Trying to add some attachment points to a plastic cab

[WCarp]

I need to add two more attachment points, to fix a poor design, one each on the long side in the center between two existing points to a plastic material on a cab of a tractor. Since the manufacturer did not properly space the bolts that attach an access cover to the cab, the thin plastic access cover ~0.1 inches thick bows substantially between the bolts which are spaced 16.5 inches apart as a result of the pressure of the ultra-soft neoprene sealing gasket (.75 inches W x .5 inches H) which then creates a sealing issue. The plastic material at the front of the access hole is 0.150 inches and the plastic thickness at the rear of the access hole is 0.137 inches thick.

Does anyone have any ideas to resolve this issue? I have thought about gluing either a metal or perhaps plastic piece .75 inches wide to the underside of the cab but the glued surface area would have to be made to conform very closely to the curved lip at the edge of the hole so the glue or epoxy would hold well.


Does anyone have any suggestions on how to resolve this problem? A major problem is that I cannot find a way on this forum that allows me to attach photos that are on my computer to show the issues!

Thanks

[Highpower]

Here is the link to the "How To" on posting pictures here. http://www.metalworkingfun.com/showthread.php?tid=1006
Give it a shot and see if it works for you.

I don't remember if there is a set minimum number of posts you need to have before the software will allow it, but one of the ADMIN members here will probably be along soon to confirm or deny that.

It definitely seems some pictures would go a long way here in getting you some ideas.
And welcome to the forum!

[Dr Stan]

Ditto on the welcome and also on Highpower's point re pics.

[EdK]

No post number necessary to add attachments to posts.

Ed

[Vinny]

There is a limit on maximum size (in bytes) of the pic, so if it's large and the attach fails, try shrinking it.

Welcome to the forum!!!

[WCarp]

Thanks for your help letting me know how to attach photos---they are attached now. They should help a lot in figuring out what I need help with.

   

   

   

   

   

[Highpower]

Personally I would remove all the old sealing foam, clean up all the surfaces and replace it. Then I would try heating the warped surfaces of the opening with a heat gun and attempt to pull them up to straighten them again.

If you really want to add additional fastening points to the center portion of the cover perhaps a couple of short pieces of flat bar that are drilled and tapped on one end would do. Drill two holes in the cover where needed, insert the screws and then thread the flat bars onto the screws. Use them as a sort of one-sided toggle bolts that would hook under the opening of the cab. Similar to the way a kitchen sink might be attached to a counter top, but upside down.     https://www.youtube.com/watch?v=gGCF2QMEs6M

A more severe approach if you want to add more reinforcement under the opening would be to drill out the rivnuts (threaded inserts) in the opening and install longer pieces of flat bar across the underside of the opening. Drill the flat bar to match the holes on the opening and secure it all together with new rivnuts. Problem is, if you don't already have the tooling - threaded inserts are an expensive investment. Been there done that times 2. (Imperial and metric.) I do think trying to use glue in this case would be short lived however.

Hopefully someone else has better ideas. I'm afraid that's about all I can think of.

[Dr Stan]

Heat will only help if its a thermoset plastic and then it may make matters worse.  I'd go with Highpower's "more severe approach".