Flatbed and composite panel build on Dodge 2500
- Thread starter Jeep
- Start date
I'll take advantage of gravity for that one! Had to build the bathroom components to get a fixed size, was the only real variable in the design, everything else pretty much has a fixed dimension to work with. Now that that is established I can finalize the floor plan and get it under construction.
Powder coating is much better wearing and there is no risk of the adhesive pulling the powder coat off once it is bonded and sealed in place. Goes with the lifetime build philosophy, 20 years down the road a bathroom restoration might mean a good cleaning and some new appliances. Like any finish prep is the difference between a quality or poor finish, everything we do is media blasted with the correct media for the base material, pre heated to off gas, electrostatic applied, and baked. In the case of steel, we use a zinc rich primer before the colour coat, really corrosion resistant. With paints we use Endura, or polymer based aliphatic coatings which are really cool, but they all have their respective places. You should have the outside of your rig shot with an aliphatic, expensive but extremely scratch resistant and self healing, brush scratches disappear over night!
Winner winner
Did some more adhesive testing. Tried some Silaprene with a solvent base to see if it would cure in the channel, no luck what so ever, pulled apart at 600 psi on the test gauge which is 301 pounds force, it never cured at all. Sika 221 was next, it had the same issues on the aluminum side with curing, fiberglass side was fine, not what I would call a full cure after 7 days but definitely pretty solid, test results mimic the 252 when you take into consideration the specifications for both products, it let go at 1900 psi which is 3781 pounds force. Then....the magic stuff....the 2 component polyurethane came in. It flowed in easily, set up in 3 minutes, and we let it cure 18 HOURS, absolutely no odor, easy clean up but you gotta move! It only made sense that a full cure would double the strength, and it did. We bounced the handle on the test pump to get it to go past 5000 psi, several times, which is over 10 000 pounds force, we recorded 4600 pounds which is 9154 pounds force trying to get a pic of the gauge at the max pressure we could achieve. And then...the panel broke! Upon close investigation we found the adhesive was just starting to let go, indicating a nice balance between adhesive and panel strength. The test plate was also seriously deformed, and we used 2 styles of 1/4" structural coated rivets to evaluate mechanical fastener performance. The retained mandrel rivets had absolutely no issue, straight and tight, the rivets that "sometimes" retain the mandrel were all bent in the direction of pull and the test plate was a little loose after the test. Even though the test went to ultimate failure, we will not use the rivets that deformed, there simply is not enough price difference to justify their use, you still might have to get home after a hit or collision or other minor disaster, best to contribute to the side that will get you out as safe as possible. You will also notice that the pull plates were anchored to one side of the panel extrusion rather than centered, this was designed to impart an angular load, I haven't seen to many perfectly square pulls or hits in the real world!
So the benefits of designing a complete system and testing before building look really attractive. I have a very structural 6061 aluminum perimeter extrusion that mechanically and geometrically fixes the panel in place, you can anchor racks, jacks, panels, ladders fast, easy, and very, very strong. There is an engineered to manufacturer spec glue channel to ensure proper amounts of adhesive are used, can't put too much in, and easy to tell when full, it comes out the ends, the glue channel is beneficial in that it also completely protects the adhesive bond from UV light, impact, and direct water spray...should last a lifetime. Several adhesives were tested as well as variable panel skin materials, we can use 221, 252, or pretty much any single component urethane where they will be exposed to enough atmosphere to cure, I will stick to what I have tested there and will most likely still use quite a bit of 252. We know 2 component polyurethanes purely kick ***, plain and simple, every glue channel will get that stuff, and it will also allow me to design future extrusions around such an impressive adhesive, it makes a very robust, attractive component with no question of state of cure, I like it a lot. We have tested panels, at 10 000 pounds per foot before failure I'm happy going with the skin thickness selected, you can save a lot of weight when you are dealing with 1000 square feet of surface area. In some applications I will be fattening up the skins but that's another story.
The only negative I have with the system is it does have a cold bridge, not much of one as the extrusion is designed as so, but it does have one. My solution will be Aerogel and a non conductive trim with a good R value around the interior perimeter. That will also double as a wiring chase, worked very well on my 650.
Ready set go!
This is good!
Failure point.
The pull plate, never bent one yet, almost destroyed this one!
