Cowl Vent Repair
- Thread starter zigmont
- Start date
Well, color me confused. You asked our opinion, and 100% of the responses were "bad idea". You even admit this was the response on other forums. Yet you plan on going ahead with it. How am I doing?
You can do as you like, but could you explain why? The procedure you contemplate sounds like at least as much work as the conventional procedure, perhaps more.
Cowl repair
You asked why 2+2 GT. This is why:
I welded my last cowl on, but was concerned about the layers of metal between the welds. No matter how tight you clamp the area where the weld is, the space between welds will not be water tight. Water can wick (via capillary action) it's way between the layers and begin to rust the metal, especially around the welds. I am willing to do whatever it takes to prevent this.
The adhesive would definitely do the job of sealing as it is waterproof. I may even weld the area under the windshield as water encroachment is not an issue there.
Being concerned that the adhesive alone would not keep the cowl attached, I opted to supplement it with screws, that when screwed through the adhesive would also be bonded similar to locktite, and they could not vibrate loose. I have even considered putting 1/4-28 grade 8 bolts with nuts and Locktite through where every spot weld was drilled out. If anyone doesn't believe that a grade 8 bolt would not be stronger then a spot weld, then they must be about as smart as the person who referred to me as a hack. BTW the contraction for you are is you're. not your. DUH!
Again, thanks for all of the responses.
You asked why 2+2 GT. This is why:
I welded my last cowl on, but was concerned about the layers of metal between the welds. No matter how tight you clamp the area where the weld is, the space between welds will not be water tight. Water can wick (via capillary action) it's way between the layers and begin to rust the metal, especially around the welds. I am willing to do whatever it takes to prevent this.
The adhesive would definitely do the job of sealing as it is waterproof. I may even weld the area under the windshield as water encroachment is not an issue there.
Being concerned that the adhesive alone would not keep the cowl attached, I opted to supplement it with screws, that when screwed through the adhesive would also be bonded similar to locktite, and they could not vibrate loose. I have even considered putting 1/4-28 grade 8 bolts with nuts and Locktite through where every spot weld was drilled out. If anyone doesn't believe that a grade 8 bolt would not be stronger then a spot weld, then they must be about as smart as the person who referred to me as a hack. BTW the contraction for you are is you're. not your. DUH!
Again, thanks for all of the responses.
Ya had me goin' there for a sec. Do me a favor and start another paragraph before you flame somebody- you had me reviewing my posts for the contraction!
You have an interesting reason for using glue. Pity it was not part of your original post. The hem (pinchweld) used in the cowl is only really exposed to the problem you postulate near the drain outlet on either front corner. With seam sealer on the outside, and corrosion-resistant non-hardening sealant on the inside, this problem can really be ignored. I have seen many cowl repairs done, including the cowl on my 66, and with minimal attention after welding a return of corrosion is not really an issue. Do as you think best, for your purposes. I have not seen the problem you are concerned about as significant, perhaps you live in a more corrosion-prone area than I.
StangDreamin'
Founding Member
"Right or wrong"??? You're going to trust your life -and those of drivers around you- to "right or wrong"????
Where do you live? I'm asking with fervent hopes of finding out that you're nowhere near where myself or any of my loved ones might be driving when you practice this little experiment in Darwinism
The adhesive: I'd sure as (Hades) be researching the living (crud) out of that adhesive before comitting to this project. And by "research"; I mean a lot more information than one finds in a Flea-Bay ad!
Any adhesive used to join two pieces of a 'low-porosity' substance (like sheetmetal) is not going to have the shear strength of the substance itself - the molecular bonding just isn't covalent enough for this. At least welding will bond the two metal parts with a compatible material - more metal!
Also I'm trying to wrap my brain around the thought that you're going to try this on rusty metal. You've already expressed that your existing cowl is rotted, and that the 'donor' cowl is coming from a car exhibiting a lot of rust - WHAAAA-AAA-AT???
#8 sheetmetal screws: Funny you should mention this! Yesterday while hanging some (more) shelf brackets in my daughter's room; I managed to twist the heads off THREE (3) #8 sheetmetal screws while boring them into the 51-yr-old desert-baked studs in my house walls -with an 18volt Ryobi cordless driver/drill! That was simple, slow rotational torque; not the torque combined with percussive vibration such as your cowl will be experiencing as you drive on less-than-laser-smooth pavement.
