Here's the heater box as it arrived.
First thing I do is grind down the rivets so I can remove the vent inside.
This heater box had a lot of sealer on it, so next job was to remove it.
It also had sealer around where the motor mounts. It doesn't matter that it's there for cutting the box down, but it's annoying so I removed it.
After that I trimmed a few of the little gussets off, to make doing the filler work a lot easier after the glassing has been done.
I use a 1mm cutting disc to rim the little gussets out.
After that I sand the area I'm going to be modifying with 120 grit dry, inside and out.
Next job is to mark out where you want to cut. This depends on how much clearance you want to make. I'm doing the same cut I did on my brothers car to clear the LS1 as this car is also LS powered.
I made a board so I can screw the heater box to so when I cut and glass the box it keeps its shape. I don't think it's 100% necessary to do this, but I felt it was worth the effort when doing my brothers car as I wanted it to be perfect. Luckily I've still got the board so will use it again. It's just 19mm MDF with the inner shape of the heater box cut into it with a jigsaw. This allows me to mount the heater box to the board but have full access to the inside to do the glassing.
I'm cutting at the base of the thick radius that goes around the edge, so when I glass it back together it will still have the nice rounded edge.
Here's the view inside when mounted to the board. Plenty of room to fibreglass it back together.
Chop chop : )
Because I'm going for a fairly hefty chop on this one, I've marked out just under the radius and will cut the whole side section off.
Then it's just a matter of cutting the pieces to get them to sit the best you can. It doesn't have to be perfect at this stage, as fibreglass and filler can do wonderful things : )
Tape it all into position so it can't move, and also make sure it's sealed so the resin doesn't come out the top and make a mess.
There's a few gaps here, but the fibreglass will make short work of them.
I'm not a fibreglasser by any means, so to make sure I didn't take too long after mixing the resin I cut all the matting beforehand. I cut a few different sized pieces and tried them in place to make sure I had everything I needed once the resin was mixed up.
When I did my brothers one I was told to use a syringe to mix the catalyst. I had a lot of trouble finding one big enough and ended up getting one from the vet : )
The resin I use is mixed with either 1% or 2% catalyst. Because it's been a bit chilly I went with 2%.
I also donned some sexy gloves. I hate getting sticky resin all over me!
I'm not sure if it's the right thing to do, but after cleaning the heater box with acetone I paint a thick layer of resin on first before laying on any matting. I feel it helps get into the nooks a bit better.
After 3 layers it looked like this
Once dried and unscrewed, there were a few spikey bits that needed sanding off.
Peel off the tape. I then gave it a quick sand down with a 36 disc on the grinder to smooth out any lumpy bits.
Then ice the cake : ) Obviously I don't ice cakes for a living, but you can see here how much easier it is by cutting those little gussets off at the start.
This shows the slimmer profile.
Still plenty of room for air to still travel inside.
Looks a bit "killer whale" : )
Then prime it up.
That's it really. Obviously you can cut it to any shape you want/need, but that's the basic process I use.
Hope that's of some help to someone???
Edited by dirtbag, 16 August 2011 - 12:04 AM.
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