Well Steve, look on the bright side. Both Al and Mark will have flown their planes till they're worn out and I will be still hacking the Hurri   

Go outside with a bit of gas and a rag, pour a little in and wipe it out after all the foam melts.
Give it a few minutes to flash off and give it a rub with an acetone moistened rag, and lay your glass.

Thanks for the info.

Cans of expanding foam are not affected by gas but does absorbe it.   
Had to dig the foam out wighout ripping my outer shell. Put a few small nicks in it but easily patched. Laid some thick fb inside and hopefully this works.
Need a lot more practise doing fb.

Glassed the ailerons and am working on the wing filets.
Then a lot of sanding will becdone next.

The cowl seem to be coming along. Need to sand and smooth it a bit. Test fitted the glassed exhaust stacks. Still fit 
Added the new coolers to the wing bottom and shaping the wing fillets.

Looking like a spit now 

Mark; your mods are looking great; the large Vokes filter really makes a statement.  It's gonna be a serious looking airplane.

Looking at the asymmetrical radiator configuration of your moddel made me realize that I don't know exactly what cooled what in the earlier variants.  I'm pretty sure that the circular rad under the port wing just cooled the oil, and the rectangular one under the stbd wing  cooled the glycol, but I don't know if there was a second core under the stbd wing to cool oil as well.  I see another trivia chase in my future.

Keep posting pics of your progress.

I do think the small around one was for the oil. My cutaways show the mk9 so don't know if the large oval had some in it.
Kinda funny, I have a picture book on late marks 7-24 and another one on early marks  1-2. Somehow i missed the mk5. My spitfire book (Alfred Price) has low res pics so not the best for referencing specific details.

Been  slow but steady progress.
Added the underside blisters and ailerons, servos are mounted now.

Since the mk5 was the first to main the 20mm armament I gave it a shot. 
I wanted them removable for tranport and hangar damage avoidance. I mounted short carbon tube into the leadjng edge for the base. Used magnets to hold the barrels in place. Mounted another short carbon tube into pine and turned to shape. I will add tiny carbon tube for the protrouding barrels once painting starts.
The Eflight retracts were next but I need new gear legs. The legs are too long and worse, the leg coil of the stock gear sits right at the formers and support for the lg blocks. I will buy some 5mm music wire to make new legs...or buy some small oleo legs.
The 15cc engine was installed so I could mount the cowl and finish forming/shaping the nose blisters. I cut a disc to help align the cowl to the spinner that is still on order. 
Next was to get the pilot into the office. I discovered the existing vac formed headrest and "office" that was installed were way too low. Since I only had a bust figure to man the office, I decided to rip out the cockpit and sealed it over.
The canopy is badly frosted. Thought it was caked on saw dust and such but after soaking in water and trying to clean it made no difference in the look. A stop at wally world for some future floor polish has helped. Still not great but better than before.

Need to mount gas tank, fuselage electronics and this will be ready for painting. 

All your hard work is paying off Mark.
Very impressive !!

The 20mm cannons are a simple setup. I keep magnets from old foamies and most are round and I think 8mm. These are my retainers. I used two carbon tubes that i plug with balsa. Once I have the depth of the plug to my liking i ca it into the rod. I find that magnets flip while going down the tube so I mark the "up" side. Once it land properly i ca it to the balsa plug.
The rod for the cannon is too small for the magnet to slid into but they are the same outer diameter. I glued the magnet onto the end of the rod. I next drill some wood to fit over the carbon rod. From there it is just shaping.
The pics are of the failed pieces but show the process.

Spent the morning sanding. Not one of my favourite tasks.
And then started painting. I wanted a worn, dirty look but over did it and my attempts to fix just over did it more.  not quite the look I was going for. Hope i can fix it up later when the decals are on and weathered.

I do like how the exhaust stacks came out.

I like it!  Stacks look very nice.