(As an aside: Hanging a four-gang box with only ONE number 8 screw???
Day-yum! The NEC must be substantially different in your part of the country!!! )
For God's sake, just drag your wire-feed out to the garage and do the job properly!
If you've not enough cabling to get all the way to the car, you can just make an extension cord for primary power.
Just use some 14 ga. Romex; with the advances in copper refining, you don't NEED that expensive 10 guage S#!T
Duh? And you asked me how old I am? I love typo and spelling nuts on a car forum!
You have
received the exact same replies at ford muscle, Every single person on every forum you posted this at has given you the exact same reply. "Don't put that car on the road next to me". You just copy and paste your replies on every board. You never wanted any opinions when you posted this. You just wanted to say "look at me I'm a glue and screw guy". Good luck with that.crapola
Cowl repair
I've taken about all of the abuse I care to. It's time you were educated.
I suppose that even if I said that I would bolt the cowl on with 100 1/4" grade 8 bolts, there would still be those who insist welding would be stronger. Notwithstanding that the tensile strength of a 1/4" grade 8 bolt is over 6000 pounds. The combined strength of 100 of these babies would be 600,000 pounds. Thats 300 tons folks (about the weight of 200 Mustangs)
If you don't believe me, We'll do the math. Lets see.....Grade 8 steel has a tensile strength of 150,000 pounds per square inch the cross sectional area of a 1/4 bolt would be Pi x R2 or 3.1416 x .125 x.125= .0490875. Multiply that x 150000 = 7,363 pounds. I was being conservative when I said 6000.
Do you get it yet?
So tell me again that welding would be stronger then using 1/4" bolts so I can tell you that you are dumber than dirt
So if you don't believe I can bolt this cowl on and merely use the adhesive as a sealer Your head is not on top of your body, but in a much different place. Let's go a step further.
A #8 bolt is about 1/8" in diameter. A 1/8" bolt has 1/4 the cross sectional area as a 1/4" bolt, so devide 7363 by 4 and you will come up with about 1,840 psi of tensile strength. Even if the tensile strength was 1000 pounds, the combined strength of 100 would be 100,000 pounds. Thats 50 tons folks. With 50 tons of force you could twist a Mustang like an aluminum beer can. That flimsy 20 ga metal would tear off before you pop the head on one of those babies.
So tell me again that I couldn't bolt the cowl on with 110 #8 grade 8 bolts and merely use the adhesive as a sealer so I can tell you you are dumber than dirt a second time.
I told you that I had done the research didn't I?
I am eagerly looking forward to the next post where someone says "I don't care what you say, I still think you should weld the cowl like Ford did."
And I'm telling you again..... Ford chose spot welds because they were the CHEAPEST way to put the car together. Not the ONLY way. Nuff said.
I've taken about all of the abuse I care to. It's time you were educated.
I suppose that even if I said that I would bolt the cowl on with 100 1/4" grade 8 bolts, there would still be those who insist welding would be stronger. Notwithstanding that the tensile strength of a 1/4" grade 8 bolt is over 6000 pounds. The combined strength of 100 of these babies would be 600,000 pounds. Thats 300 tons folks (about the weight of 200 Mustangs)
If you don't believe me, We'll do the math. Lets see.....Grade 8 steel has a tensile strength of 150,000 pounds per square inch the cross sectional area of a 1/4 bolt would be Pi x R2 or 3.1416 x .125 x.125= .0490875. Multiply that x 150000 = 7,363 pounds. I was being conservative when I said 6000.
Do you get it yet?
So tell me again that welding would be stronger then using 1/4" bolts so I can tell you that you are dumber than dirt
So if you don't believe I can bolt this cowl on and merely use the adhesive as a sealer Your head is not on top of your body, but in a much different place. Let's go a step further.
A #8 bolt is about 1/8" in diameter. A 1/8" bolt has 1/4 the cross sectional area as a 1/4" bolt, so devide 7363 by 4 and you will come up with about 1,840 psi of tensile strength. Even if the tensile strength was 1000 pounds, the combined strength of 100 would be 100,000 pounds. Thats 50 tons folks. With 50 tons of force you could twist a Mustang like an aluminum beer can. That flimsy 20 ga metal would tear off before you pop the head on one of those babies.
