I had to go to the fab shop today and was talking with the guy I know down there. He definately feels there would be a need to have a piece under the fiberglass. He was also suggesting to countersink the holes to help alleviate cracking. He then suggested a tape by 3M. It's called 3M VHB (Very High Bond).

3M VHB

I don't know if this is the same stuff Lund uses or if it is more heavy duty than theirs. It says it can be used in place of rivets, which would be good for our hoods, plus save time drilling, which could be a prob for many people, plus now no one needs a pop rivet gun. It will leave the louvers smoother and cleaner looking on the outside. I am just making sure 3M says it can be used on the aluminum and fiberglass. The aluminum I'm sure, but I am double checking the fiberglass.

This would only require one aluminum plate for the louvers (no underside support) and no drilling for rivets. Just one hole cutout for each side.

What are your thoughts on the 3M VHB tape?

 

As I just PM'd you, you are not sticking it to fiberglass -- you are sticking it to the body paint which the tape is designed to bond to. Non-issue.

I like the idea of the tape UNLESS you get it on there crooked. Then you're screwed.

 

Ok, I will stop Pm'ing you since i also put it here...oh you left out the non-issue part in the PM...I thought you were saying it wouldn't work b/c of the paint...maybe I misread what you said.

The way i see it, there are more ways to screw up the drilling and pop riveting then there is to taping it on. This stuff replaces rivets and fasteners in all sorts of applications. I think it would be a great alternative to rivets, especially since a lot of people are concerned with cracking the fiberglass.

 

Which looks better? The only difference is the top of the image: the angle of the front edge of the louver (the end closest to the front of the truck). The one on the left is not as sharp. Both are such that the leading edge is sharper than the rear, astetics only, so neither is actually a parallelogram.




Again, the top is the leading edge (front of truck). The bottom is towards the windshield. The louvers are opened towards the bottom (or towards the windshield) so the hot air rises out and blows away. (it isn't collecting air, it's extracting air).

 

glued and screwed is the best way
why not use some small stainless screws and nuts
you can have the shop cut a backing plate of the same dims as the top and drill straight through everything
fancy tops for show (hex or allen tops) or oval tops for a smoother look
http://www.boltdepot.com/metric-socket-products.aspx

 

He actually went through all those possiblities today.

There is a 3M "glue", called 3M 5200. But I figure "glue" would be messy and thickness variances are possible.

Nifty looky screws or nuts and bolts but that requires small holes in the fiberglass and i dont know how the hoods will take to that. Plus its bad enough having to cutout the big holes. And it's possible to screw up the hole locations on the hood.
Plus the backing plate will add to the cost.

The 3M tape looks to be the "best" method overall. It offers the adhevsiveness required (replaces rivets and fasteners in many applications), it isn't messy like glue, and doesnt require drilling holes.

 

Mike, you just run a thin line of glue/silcone - no mess no fuss
the 5200 is what I use on the boats - works great and does not ruin the finish on fiberglass/gel coat
in this application I would use it more to damper any vibration then to hold the vent in place
Screws unlike rivets are easier to torque correctly

fiberglass drills and cuts with ease
hard like a rock but quickly yields to steel bits or teeth
3M tape will work fine too, just install it when everything is at least 60 degrees

will these slip in from the top?
this way your hood cut does not have to be perfect and the vent will act as its own trim ring
below even some ss flat washers could act as a backing plate
get big ones with correct hole size and cut off one side for a flat edge

I thought the fancy screws would look better than rivets
rivets will need holes to be drilled around the hood opening same as screws
are you going to fab up some weather covers for when the truck is parked in rain?

 

I avoided this thread for awhile now because I was thinking of something different. Anything to reduce heat is good so I'd be in on this but I'd need help installing cuz I don't trust myself with my baby :)

 

He he! I can see a mod day with the local guys to put these on. What do you think, Mike?

I like the right hand one a little better in your sketches above, by the way.

If we use the tape, the edges have to be flared down a bit to hide it, don't they? Are you including that in the design? Complicates it a bit on a custom shape doesn't it? I'm afraid with that you're into more for tooling.

If the are screwed or riveted down, then they will fit flush. Just a thought that occured to me.

 

Definately need a mod day John
I have a 4" angle grinder.

I see what your saying about the flare down John. But I was thinking of leaving it. The tape is maybe .045" thick which is half the thickness of the sheet metal. I dont know, but doubt the gap will be too noticeable. The tape itself is supposed to keep water out, but maybe adding a bead of caulk or something may be good and help cover the gap itself too.

