Monday, May 19, 2008

Finishing Up the Putty Patches

Sunday was a really beautiful day in Honolulu and I got a lot done on my E9. The volcano on the Big Island is erupting and for several weeks the winds have been coming from the south, blowing clouds of sulpher ladden gas over Oahu that make Honolulu look like Beijing in August. On Sunday the wind, what little there was, came from the East. The sky was blue. No rain. Spectacular.

Next Sunday is the annual All British Car meet. I'll be there with my '74 Lotus Europa, and because the weather was so nice I drove the Lotus to the shop. The problem with that is that people keep coming over to ask about it. I love showing off my Lotus, but I love working on my E9, too.

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The first order of business was to grind down the putty I applied last time. My trusty CP 854 4"grinder cuts through the POR-15 Epoxy Putty with ease, but the contours around the tail light are too complex for a grinder, so I switched to a hand sanding block loaded with 40-grit paper. A lot slower than the grinder, but accurate.

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Like I said before, I don't want to grind down to the surrounding metal surface for fear the patch will fall out the back. In this case this works well because for unknown reasons there is a thick layer of primer in this area and my putty patches should not be thicker than the surrounding finish. I guess the proper technique in thinner spots will be to dimple in the edges of the holes.

As the hand sanding progressed I could see where I was starting to sand through some of the surrounding POR-15 paint I had appled previously. I decided it was more important to level and feather the putty spots, which meant I would have to repaint the exposed areas. When I was done feathering I roughed up all of the surrounding POR-15 coat with 400-grit and painted everything. Next time I'll apply another coat and start building thickness with some kind of aerosol primer, using the black layer as a check layer.

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I spent the rest of the time tweaking the patch for below the rear window. I continued what I started last week, using a pair of vice grip pliers to restore the bends, then carefully shrinking, stretching, and twisting to align the piece with the cut out slot where it will go I got to where the patch fits inside the slot, but it needs more tweaking.

One thing I need to buy is some aerosol sanding primer compatible with my base coat paint system.

I finished the day with a drive out to Hawaii-Kai where I sat outside Starbucks watching Japanese tourists gawking at the Lotus.

Sunday, May 11, 2008

Fun with putty, more shrinking and stretching

This post covers last week and this week. Last week was the Sunday after our gamelan concert on Saturday night, so I got a late start and was very tired even then, with the result that I did not accomplish very much. This Sunday was Mother's Day, but that did not cut into my car time because we had dinner at my mother-in-law's, as usual. Chinese food, from Duk Yee, classic local style Cantonese food. The lesson in all this is that when you undertake a large project, be it a car restoration, a house remodeling, or building a boat in your backyard, you need to allow time for the multitude of activities that life has to offer. It's all about balance.

Note: When I was uploading the pics for this blog to Flicker the response time was ridiculously slow. The uploader even dropped one pic, so that was will appear on Flicker out of sequence. I suspect the reason was people uploading pics from their Mother's Day activities. I upload using Flicker Uploadr for Mac OS X.

The last time I wrote I had ground out some rust-throughs around the right-hand rear tail light to experiment with POR-15 Epoxy Putty as a small hole patching solution. The last step that day was to do the POR-15 wash - prep - paint routine. Last week I mixed up my first batch of putty and filled in the holes.

In anticipation of the putty gushing through the holes I cut a piece of cardboard to function as a backing. The idea was to get the putty to spread out on the back side of the panel. This worked very well, although the cardboard has to be helped by a slender screw driver. As I worked the putty I discovered that even with the cardboard the putty would ooze through the holes rather than build up a solid slug, so I stopped trying to do it in a single step. I let the putty form valleys, or craters, where the holes were, the idea being to use those as a foundation for a second application. This worked really well.

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The cardboard did cause the putty to form mushrooms on the back side of the panel, which is a good way to make it stick. I suppose I should consider window screen, too, especially for larger areas that I can reach. This section was difficult because there is an inner panel blocking easy access (thus the cardboard trick).

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Today began with grinding down the putty. I am pleased to report that POR-15 Epoxy Putty is perfect for grinding. It feels harder than typical body filler, yet it grinds cleanly and with good control. As easy as cake.

In this next pic you can see where I have ground away most of the high spots, and how this reveals the places where I let the putty push though the holes. Those darker areas are not holes, they are just sunken in a bit. There are three large areas along the top edge of the tail light opening, plus one closer to the trunk opening.


I did not want to grind down to bare metal as this would break the POR-15 seal. It might also weaken the putty patch so much it will fall in. This entire area was ground down to bare metal, and getting there required grinding through a thick layer of primer and paint. So my plan is to create a rivet head effect, and build up the surrounding area back to original thickness using more traditional means.

After grinding I roughed up the recessed areas with 400 grit sandpaper, then mixed up a small batch of putty and filled in the low spots. While it was setting I worked on the rear window patch. At the end of the day I ground down the second layer and discovered that I had not used enough at the upper-left corner of the tail light opening, so I added some more.


The sheet metal work was all about dealing with the height of the piece. I was very close with the curve, but the center was too high. I decided to work on the right-hand side first, and to bring the end up by shrinking the top edge and stretching the bottom. Up until now I always did the same operation on both edges.

After stretching the bottom the work had a lot of twist.

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Shrinking the top took out a lot of the twist, and to get ride of the rest I held the work in the vise and twisted it by hand.

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As I worked on the fit I noticed that the two lengthwise bends were opening up. I had made these by bending the piece along the edge of a steel table, but now that the piece was curved I could no longer do it that way. First I tried holding the work gently in the vise and bending with a vice-grip plier with a broard clamping jaw. This worked well in some places, but sometimes it was too tight, so I ended up holing the piece on the table with another vice-grip plier. I did't get of photo of that. It worked, but it is slow.


After working the entire right half I ended up focusing my attention on the last foot, and managed to get back the original shape. Next time I will have to continue the process all the way to the other end.

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