Thread: One way to build a '32 sedan

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[QUOTE=Ken Thurm;402587]Don -- Thanks, yes, that's exactly what I got. I just imagined after the interior is all in and I'm cruising down the road and at a certain speed the harmonics from the wind and the vibration of the motor creating this rubbing of the roof to the bows and driving me nuts.

Ken, that 3M panel adhesive is great to work with. We used it between each floor rib in Dans subframe and the sheetmetal floor.

It will definitely dampen out any harmonics in your roof, that stuff is just like welding the two parts together. Oh, did you get the special gun for applying it yet?

Don

Ken, we may have an update. Dan just came in and I showed him what you are doing, and he said he isn't 100% sure, but he has seen threads where someone did the 3M routine on the bows and when the top heated up from the sun it would distort the top because the metal couldn't expand or contract because it was glued down so tightly to the bows. He has heard it is better to put a thin strip of weather stripping on top of each bow to dampen out any harmonics.

Not 100% certain, but that is what he has seen others post.

Don

If it sticks like it does on our race cars, it will distort. I read where Ron Covell will use one side (hairy side I think) of some velcro on his roof bows.

A lot of interior to framing work is held in place with velcro on boeing airplanes

I'd consider a good silicone caulk. It will hold enough to stop resonation, but has enough flex to let the exterior expand and contract with the weather.

Thanks Ken, I knew I wouldn't get off easy.

I wouldn't worry about connecting the ribs to the roof, foil backed dynamat will slip between them (about 1/8", 3/16" thick), never fall off and kill any harmonic problems.

I use a rubber roller and a heat gun, or lay it outside on the concrete on a 80°+ day to help it form, and adhere better

Jerry - Great story, there are a few more around here I really miss. I think they leave us way to early.

I want to thank all of you for the warning on the caulking. I looked at what I had today and it isn't the 3M, It's a type that flexes so it allows the material to move and it is good to, I think, 600 degrees. I remember asking the guy about the heat because I'm going to have this thing powder coated in primer again when I get the roof done and I know they use about 400 degrees in the oven for drying.
The roof lays right on those bows I made there is no room for insulation or Velcro. That's why I made them so the roof is solid. I think when I apply the caulking it will squeeze out next to the ribs to hold it in place.
Ken

Originally Posted by jerry clayton

A lot of interior to framing work is held in place with velcro on boeing airplanes

And just when we thought was safe to get back on a plane!!!!

Hi Ken,can I add a little advice on the sealer adhesive? Any urethane sealer/adhesive needs minimum 2mm of thickness between the two surfaces to bond to full strength so if your bows are within that it should work fine. Squeezing to much sealer out of the joint is only waste product. Sikaflex brand of urethane's make a wide range of product for heat and elasticity that would allow for any movement required.
Sorry if I am bombarding you with information that you probably are fully aware of.

Not at all, thanks for the information. My plan was to take my finger and push the excess in bonding the bow to the roof on both sides. Doesn't sound like that is going to work.
Ken

Oh please use disposable gloves when using product like that as once on your skin very very hard to remove and you certainly don't think your lovely wife Tina will want your dirty mitts all over her.

I thought I would be welding the top in today, but I wanted to detail the bows and make some minor adjustments to make sure the sheet metal would touch the bows from side to side. By the time I welded the brackets to the bows and the roof to the bows and ground everything off the day was shot. So next week I should have it in.
Ken

I got a few things done on the sedan this week end. I had this real heavy wall stainless tubing that I have been using for a door stop far at least 10 years. I turned it into a steering column I new I was saving it for something. I machined some nylon bushings to support the top and bottom of the column.
Finished the steering inside the car, shortened the chain got the adjusters in and mounted the steering. it all seems to work so far. I picked up the material for the drag link, I will drill and tap it tomorrow, then I can actually steer it and see if I have a go cart or a car, (if I did my geometry right) It should be 2 1/2 turns lock to lock.
Welded the two pieces of roof together and am ready to weld it in. That's it.
Ken

Looks good , Ken. Do you have the ability to change ratios on that steering chain setup by changing sprockets or something, in case you find your steering is too quick?

Don

Thats correct Don, i've seen it happen here in england, when the temp gets up to around 79-80 things start moving.

Originally Posted by Itoldyouso

Ken, we may have an update. Dan just came in and I showed him what you are doing, and he said he isn't 100% sure, but he has seen threads where someone did the 3M routine on the bows and when the top heated up from the sun it would distort the top because the metal couldn't expand or contract because it was glued down so tightly to the bows. He has heard it is better to put a thin strip of weather stripping on top of each bow to dampen out any harmonics.

Not 100% certain, but that is what he has seen others post.

Don