Several questions on convertible tops and removable hardtops

Question:

I’m finishing my 1968 Austin-Healey Sprite project, my first experience with British sports cars and convertibles. My questions are directed at the soft top and the hard top.

Aside from my specific application, I’m hoping that the problems are generic enough to be interesting to other readers— fixing unraveling stitches in a new soft top and hairline cracks in old fiberglass.

The soft top was unused, but came with the junkyard car some 25 (or is that 30?) years ago. So I don’t know much about its origin. The name Regalite is embossed in the rear window but I’m not sure whether that refers to the window, top or both. Since I’ve had it, it’s been stored in the garage and was never unfolded. It is of the vinyl-on-cloth variety and I suspect that it falls somewhere in the lower end of the quality range. Since it’s been stored out of the sun I’m guessing that age is not an issue. I figured that this top would provide good practice before installing a better quality top somewhere down the line.

The problem is with the stitches that start in the body of the top near the front corners in the area that goes over the side windows (this is happening the same way on both sides). The stitches are unraveling where they start and the unraveling wants to continue rearward. The top is freshly installed and I avoid touching that spot so it’s only gone about an inch or so on each side. Can you recommend a way to patch this area so that the unraveling might stop and also to stop potential leaks in that area? I thought about using contact cement to glue some band-aid type patches on top.

In any event, I realize that this top probably won’t last very long anyway, but I’d like to keep some of the problem spots in check until the rest of the top catches up.

Aside from that, what are your suggestions for maintenance and care? Can you recommend a better/best quality top to use when I finally replace this one?

The hard top was made by Snugtop (it looks like from back in the day) and I purchased it used online. It’s in fair condition with no apparent structural damage. However, all of the rubber seals need to be replaced and the fiberglass exterior has some hairline cracks near corner areas. Most of the cracks run along the curve over the rear window. Each crack is only about 6 inches long, but there are quite a few (30 or so) which span the width of the rear window in an area about two inches wide. It doesn’t appear that the cracks go deep so I’m guessing that the problem is mainly cosmetic and that they are caused from stress, sun or age.

The person that I bought the top from thought that it was covered with vinyl. In fact, he had noted that the vinyl had cut marks in it. Since then I’m realizing that this is a common mistake causing people to want to treat their tops with some kind of vinyl moisturizer before selling them. My plans were to strip the vinyl and paint. Actually, the top is completely fiberglass and the vinyl texture and black exterior is molded directly into the shell.

I could use some guidance for repairs since none of my shop folks seem to have any best suggestions. I’m thinking that it would be simplest (and most economical) if I could remedy the hairline cracks and then paint since I can do that myself, but some have suggested covering with real vinyl or cloth.

Would it be reasonable to sand off the vinyl texture or would that be a nightmare? If I cover with vinyl or cloth what would you recommend? Any recommendations for a resource for rubber seals?

Answer:

Regalite Plastics Corporation was formed in 1982 as a division of O’Sullivan Corporation (previously called O’Sullivan Rubber Company). Regalite had a vinyl calendering plant in Newton Upper Falls, Massachusetts, and they provided the material used for convertible top rear windows to a lot of the companies making the tops.

As far as the unraveling thread is concerned, I would first determine why the stitching is coming apart. If the thread is very weak then it will continue to come apart. If the material the thread is supposed to hold together is very weak so that the thread is essentially pulling out of it then it will continue to do so. If the ends of the stitched threads were not secured then you can fix this with some good-old-fashioned sewing techniques. Assuming the underlying top material is good, you can use a needle and thread to secure the loose stitching. You

also can continue the stitching with your needle and thread utilizing the same holes in the top it originally used and then securely tie the thread on the underside of the top when you get to the end. You obviously should use thread that matches the original stitching for this operation. If the original thread is simply falling apart you can try saturating it with contact cement. I think this will prolong the life of the top, especially if you don’t put it up and down a lot, but it’s not going to look particularly good. The same is true for gluing vinyl patches over the stitched areas. It should be functionally OK if the areas are not stressed too much but it won’t be particularly pretty.

Regarding the care of a vinyl convertible top in general, the best things you can do are keep it clean, leave it in the “up” position as much as is feasible, and keep it out of the sun as much as possible. A name-brand vinyl dressing may prolong the life of the top but I’m not entirely sold on this. It does make most people feel better to apply one and it certainly makes the people who manufacture and sell the products feel better, but I’m not convinced that these “anti-aging” products actually work.

Another factor that’s often overlooked when trying to maximize a top’s lifespan is the quality of the installation. Proper underlayment and a taut but not over-stressed fit will go a long way in preventing wear spots and tears.

Regarding a better or best quality replacement top, if money is no object you can have a talented interior specialist make a new top for your car using extremely high-quality material such as Sonnenland or Haartz Stayfast canvas. For a more modest cost you can buy a high-quality, off-the-shelf top from World Upholstery & Trim (worlduph.com) or any number of other suppliers.

As far as the hardtop goes, I happened to recently come across a 1962 Corvette with a simulated vinyl covering on its hardtop and was told that back in the 1960s and early 1970s people often sprayed hardtops with a material that was meant to look like vinyl. It sounds as though your top was likely sprayed with the same material and you can certainly remove this by sanding it off. A DA sander in the hands of someone who’s experienced and good will make quick work of the coating. If you’re not experienced and good with a power sander you are likely to do more harm than good. I suspect that chemical paint stripper will also get it off so try that first if you’re not comfortable with sanding.

The cracks you see may be in the faux vinyl covering only or may be in the underlying fiberglass. You can determine this once you have removed the covering. If the fiberglass is cracked then you can repair it the same way you would repair any cracks in fiberglass. Grind each crack in a “V” shape, build it up above the original surface level with layers of resin-soaked random fiberglass matte, sand it down after it dries, and finish it off with a thin layer of body filler, if necessary.

If you want to cover the hardtop with vinyl or cloth, the underlying process is basic; cut the material to fit and glue it down with a compatible adhesive. Having said that, it’s not as simple as it sounds so if you’re not good with your hands and very patient you’re probably better off paying an experienced professional.

As far as the weatherstrip for the hardtop goes, I don’t have a real good solution. California auto parts retailer Robert Kyle launched Snugtop in 1959 to manufacture hardtops for European imports. Kyle had been selling imported hardtops for imported cars but there were pervasive quality control problems so he decided to make his own tops. The company is still in business, primarily making fiberglass truck caps and tonneau covers, but understandably they don’t carry rubber seals for your Austin-Healey top. My best suggestion is to create a dimensionally accurate cross-sectional drawing of the seals you need and try to match them as closely as possible to something currently available. Steele Rubber Products (steelerubber.com) is a good starting point.