As for the washers...good idea, we already thought of it, but it would be a PITA to hold the washer in place and try to put these on. Plus the thru holes are so close together, and with mass production, the sheet metal back plates would just be easier.

The louvers would drop down onto the hood. So the hole you cutout for the heat to escape does not have to be perfect. Just cut, spray it with some paint to protect the hood (don't know if that is as important with fiberglass as it is with steel) and then fasten the louver to the hood.

Weather covers? Interesting. I dont think necessary though. Placement of the louvers will be key here. You dont want to place them over, say the alternator, or any other electrical devices. The louvers themselves are supposed to cover the holes, to an extent. Unless it's a sideways rain, too much shouldn't get in.

With the design on the right, I may have to extend the lengths a bit. The narrowest gap on the top is only about .6xx". This would mean on ly the 1/2" tape would fit. This could be extended by extending the lengths equally and thus keeping the same angle, which I imagine is what you are saying is more astecically pleasing John.

 

freshly cut fiberglass does not need edge protection Mike
you want to get the outside edge of these as flush as possible to the hood or dirt (junk) will get in the void and break down the tape
water will get into the engine compartment through these vents, that is for sure
as you mentioned position them over components that will not be effected too badly
do magnetics stick to stainless? if so you can buy sheets of magnetic plastic (like for signs, refridgerator magnetics, etc....) and cut them to fit
don't toss out those fancy bolts yet, they will work well here and look trick too
just a little line of sealant and those round heads will have this mod tight and flush to the hood line

 

Wouldn't the tape and a line of sealant have these tight...not quite flush...but really, how thick is .045"?

I am trying to make this as easy as possible for everyone. We may not have a huge issue with drilling, but others may and that would cause them to stray away from getting some. With tape, anyone can do it.

I like the look of the rivets or maybe some nice fasteners, but I am willing to sacrafice some of the look for ease of install.

 

Half of a tenth of an inch. Both visible and capable of catching dirt.

 

Cute...I realize .045 is (a little less than) half of a tenth of an inch. And actually, the fasteners won't make it air tight, there is still the possibility of catching dirt...so would caulk still be used?

If dirt is the issue, caulk can easily solve that.

If it's the height than I can put the holes back in and add the backing plate, but the price would go up and require through holes in the hood, and there were a good amount of holes.

I can set it up either way. That's not an issue, I just want to do it that will get the most interest from others and be easy to install and look good as well. Either way the function will be the same.

 

There seems to be some preference issues on how to fasten. Using the tape will result in a gap and the louver not being flush with the hood. The tape thickness is maybe .045", small but perhaps thick enough. The other method of using fasteners, whether it be rivets or screws/bolts, requires several holes to be drilled into the hood.

Anyone who has interest in the louvers, what is your preference? Would one method deter anyone interested from following through with this? How would you guys like to see these attached?

 

Well, the idea of sealant around the edges is probably acceptable. You're right about the PITA of drillling, and it would cost more to make them.

 

Here is how I see it: If you are spending 130 bucks for the luvers..... why pay 2 bucks to mount them. I think Neil is right with the bolts/screws. These thing will be on your truck forever.... If I was getting na set nI would want them to be held on securly with a bolt of sorts not 3m tape that will peel.... wear... or come loose after a few cold winters and hot summers... But that is just my hummble opinion.

 

Good point, Doc, but we're trying NOT to pay that much by getting them fabricated to Mike's design. If we buy them for $139 they are pre-drilled so it's a no brainer to use screws or rivets. What we would like to do (if it's feasible and we're not sure yet) is have them made for less money without holes and mount them more easily.

But you may be right: they're going to be there forever once we've cut a hole in the hood! So, perhaps it might be better to just go all the way and use fasteners of some sort instead of adhesive.

 

well you figure you will be cutting a 6 x 8 hole in your hood. Knowing you (wink) you will use a template like the onwe used for the keypad mod.... just drill a few extra holes and whoo la!. Again, I understand you want to KISS but it wil be what people see... it may take 10 min to mount them with glue and an hour by bolting but it is an hour of work for a lifetime of looks!

 

I will see how much more for the backing plate.

 

I would prefer screws/rivets.

 

I think i would too, even if it is a little more drilling.

The backing plate I just found out today will have a very minimal cost. So the price will not double...

 

you should be able to temporarily attach the louver (just to keep it in place) and drill straight through it and the hood for the bolt down
don't forget about using cut down washers if the backing plate is costly
they will work fine and be cheap too

 

Yeah i was thinking locate it on the hood where you want. Drill one of the thru holes. Fasten the corner. Then do the same for the diaganol corner and then you should be able to drill the rest out.

 

did this ever become an available product?