Project Extended Pop-Top Aerodynamic Camper Shell ('99 Tacoma) - Page 5 - Fuel Economy, Hypermiling, EcoModding News and Forum

a8ksh4 · 09-20-2012, 03:30 PM

Reading Bobo's thread, and just hanging around here again, is getting me back into thinking about the challenge of MPG....

Need to get rid of my mechanical rad fan, install an engine cut-off switch, shave the mirrors, build an air dam, etc... and leave work early enough on Fridays that I don't feel like I need to hurry, driving up the freeway, to go wherever for the weekend. :P

bondo · 09-20-2012, 04:59 PM

I want to warn you, if you are not already aware of this fact, you cannot, I repeat cannot, fiberglass over the type of foam you are using. The styrenes in the resin will attack the foam and basically melt all your hard work into a sticky mess.

You need to put a barrier between the foam and the fiberglass resin before you laminate. Industrial strenght aluminum foil, available at any restaurant supply company, works great. It can be spray glued to the foam. 3M spray adhesive works best.

Carefully cover all the foam with the aluminum foil and tape the intersecting edges with 3M blue painters masking tape. ( I am not a sales rep for 3M, their products just seem to work best, from experience.) Then you can safely fiberglass over the foam.

Best of luck on your project,

Bondo

ChazInMT · 09-20-2012, 05:06 PM

Would the adhesive back aluminum foil tape used in HVAC work as well on the seams? I'd think it would give you a more uniform surface.

a8ksh4 · 09-20-2012, 05:12 PM

Oh, I had though that it was okay to lay the glass directly over the foam so long as I used an epoxy resin, rather than a polyester resin. Is that not true?

bondo · 09-20-2012, 05:17 PM

Quote:

Originally Posted by ChazInMT

Would the adhesive back aluminum foil tape used in HVAC work as well on the seams? I'd think it would give you a more uniform surface.

It would work but it would take a lot of rolls to cover that many square feet. Also the aluminum foil tape is pricey per roll. The aluminum foil tape would work good on the edges. You can cover alot more real estate with a big piece of aluminum foil both faster and a lot cheaper.

Bondo

bondo · 09-20-2012, 05:19 PM

Quote:

Originally Posted by a8ksh4

Oh, I had though that it was okay to lay the glass directly over the foam so long as I used an epoxy resin, rather than a polyester resin. Is that not true?

Glad to hear you are using epoxy resin. It is the best by far. I just wanted to warn you what the polyester resin would do.

Carry on,

Bondo

a8ksh4 · 09-20-2012, 05:21 PM

Ok, cool! Thanks for the heads up, Bondo.

Weather Spotter · 09-20-2012, 07:17 PM

I used (Dow brand) blue foam and polyester resin and it only melted in about 1/8". i found that if I made the foam the size I wanted the final shape to be the fiberglass would melt in and (stick hard) as well as end up the same size as the foam had been.

It might not be the same for you but thats what worked on my tail.

HydroJim · 09-20-2012, 08:02 PM

This is a really cool project you've got going on. Can't wait to see the finished product.

ron · 09-20-2012, 09:41 PM

I watched a series of 6 segments using pink polyester foam and poly resin and they had no reaction between it, they were making a t-bucket. I think the 3in radious solution you came up with was a good one adds strength , and you beat me to the foam seal between the cab and cover . I dont use my campershell on my 2003 techoma it works my mpg by 4-5mpg . I need a cover and if what you are making works ABA I will copy it if you dont mind.