Written by on July 25, 2016
The driprail on a 1940 Ford is sandwiched between the roof panel and the quarter window panel. This column addresses some of the issues involved with repairing or replacing these driprails.
Q. I have a 1940 Ford coupe and it needs to have a new driprail spliced in above the quarter window on the driver side. I bought a new driprail from Dick Spadaro in New York, which is very nicely made. I cut it in half, and want to weld it into place, but I can’t find anyone who will do it.
Do you recommend drilling holes in the new driprail and just tacking to the inner doorjamb about every inch or so? I’d like to MIG weld this, but if you think TIG welding is best, I can take the car to a professional.
A. You have lots of good questions, and I’ll work through them one at a time.
Replacing the driprail on your 1940 Ford can be a little challenging. The problem is that the flange on the driprail is sandwiched between the quarter-panel and roof, and to do a proper job of replacing it, you will have to separate the roof from the quarter. They are joined by spot welds, and while it’s not a huge job to simply drill through the welds, you’ll have to do some major bracing on the body to prevent it from getting out of shape, as that structural joint is disassembled.
Once that joint is separated, it’s not too hard to slip the new driprail into place, and plug weld the panels back together. You can also plug weld the driprail into the door opening area of the roof panel.
For anyone who doesn’t know the term “plug welding,” it involves drilling a hole, perhaps 5/16-inch diameter, through one panel, positioning the panel with holes so it overlaps another panel, and joining the panels by filling the hole with weld. This makes a joint very similar to a factory spot weld.
While MIG welding should be fine for most of this job, I don’t recommend trying to butt-weld your new driprail to the old one with a MIG. The small section of the driprail makes it just too fragile for that process, and in my opinion the risk of melting the edges away is very high. TIG welding is much better for butt welding tiny, delicate sections like that. Depending on how much of your driprail is damaged, it may be best to replace it entirely.
Q. I just read your suggestions about a bolt-in roof insert in STREET RODDER. Much easier than welding the panel to the frame is to glue it using 3M Panel Bonding Adhesive 08115 or 08116, or Impact Resistant Adhesive 07333. Any of these will provide a permanent, solid, sealed bond without any heat or warping. If you create a good fit on the edge, wiping the excess adhesive after clamping will result in a smooth, sealed edge.
Most cars built today make extensive use of adhesives in construction and repair. Best of all, you use no heat or special tools. The result is a solid, continuous, corrosion proof joint. Hard to beat in many applications.
BAR Audits and Training
Via the Internet
A. Larry thanks so much for sharing this great idea with our readers. I have done very little work with panel adhesives, but I recognize that they do offer an alternative to joining panels by welding, and in many cases the result can be superior.
You can email your questions to Professor Hammer at email@example.com, or mail to: Covell Creative Metalworking, 106 Airport Blvd., Suite 105, Freedom, CA 95019; you’ll receive a personal reply! Ron Covell has made many DVDs on metalworking, and he offers an ongoing series of workshops across the nation. Check them out online atcovell.biz, or call for a current schedule of workshops and a free catalog of DVDs. Phone (800) 747-4631, or (831) 768-0705. You’ll also enjoy Ron’s YouTube channel;youtube.com/user/covellron.