples are made from stainless steel, which isn't suitable - the plan is to make them from spring steel, which is the next step in the development process.
Comanche Scott
Expedition Leader
Clean, simple and inexpensive. Perfect! :victory:
kantidesai
New member
Dear jscherb :
I can't imagine your afford on this types of the projects, I am also working on such a projects on Corvette.
i like to discuss with you when you reply here or if possible on my email. i dont know i can post my email here or not as i did not read all rules.
But on my corvette projects i always have some questions to the person have expertise on automotive modification. please reply me on email if you can request to admin so can get some opinion from you about some clams and about some bonding of fiberglass . i will really appreciate your guidance.
Admin . please send me message on my email whatever Mr jscherb send to you.
I can't imagine your afford on this types of the projects, I am also working on such a projects on Corvette.
i like to discuss with you when you reply here or if possible on my email. i dont know i can post my email here or not as i did not read all rules.
But on my corvette projects i always have some questions to the person have expertise on automotive modification. please reply me on email if you can request to admin so can get some opinion from you about some clams and about some bonding of fiberglass . i will really appreciate your guidance.
Admin . please send me message on my email whatever Mr jscherb send to you.
jscherb
Expedition Leader
About the only thing I know about Corvettes is that they're made of the SMC variant of fiberglass, so when doing modifications to the body you'll need to use an SMC-compatible polyester resin or an epoxy resin. The technique I described of using the expensive SMC-resin only for the bonding layer followed by inexpensive ordinary polyester resin can be used to reduce costs. But other than that I have no knowledge that's specific to Corvettes - I've never owned one, never even ridden in one.
kantidesai
New member
Jscherb. Thanks for reply. I understand your points, most things i taken care, only weatherstrip and some machining parts is under final designing to launch Kit in market,
One thing i have problem is i am looking any solid liquid adhesive like some black dried black joint filler i seen in Corvette. so it can make solid cube to stuck on fiberglass floor of Corvette at one place,
i will place image here today so you can see what i am expecting.
due to the of Gas tank under the floor , i can not drill fiberglass tub on floor to mount my supportive pole . some of friends told me Monkey glue will be hard enough but in stores i found only Gorilla glue
i am a small businessman and my Next project will be SUV s like jeep to modify.
on Jeep I am planning to make short easy way to make perpendicular wall with aluminum designed extrusion to support side walls, instead of little lengthy fiberglass flange. so right angle strip can be month permanent on edge with bolts. can you suggest me on any issues.?
jscherb
Expedition Leader
When I need a liquid adhesive to fill a space, I use liquid epoxy, and if I need it a specific color. I tint it. There are a number of very good liquid epoxies on the market, West System is one. Recently when I was building my JK Safari Cab hardtop I needed to fill the drip rails on the roof, which were bonded to the roof panel but needed to be filled so they were sealed and for cosmetic reasons. I used West Marine liquid penetrating epoxy (https://www.westmarine.com/buy/west-marine--penetrating-epoxy--P015023724?recordNum=21), tinted it white with tint intended for fiberglass and epoxy work, and poured it in the drip rail where it self-leveled. A few photos of the filled drip rails:
Without a photo of what you're trying to do I don't know if this is an appropriate solution. Depending on how large your "solid cube" needs to be, this might not be appropriate (or might be too expensive).
Based on your description I can't visualize what you're trying to do so I can't offer any advice, sorry.
Namaste.