1935 Chevy school bus - Page 10

ol trunt · 08-17-2012, 08:56 PM

Hello all, I made some more progress with the pop top this week. The Rustoleum I used to paint the parts with was finally hard enough to allow bench assembly. The piano hinge is now complete and installed on the roof section as is ihe first layer of polycarbonate (translucent central section of the pop up). I'll glue the second layer on this Sunday and then the top will be ready for final installation on the bus. I expect to get the weatherstrip in on Monday so I should be able to do the install on Tuesday.

I am using windshield mastic to hold the plastic in place (polyurethane) and had originally planned to use a "Z" bar as well. However, after doing some testing of the stickiness of the mastic I don't think the "Z" bar is necessary. I glued two pieces of polycarbonate together with a small amount of mastic, let it cure a week and then tried to pull the two plastic pieces apart. I pried and twisted in an effort to break the bond and not until I held one piece in the bench vise and grabbed the other piece with a vice-grip and pulled as hard as I could did I get failure. The bond between the plastic and the mastic held but the plastic material itself finally gave up (see pic).

I also tested how well Rusoleum worked as a substrate for the mastic and discovered that the mastic easily pulled the Rustoleum off its primed new steel base--not a good sign if I want the polycarbonate to stay in place. I talked to the guy at the glass shop where I bought the mastic and he said the best bond would be achieved by bonding the poly directly to bare steel--which is what I did. I am finally ALMOST done with the pop up unless some new devils present themselves

roach711 · 08-17-2012, 10:20 PM

Nice work!

Im a woodworker myself and have never done much metal fabricating so you, Tango and Chev49 amaze me. I need to find a house with a big old pole barn then pick up welders and big, honkin' jacks.

My first project will be to put a bus body on an abrams tank frame. The ultimate off-road bus!

ol trunt · 08-17-2012, 10:23 PM

I would most definately be cowed with admiration!

Tango · 08-17-2012, 11:44 PM

Lookin' Good Trunt --- And you are definitely using the good stuff. Sika has some of the most advanced adhesives on the planet and make some really bada$$ glue. I used one of their products on the sheetmetal of my old B-Bird when I raised the roof 19" and did a similar test at a buddy's oil patch lab. Same results on 15 gauge steel (BB uses an odd sized metal on their bodywork). The sheetmetal sheared before the glue joint. I'd been told it was stronger than welding, but if I hadn't seen it, would never have believed it. I also use their "Bonding Agent" in my cement work. Like the Monkees used to say..."I'm a Believer".

Can't wait to see that puppy installed!

somewhereinusa · 08-18-2012, 06:55 AM

Good looking fabrication!!!

GreyEagle · 08-18-2012, 08:18 AM

Super nice job on the roof.......

chev49 · 08-18-2012, 09:19 AM

The windshield mastic is great stuff that i use for lots of things. However some of the glues or calks if ya like that term that glue things like sheet metal panels together will sometimes shear under a stress load or by excessive heat. For example, i worked on a pickup a few months ago that had a ladder rack, and the glue that bonded the outside panel to the inside box, had sheared.. didnt fix it with more glue... used mig.
So if ya see a modern pickup that the sides of the bed are floppy....

ol trunt · 08-18-2012, 04:19 PM

I've seen that sort of thing too and I like you remain a little skeptical of glues. We don't have much choice when we buy a vehicle when it comes to the use of glue. Before I chose to use glue I considered the down side and the worst case scenero seems to be that a couple of pounds sheet of plastic would be ripped from my roof and I would have an instant convertable and perhaps, ( what is it they call it?) --colateral damage. I know the windshield glue can stand the heat and the polycarbonate is guaranteed (for 10 years) not to do a lot of stuff including not to deform when exposed to temps under 200 degrees. I guess ya pays ya money an ya takes ya chances.

bansil · 08-18-2012, 05:20 PM

Quote:

Originally Posted by ol trunt

I've seen that sort of thing too and I like you remain a little skeptical of glues. We don't have much choice when we buy a vehicle when it comes to the use of glue. Before I chose to use glue I considered the down side and the worst case scenero seems to be that a couple of pounds sheet of plastic would be ripped from my roof and I would have an instant convertable and perhaps, ( what is it they call it?) --colateral damage. I know the windshield glue can stand the heat and the polycarbonate is guaranteed (for 10 years) not to do a lot of stuff including not to deform when exposed to temps under 200 degrees. I guess ya pays ya money an ya takes ya chances.

sorry...that just sounds like the most getto ...info-mercial ever

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J/K it was funny to read tho

bansil · 08-18-2012, 05:23 PM

Quote:

Originally Posted by bansil

Quote:

Originally Posted by ol trunt

I've seen that sort of thing too and I like you remain a little skeptical of glues. We don't have much choice when we buy a vehicle when it comes to the use of glue. Before I chose to use glue I considered the down side and the worst case scenero seems to be that a couple of pounds sheet of plastic would be ripped from my roof and I would have an instant convertable and perhaps, ( what is it they call it?) --colateral damage. I know the windshield glue can stand the heat and the polycarbonate is guaranteed (for 10 years) not to do a lot of stuff including not to deform when exposed to temps under 200 degrees. I guess ya pays ya money an ya takes ya chances.

sorry...that just sounds like the most getto ...info-mercial ever

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J/K it was funny to read tho

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.mmmm maybe this where folks say "you shouldn't post.. whil-ist sipping the cider

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cy-ya.....g-night....ya'll
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maybe

ol trunt · 08-18-2012, 06:15 PM

I for one am in complete favor of the pre (and post) sip of vino--pre and post most anything. BTW, some guy told me that with all the toilet bowl bolts sticking up out of the top of my bus that the whole thing looked like a giant blue toaster! He then went on to say that he liked cinamon toast best. So I cut the bolts off---still looks like a toaster

Tango · 08-18-2012, 11:31 PM

Mmmmmmm --- Love cinnamon toast! (as long as it has raisins).

bansil · 08-19-2012, 05:29 AM

X2

ol trunt · 08-23-2012, 07:13 PM

I spent some more time on the "toaster" this week and finally have the pop up top assembled. At the last minute I decided I needed to mechanically attach the plastic to the roof as well as glue it.