Sills

[rozentas]

Hi all, I am starting a topic on this forum to carry on from my topic in the Engine forum section""Engine noise Spitfire 1500"

I have removed my engine , the steering and suspension, and am going to rebuild the engine bay when I have painted it. Then I was planning to rebuild the engine but I have found that a PO has installed some new sills which are still in good condition but he did not repair or replace the inner sill, and strenghthener and the floor is rotten where it joins to the front of the inner sill and bulkhead. Also the very bottom of the lower A post is rotten just by the sill cover adjacent to the bulkhead. 

I need some advice about which way to tackle the rot.

I know I could remove the outer sill, strenghthener and inner sill, while bracing the car and replace the lot, but I have never done anything like this before and so would it be an option to cut off the bottom half of the outer sill and then get access to repair the strenghthener, inner sill and floor, then weld back the bottom of the outer sill?

Also with regard to painting the chassis now I have degreased it.........I am thinking Kurust, 2 coats of red oxide primer, then would the club's top coat paint be ok over this base, or have you experience of a better option?

       

[Dick Twitchen]

Having had to deal with similar, but worse, I would suggest you give the doors a look at before leaping in.  With the alignment associated with sills and A Posts then having sound and straight doors to build the structure around makes life easier.  It also means you can leave the doors in place whilst much of the work is done, reverting to bracing later on.  It was one of the first things I learnt on a classic car panel restoration course I did 15 years ago when leaving the RN but by then too late!

Dick

[rozentas]

Have cut out the rot in the floor then welded in new sections. I used red oxide primer to cover the new patches and then bought some Tetrosyl seam sealer for the welds.  The sealer reacted with the primer which melted.  So cleaned off the seam sealer and reprimed the welded area.  Bought some Tiger Seal which went on great.  Left it overnight to cure then put on another coat of primer.  This would not dry properly over the Tiger Seal it stayed sticky

 Would be grateful for some advice on what make of primer, seam sealer top coat and clear coat are compatible with the shop’s cellulose top coat supplied by Sayers

[rozentas]

Am following your advice re doors and bracing Dick........thanks

[Badwolf]

I don't know if this would work for you but these are the materials that I have been advised to use but must stress, I am way behind in my plans for painting and have not ttied them yet:

1. Treat surface rust with Bilthamber Hydrate 80 (there are other rust treatments which have been used with success by other members)

2. Seal seams - I also have the Tetrosyl product

3. Prime with 2k primer using 4" gloss paint roller or brush

4. Make good dips/valleys with filler (upol fantastic)/ upol dolphin (fine) filler/finish with ultra fine filler (upol dolphin glaze)

5. Re-prime as needed

6. Rub down and top coat (I am using club top coat celluose)

Some advocate the use of an acid etch primer as a first coat or between the 2k and top coat. This varies from restorer to restorer. If you do use this or any other single pack primer it must be BONE DRY  before painting over as this absorbs and traps moisture which causes the top coat to blister as I found out to my cost.

Other contributors will have variations/their own views, but I have been advised this plan mainly (not the acid etch between coats, that was from another forum!!) by two respected restorers (when life lets me get on with it - good luck)

[Clive]

Seam sealer goes on thick, maybe a few mm at times. Therefore it may cure overnight, but it may well keep releasing vapour for longer?? I have not had issues using 2k paints/primers over tigerseal/similar, but it is usually a week gap.

Cellulose is about the most aggressive paint for causing reactions when applied, but is fine with cellulose or 2k primers. 

Etch primer is used on bare metal or fibreglass. Not heard of it being used over painted surfaces, and again some (Acid 8 ) WILL cause a reaction with paint under it if it is not compatible, other brands don't seem as aggressive (or good)

I like dolphin glaze for fine finishing, but using an acrylic stopper has improved my finish loads, or save me loads of time.... brilliant stuff for when you find an imperfection in your topcoat. Just pop some on, leave 10 mins, flat and re-coat...I also used it extensively when I sprayed a hardtop for a friend who used a flapwheel to finish the paint removal. About 100 or so tiny scuffs that didn't show until I put the primer on....The stopper was so easy to sort them out.

[Badwolf]

Clive - I did wonder about the info I got (not from the experts but from another forum) about the acid etch over primer. Probably my mis-understanding. Thanks for correcting. It all helps and I have revised my post to include your info.

[Clive]

My post comes from good and bad experiences, and advice from a friend who has been a professional bodyworker for over 50 years (but I never said how many over 50!) What he doesn't know really isn't worth knowing.... he still works part time and gets the "difficult" jobs at the body shop.... the youngsters do the bread and butter stuff.

[Badwolf]

The sharing of the good and bad experiences is what makes this forum so worthwhile. What works for some don't for others but its the experience sharing that I find so valuable

[rozentas]

Has anyone replaced the rear outer wheel arch without removing the rear wing.............can it be done? 

Steve

[Clive]

Not done it, but getting the old arch off  from the lip would be tricky? But if you can go that and get access to clean everything up, it may well be better in terms of lining it all up.

[Colin Lindsay]

Clive's right; removing the old one sufficiently to get a new one into the correct position would be fiddly; but with care yes it could be done. (Says Colin who can't fix bodywork to save his life...)

[Clive]

And another issue may be physically getting the new one in position. It may need cutting in half and then welding back together to do that.

Again not really an issue, and may even have the benefit of allowing more adjustment. I know the best way of fitting the outer arch is to weld it to the wing first, then to the inner section once the wing is in place. I guess so any dressing is buried out of sight.

[RogerH]

Hi Folks,

being an ex-aerospace engineer I have my views on the use of etch primer. I always thought it was specific to Aluminium and magnesium and their alloys. (reactive materials)

Reading Clive's reply above got me scratching my head as to why you would use it on (mild) steel where a key is easy to achieve and fibreglass (bad keying but how does the acid attack it.

So I had a Google (they can't touch you for it) and I found this  https://www.phoenix-paints.co.uk/etch-primer

I have to accept it as they have bothered to investigate it etc.

 

Learning something new each day

 

Roger