Bond Lexan to metal frame?

[locknut]

The coefficient of expansion of polycarbonate is 65 x 0.000001 x length x change in temperature ｰC.
How big is your piece of lexan? It moves a lot more than steel in the same temperature range. Try bonding one side and having the opposite edge in a flexible gasket or groove that is deep enough to expand into during the hot days.
Using urethane to bond lexan can cause some crazing in the plastic due to its solvent content, but urethane sticks to nearly everything.
I've seen some silicones fail to bond with lexan, mostly the acetoxy silicones (smells like vinegar) won't hold well, but the neutral cure silicones will do ok.
3M makes Very High Bond (VHB) tapes that are used in vehicle assembly. Those will work well as long as you have room for expansion.

Thanks for posting that formula.The large piece is 28X38.I think I need to sand a little to allow for expansion.

 

[Steve C]

Thanks for posting that formula.The large piece is 28X38.I think I need to sand a little to allow for expansion.

Is this going "between the steel" or is it a lap joiont on top of the steel?

 

[Eagleview]

locknut , maybe the next job will be to make a wheelie bar or roll bar for that mower . Your avatar scares the cr.. out of me and I put my machines in some bad spots . One jerky clutch application etc with your body weight that far back and up she'll go .

 

[bc realtor]

I hope to see some pictures of this project as a cab is definatly on my to build list for my AC TTR4400

 

[locknut]

Is this going "between the steel" or is it a lap joiont on top of the steel?

Yes between the steel tube mainframe.Some pics.



GR2000 Cab Project pictures by locknut-1 - Photobucket

 

[nickel plate]

LEXEL. Made by Saschco. Comes in clear or white and adhears far better than silicone, practically a glue. If you should get it on you (you will if you don't use rubber gloves) you'll will wear it for a week. It's a hardware store item.

 

[locknut]

I got some 3M VHB tape and it seems to be holding much better.On a sample,the tape held stronger on the lexan than it did on the raw steel which was surprising.I'm still trying to decide;do I trust this stuff or shoot some bolts thru it to be on the safe side? I like the clean no -fastener look though.

 

[locknut]

Overnite the bond to the lexan give up,so I shot some bolts thru it.Now,it looks like crap with the dimples and the wiper don't lay right.Screw it,I'm going to take the frame down to the glass shop and have them install laminated glass on it

 

[Toffy]

Go to a glass shop that installs windsheilds. Get a tube for a calking gun that they install windsheilds. PROBLEM SOLVED. Forget about coefiecent of expansion and all that stuff. I do this all the time works like a charm. Just follow the instuctions. Cheap too.

 

[Toffy]

Get the stuff they use to install windsheilds. Go to a glass shop it comes in a calking tube. Follow the instuctions and it works great have used it many times and works great. Cheep too.