So tell me again that I couldn't bolt the cowl on with 110 #8 grade 8 bolts and merely use the adhesive as a sealer so I can tell you you are dumber than dirt a second time.
I told you that I had done the research didn't I?
I am eagerly looking forward to the next post where someone says "I don't care what you say, I still think you should weld the cowl like Ford did."
And I'm telling you again..... Ford chose spot welds because they were the CHEAPEST way to put the car together. Not the ONLY way. Nuff said.
Platonic Solid
Founding Member
"Bolt"? I thought you said "sheet metal screw". The weakest link in a sheet-metal-screw assembly is the sheet-metal, not the screw.
edit: (more info)
Using a #8-18 type B or AB thread rolling screw in 20Ga. (0.036) steel drilled to 0.125 Dia. will achieve less than 1 full thread of sheetmetal engagement (0.65 thread engagement, to be exact). If you had a full thread of engagement, there would be a 0.009 sq. in. screw to sheet metal engagement area. 0.009 x 0.65 thd. engagement = 0.006 sq. in. of actual engagement. Compare that to the smallest 1/4" spot weld which bonds an area of at least 0.049 sq. in.
Bottom line – you would need at least 8 sheetmetal screws to equal the strength of one 1/4" spot weld. Plus, spot welds don’t loosen with shock and vibration.
Please post a link to the adhesive you are planning on using.
edit: (more info)
Using a #8-18 type B or AB thread rolling screw in 20Ga. (0.036) steel drilled to 0.125 Dia. will achieve less than 1 full thread of sheetmetal engagement (0.65 thread engagement, to be exact). If you had a full thread of engagement, there would be a 0.009 sq. in. screw to sheet metal engagement area. 0.009 x 0.65 thd. engagement = 0.006 sq. in. of actual engagement. Compare that to the smallest 1/4" spot weld which bonds an area of at least 0.049 sq. in.
Bottom line – you would need at least 8 sheetmetal screws to equal the strength of one 1/4" spot weld. Plus, spot welds don’t loosen with shock and vibration.
Please post a link to the adhesive you are planning on using.
Platonic Solid
Founding Member
I actually do believe we will soon be able to bond structural metals with adhesives that provide performance equal to welding. Surely special surface preparations and environmental application conditions will apply. Don't flame me, I did say "soon", as I have yet to see this product, but if it’s not here now, it's certainly on the horizon.
It remains to be seen if this product will be safe for use on previously welded structural assemblies or only for vehicles specifically engineered for its use.
Here is a revealing March 2000 article on this topic from Machine Design:
Automotive Adhesives - From Design To Repair | Machine Design
It remains to be seen if this product will be safe for use on previously welded structural assemblies or only for vehicles specifically engineered for its use.
Here is a revealing March 2000 article on this topic from Machine Design:
Automotive Adhesives - From Design To Repair | Machine Design
Cowl repair
Sorry I didn't specify that there would be nuts on those bolts. The adhesive could not help getting on the threads and would act like Locktite, preventing thr nuts from vibrating loose.
Many assemblys on aircraft are bolted together because welding would weaken the special aluminum alloys used in airceaft. They use locking nuts, which don't seem to have a problem working loose from vibration. The forum (also yourself) has been very helpful in pointing out the flaws in my idea, one of which was the sheet metal screws. So I have decided to change from sheet metal screws to #8, or even #10 (3/16) bolts with nuts. Of course I would use flat washers to increase the bonding area under the nut and the head of the bolt.
There is no way you could aproach the tension limits of #8 hardware by screwing into sheet metal. Like you said, "1 thread of engagement", which could easily pull out.
I originally had planned to use adhesive with screws to supplement the bonding strength of the adhesive, but because of input from this forum I think my primary means of attaching the cowl will be either #8 or #10 grade 8 or aircraft grade hardware, with the adhesive playing a secondary role as additional bonding strength as well as sealer to keep water from wicking between the layers of the cowl.
I may also consider welding the upper portion of the cowl as the probability of water encroachment is unlikely.
Here is a link to the metal bonding page at Fusor
Metal Adhesives
You might find the crash testing loink on this page to be interesting also.