Did some more adhesive testing. Tried some Silaprene with a solvent base to see if it would cure in the channel, no luck what so ever, pulled apart at 600 psi on the test gauge which is 301 pounds force, it never cured at all. Sika 221 was next, it had the same issues on the aluminum side with curing, fiberglass side was fine, not what I would call a full cure after 7 days but definitely pretty solid, test results mimic the 252 when you take into consideration the specifications for both products, it let go at 1900 psi which is 3781 pounds force. Then....the magic stuff....the 2 component polyurethane came in. It flowed in easily, set up in 3 minutes, and we let it cure 18 HOURS, absolutely no odor, easy clean up but you gotta move! It only made sense that a full cure would double the strength, and it did. We bounced the handle on the test pump to get it to go past 5000 psi, several times, which is over 10 000 pounds force, we recorded 4600 pounds which is 9154 pounds force trying to get a pic of the gauge at the max pressure we could achieve. And then...the panel broke! Upon close investigation we found the adhesive was just starting to let go, indicating a nice balance between adhesive and panel strength. The test plate was also seriously deformed, and we used 2 styles of 1/4" structural coated rivets to evaluate mechanical fastener performance. The retained mandrel rivets had absolutely no issue, straight and tight, the rivets that "sometimes" retain the mandrel were all bent in the direction of pull and the test plate was a little loose after the test. Even though the test went to ultimate failure, we will not use the rivets that deformed, there simply is not enough price difference to justify their use, you still might have to get home after a hit or collision or other minor disaster, best to contribute to the side that will get you out as safe as possible. You will also notice that the pull plates were anchored to one side of the panel extrusion rather than centered, this was designed to impart an angular load, I haven't seen to many perfectly square pulls or hits in the real world!
So the benefits of designing a complete system and testing before building look really attractive. I have a very structural 6061 aluminum perimeter extrusion that mechanically and geometrically fixes the panel in place, you can anchor racks, jacks, panels, ladders fast, easy, and very, very strong. There is an engineered to manufacturer spec glue channel to ensure proper amounts of adhesive are used, can't put too much in, and easy to tell when full, it comes out the ends, the glue channel is beneficial in that it also completely protects the adhesive bond from UV light, impact, and direct water spray...should last a lifetime. Several adhesives were tested as well as variable panel skin materials, we can use 221, 252, or pretty much any single component urethane where they will be exposed to enough atmosphere to cure, I will stick to what I have tested there and will most likely still use quite a bit of 252. We know 2 component polyurethanes purely kick ***, plain and simple, every glue channel will get that stuff, and it will also allow me to design future extrusions around such an impressive adhesive, it makes a very robust, attractive component with no question of state of cure, I like it a lot. We have tested panels, at 10 000 pounds per foot before failure I'm happy going with the skin thickness selected, you can save a lot of weight when you are dealing with 1000 square feet of surface area. In some applications I will be fattening up the skins but that's another story.
The only negative I have with the system is it does have a cold bridge, not much of one as the extrusion is designed as so, but it does have one. My solution will be Aerogel and a non conductive trim with a good R value around the interior perimeter. That will also double as a wiring chase, worked very well on my 650.
Ready set go!
This is good!
Failure point.
The pull plate, never bent one yet, almost destroyed this one!
It's one of the results I was looking for, a bond equivelent to the panel strength. Knowing what I know I can now put lifting lugs on top of the camper so it can be picked up and loaded with a crane or picker easily, or the gantry crane in my shop
The trailer
I got the trailer together, life got busy and it got pushed to the side. It took 2 guys a total of 12 man hours to rivet the base extrusions on, scuff all the glue channels, and put it together. We decided to use 252 on the fibreglass skin side as it held up really well in testing, and use the 2 component on the inside as that was the problem side (aluminum skin) for curing, it's an experiment that I expect will work out just fine. The 252 was laid in the glue channel heavily and relied on a "wipe" to distribute across the channel. I was sceptical about the process but after a couple extrusions went on I even reduced the amount of 252, the method works well, had full channels and some squeeze out. Things that really slowed the build down were the air caulking guns, made by Cox with a max inlet pressure of145 psi, worked really good for 10 minutes with inlet pressure regulated at 120 psi, then the blew the plumbing apart. Apparently when using with viscous adhesives like 221 and 252 you have to bring the inlet pressure down to 60 psi max, not mentioned when I bought them along with a couple cases of 252...they really slow down at that pressure, not why I bought them…..anyone know of a good gun that has no issues with 252?
Here are the rivets used for the base installation, they are 3/8 coated, retained mandrel, structural rivets, waterproof to 40 psi, 4000 pounds pull out, 6000 pounds shear, that's a 3/8 x 1 1/4" bolt beside it for comparison.