Sorry I didn't specify that there would be nuts on those bolts. The adhesive could not help getting on the threads and would act like Locktite, preventing thr nuts from vibrating loose.
Many assemblys on aircraft are bolted together because welding would weaken the special aluminum alloys used in airceaft. They use locking nuts, which don't seem to have a problem working loose from vibration. The forum (also yourself) has been very helpful in pointing out the flaws in my idea, one of which was the sheet metal screws. So I have decided to change from sheet metal screws to #8, or even #10 (3/16) bolts with nuts. Of course I would use flat washers to increase the bonding area under the nut and the head of the bolt.
There is no way you could aproach the tension limits of #8 hardware by screwing into sheet metal. Like you said, "1 thread of engagement", which could easily pull out.
I originally had planned to use adhesive with screws to supplement the bonding strength of the adhesive, but because of input from this forum I think my primary means of attaching the cowl will be either #8 or #10 grade 8 or aircraft grade hardware, with the adhesive playing a secondary role as additional bonding strength as well as sealer to keep water from wicking between the layers of the cowl.
I may also consider welding the upper portion of the cowl as the probability of water encroachment is unlikely.
Here is a link to the metal bonding page at Fusor
Metal Adhesives
You might find the crash testing loink on this page to be interesting also.
"I may also consider welding the upper portion of the cowl as the probability of water encroachment is unlikely"
This was another part I was curious about.... how would/will you seal the windshield (and install it) with 1/4" high bolt heads sticking up? I realize the early years had the weatherstrip type sealant, so it would not sit very nice on the bolt heads...
Lastly, if you weld the top, why not weld the rest of it, so the bolts will not be there?
You also mention the aircraft industry does not use lock washer... neither does the automotive industy, as a lockwasher is considered a 'rotating surface' by any/all mfg of cars. That is why they use lock sealant, or the special nuts with the metal grabbing wedges on the back of them.... or a metal based lock nut, not even a nylon one is acceptable.
This was another part I was curious about.... how would/will you seal the windshield (and install it) with 1/4" high bolt heads sticking up? I realize the early years had the weatherstrip type sealant, so it would not sit very nice on the bolt heads...
Lastly, if you weld the top, why not weld the rest of it, so the bolts will not be there?
You also mention the aircraft industry does not use lock washer... neither does the automotive industy, as a lockwasher is considered a 'rotating surface' by any/all mfg of cars. That is why they use lock sealant, or the special nuts with the metal grabbing wedges on the back of them.... or a metal based lock nut, not even a nylon one is acceptable.
StangDreamin'
Founding Member
Still, get back to me on that little percussive vibration thing and the possibility of 'egging out' the myriad 1/8-1/4-3/16-whatever holes that will be holding (?) those bolts/screws/et al.
Yes, a rosette weld -or even a properly executed spot-weld- will fail, given enough time and work-hardening. I still maintain that the sheetmetal surrounding a fastener will fail with less time/work-hardening; as even a few molecules' worth of air gap will leave the door open for the fastener to be knocked up against the surrounding sheetmetal.
Educate me - prove me wrong!
BTW: I like credited documentation.
ANOTHER OBTW: It's 'Cletus', not 'Clem'. A small point, but important to me.
StangDreamin'
Founding Member
An Example of CREDITED Documentation:
I called out 'credited documentation'.... just want to show that I can "walk the walk and talk the talk".
So here's an example:
Looking up THIS PAGE; I found that your adhesive manufacturer indicates you might be having a bad idea......
Just as an example.......
I called out 'credited documentation'.... just want to show that I can "walk the walk and talk the talk".
So here's an example:
Looking up THIS PAGE; I found that your adhesive manufacturer indicates you might be having a bad idea......
lordfulfillment.com said:
Just as an example.......
When you say you have taken all the abuse you care to, I really don't think you have really taken much abuse. Rather it was criticism that you don't want to take. I think the only abuse was a couple comments. I don't see why people have to become negative or take things so personally on these forums. It is all about sharing ideas and discussing projects, plans, ideas, problems, issues etc.
I agree that the cowl should be installed with a welder. I don't see how the other method is suitable. I do see what you are saying about wanting it sealed up though.
I agree that the cowl should be installed with a welder. I don't see how the other method is suitable. I do see what you are saying about wanting it sealed up though.
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