I got the trailer together, life got busy and it got pushed to the side. It took 2 guys a total of 12 man hours to rivet the base extrusions on, scuff all the glue channels, and put it together. We decided to use 252 on the fibreglass skin side as it held up really well in testing, and use the 2 component on the inside as that was the problem side (aluminum skin) for curing, it's an experiment that I expect will work out just fine. The 252 was laid in the glue channel heavily and relied on a "wipe" to distribute across the channel. I was sceptical about the process but after a couple extrusions went on I even reduced the amount of 252, the method works well, had full channels and some squeeze out. Things that really slowed the build down were the air caulking guns, made by Cox with a max inlet pressure of145 psi, worked really good for 10 minutes with inlet pressure regulated at 120 psi, then the blew the plumbing apart. Apparently when using with viscous adhesives like 221 and 252 you have to bring the inlet pressure down to 60 psi max, not mentioned when I bought them along with a couple cases of 252...they really slow down at that pressure, not why I bought them…..anyone know of a good gun that has no issues with 252?
Here are the rivets used for the base installation, they are 3/8 coated, retained mandrel, structural rivets, waterproof to 40 psi, 4000 pounds pull out, 6000 pounds shear, that's a 3/8 x 1 1/4" bolt beside it for comparison.
Cart before the horse
I got a door handle/latch assembly from a colleague who builds medic bodies, CMVSS and FMVSS testing has been done on his units for roof crush and these were developed to stand up to the requirement of being functional with in an upside down situation with a 3/4 ton diesel truck attached to them, nice stuff. Now roof crush testing is static and not anywhere near as stringent as ROPS testing as far as push angles and loads but still, a lot of weight was applied to the structure and it held up just fine!
The latch is here, extrusions and hinges already developed to work with the latch to retain certification are en route.
I got a door handle/latch assembly from a colleague who builds medic bodies, CMVSS and FMVSS testing has been done on his units for roof crush and these were developed to stand up to the requirement of being functional with in an upside down situation with a 3/4 ton diesel truck attached to them, nice stuff. Now roof crush testing is static and not anywhere near as stringent as ROPS testing as far as push angles and loads but still, a lot of weight was applied to the structure and it held up just fine!
The latch is here, extrusions and hinges already developed to work with the latch to retain certification are en route.
Speaking of testing….
I do ROPS design, destructive testing, and certification to various standards, CSA, SAE, ISO etc. Here are a couple pics of a structure we built for a Dodge 5500 chassis that gets used in mining applications. The side push is in an engineered point to impart loads in the area most likely to encroach on the operators zone in a worst case scenario, loads are supposed to be absorbed under those conditions, so they don't just transfer to the operator/occupant. The load in this case was just under 45 000 pounds force being applied to the top of the drivers side, the chassis is fixed only at the suspension mounting points to avoid unrealistic reinforcement. You can see in the pics that the 2 square tubes at the bottom are essentially becoming a spring, absorbing energy. Those tubes are 4x4x.250 50W, the gussets .250 50W steel, and it "just" passes. One very cool thing to note is the strength of the Dodge 5500 chassis, the frame deformed in localized areas, same with the ROPS, but would have been very easy to straighten, it was out less than an inch. That is a testament to the design of the frame and materials, it is very solid. Another truck that holds up extremely well to testing, despite what looks like a light frame is the Toyota HZJ trucks which we have done many iterations of ROPS for as they are heavily used in the mining industry. We have done testing on other North American trucks and the Dodge frame was the only one that held up to the incredible degree it did, on others we have seen frames deformed severely, this is an extreme case but I believe it is a great indicator of chassis quality.
I do ROPS design, destructive testing, and certification to various standards, CSA, SAE, ISO etc. Here are a couple pics of a structure we built for a Dodge 5500 chassis that gets used in mining applications. The side push is in an engineered point to impart loads in the area most likely to encroach on the operators zone in a worst case scenario, loads are supposed to be absorbed under those conditions, so they don't just transfer to the operator/occupant. The load in this case was just under 45 000 pounds force being applied to the top of the drivers side, the chassis is fixed only at the suspension mounting points to avoid unrealistic reinforcement. You can see in the pics that the 2 square tubes at the bottom are essentially becoming a spring, absorbing energy. Those tubes are 4x4x.250 50W, the gussets .250 50W steel, and it "just" passes. One very cool thing to note is the strength of the Dodge 5500 chassis, the frame deformed in localized areas, same with the ROPS, but would have been very easy to straighten, it was out less than an inch. That is a testament to the design of the frame and materials, it is very solid. Another truck that holds up extremely well to testing, despite what looks like a light frame is the Toyota HZJ trucks which we have done many iterations of ROPS for as they are heavily used in the mining industry. We have done testing on other North American trucks and the Dodge frame was the only one that held up to the incredible degree it did, on others we have seen frames deformed severely, this is an extreme case but I believe it is a great indicator of chassis quality.
